J. Varela

Since the seventies, positron emission tomography (PET) has become an invaluable medical molecular imaging modality with an unprecedented sensitivity at the picomolar level, especially for cancer diagnosis and the monitoring of its response to therapy. More recently, its combination with x-ray computed tomography (CT) or magnetic resonance (MR) has added high precision anatomic information in fused PET/CT and PET/MR images, thus compensating for the modest intrinsic spatial resolution of PET. Nevertheless, a number of medical challenges call for further improvements in PET sensitivity. These concern in particular new treatment opportunities in the context personalized (also called precision) medicine, such as the need to dynamically track a small number of cells in cancer immunotherapy or stem cells for tissue repair procedures. A better signal-to-noise ratio (SNR) in the image would allow detecting smaller size tumours together with a better staging of the patients, thus increasing the chances of putting cancer in complete remission. Moreover, there is an increasing demand for reducing the radioactive doses injected to the patients without impairing image quality. There are three ways to improve PET scanner sensitivity: improving detector efficiency, increasing geometrical acceptance of the imaging device and pushing the timing performance of the detectors. Currently, some pre-localization of the electron-positron annihilation along a line-of-response (LOR) given by the detection of a pair of annihilation photons is provided by the detection of the time difference between the two photons, also known as the time-of-flight (TOF) difference of the photons, whose accuracy is given by the coincidence time resolution (CTR). A CTR of about 10 picoseconds FWHM will ultimately allow to obtain a direct 3D volume representation of the activity distribution of a positron emitting radiopharmaceutical, at the millimetre level, thus introducing a quantum leap in PET imaging and quantification and fostering more frequent use of 11C radiopharmaceuticals. The present roadmap article toward the advent of 10 ps TOF-PET addresses the status and current/future challenges along the development of TOF-PET with the objective to reach this mythic 10 ps frontier that will open the door to real-time volume imaging virtually without tomographic inversion. The medical impact and prospects to achieve this technological revolution from the detection and image reconstruction point-of-views, together with a few perspectives beyond the TOF-PET application are discussed.

The ratio of cross-sections for muon pair production through the Drell-Yan process in p − p and p − d reactions has been measured at y ≈ 0, with 450 GeVc incident protons. The asymmetry ADY = δpp − δpnδpp+δpn amounts to −0.09 ± 0.02 ± 0.025. The ratio ud of the nucleon sea structure functions derived from this measurement amounts to 0.51 ± 0.04 ± 0.05 at x = 0.18 and suggests that isospin symmetry is broken in the light quark sea of the nucleon.

The study of oxygen-uranium reactions at 200 GeV/nucleon shows a significant transverse energy dependence of the yield of JΨ's relative to muon pairs produced in the mass continuum. This feature, observed for the first time, is in agreement with predictions from quark-gluon plasma formation, although alternative explanations by hadronic effects cannot be ruled out at this stage.

We present the angular distributions of muon pairs obtained in a high-statistics experiment using a 194-GeV/c π- impinging on a tungsten target. Our results are based on the analysis of 145,000 events with positive Feynmanx and mass above 4.07 GeV/c2, excluding the ϒ region. Simple first-order QCD relations allow us to determine the ratio of annihilation with hard-gluon emission to the sum of annihilation with hard-gluon emission and hard-gluon Compton scattering, which is found to be about 58% to 75%. We determine the parton square intrinsic transverse momenta to be of the order of 0.6 (GeV/c)2, and about 30% larger in the pion than in the nucleon. At largex 1, our data agree with the higher-twist hypothesis, and support the interpretation of the relevant scale parameter as the dimuon square transverse momentum.

A 64-channel ASIC for Time-of-Flight Positron Emission Tomography (TOF PET) imaging has been designed and simulated. The circuit is optimized for the readout of signals produced by the scintillation of a L(Y)SO crystal optically coupled to a silicon photomultiplier (SiPM). Developed in the framework of the EndoTOFPET-US collaboration [1], the ASIC is integrated in the external PET plate and performs timing, digitization and data transmission for 511 keV and lower-energy events due to Compton scattering.

We present a readout and digitization ASIC featuring low-noise and low-power for time-of flight (TOF) applications using SiPMs. The circuit is designed in standard CMOS 110 nm technology, has 64 independent channels and is optimized for time-of-flight measurement in Positron Emission Tomography (TOF-PET). The input amplifier is a low impedance current conveyor based on a regulated common-gate topology. Each channel has quad-buffered analogue interpolation TDCs (time binning 20 ps) and charge integration ADCs with linear response at full scale (1500 pC). The signal amplitude can also be derived from the measurement of time-over-threshold (ToT). Simulation results show that for a single photo-electron signal with charge 200 (550) fC generated by a SiPM with 320 pF capacitance the circuit has 24 (30) dB SNR, 75(39) ps r.m.s. resolution, and 4(8) mW power consumption. The event rate is 600 kHz per channel, with up to 2 MHz dark counts rejection.

The design and evaluation of the imaging system Clear-PEM for positron emission mammography, under development by the PEM Consortium within the framework of the Crystal Clear Collaboration at CERN, is presented. The proposed apparatus is based on fast, segmented, high atomic number radiation sensors with depth-of-interaction measurement capabilities, and state-of-the-art data acquisition techniques. The camera consists of two compact and planar detector heads with dimensions 16.5/spl times/14.5 cm/sup 2/ for breast and axilla imaging. Low-noise integrated electronics provide signal amplification and analog multiplexing based on a new data-driven architecture. The coincidence trigger and data acquisition architecture makes extensive use of pipeline processing structures and multi-event memories for high efficiency up to a data acquisition rate of one million events/s. Experimental validation of the detection techniques, namely the basic properties of the radiation sensors and the ability to measure the depth-of-interaction of the incoming photons, are presented. System performance in terms of detection sensitivity, count-rates and reconstructed image spatial resolution were also evaluated by means of a detailed Monte Carlo simulation and an iterative image reconstruction algorithm.

A new method for obtaining depth of interaction (DOI) information in PET detectors is presented in this study, based on sharing and redirection of scintillation light among multiple detectors, together with attenuation of light over the length of the crystals. The aim is to obtain continuous DOI encoding with single side readout, and at the same time without the need for one-to-one coupling between scintillators and detectors, allowing the development of a PET scanner with good spatial, energy and timing resolutions while keeping the complexity of the system low. A prototype module has been produced and characterized to test the proposed method, coupling a LYSO scintillator matrix to a commercial SiPMs array. Excellent crystal separation is obtained for all the scintillators in the array, light loss due to depolishing is found to be negligible, energy resolution is shown to be on average 12.7% FWHM. The mean DOI resolution achieved is 4.1 mm FWHM on a 15 mm long crystal and preliminary coincidence time resolution was estimated in 353 ps FWHM.

Preliminary results suggest that Positron Emission Mammography (PEM) can offer a noninvasive method for the diagnosis of breast cancer. Metabolic images from PEM contain unique information not available from conventional morphologic imaging techniques and aid in expeditiously establishing the diagnosis of cancer. A dedicated machine seems to offer better perspectives in terms of position resolution and sensitivity. This paper describes the concept of Clear-PEM, the system presently developed by the Crystal Clear Collaboration at CERN for an evaluation of this approach. This device is based on new crystals introduced by the Crystal Clear as well as on modern data acquisition techniques developed for the large experiments in high energy physics experiments.

In a search for quark-gluon plasma formation, the production of J/ψ and muon pairs in the mass continuum region is studied in oxygen-uranium and sulphur-uranium interactions. The yield of J/ψ relative to the continuum is measured to be a decreasing function of the neutral transverse energy produced in the collision, i.e. of the energy density. A comparison is made with proton-uranium reactions.

We present a measurement of the production of muon pairs in 194 GeV/c π−-tungsten interactions. A sample of 155,000 events with mass higher than 4.07 GeV/c2 has been used to determine the differential cross-section as a function of the scaling variables $$\sqrt \tau $$ andx F .

Poor mental health is an under-recognised burden in rural locations. This is evident in suicide rates that are 40% higher in rural communities than in urban ones, despite a similar prevalence of mental disorders. The level of readiness and engagement of rural communities to adapt or even acknowledge poor mental health can impact effective interventions. For interventions to be culturally appropriate, community engagement should include individuals, their support networks and relevant stakeholders. Community participation guides people living in rural communities to be aware of and take responsibility for community mental health. Community engagement and participation foster empowerment. This review examines how community engagement, participation and empowerment were used in the development and implementation of interventions aimed at improving mental health of adults residing in rural communities.Databases CINAHL, EmCare, Google Scholar, Medline, PsychInfo, PubMed and Scopus were systematically searched from database inception to July 2021. Eligible studies included adults living in a rural cohort where community engagement was used to develop and implement a mental health intervention.From 1841 records identified, six met the inclusion criteria. Methods were both qualitative and quantitative, including participatory-based research, exploratory descriptive research, community-built approach, community-based initiative and participatory appraisal. Studies were located in rural communities of the USA, UK and Guatemala. Sample size ranges was 6-449 participants. Participants were recruited using prior relationships, project steering committee, local research assistants and local health professionals. All six studies underwent various strategies of community engagement and participation. Only two articles progressed to community empowerment where locals influenced one another independently. The underlying purpose of each study was to improve community mental health. The duration of the interventions ranged from 5 months to 3 years. Studies on the early stages of community engagement discovered a need to address community mental health. Studies where interventions were implemented resulted in improved community mental health.This systematic review found similarities in community engagement when developing and implementing interventions for community mental health. Community engagement should involve adults residing in rural communities when developing interventions - if possible, both with a diverse gender representation and a background in health. Community participation can include upskilling adults living in rural communities and providing appropriate training materials to do so. Community empowerment was achieved when the initial contact with rural communities was through local authorities and there was support from community management. Future use of the strategies of engagement, participation and empowerment could determine if they can be replicated across rural communities for mental health.

The differential cross-section for dimuon production by 194 GeV/c π− onW, as measured by the NA10 Collaboration, is compared with theoretical models. The wide kinematical range of the data, extending well above the ϒ resonances, provides the opportunity of a comparison with 'realistic' Drell-Yan models, i.e. with those allowing for scaling violation in the hadronic structure functions. The data in fact clearly indicate the failure of the 'naïve' Drell-Yan model, while the available 'realistic' versions (leading logarithm approximation and next-to-leading logarithm approximation in first order QCD), although giving a better description of the data, still disagree in thex F and $$\sqrt \tau $$ dependences of the cross-section at high dimuon masses. This disagreement is referred to here as 'anomalous' scaling violation. The dependence of the results on external inputs (nucleon and pion-sea structure functions) is analysed; it is shown that in the next-to-leading logarithm approximation the value 〈K〉=1.03±0.03 (stat.) can be obtained for the ratio experimental/theoretical cross-section.

The dimuon production in 200 GeV/nucleon oxygen-uranium interactions is studied by the NA 38 Collaboration. The production ofJ/ψ, correlated with the transverse energyET, is investigated and compared to the continuum, as a function of the dimuon massM and transverse momentumPT. A value of 0.64±0.06 is found for the ratio (ψ/Continuum at highET)/(ψ/Continuum at lowET), from which theJ/ψ relative suppression can be extracted. This suppression is enhanced at lowPT.

The high-luminosity phase of operation of the CERN Large Hadron Collider (HL-LHC) will pose new challenges to the detectors and their readout electronics. In particular, the Compact Muon Solenoid (CMS) barrel electromagnetic calorimeter will require a full redesign of the electronic readout chain in order to cope with the increase in luminosity and trigger rate. In this framework, a new application-specific integrated circuit (ASIC) integrating A/D conversion, lossless data compression, and high-speed transmission has been developed and tested. The ASIC, named Lisboa-Torino Ecal Data Transmission Unit (LiTE-DTU), is designed in a commercial CMOS 65-nm process and embeds two 12-bit, 160-MS/s analog-to-digital converters (ADCs), a data selection and compression logic, and a 1.28-Gb/s output serial link. The high-speed 1.28-GHz clock is generated internally from the 160-MHz input by a clock multiplication phase-locked loop (PLL). The circuit has been designed implementing radiation-tolerant techniques in order to work in the harsh environment of the HL-LHC upgrade. The LiTE-DTU is currently in the preproduction phase. A sample of 600 chips has been tested and incorporated into front-end (FE) boards for systems performance testing.

A detailed study of J/ψ, ψ′ and Drell-Yan production in S-U collisions has been performed by experiment NA38 at the CERN SPS. This paper presents production cross sections and their centrality dependence, based on the largest sample of S-U events collected by the experiment.

The production of the J/ψ and ψ′ charmonia states has been studied, through their dimuon decay, in proton, Oxygen and Sulphur induced reactions, by the NA38 experiment at the CERN SPS. The proton data was collected with beams of 200 and 450 GeV, while the ion beams had an energy of 200 GeV per incident nucleon. The J/ψ production cross-section per nucleon-nucleon collision exhibits a remarkably continuous pattern, as a function of the product of the mass numbers of the interacting nuclei, from pp up to S-U reactions. The same pattern is observed within S-U collisions, as a function of the collision centrality. While in p-A interactions both charmonia states exhibit the same A-dependence, in S-U collisions the ψ′ production is very strongly suppressed.

Ψ′ and J/Ψ yields are compared in p-W, p-U and S-U interactions at 200 GeV/nucleon. Their ratio decreases from proton-t to sulphur-induced reactions. It also decreases in sulphur-induced reactions from peripheral to central collisions. This result could indicate that the Ψ′ and J/Ψ suppression mechanisms have different origins in p- and S-induced reactions.

The study of the Jψ transverse momentum distribution in oxygen-uranium reactions at 200 GeV/nucleon shows that 〈PT〉 and 〈PT2〉 increase with the transverse energy of the reaction. Muon pairs in the mass continuum do not exhibit the same behaviour. The comparison of the Jψproduction rates in central and peripheral collisions shows a significant diminution for low PT central events.

Muon-pair production has been measured in pCu, pU, OCu, OU and SU collisions at 200 GeV per nucleon. The cross sections are compatible with the atomic number dependence (Aproj.Atarg.)α where α=0.91±0.04 for the J/ψ resonance and α=1.01±0.04 for muon pairs produced in the mass continuum between 1.7 and 2.7 GeV/c2.

We present the experimental results obtained with TOFPET2, a readout and digitization ASIC for radiation detectors using Silicon Photomultipliers. The circuit is designed in CMOS 110 nm technology, has 64 independent channels and is optimized for time-of-flight measurement in PET or other applications. The chip has quad-buffered TDCs and charge integration ADCs in each channel. The chip tape-out was done in September 2016 and first tests started in beginning March 2017. Coincidence Time Resolution (CTR) of 164ps FWHM has been measured with 22Na point source. The energy resolution achieved for the 511keV peak is 10.5% FWHM.

We present a readout and digitization ASIC featuring low-noise and low-power for time-of flight (TOF) applications using SiPMs. The circuit is designed in standard CMOS 110 nm technology, has 64 independent channels and is optimized for time-of-flight measurement in Positron Emission Tomography (TOF-PET). The input amplifier is a low impedance current conveyor based on a regulated common-gate topology. Each channel has quad-buffered analogue interpolation TDCs (time binning 20 ps) and charge integration ADCs with linear response at full scale (1500 pC). The signal amplitude can also be derived from the measurement of time-over-threshold (ToT). Simulation results show that for a single photo-electron signal with charge 200 (550) fC generated by a SiPM with (320 pF) capacitance the circuit has 24 (30) dB SNR, 75 (39) ps r.m.s. resolution, and 4 (8) mW power consumption. The event rate is 600 kHz per channel, with up to 2 MHz dark counts rejection.

We present the experimental characterization of the TOFPET2, a readout and digitization ASIC for radiation detectors using Silicon Photomultipliers. The circuit is designed in CMOS 110 nm technology, has 64 independent channels and is optimized for time-of-flight measurement in PET or other applications. The chip has quad-buffered TDCs and charge integration QDCs in each channel. The Coincidence Time Resolution (CTR) of 511 keV photon pairs from a 22Na point source measured with 2 × 2 × 3 mm3 LSO:Ce crystals co-doped with 0.2% Ca is 118 and 119 ps FWHM when using respectively the SiPMs NUVHD 40um from Fondazione Bruno Kessler (FBK) and the S14160-3050HS MPPC from Hamamatsu Photonics (HPK). The energy resolution obtained for the 511keV photopeak is 10.5 and 12% FWHM when using respectively the SiPMs PM3325-WB from KETEK and the QFBR-S4N44P164S from Broadcom Inc.

J/ψ and ψ′ production cross-sections are measured in pp and pd collisions at 450 GeV/c at the CERN-SPS. The Drell-Yan cross section for muon pairs in the mass range [4.3–8.0] GeV/c2 is also determined in the same experiment.

The transverse energy ET distributions of nucleus-nucleus collisions are studied in the framework of a simple geometrical model. The distributions for inclusive production of Jψ and muon pairs in the mass continuum are analyzed. The shape of the ET distribution of the continuum agreed with the model. The previously oberved decrease of the ratio (Jψ)/continuum with increasing ET is due to the behavior of the Jψ.

The Geant4 Monte Carlo radiation transport toolkit provides the basic services and infrastructure required for the development of flexible simulation frameworks and applications, which have found generalized use in high energy physics, nuclear physics, astrophysics, and medical physics research. Object-oriented design provides the possibility to implement or modify any physics process in Geant4 without changing other parts of the code. This feature makes Geant4 open to extension of its physics modeling capabilities and to the implementation of alternative physics models. In this paper, the development of a simulation platform for performance studies and detector optimization of the Clear-PEM scanner, a high-performance positron emission mammography prototype, and the implementation of precise low energy bremsstrahlung angular generators for the Geant4 LowE category are described.

Combining the advantages of different imaging modalities leads to improved clinical results. For example, ultrasound provides good real-time structural information without any radiation and PET provides sensitive functional information. For the ongoing ClearPEM-Sonic project combining ultrasound and PET for breast imaging, we developed a dual-modality PET/Ultrasound (US) phantom. The phantom reproduces the acoustic and elastic properties of human breast tissue and allows labeling the different tissues in the phantom with different concentrations of FDG. The phantom was imaged with a whole-body PET/CT and with the Supersonic Imagine Aixplorer system. This system allows both B-mode US and shear wave elastographic imaging. US elastography is a new imaging method for displaying the tissue elasticity distribution. It was shown to be useful in breast imaging. We also tested the phantom with static elastography. A 6D magnetic positioning system allows fusing the images obtained with the two modalities. ClearPEM-Sonic is a project of the Crystal Clear Collaboration and the European Centre for Research on Medical Imaging (CERIMED).

The EndoTOFPET-US project aims to develop a multimodal detector to foster the development of new biomarkers for prostate and pancreatic tumors. The detector will consist of two main components: an external plate, and a PET extension to an endoscopic ultrasound probe. The external plate is an array of LYSO crystals read out by silicon photomultipliers (SiPM) coupled to an Application Specific Integrated Circuit (ASIC). The internal probe will be an highly integrated and miniaturized detector made of LYSO crystals read out by a fully digital SiPM featuring photosensor elements and digital readout in the same chip. The position and orientation of the two detectors will be tracked with respect to the patient to allow the fusion of the metabolic image from the PET and the anatomic image from the ultrasound probe in the time frame of the medical procedure. The fused information can guide further interventions of the organ, such as biopsy or in vivo confocal microscopy.

We report in this article on the Fast Timing in Medical Imaging workshop, (Valencia, 2 June 2022). The workshop gathered 104 attendees from all over the world, with representatives from the academic and industrial sectors. During three very dense days, nuclear medicine physicians, radiologists, oncologists, immunologists, and biologists have debated with physicists, engineers, technologists of different disciplines, as well as with medical imaging industry representatives to devise about the importance of improving the timing performance of a new generation of medical imaging instrumentation, with a special focus on positron emission tomography scanners toward the ultimate goal of 10-ps coincidence time resolution (CTR), allowing a millimeter 3-D spatial resolution on an event-to-event basis by time-of-flight (TOF) techniques. This article summarizes the most up-to-date developments on the roadmap toward the 10-ps time of flight challenge based on the contributions to this workshop.

Absolute J/ψ and ψ′ production cross sections have been measured at the CERN SPS, with 450 GeV/c protons incident on a set of C, Al, Cu and W targets. Complementing these values with the results obtained by experiment NA51, which used the same beam and detector with H and D targets, we establish a coherent picture of charmonia production in proton-induced reactions at SPS energies. In particular, we show that the scaling of the J/ψ cross section with the mass number of the target, A, is well described as Aα, with αψ=0.919±0.015. The ratio between the J/ψ and ψ′ yields, in our kinematical window, is found to be independent of A, with αψ′−αψ=0.014±0.011.

We describe the design, construction and performance of a high-resolution spectrometer used at CERN to study the production of high-mass muon pairs by intense hadron beams. We also discuss the on- and off-line software used with this spectrometer.

The Clear-PEM scanner for positron emission mammography under development is described. The detector is based on pixelized LYSO crystals optically coupled to avalanche photodiodes and readout by a fast low-noise electronic system. A dedicated digital trigger (TGR) and data acquisition (DAQ) system is used for on-line selection of coincidence events with high efficiency, large bandwidth and small dead-time. A specialized gantry allows to perform exams of the breast and of the axilla. In this paper we present results of the measurement of detector modules that integrate the system under construction as well as the imaging performance estimated from Monte Carlo simulated data.

A 64-channel ASIC for TOF PET imaging is presented. The circuit provides time and energy measurements of events produced by a SiPM coupled to a L(Y)SO fast scintillator. This ASIC is developed in the framework of the EndoTOFPETUS collaboration as an option for the readout of external 200×200 mm plate detector, which consists of 3×3×15 mm crystals and 3×3 mm (active area) SiPMs. Using the chip with non-segmented and/or higher light yield crystals is possible. The same applies for photodetectors with different gain, polarity, or even higher dark count rate. The targeted 200 ps timing resolution for the system and the need for a low power consumption have driven the choice of a closed-loop amplifier input stage and a 50 ps time binning TDC based on analogue interpolation. A power consumption between 5 to 10 mW per channel is expected to guarantee a SNR of at least 20 dB for the single photon, using a SiPM with 320 pF terminal capacitance.

An innovative Cylindrical Gas Electron Multiplier (CGEM) detector is under construction for the upgrade of the inner tracker of the BESIII experiment. A novel system has been worked out for the readout of the CGEM detector, including a new ASIC, dubbed TIGER -Torino Integrated GEM Electronics for Readout, designed for the amplification and digitization of the CGEM output signals. The data output by TIGER are collected and processed by a first FPGA-based module, GEM Read Out Card, in charge of configuration and control of the front-end ASICs. A second FPGA-based module, named GEM Data Concentrator, builds the trigger selected event packets containing the data and stores them via the main BESIII data acquisition system. The design of the electronics chain, including the power and signal distribution, will be presented together with its performance.

In this paper we present a study on the production of the Jψ and ψ′ resonances, decaying into muon pairs, in S-U collisions, at 200 GeV per incident nucleon. We find that the ratio between ψ′ and tJψ yields decreases as ET, the neutral transverse energy produced in the collision, increases. There is also a clear decrease of this ratio when going from p-W to S-U interactions. Assuming the high mass continuum to be Drell-Yan we discuss the possible understanding of the intermediate dimuon mass region as a superposition of Drell-Yan (extrapolated down in mass) and muon pairs from the semileptonic decays of charmed mesons. The p-W data is found to be explained by this procedure. However, the S-U data seems to be incompatible with a linear extrapolation from the proton-nucleus results.

In the framework of the Clear-PEM project for the construction of a high-resolution scanner for breast cancer imaging, a very compact and dense frontend electronics system has been developed for readout of multi-pixel S8550 Hamamatsu APDs. The frontend electronics are instrumented with a mixed-signal Application-Specific Integrated Circuit (ASIC), which incorporates 192 low-noise charge pre-amplifiers, shapers, analog memory cells and digital control blocks. Pulses are continuously stored in memory cells at clock frequency. Channels above a common threshold voltage are readout for digitization by off-chip free-sampling ADCs. The ASIC has a size of 7.3×9.8mm2 and was implemented in a AMS 0.35μm CMOS technology. In this paper the experimental characterization of the Clear-PEM frontend ASIC, reading out multi-pixel APDs coupled to LYSO:Ce crystal matrices, is presented. The chips were mounted on a custom test board connected to six APD arrays and to the data acquisition system. Six 32-pixel LYSO:Ce crystal matrices coupled on both sides to APD arrays were readout by two test boards. All 384 channels were operational. The chip power consumption is 660 mW (3.4 mW per channel). A very stable behavior of the chip was observed, with an estimated ENC of 1200–1300e- at APD gain 100. The inter-channel noise dispersion and mean baseline variation is less than 8% and 0.5%, respectively. The spread in the gain between different channels is found to be 1.5%. Energy resolution of 16.5% at 511 keV and 12.8% at 662 keV has been measured. Timing measurements between the two APDs that readout the same crystal is extracted and compared with detailed Monte Carlo simulations. At 511 keV the measured single photon time RMS resolution is 1.30 ns, in very good agreement with the expected value of 1.34 ns.

A mixed-signal ASIC for timing and energy measurements with radiation detectors is described. The chip embeds 64 channels, each of which features a charge-sensitive amplifier followed by a dual-shaper coupled to low-offset discriminators. A versatile back-end, incorporating low-power Time to Digital Converters and Wilkinson Analog to Digital Converters with derandomizing buffers allows to encode both the time of arrival and the charge of the input signal. The ASIC is designed for a maximum detector capacitance of 100 pF and an event rate in excess of 60 kHz per channel. A peak detector samples the input signal with an excellent linearity in the range 5÷55 fC. Charge digitization with Time-over-Threshold is also supported to extend the dynamic range. Fabricated in a 110 nm CMOS process, the chip dissipates 10 mW/channel. The ASIC was primarily developed to readout the cylindrical GEM detector of the BESIII experiment. For its characteristics it can serve however a broad class of radiation sensors, including silicon microstrip detectors.

Abstract The barrel section of the novel MIP Timing Detector (MTD) will be constructed as part of the upgrade of the CMS experiment to provide a time resolution for single charged tracks in the range of 30–60 ps using LYSO:Ce crystal arrays read out with Silicon Photomultipliers (SiPMs). A major challenge for the operation of such a detector is the extremely high radiation level, of about 2 × 10 14 1 MeV(Si) Eqv. n/cm 2 , that will be integrated over a decade of operation of the High Luminosity Large Hadron Collider (HL-LHC). Silicon Photomultipliers exposed to this level of radiation have shown a strong increase in dark count rate and radiation damage effects that also impact their gain and photon detection efficiency. For this reason during operations the whole detector is cooled down to about -35°C. In this paper we illustrate an innovative and cost-effective solution to mitigate the impact of radiation damage on the timing performance of the detector, by integrating small thermo-electric coolers (TECs) on the back of the SiPM package. This additional feature, fully integrated as part of the SiPM array, enables a further decrease in operating temperature down to about -45°C. This leads to a reduction by a factor of about two in the dark count rate without requiring additional power budget, since the power required by the TEC is almost entirely offset by a decrease in the power required for the SiPM operation due to leakage current. In addition, the operation of the TECs with reversed polarity during technical stops of the accelerator can raise the temperature of the SiPMs up to 60°C (about 50°C higher than the rest of the detector), thus accelerating the annealing of radiation damage effects and partly recovering the SiPM performance.

The CMS detector will be upgraded for the HL-LHC to include a MIP Timing Detector (MTD). The MTD will consist of barrel and endcap timing layers, BTL and ETL respectively, providing precision timing of charged particles. The BTL sensors are based on LYSO:Ce scintillation crystals coupled to SiPMs with TOFHIR2 ASICs for the front-end readout. A resolution of 30-60 ps for MIP signals at a rate of 2.5 Mhit/s per channel is expected along the HL-LHC lifetime. We present an overview of the TOFHIR2 requirements and design, simulation results and measurements with TOFHIR2 ASICs. The measurements of TOFHIR2 associated to sensor modules were performed in different test setups using internal test pulses or blue and UV laser pulses emulating the signals expected in the experiment. The measurements show a time resolution of 24 ps initially during Beginning of Operation (BoO) and 58 ps at End of Operation (EoO) conditions, matching well the BTL requirements. We also showed that the time resolution is stable up to the highest expected MIP rate. Extensive radiation tests were performed, both with x-rays and heavy ions, showing that TOFHIR2 is not affected by the radiation environment during the experiment lifetime.

Low mass muon pair production at high PT and low XF studied in pU, OU and SU 200 GeV per nucleon react ions. When energy density or projectile mass are increased, φ production is enhanced as compared with the yield of muon pairs in the mass continuum (1.7<Mμμ< 2.4 GeV/c2), whereas the production of ω and ϱ, experimentally unresolved, remains approximately constant. This φ enhancement is in agreement with predictions based on quark-gluon plasma formation and, together with the previously reported J/Ψ suppression, puts severe constraints on a purely hadronic description of nucleus-nucleus collisions.

This study was undertaken to determine the value of using dual-time point 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging to distinguish malignant from benign pulmonary lesions after lesion detection by conventional computed tomography chest imaging. Patients referred for characterization of lung lesions were included in this prospective study. Eighty-three patients had histopathologic confirmation of disease. Patients underwent FDG-PET coincidence imaging, performed with a dual-headed gamma camera at 1 h (“early” scan) and 3 h (“late” scan) after injection of 185 MBq of FDG. Studies were read independently by 2 physicians who had knowledge of the lesion location but not the final diagnosis. For both early and late images, readers graded FDG lesion uptake intensity on a scale of 1 (definitively benign) to 5 (definitively malignant) and classified studies dichotomously for malignancy. Tumor-to-background (T:B) ratios were computed using contralateral lung sites as controls. Sixty one lesions (74 %) were non-small cell lung cancer, and 10 (12 %) were other primary tumors or metastases. Twelve lesions (14 %) were benign. T:B ratios were significantly higher for early versus late scans (+5.1 ± 4.9 versus +8.2 ± 8.7, p = 0.01, n = 71) for malignancies but not for benign lesions (+3.1 ± 3.4 versus +2.6 ± 2.2, n = 12). The percent change of T:B ratios was higher for malignant than benign lesions (+48.3 ± 40.2 % versus +7.2 ± 22.8 %, p = 0.0009). No malignant lesion of any type demonstrated a time-decrease in FDG T:B ratios. The accuracy and sensitivity of lesion characterization were significantly higher for late scans than early scans for dichotomous visual readings. Quantitative analysis was found to provide significantly higher sensitivity and accuracy than visual analysis for lesion characterization, with no significant difference in test specificity. In malignant pulmonary nodules, there is a progressive, although variable, increase in FDG uptake over time. Increasing FDG uptake is a nonspecific finding, as some benign lesions also demonstrate increasing uptake, particularly those associated with granulomas. The use of late PET images increases the accuracy and sensitivity of visual detection of malignancy. Determinar cuál es el valor del estudio en dos fases en la tomografía por emisión de positrones con 18F-fluordesoxiglucosa (FDG-PET), a la hora de diferenciar lesiones pulmonares entre benignas y malignas, detectadas por tomografía axial computarizada. Estudio prospectivo de 83 pacientes remitidos a nuestro centro para la caracterización de lesiones pulmonares, en los que se obtuvo la confirmación histopatológica de la lesión. Se realizó FDG-PET con gammacámara en detección de coincidencia a la hora (estudio inicial) y a las tres horas (estudio tardío) de la inyección de 185 MBq de FDG. Dos médicos nucleares que sólo conocían la localización de la lesión, pero no el diagnóstico final, interpretaron de forma independiente los estudios. Tanto el estudio inicial como el tardío fueron clasificados de acuerdo a la intensidad de la lesión, usando una escala visual de 1 (definitivamente benigno) a 5 (definitivamente maligno). Además, para obtener una dicotomía se determinó si se consideraba el estudio maligno o benigno. Se calcularon los índices tumor/no tumor (T:B) usando el pulmón contralateral como control. Sesenta y una lesiones (74 %) fueron carcinomas pulmonares no microcíticos, y 10 (12 %) fueron otros tumores primarios o metástasis. Doce lesiones (14 %) fueron benignas. Los índices T:B fueron significativamente más elevados para los estudios tardíos que para los iniciales en lesiones malignas, pero no en las benignas. El porcentaje de cambio en los índices (T:B) fue mayor para las lesiones malignas que para las benignas. Ninguna lesión maligna mostró una disminución del índice T:B entre los dos estudios. Con la interpretación en dicotomía, se obtuvo una mayor precisión y sensibilidad en la caracterización de las lesiones en los estudios tardíos que en los iniciales. El análisis cuantitativo proporcionó una mayor sensibilidad y precisión en la caracterización de las lesiones en comparación con el análisis visual, sin diferencias significativas en la especificidad. Los nódulos pulmonares malignos muestran un incremento progresivo, aunque variable en la captación de FDG, con el transcurso del tiempo. Sin embargo, este aumento de FDG no es específico, ya que algunas lesiones benignas también se pueden comportar de manera similar, especialmente los granulomas. El uso de las imágenes tardías en la FDG-PET incrementa la sensibilidad y la precisión en el análisis visual de estos estudios.

We have developed a Time-of-flight high resolution and commercially viable detector module for the application in small PET scanners. A new approach to depth of interaction (DOI) encoding with low complexity for a pixelated crystal array using a single side readout and 4-to-1 coupling between scintillators and photodetectors was investigated. In this method the DOI information is estimated using the light sharing technique. The detector module is a 1.53×1.53×15 mm3 matrix of 8×8 LYSO scintillator with lateral surfaces optically depolished separated by reflective foils. The crystal array is optically coupled to 4×4 silicon photomultipliers (SiPM) array and readout by a high performance front-end ASIC with TDC capability (50 ps time binning). The results show an excellent crystal identification for all the scintillators in the matrix, a timing resolution of 530 ps, an average DOI resolution of 5.17 mm FWHM and an average energy resolution of 18.29% FWHM.

Muon pairs produced in PbPb interactions at 158 GeV/c per nucleon and in p-A interactions at 400 GeV/c, together with older S-U results obtained at 200 GeV/c are used to study the transverse momentum and transverse mass distributions of the J/Ψ.

Positron emission mammography (PEM) can offer a non-invasive method for the diagnosis of breast cancer. Metabolic images from PEM using 18F-fluoro-deoxy-glucose, contain unique information not available from conventional morphologic imaging techniques like X-ray radiography. In this work, the concept of Clear-PEM, the system presently developed in the frame of the Crystal Clear Collaboration at CERN, is described. Clear-PEM will be a dedicated scanner, offering better perspectives in terms of position resolution and detection sensitivity.

The mean squared transverse momentum of J/ψ's measured in pCu, pU, OCu, OU and SU collisions at 200 GeV/ nucleon is analyzed in terms of initial state interactions. Taking this effect into account, the mechanism which suppresses the J/ψ production in ion-induced collisions would only have a weak PT dependence.

The Clear-PEM detector system is a compact positron emission mammography scanner with about 12000 channels aiming at high sensitivity and good spatial resolution. Front-end, Trigger, and Data Acquisition electronics are crucial components of this system. The on-detector front-end is implemented as a data-driven synchronous system that identifies and selects the analog signals whose energy is above a predefined threshold. The off-detector trigger logic uses digitized front-end data streams to compute pulse amplitudes and timing. Based on this information it generates a coincidence trigger signal that is used to initiate the conditioning and transfer of the relevant data to the data acquisition computer. To minimize dead-time, the data acquisition electronics makes extensive use of pipeline processing structures and derandomizer memories with multievent capacity. The system operates at 100-MHz clock frequency, and is capable of sustaining a data acquisition rate of 1 million events per second with an efficiency above 95%, at a total single photon background rate of 10 MHz. The basic component of the front-end system is a low-noise amplifier-multiplexer chip presently under development. The off-detector system is designed around a dual-bus crate backplane for fast intercommunication between the system boards. The trigger and data acquisition logic is implemented in large FPGAs with 4 million gates. Monte Carlo simulation results evaluating the trigger performance, as well as results of hardware simulations are presented, showing the correctness of the design and the implementation approach

Muon pair production is studied in p-W and SU collisions at 200 GeV per nucleon, as a function of transverse momentum PTμμ. The inclusive ϱ+ω and Φ differential cross-sections dσdPT are measured in the dimuon decay channel, for PT ≥ 0.6 GeV/c, in the central rapidity region, 3.0≤ y ≤ 4.0. Assuming the power law A-dependence σ = σ0(Abeam·Atarget)α, the study of the integrated cross-sections for p-W and SU collisions leads to αϱ+ω = 1.00±0.02±0.07 and αΦ = 1.23±0.03±0.05, showing clear evidence of Φ enhancement in SU interactions as compared to p-W collisions.

The dimuon production in 200 GeV/nucleon O-U, O-Cu, S-U and p-U reactions is studied in function of transverse energy ET produced by the collision. The J/ψ production relative to continuum events is suppressed for heavy ion induced reactions when ET increases. This suppression is enhanced at low transverse momentum. The π and K meson distributions extracted from the data, have, for each reaction, a similar average transverse momentum which increases only slightly with the transverse energy.

We show that clustering of nucleons, with confinement-size changes, naturally explains and accurately describes recent data on the $A$ dependence of deep-inelastic nuclear cross sections. Predictions for gluon distributions in nuclei are given.

The main aspects of the design and test (D&T) of a reconfigurable architecture for the Data Acquisition Electronics (DAE) system of the Clear-PEM detector are presented in this paper. The application focuses medical imaging using a compact PEM (Positron Emission Mammography) detector with 12288 channels, targeting high sensitivity and spatial resolution. The DAE system processes data frames that come from a front-end (FE) electronics, identifies the relevant data and transfers it to a PC for image processing. The design is supported in a novel D&T methodology, in which hierarchy, modularity and parallelism are extensively exploited to improve design and testability features. Parameterization has also been used to improve design flexibility. Nominal frequency is 100 MHz. The DAE must respond to a data acquisition rate of 1 million relevant events (coincidences) per second, under a total single photon background rate in the detector of 10 MHz. Trigger and data acquisition logic is implemented in eight 4-million, one 2-million and one 1-million gate FPGAs (Xilinx Virtex II). Functional Built-In Self Test (BIST) and Debug features are incorporated in the design to allow on-board FPGA testing and self-testing during product lifetime.

The CMS data acquisition system is designed to build and filter events originating from 476 detector data sources at a maximum trigger rate of 100 kHz. Different architectures and switch technologies have been evaluated to accomplish this purpose. Events will be built in two stages: the first stage will be a set of event builders called front-end driver (FED) builders. These will be based on Myrinet technology and will pre-assemble groups of about eight data sources. The second stage will be a set of event builders called readout builders. These will perform the building of full events. A single readout builder will build events from about 60 sources of 16 kB fragments at a rate of 12.5 kHz. In this paper, we present the design of a readout builder based on TCP/IP over Gigabit Ethernet and the refinement that was required to achieve the design throughput. This refinement includes architecture of the readout builder, the setup of TCP/IP, and hardware selection.

An analogue CMOS front-end for triggering and amplification of signals produced by a silicon photomultiplier (SiPM) coupled to a LYSO scintillator is proposed. The solution is intended for time-of-flight measurement in compact Positron Emission Tomography (TOF-PET) medical imaging equipments where excellent timing resolution is required ( ≈ 100ps). A CMOS 0.13μmtechnology was used to implement such front end, and the design includes preamplification, shaping, baseline holder and biasing circuitry, for a total silicon area of 500x90 μm. Waveform sampling and time-over-threshold (ToT) techniques are under study and the front-end provides fast and shaped outputs for time and energy measurements. Post layout simulation results show that, for the trigger of a single photoelectron, the time jitter due to the pre-amplifier noise can be as low as 15 ps (FWHM), for a photodetector with a total capacitance of 70 pF. The very low input impedance of the pre-amplifier ( ≈ 5Ω) allows 1.8 ns of peaking time, at the cost of 10 mW of power consumption.

For the upgrade of the inner tracker of the BESIII spectrometer, planned for 2018, a lightweight tracker based on an innovative Cylindrical Gas Electron Multiplier (CGEM) detector is now under development. The analogue readout of the CGEM enables the use of a charge centroid algorithm to improve the spatial resolution to better than 130 um while loosening the pitch strip to 650 um, which allows to reduce the total number of channels to about 10 000. The channels are readout by 160 dedicated integrated 64-channel front-end ASICs, providing a time and charge measurement and featuring a fully-digital output. The energy measurement is extracted either from the time-over-threshold (ToT) or the 10-bit digitisation of the peak amplitude of the signal. The time of the event is generated by quad-buffered low-power TDCs, allowing for rates in excess of 60 kHz per channel. The TDCs are based on analogue interpolation techniques and produce a time stamp (or two, if working in ToT mode) of the event with a time resolution better than 50 ps. The front-end noise, based on a CSA and CR-RC2 shapers, dominate the channel intrinsic time jitter, which is less than 5 ns r.m.s.. The time information of the hit can be used to reconstruct the track path, operating the detector as a small TPC and hence improving the position resolution when the distribution of the cloud, due to large incident angle or magnetic field, is very broad. Event data is collected by an off-detector motherboard, where each GEM-ROC readout card handles 4 ASIC carrier PCBs (512 channels). Configuration upload and data readout between the off-detector electronics and the VME-based data collector cards are managed by bi-directional fibre optical links.

The Trigger Supervisor is an online software system designed for the CMS experiment at CERN. Its purpose is to provide a framework to set up, test, operate and monitor the trigger components on one hand and to manage their interplay and the information exchange with the run control part of the data acquisition system on the other. The Trigger Supervisor is conceived to provide a simple and homogeneous client interface to the online software infrastructure of the trigger subsystems. The functional and nonfunctional requirements, the design, the operational details, and the components needed in order to facilitate a smooth integration of the trigger software in the context of CMS are described.

Clear-PEM is a dedicated PET scanner for breast and axilla cancer diagnosis, under development within the framework of the Crystal Clear Collaboration at CERN, aiming at the detection of tumors down to 2 mm in diameter. The camera consists of two planar detector heads with active dimensions 16.0×14.5 cm2. Each head has 96 Clear-PEM detector modules consisting of 32 LYSO:Ce pixels with dimensions 2×2×20 mm3 packed in a 4×8 BaSO4 reflector matrix compressed between two Hamamatsu S8550 APD arrays in a double-readout configuration for Depth-of-Interaction (DoI) determination. The modules are individually measured and characterized before being grouped into Supermodules (comprised of 24 modules). Measured properties include photo-peak position, relative gain dispersion, energy resolution, cross-talk and DoI resolution. Optical inspection of matrices was also performed with the aid of a microscope, to search for pixel misalignments and matrix defects. Modules’ performance was thoroughly evaluated with a 511 keV collimated beam to exactly determine DoI resolution. In addition, a fast quality control (QC) procedure using flood irradiations from a 137Cs source was applied systematically. The overall performance of the 24 detector modules complies with the design goals of the Clear-PEM detector, showing energy resolution around 15%, DoI resolution of about 2 mm and gain dispersion among pixels of 15%.

For an efficient data taking, the Electromagnetic Calorimeter data of the CMS experiment must be limited to 10% of the full event size (1MB). Other requirements limit the average data size to 2kB per data acquisition link. These conditions imply a reduction factor of close to twenty on the data collected. The data filtering in the readout of the Electromagnetic Calorimeter detector is discussed. Test beam data are used to study the digital filtering applied in the readout channels and a full detector simulation allows to estimate the energy thresholds to achieve the desired data suppression factor.

A dedicated implementation of list-mode maximum-likelihood expectation-maximization (MLEM) reconstruction for the ClearPEM system is presented. The system is composed of two face-to-face detectors, which can be rotated to acquire data from different angular positions. Due to the specific design with irregular sampling and depth of interaction capability, the possible number of lines of response (LOR) is significantly greater than the number of detected events in a standard clinical study. Because reconstruction methods based on data histogramming to sinogram lead to a high computational cost and/or a loss of the intrinsical system resolution, it is necessary to consider the processing of events in list-mode during the reconstruction. The presented method adopted EM algorithm to maximize the logarithmic likelihood function that is expressed in list-mode. The voxel efficiency is corrected by pre-calculated efficiency maps based on flood phantom acquisitions. The method is also implemented with parallelization by distributing the calculation of the acquired events into different threads for significantly increasing computational speed. The results of a Derenzo phantom study show that the presented algorithm can achieve a similar result as 3D-OSEM reconstruction based on data histogramming with significantly lower reconstruction time (6 times faster with one thread, 20 times faster with 8 threads distributed in 8 CPU cores). In clinical studies with lower acquired events, the acceleration ratio can be even higher. The result from a breast phantom study shows that lesions with 15 mm in diameter, each, as well as a small lesion with 5 mm in diameter are clearly visible and can be characterized. The mouse imaging studies show also great potential of the system in small animal applications.

Abstract The transverse mass differential cross-sections for the ϱ + ω and Φ resonances is obtained, in the central rapidity region, in p - W and S  U interactions at 200 GeV/nucleon. The measured ϱ + ω and Φ temperatures are ∼ 15% higher in S  U as compared to p - W collisions. The ratio of cross-sections times branching ratios into the dimuon channel B Φ σ Φ (B ϱ σ ϱ + B ω σ ω ) is studied as a function of the energy density reached in the collision and of the dimuon transverse momentum. The measured ratio is 2 to 3 times larger in S  U than in p - W collisions and an enhancement is observed in S  U interactions with increasing energy density.

The NA38 experiment measures muon pair production in 200 GeV per nucleon nucleus-nucleus interactions at the CERN SPS. Dimuon production is studied as a function of the neutral transverse energy produced in the collisions, which reflects the energy density reached in the interaction. The J/ψ yield relative to muon pairs in the mass continuum decreases with increasing energy density. The atomic number dependence of the cross sections has been studied using the parametrization σ ∞ (Aproj.Atarg.)α which leads to α = 0.91 ± 0.04 for the J/ψ, and α = 1.01 ± 0.04 for muon pairs in the mass range [1.7, 2.7] GeV/c2. The study of dimuon transverse momentum distributions shows an enhancement of the J/ψ suppression for low PT values. The average values 〈PT〉 and 〈PT2〉 increase with increasing transverse energy in case of the J/ψ, and are rather flat for muon pairs in the mass continuum. Such a behaviour is expected in case of quark-gluon plasma formation. However, a model based on parton multiple scattering in the initial state leads to a variation of 〈PT2〉 as a function of the mean thickness of nuclear matter encountered by the partons, which seems also to account for the observed effect. In addition, low mass dimuons are studied. An enhancement of the φ/(ϱ + ω) ratio is observed with increasing energy density.

The design and evaluation of the imaging system Clear-PEM for positron emission mammography, under development by the PEM Consortium within the framework of the Crystal Clear Collaboration at CERN, is presented. The proposed apparatus is based on fast, segmented, high atomic number radiation sensors with depth-of-interaction measurement capabilities and state-of-the-art data acquisition techniques. The camera consists of two compact and planar detector heads with adequate field-of-view dimensions for breast and axilla imaging. Low-noise integrated electronics provide signal amplification and analog multiplexing based on a new data-driven architecture. The coincidence trigger and data acquisition architecture makes extensive use of pipeline processing structures and multi-event memories for high efficiency up to a data acquisition rate of one million events/s. Experimental validation of the detection techniques, namely the basic properties of the radiation sensors and the ability to measure the depth-of-interaction of the incoming photons, are presented. System performance in terms of detection sensitivity, count-rates and reconstructed image spatial resolution were also evaluated by means of a detailed Monte Carlo simulation and an iterative image reconstruction algorithm.

In the framework of the Clear-PEM project for the construction of a high-resolution and high-specificity scanner for breast cancer imaging, a Positron Emission Mammography tomograph has been developed and installed at the Instituto Português de Oncologia do Porto hospital. The Clear-PEM scanner is mainly composed by two planar detector heads attached to a robotic arm, trigger/data acquisition electronics system and computing servers. The detector heads hold crystal matrices built from 2 × 2 × 20 mm3 LYSO:Ce crystals readout by Hamamatsu S8550 APD arrays. The APDs are optically coupled to both ends of the 6144 crystals in order to extract the DOI information for each detected event. Each one of 12288 APD's pixels is read and controlled by Application Specific Integrated Circuits water-cooled by an external cooling unit. The Clear-PEM frontend boards innovative design results in a unprecedented integration of the crystal matrices, APDs and ASICs, making Clear-PEM the PET scanner with the highest number of APD pixels ever integrated so far. In this paper, the scanner's main technical characteristics, calibration strategies and the first spectrometric performance evaluation in a clinical environment are presented. The first commissioning results show 99.7% active channels, which, after calibration, have inter-pixel and absolute gain distributions with dispersions of, respectively, 12.2% and 15.3%, demonstrating that despite the large number of channels, the system is uniform. The mean energy resolution at 511 keV is of 15.9%, with a 8.8% dispersion, and the mean CDOI−1 is 5.9%/mm, with a 7.8% dispersion. The coincidence time resolution, at 511 keV, for a energy window between 400 and 600 keV, is 5.2 ns FWHM.

The purpose of this paper is to present a novel built-in Clock Domain Crossing (CDC) test and diagnosis methodology for Globally Asynchronous, Locally Synchronous (GALS) systems. The methodology allows design and prototype validation, low maintenance and repair costs, and production / lifetime at-speed test. Moreover, high resolution diagnosis is obtained, to identify which device(s) and/or communication channel(s) is (are) faulty. This is not trivial in GALS systems, for which the CDC issue is challenging. The underlying principle of the proposed methodology is to embed a CDC test and diagnosis (CDC T&D) structure in each locally synchronous domain. Complete device-to-device communication channels are tested, including transceivers, buses, and board connectors. Identical test patterns (generated to detect static (stuck-at, shorts and open faults) and dynamic (crosstalk) faults) are used in each FPGA. The proposed CDC T&D methodology is validated in a case study, the acquisition electronics of a complex multi-board, multibus, multi-FPGA (nine Xilinx™ xc2v4000-4bf957) system. Test and validation results are presented.

The EndoTOFPET-US system is a multi-modal imaging system, combining Time of Flight PET (200 ps time resolution) and Ultra-Sound into an endoscopic probe. The PET component has an asymmetric configuration. The in-probe detector is based on 0.8 × 0.8 × 10 mm3 LYSO crystal fibers, read by a Geiger mode SIPM with digital output. The other detector is a 200 × 200 mm external plate, based on 3 × 3× 15 mm3 LYSO crystals, coupled to discrete 3 × 3 SiPMs read by a 64 channel ASIC. A compact data acquisition system based on digital reconfigurable electronics is proposed. FGPAs on the front end concentrate event data and transmit it to an external trigger. The probe electronics also transmit event data to the trigger. The trigger is a single PCIe card which sits directly in the acquisition computer. A preliminary event selection is performed directly in the trigger FPGA, while more sophisticated event processing is handled by software. The system is capable of handling rates up to 40 MHz from the external plate and 200 kHz from the probe.

We have developed a highly integrated, fast and compact readout electronics for Silicon Photomultiplier (SiPM) based Time of Flight Positron Emission Tomography (TOF-PET) scanners. The readout is based on the use of TOP-PET Application Specific Integrated Circuit (PETsys TOFPET1 ASIC) with 64 channels, each with its amplifier, discriminator, Time to Digital Converter (TDC) and amplitude determination using Time Over Threshold (TOT). The ASIC has 25 ps r.m.s. intrinsic time resolution and fully digital output. The system is optimised for high rates, good timing, low power consumption and low cost. For validating the readout electronics, we have built a technical PET scanner, hereafter called ``demonstrator'', with 2'048 SiPM channels. The PET demonstrator has 16 compact Detector Modules (DM). Each DM has two ASICs reading 128 SiPM pixels in one-to-one coupling to 128 Lutetium Yttrium Orthosilicate (LYSO) crystals measuring 3.1 × 3.1 × 15 mm3 each. The data acquisition system for the demonstrator has two Front End Boards type D (FEB/D), each collecting the data of 1'024 channels (8 DMs), and transmitting assembled data frames through a serial link (4.8 Gbps), to a single Data Acquisition (DAQ) board plugged into the Peripheral Component Interconnect Express (PCIe) bus of the data acquisition PC. Results obtained with this PET demonstrator are presented.

Positron Emission Tomography (PET) scanners require high performances in term of spatial resolution and sensitivity to allow early detection of cancer masses. In small animal and organ dedicated PET scanners the Depth of Interaction (DOI) information has to be obtained to avoid parallax errors and to reconstruct high resolution images. In the whole body PET, the DOI information can be useful to correct for the time jitter of the optical photons along the main axis of the scintillator, improving the time performances. In this work we present the development of PET module designed to reach high performance as compared to the current scanners while keeping the complexity of the system reasonably low. The module presented is based on a 64 LYSO (Lutetium-yttrium oxyorthosilicate) crystals matrix and on a 4×4 MPPC (Multi Pixels Photon Counter) array as detector in a 4 to 1 coupling between the crystals and the detector and a single side readout. The lateral surfaces of the crystals are optically treated to be unpolished. The DOI and the energy resolution of the PET module are presented and a fast method to obtain the DOI calibration is discussed.

We report on the design of a full custom amplifier-comparator readout chip for silicon detectors with internal gain designed for precise timing applications. The ASIC has been developed in UMC 110 nm CMOS technology and is aimed to fulfill the CMS-TOTEM Precision Proton Spectrometer (CT-PPS) time resolution requirements (∼ 30 ps per detector plane). It features LVDS outputs and the signal dynamic range matches the requirements of the High Precision TDC (HPTDC) system. The preliminary measurements results with a test board are included.

The next generation of organ specific Positron Emission Tomography (PET) scanners, e.g. for breast imaging, will use partial ring geometries. We propose a component-based Maximum-Likelihood (ML) estimation of normalisation factors for 3D PET data reconstruction applicable to partial ring geometries. This method is based on the Software for Tomographic Image Reconstruction (STIR) for full ring PET and is validated for a stationary partial ring scanner. The model includes the estimation for crystal efficiencies and geometric factors. The algorithm is validated using Maximum Likelihood Estimation Method (MLEM) based 3D reconstruction in STIR using Geant4 Application for Tomographic Emission (GATE) simulation data for full and partial ring scanners and experimental data from a demonstrator with partial ring geometry. The uniformity of the reconstructed images of simulated cylindrical and NEMA-IQ phantoms in both scanner geometries and the image of a line source in the partial ring demonstrator is assessed. The results have shown that uniform images in both axial and transaxial directions are obtained after applying the estimated normalisation factors. The accuracy of the algorithm is validated by comparing the normalisation factors between the full and partial ring systems in simulation. We have shown that the estimated normalisation factors are almost identical, even though the separate components are not. This proves that the ML estimation of the 3D normalisation factors is valid and can be applied to the partial ring scanner.

We have measured the relative cross sections for muon pair production by 280 GeV/c negative pions on three different targets: carbon, copper, and tungsten. The value of α obtained from the parametrization σ = constant × Aα is 0.94 ± 0.02 ± 0.02, whereas the parametrization σ≈σ0(ZA) Aα′, where σ0(ZA) is given by the Drell-Yan model, leads to α′ = 0.97 ±0.02±0.02. This last result is in agreement with the quark additivity rule which is inherent in the Drell-Yan model, no dependence is observed on the transverse momentum of the muon pair.

Electronics and data acquisition systems are important components of radiation detectors applied to medical imaging. The performance of these systems has strong implications on crucial parameters of imaging devices, like the sensitivity and the image background noise. The paper presents a review of the functionality, typical architectures and main components of the electronics and data acquisition systems in medical imaging.

The Clear-PEM scanner is a device based on planar detectors that is currently under development within the Crystal Clear Collaboration, at CERN. The basis for 3D image reconstruction in Clear-PEM is the software for tomographic image reconstruction (STIR). STIR is an open source object-oriented library that efficiently deals with the 3D positron emission tomography data sets. This library was originally designed for the traditional cylindrical scanners. In order to make its use compatible with planar scanner data, new functionalities were introduced into the library's framework. In this work, Monte Carlo simulations of the Clear-PEM scanner acquisitions were used as input for image reconstruction with the 3D OSEM algorithm available in STIR. The results presented indicate that dual plate PEM data can be accurately reconstructed using the enhanced STIR framework.

This paper presents the implementation of the Timing, Trigger and Control (TTC) system of the CMS Experiment currently under construction at CERN. The TTC system distributes the system clock for the experiment as well as the first level Triggers and synchronization commands. The overall system is described, highlighting the differences from the original concept of the CERN RD-12 collaboration in terms of overall system architecture. Details are given of the two VME-format electronics boards that implement the necessary functionality required by the system design changes.

Positron Emission Mammography (PEM) with 18F-Fluorodeoxyglucose (18F-FDG) is a functional imaging technique for breast cancer detection. The development of dedicated imaging systems with high sensitivity and spatial resolution are crucial for early breast cancer diagnosis and an efficient therapy. Clear-PEM is a dual planar scanner designed for high-resolution breast cancer imaging under development by the Portuguese PET Mammography consortium within the Crystal Clear Collaboration. It brings together a favorable combination of high-density scintillator crystals coupled to compact photodetectors, arranged in a double readout scheme capable of providing depth-of-interaction information.

The CMS experiment at the LHC at CERN will start taking data in 2008. To configure, control and monitor the experiment during data-taking the Run Control system was developed. This paper describes the architecture and the technology used to implement the Run Control system, as well as the deployment and commissioning strategy of this important component of the online software for the CMS experiment.

The Data Acquisition System of the Compact Muon Solenoid experiment at the Large Hadron Collider reads out event fragments of an average size of 2 kB from around 650 detector front-ends at a rate of up to 100 kHz. The first stage of event-building is performed by the Super-Fragment Builder employing custom-built electronics and a Myrinet optical network. It reduces the number of fragments by one order of magnitude, thereby greatly decreasing the requirements for the subsequent event-assembly stage. Back-pressure from the down-stream event-processing or variations in the size and rate of events may give rise to buffer overflows in the subdetector's front-end electronics, which would result in data corruption and would require a time-consuming re-sync procedure to recover. The Trigger-Throttling System protects against these buffer overflows. It provides fast feedback from any of the subdetector front-ends to the trigger so that the trigger can be throttled before buffers overflow. This paper reports on new performance measurements and on the recent successful integration of a scaled-down setup of the described system with the trigger and with front-ends of all major subdetectors. The on-going commissioning of the full-scale system is discussed.

The ClearPEM detector is a dual planar Positron Emission Mammography (PEM) scanner that was developed within the framework of the international Crystal Clear Collaboration at CERN. The scanner is being used for preclinical studies and the new phase of the clinical trials will start on the second half of November. A second prototype was build and installed (ClearPEM-Sonic). The main results presented in this paper were obtained with the first prototype. The scanner image performance was evaluated using gelatin phantoms. The methodology included the quantification of the homogeneity (BV) and statistical noise (COV). Lesion detectability was evaluated using parameters such as lesion to background noise (LTBN) and lesion contrast recovery coefficient (CRC). Results indicate BV and COV of the order of 5-9% and 20-24%, respectively. ClearPEM images have been found globally homogeneous showing no artifacts. Small lesion to background ratio (LTB) and lesions of dimensions smaller than 3 mm showed less good contrast, but in most cases we report CRC values between 80% and 100%. The detection of lesions is feasible down to 2-3 mm in diameter.

ClearPEM-Sonic is an innovative imaging device specifically developed for breast cancer. The possibility to work in PEM-Ultrasound multimodality allows to obtain metabolic and morphological information increasing the specificity of the exam. The ClearPEM detector is developed to maximize the sensitivity and the spatial resolution as compared to Whole-Body PET scanners. It is coupled with a 3D ultrasound system, the SuperSonic Imagine Aixplorer that improves the specificity of the exam by providing a tissue elasticity map. This work describes the ClearPEM-Sonic project focusing on the technological developments it has required, the technical merits (and limits) and the first multimodal images acquired on a dedicated phantom. It finally presents selected clinical case studies that confirm the value of PEM information.

The CMS Detector will be upgraded for the HL-LHC to include a MIP Timing Detector (MTD). The MTD will consist of barrel and endcap timing layers, BTL and ETL respectively, providing precision timing of charged particles. The BTL sensors are based on LYSO:Ce scintillation crystals coupled to SiPMs with TOFHIR2 ASICs for the front-end readout. A resolution of 30–40 ps for MIP signals at a rate of 2.5 Mhit/s per channel is expected at the beginning of HL-LHC operation. We present an overview of the TOFHIR2 requirements and design, simulation results and the first measurements with TOFHIR2A silicon samples.

Abstract The readout electronics for the CMS electromagnetic calorimeter is undergoing a re-design in order to cope with the LHC ugrade. In particular, a fourfold increase in the sampling frequency (from 40 to 160 MS/s) is required. Therefore a new readout ASIC has been developed. The ASIC, named LiTE-DTU, is designed in a CMOS 65 nm technology. The LiTE-DTU embeds two 12 bit, 160 MS/s ADCs, a time window based sample selection, lossless data compression and 1.28 Gb/s serialization. An on-chip PLL provides the 1.28 GHz clock required by the ADCs and the serializers from the 160 MHz clock.

We have studied the production of J/ψ, ψ′ and prompt muon pairs in the mass continuum from a sample of sulfur-uranium interactions at 200 GeV/c per nucleon. We report, in this letter, results obtained for the transverse momentum distributions and their dependence on the transverse energy released in the collision, used as an estimator of the centrality of the nucleus-nucleus interaction.

The Clear-PEM detector is a positron emission mammography scanner based on a high-granularity avalanche photodiode readout with 12 288 channels. The front-end sub-system is instrumented with low-noise 192:2 channel amplifier-multiplexer ASICs and free-running sampling ADCs. The off-detector trigger, implemented in a FPGA based architecture, computes the pulses amplitude and timing required for coincidence validation from the front-end data streams. A high-level C++ simulation tool was developed for data acquisition performance analysis and validated at bit-level against FPGA VHDL testbenches. In this work, simulation studies concerning the performance of the on-line/off-line energy and time extraction algorithms and the foreseen detector energy and time resolution are presented. Time calibration and trigger efficiency are also discussed.

Located between the on-detector front-end electronics and the global data acquisition system (DAQ), the off-detector electronics of the CMS electromagnetic calorimeter (ECAL) is involved in both detector readout and trigger system. Working at 40 MHz, the trigger part must, within ten clock cycles, receive and deserialize the data of the front-end electronics, encode the trigger primitives using a nonlinear scale, assure time alignment between channels using a histogramming technique and send the trigger primitives to the regional trigger. In addition, it must classify trigger towers in three classes of interest and send this classification to the readout part. The readout part must select the zero suppression level to be applied depending on the regions of interest determined from the trigger tower classification, deserialize front-end data coming from high-speed (800 Mb/s) serial links, check their integrity, apply zero suppression, build the event and send it to the DAQ, monitor the buffer occupancy and send back pressure to the trigger system when required, provide data spying and monitoring facilities for the local DAQ. The system, and especially the data link speed, the latency constraints and the bit-error rate requirements have been validated on prototypes. Part of the system is about to go to production.

We present an overview of the Clear-PEM breast imaging scanner. Clear-PEM is a unique dual-head Positron Emission Mammography scanner using APD-based detector modules that are capable of measuring depth-of-interaction (DOI) with a resolution of 2 mm in 20 mm long LYSO:Ce crystals. Such capability leads to an image spatial resolution of 1.2 mm and a high efficiency, foreseeing the detection of 3 mm breast lesions in less than 7 minutes exams. The full system comprises 192 detector modules in a total of 6144 LYSO:Ce crystals and 384 32-pixel APD arrays readout by ASICs with 192 input channels that represents an unprecedented level of integration in PET systems. Throughout the project and besides the detector module, we had developed dedicated Frontend and Data Acquisition electronics, the mechanical design and construction of the detector heads and the robotic gantry, as well as all the software that include calibration (energy, time and DOI), normalization and image reconstruction algorithms. In this work we will discuss the developments and present the commissioning results of the detector before the beginning of the clinical trials program, scheduled for the end of the present year.

We present results on the characterization of the Clear-PEM breast imaging scanner. Clear-PEM is a dual-head Positron Emission Mammography scanner using APD-based detector modules that are capable of measuring depth-of-interaction (DOI) with a resolution of 2 mm in LYSO:Ce crystals. The full system comprises 192 detector modules in a total of 6144 LYSO:Ce crystals and 384 32-pixel APD arrays readout by ASICs with 192 input channels, which represents an unprecedented level of integration in APD-based PET systems. The system includes Frontend and Data Acquisition electronics and a robotic gantry for detector placement and rotation. The software implements calibration (energy, time and DOI), normalization and image reconstruction algorithms. In this work, the scanner main technical characteristics, calibration strategies and the spectrometric performance in a clinical environment are presented. Images obtained with point sources and extended uniform sources are also presented. The first commissioning results show 99.7% active channels. After calibration, the dispersion of the channels absolute gain is 15.3%, which demonstrate that despite the large number of channels the system is rather uniform. The mean energy resolution at 511 keV is 15.9% for all channels, and the mean DOI constant is 5.9%/mm, which is consistent with a 2 mm DOI resolution, or better. The coincidence time resolution at 511 keV, for a energy window between 400 and 600 keV, is 5.2 ns FWHM. The image resolution measured with point sources was found to be of the order of 1.3 mm FWHM. The DOI capability was found to have a strong impact on the image sharpness. Images of extended uniform <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">68</sup> Ge sources, corrected for sensitivity and for the artifacts due detector dead spaces, have good uniformity. First clinical breast images are presented.

The Large Hadron Collider will deliver up to 32 million physics collisions per second. This rate is far too high to be processed by present-day computer farms, let alone stored on disk by the experiments for offline analysis. A fast selection of interesting events must therefore be made. In the CMS experiment, this is implemented in two stages: the Level-1 Trigger of the CMS experiment uses custom-made, fast electronics, while the experiment's high-level trigger is implemented in computer farms. The Level-1 Global Trigger electronics has to receive signals from the subdetector systems that enter the trigger (mostly from muon detectors and calorimeters), synchronize them, determine if a pre-set trigger condition is fulfilled, check if the various subsystems are ready to accept triggers based on information from the Trigger Throttling System and on calculations of possible dead-times, and finally distribute the trigger decision (``Level-1 Accept'') together with timing signals to the subdetectors over the so-called ``Trigger, Timing and Control'' distribution tree of the experiment. These functions are fulfilled by several specialized, custom-made VME modules, most of which are housed in one crate. The overall control is exerted by the central ``Trigger Control System'', which is described in this paper. It consists of one main module and several ancillary boards for input and output functions.

For the EndoTOFPET-US experiment, the TOFPET ASIC has been developed as a front-end chip to read out data from silicon photomultipliers (SiPM) [1]. It introduces a time of flight information into the measurement of a PET scanner and hence reduces radiation exposure of the patient [2]. The chip is designed to work with a high event rate up to 100 kHz and a time resolution of 50 ps LSB. Using two threshold levels, it can measure the leading edge of the event pulse precisely while successfully suppressing dark counts from the SiPM. This also enables a time over threshold determination, leading to a charge measurement of the signal's pulse.

Hydroxycinnamic acids are lipophilic compounds naturally present in grape must, and proposed to have antimicrobial properties.Consequently, microorganisms that grow in media containing these acids must have efficient adaptation mechanisms.In Saccharomyces cerevisiae hydroxycinnamic acids enter into the cell where they are deprotonated causing a decrease in internal pH, this variation in the intracellular pH is counteracted by an increase in the activity of the H + -ATPase pump Pma1p.Dekkera bruxellensis however, is able to transform hydroxycinnamic acids into volatile-less toxic derivates, a mechanism used by few yeast species.Nonetheless, D. bruxellensis could also have an adaptation mechanism similar to that of S. cerevisiae.Our results showed that hydroxycinnamic acids caused a longer lag phase during D. bruxellensis growth, particularly when supplementing media with ferulic acid.Additionally, extracellular pH decreased while Pma1p activity increased during lag phase in media supplemented with p-coumaric acid.These results suggest the existence of a complementary mechanism of resistance to hydroxycinammic acids in D. bruxellensis which involves the H + -ATPase pump Pma1p.

The ClearPEM scanner is a dedicated system to perform breast imaging with the ability of measuring DOI, allowing an image spatial resolution close to 1.5 mm. The DOI is measured by calculating the amplitude asymmetry between the signals produced by two APD, one in the top and other in the bottom of the crystal. The DOI resolution measured in laboratory tests is 2.0 mm. In this paper we present a method to periodically confirm this value with the scanner fully mounted. The DOI resolution obtained with this method was 2.8 mm, which is consistent with the resolution measured during the laboratory tests.

This paper describes the selective read-out processor (SRP) proposed for the electromagnetic calorimeter (ECAL) of the Compact Muon Solenoid (CMS) experiment at LHC (CERN). The aim is to reduce raw ECAL data to a level acceptable by the CMS data acquisition (DAQ) system. For each positive level 1 trigger, the SRP is guided by trigger primitive generation electronics to identify ECAL regions with energy deposition satisfying certain programmable criteria. It then directs the ECAL read-out electronics to apply predefined zero suppression levels to the crystal data, depending whether the crystals fall within these regions or not. The main challenges for the SRP are some 200 high speed (1.6 Gbit/s) I/O channels, asynchronous operation at up to 100 kHz level 1 trigger rate, a 5-/spl mu/s real-time latency requirement and a need to retain flexibility in choice of selection algorithms. The architecture adopted for the SRP is based on modern parallel optic pluggable modules and high density field programmable gate array (FPGA) devices with embedded processors and multigigabit transceivers. Implementation studies to validate proposed solutions are presented. The performance of envisaged selection algorithms is investigated with the CMS detector simulation software. The robustness of optical communication channels is estimated via direct measurements and calculations. The feasibility to perform data reduction operations within the allocated timing budget is verified by running a representative SRP firmware on a development board with a Xilinx Virtex2Pro FPGA device.

The Clear-PEM device is a positron emission mammography (PEM) unit based on planar detectors and is currently under development. We have developed a 2D algebraic reconstruction technique (ART) algorithm using linograms to reconstruct Clear-PEM data. In this work we evaluate three different methods of calculating the system matrix used by the ART algorithm, which we designate as the pixel-, ray- and tube-driven methods, respectively. The methods were tested using Monte Carlo simulated data. The results obtained show that ART algorithm allows, for these cases, accurate image reconstruction and indicate that a more accurate modeling of the image system matrix using tubes of response (TORs) provides the best image evaluation indexes.

The CMS Detector will be upgraded for the High-Luminosity LHC to include a MIP Timing Detector (MTD). The MTD will consist of barrel and endcap timing layers, BTL and ETL, respectively, providing precision timing of charged particles. The BTL sensors are based on LYSO:Ce scintillating crystals coupled to SiPMs that are read out by TOFHIR2 ASICs in the front-end system. A resolution of 30 ps for MIP signals is expected at the beginning of HL-LHC operation degrading to 60 ps at the end of operation due to the SiPMs radiation damage. Relative to the first version of the front-end ASIC, TOFHIR2X implements improved circuitry for mitigation of the SiPM dark current noise as well as a new current mode discriminator. We present an overview of the TOFHIR2 requirements and design, simulation results and the first measurements with TOFHIR2X silicon samples coupled to LYSO/SiPM prototype sensors.

Jψ and ψ′ production cross sections are studied for several proton induced reactions and in SU collisions, in the NA38 experiment, by measuring the resonances' decays in the muon pair channel. Whereas in p-A interactions the ψ′/J/ψ ratio remains constantin going from p-p and p-d collisions to p-W and p-U, with a mean value of 1.76% ± 0.04%, in the SU data it exhibits half of this value and decreases as centrality of the collision increases. Also studied are the differences between the γπ0 ratio yields correlated with the Jψ mass range and other dimuon masses; no significant effect is seen.

The results in dilepton production in nucleus-nucleus collisions, collected at the CERN's heavy ions experimental program, are summarized. The measurement of the dimuon mass spectrum shows a suppression of the J/ψ relative to the continuum and an enhancement of the φ production, in central collisions. Both results are expected in the framework of the quark-gluon plasma formation, but more conventional models are also able to explain the present data.

A photoacoustic technique is used for studying topically applied substance absorption in human skin. The proposed method utilizes a double-chamber PA cell. The absorption determination was obtained through the measurement of the thermal effusivity of the binary system substance–skin. The theoretical model assumes that the effective thermal effusivity of the binary system corresponds to that of a two-phase system. Experimental applications of the method employed different substances of topical application in different parts of the body of a volunteer. The method is demonstrated to be an easily used non-invasive technique for dermatology research. The relative concentrations as a function of time of substances such as ketoconazol and sunscreen were determined by fitting a sigmoidal function to the data, while an exponential function corresponds to the best fit for the set of data for nitrofurazona, vaseline and vaporub. The time constants associated with the rates of absorption, were found to vary in the range between 10 and 58 min, depending on the substance and the part of the body.

The Clear-PEM detector system is a compact positron emission mammography scanner with about 12,000 channels aiming at high sensitivity and good spatial resolution. Front-end, trigger and data acquisition electronics are crucial components of this system. Front-end system is implemented as a data-driven synchronous design that identifies and multiplexes the analogue signals (channels) whose associated energy is above a pre-defined threshold. The trigger and data acquisition logic uses digitized front-end data streams and computes the pulses amplitude and timing. Based on this information it generates a coincidence trigger signal that is used to initiate the conditioning and transfer processes of the corresponding data towards the data acquisition computer. To minimize dead-time, data acquisition electronics architecture makes extensive use of pipeline processing structures and de-randomizer memories with multi-event capacity. The system operates at 100 MHz clock frequency and is capable to sustain a data acquisition rate of 1 million events per second with efficiency above 95%, under a total single photon background rate of 10 MHz. The basic component of the front-end system is a low-noise amplifier-multiplexer chip presently under development The off-detector system is designed around a dual-bus crate backplane for fast intercommunication among system modules. The trigger and data acquisition logic is implemented in large FPGAs with 4 million gates. Monte Carlo simulation results of the trigger efficiency, as well as results of hardware simulations are presented, showing the correctness of the design and implementation approach.

The imaging system Clear-PEM for positron emission mammography, under development within the framework of the Crystal Clear Collaboration at CERN, is presented. The detector is based on pixelized LYSO crystals optically coupled to avalanche photodiodes (APD) and readout by a fast low-noise electronic system. A dedicated digital trigger and data acquisition system is used for on-line selection of coincidence events with high efficiency, large bandwidth and negligible dead-time. The detector module performance was characterized in detail.

Experimental evaluation of the imaging system Clear-PEM for positron emission mammography, under development within the framework of the crystal clear collaboration at CERN, is presented in terms of its long-term stability. The detector modules and experimental setup are described. Time evolution results of signal yield, energy resolution, depth-of-interaction and inter-channel crosstalk for a reference detector module are reported.

The CMS data acquisition (DAQ) system relies on a purely software driven high level trigger (HLT) to reduce the full Level 1 accept rate of 100 kHz to approximately 100 Hz for archiving and later offline analysis. The HLT operates on the full information of events assembled by an event builder collecting detector data from the CMS front-end systems. The HLT software consists of a sequence of reconstruction and filtering modules executed on a farm of O(1000) CPUs built from commodity hardware. This paper presents the architecture of the CMS HLT, which integrates the CMS reconstruction framework in the online environment. The mechanisms to configure, control, and monitor the filter farm and the procedures to validate the filtering code within the DAQ environment are described.