L. Romero

Noncommunicable diseases (NCD), such as obesity, diabetes, and cardiovascular disease, are defining healthcare challenges of the 21st century. Medical infrastructure, which for decades sought to reduce the incidence and severity of communicable diseases, has proven insufficient in meeting the intensive, long-term monitoring needs of many NCD disease patient groups. In addition, existing portable devices with rigid electronics are still limited in clinical use due to unreliable data, limited functionality, and lack of continuous measurement ability. Here, a wearable system for at-home cardiovascular monitoring of postpartum women-a group with urgently unmet NCD needs in the United States-using a cloud-integrated soft sternal device with conformal nanomembrane sensors is introduced. A supporting mobile application provides device data to a custom cloud architecture for real-time waveform analytics, including medical device-grade blood pressure prediction via deep learning, and shares the results with both patient and clinician to complete a robust and highly scalable remote monitoring ecosystem. Validated in a month-long clinical study with 20 postpartum Black women, the system demonstrates its ability to remotely monitor existing disease progression, stratify patient risk, and augment clinical decision-making by informing interventions for groups whose healthcare needs otherwise remain unmet in standard clinical practice.

The masses, total widths, and leptonic widths of three triplet $s$-wave $b\overline{b}$ states $\ensuremath{\Upsilon}(4S)$, $\ensuremath{\Upsilon}(5S)$, and $\ensuremath{\Upsilon}(6S)$ are determined from measurements of the ${e}^{+}{e}^{\ensuremath{-}}$ annihilation cross section into hadrons for $10.55<W<11.25$ GeV. The resonances are identified from potential model results and their properties are obtained with the help of a simplified coupled-channels calculation. We find $M(4S)=10.577$ GeV, $\ensuremath{\Gamma}(4S)=25$ MeV, ${\ensuremath{\Gamma}}_{\mathrm{ee}}(4S)=0.28$ keV; $M(5S)=10.845$ GeV, $\ensuremath{\Gamma}(5S)=110$ MeV, ${\ensuremath{\Gamma}}_{\mathrm{ee}}(5S)=0.37$ keV; $M(6S)=11.02$ GeV, $\ensuremath{\Gamma}(6S)=90$ MeV, ${\ensuremath{\Gamma}}_{\mathrm{ee}}(6S)=0.16$ keV.

The Argon Dark Matter (ArDM) experiment consists of a liquid argon (LAr) time projection chamber (TPC) sensitive to nuclear recoils, resulting from scattering of hypothetical Weakly Interacting Massive Particles (WIMPs) on argon targets. With an active target mass of 850 kg ArDM represents an important milestone towards developments for large LAr Dark Matter detectors. Here we present the experimental apparatus currently installed underground at the Laboratorio Subterráneo de Canfranc (LSC), Spain. We show data on gaseous or liquid argon targets recorded in 2015 during the commissioning of ArDM in single phase at zero E-field (ArDM Run I). The data confirms the overall good and stable performance of the ArDM tonne-scale LAr detector.

Atherosclerosis is a prominent cause of coronary artery disease and broader cardiovascular diseases, the leading cause of death worldwide. Angioplasty and stenting is a common treatment, but in-stent restenosis, where the artery re-narrows, is a frequent complication. Restenosis is detected through invasive procedures and is not currently monitored frequently for patients. Here, we report an implantable vascular bioelectronic device using a newly developed miniaturized strain sensor via microneedle printing methods. A capillary-based printing system achieves high-resolution patterning of a soft, capacitive strain sensor. Ink and printing parameters are evaluated to create a fully printed sensor, while sensor design and sensing mechanism are studied to enhance sensitivity and minimize sensor size. The sensor is integrated with a wireless vascular stent, offering a biocompatible, battery-free, wireless monitoring system compatible with conventional catheterization procedures. The vascular sensing system is demonstrated in an artery model for monitoring restenosis progression. Collectively, the artery implantable bioelectronic system shows the potential for wireless, real-time monitoring of various cardiovascular diseases and stent-integrated sensing/treatments.

We have observed production of monochromatic low-energy photons in ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ interactions between 10.6 and 11.2 GeV/${c}^{2}$. We show that this signal is associated with the production of b-flavored meson pairs, and interpret it as due to the decay ${B}^{\mathrm{*}}$\ensuremath{\rightarrow}B+\ensuremath{\gamma}. This is the first experimental evidence for the existence of vector b\ifmmode \bar{u}\else \={u}\fi{} or bd\ifmmode\bar\else\textasciimacron\fi{} bound states. We determine the mass difference of the vector and pseudo- scalar states, M(${B}^{\mathrm{*}}$)-M(B), to be 52\ifmmode\pm\else\textpm\fi{}2\ifmmode\pm\else\textpm\fi{}4 MeV.

The design and operation of precision drift chambers with multisampling as well as the concepts and methods for reaching an extraordinary degree of precision in mechanics and calibration are described. Specific instruments were developed for this purpose. The concept of reproducible positioning and the implementation to 30 μm accuracy, showing stability over three years, is given. Calibration and analysis with UV-laser and cosmic test measurements are outlined with the critical results. The experience of calibration and reliability of the large system in an actual L3 running experiment is analyzed. The resolution under “battle conditions” at LEP resulted in Δpp = (2.50±0.04)% at 45.6 GeV and will be presented in detail. The concept is well suited for future TeV energies.

The Argon Dark Matter (ArDM-1t) experiment is a ton-scale liquid argon (LAr) double-phase time projection chamber designed for direct Dark Matter searches. Such a device allows to explore the low energy frontier in LAr with a charge imaging detector. The ionization charge is extracted from the liquid into the gas phase and there amplified by the use of a Large Electron Multiplier in order to reduce the detection threshold. Direct detection of the ionization charge with fine spatial granularity, combined with a measurement of the amplitude and time evolution of the associated primary scintillation light, provide powerful tools for the identification of WIMP interactions against the background due to electrons, photons and possibly neutrons if scattering more than once. A one ton LAr detector is presently installed on surface at CERN to fully test all functionalities and it will be soon moved to an underground location. We will emphasize here the lessons learned from such a device for the design of a large LAr TPC for neutrino oscillation, proton decay and astrophysical neutrinos searches.

Neutron production induced by ($\alpha$,n) reactions is important in various scenarios. One of the most relevant ones is related to underground dark matter experiments, where the neutrons produced by the $\alpha$-decay from radioactive contaminants in the detector materials can generate an irreducible background, limiting the sensitivity of the experiment. A precise estimate of the background due to these neutrons is crucial for the experiments currently taking data and for the design of the next generation detectors. In this work, we prove that Geant4 can be used to calculate neutron yields and energy spectra induced by $\alpha$-decay. These neutrons are produced according to the information compiled in data libraries originally written in the ENDF-6 format. In this article we also review the different databases available, showing the differences and similarities among them. Finally, we compare several Geant4 neutron production yields and spectra with experimental data and other codes.

We have observed muons from the semileptonic decay B → Xμν where B meson are produced in e+e− annihilations into hadrons at the γ(4S) resonance (10.58 GeV). We obtain a branching ratio of (11.2 ± 0.9 ± 1.0)% for B → Xμν. We have also measured the production of energetic muons in hadronic e+e− annihilations in the energy region above the γ(4S) from 10.6 GeV to 11.2 GeV.

To optimise the design of the light readout in the ArDM 1-ton liquid argon dark matter detector, a range of reflector and WLS coating combinations were investigated in several small setups, where argon scintillation light was generated by radioactive sources in gas at normal temperature and pressure and shifted into the blue region by tetraphenyl butadiene (TPB). Various thicknesses of TPB were deposited by spraying and vacuum evaporation onto specular 3MTM-foil and diffuse Tetratex® (TTX) substrates. Light yields of each reflector and TPB coating combination were compared. Reflection coefficients of TPB coated reflectors were independently measured using a spectroradiometer in a wavelength range between 200 and 650 nm. WLS coating on the PMT window was also studied. These measurements were used to define the parameters of the light reflectors of the ArDM experiment. Fifteen large 120 × 25 cm2 TTX sheets were coated and assembled in the detector. Measurements in argon gas are reported providing good evidence of fulfilling the light collection requirements of the experiment.

The Argon Dark Matter experiment is a ton-scale double phase argon Time Projection Chamber designed for direct Dark Matter searches. It combines the detection of scintillation light together with the ionisation charge in order to discriminate the background (electron recoils) from the WIMP signals (nuclear recoils). After a successful operation on surface at CERN, the detector was recently installed in the underground Laboratorio Subterráneo de Canfranc, and the commissioning phase is ongoing. We describe the status of the installation and present first results from data collected underground with the detector filled with gas argon at room temperature.

We present a detailed study of the decays ϒ′ → π+π−ϒ and ϒ′ → π0π0ϒ, where the ϒ decays subsequently to e+e− or μ+μ−. The results are obtained from a sample of 146 000 ϒ′ decays observed with the CUSB detector at the Cornell Electron Storage Ring. We derive branching fractions of (18.9 ± 2.6)% for ϒ′ → π′π−ϒ and (10.3 ± 2.3)% for ϒ′ → π0π0ϒ, and determined partial widths for these decays. Invariant mass and angular distributions of both the π+π− and π0π0 systems are presented. We also set a limit on the branching fraction for ϒ′ → ηϒ of less than 0.2% at the 90% confidence level.

We report on a measurement of the attenuation length for the scintillation light in the tonne size liquid argon target of the ArDM dark matter experiment. The data was recorded in the first underground operation of the experiment in single-phase operational mode. The results were achieved by comparing the light yield spectra from 39Ar and 83mKr to a description of the ArDM setup with a model of full light ray tracing. A relatively low value close to 0.5 m was found for the attenuation length of the liquid argon bulk to its own scintillation light. We interpret this result as a presence of optically active impurities in the liquid argon which are not filtered by the installed purification systems. We also present analyses of the argon gas employed for the filling and discuss cross sections in the vacuum ultraviolet of various molecules in respect to purity requirements in the context of large liquid argon installations.

Distal arthrogryposis (DA) is a collection of rare developmental disorders characterized by congenital joint contractures. Most arthrogryposis mutations are in muscle- and joint-related genes, and the anatomical defects originate cell-autonomously within the musculoskeletal tissues. However, gain-of-function (GOF) mutations in PIEZO2, a principal mechanosensor in somatosensation, cause DA subtype 5 via unknown mechanisms. We show that expression of a GOF PIEZO2 mutation in proprioceptive sensory neurons mainly innervating muscle spindles and tendons is sufficient to induce DA5-like phenotypes in mice. Overactive PIEZO2 causes anatomical defects via increased activity within the peripheral nervous system during postnatal development. Surprisingly, overactive PIEZO2 is likely to cause joint abnormalities via increased exocytosis from sensory neuron endings without involving motor circuitry. This reveals a role for somatosensory neurons: excessive mechanosensation within these neurons disrupts musculoskeletal development. We also present proof-of-concept that Botox injection or dietary treatment can counteract the effect of overactive PIEZO2 function to evade DA-like phenotypes in mice when applied during a developmental critical period. These approaches might have clinical applications. Beyond this, our findings call attention to the importance of considering sensory mechanotransduction when diagnosing and treating other musculoskeletal disorders. Acknowledgements: Our work is supported by National Institutes of Health grant (R35 NS105067, R01 DE022358, R25 SC3GM127195, R25 GM07138, R01GM133845, intramural) and Howard Hughes Medical Institute.

Abstract The age and stroke-associated decline in musculoskeletal strength degrades the ability to perform daily human tasks using the upper extremities. Here, we introduce an intelligent upper-limb exoskeleton system that utilizes deep learning to predict human intention for strength augmentation. The embedded soft wearable sensors provide sensory feedback by collecting real-time muscle activities, which are simultaneously computed to determine the user’s intended movement. Cloud-based deep learning predicts four upper-limb joint motions with an average accuracy of 96.2% at a 500–550 ms response rate, suggesting that the exoskeleton operates just by human intention. In addition, an array of soft pneumatics assists the intended movements by providing 897 newtons of force while generating a displacement of 87 mm at maximum. The intent-driven exoskeleton can reduce human muscle activities by 3.7 times on average compared to the unassisted exoskeleton.

ArDM-1t is the prototype for a next generation WIMP detector measuring both the scintillation light and the ionization charge from nuclear recoils in a 1-ton liquid argon target. The goal is to reach a minimum recoil energy of 30 keVr to detect recoiling nuclei. In this paper we describe the experimental concept and present results on the light detection system, tested for the first time in ArDM on the surface at CERN. With a preliminary and incomplete set of PMTs, the light yield at zero electric field is found to be between 0.3-0.5 phe/keVee depending on the position within the detector volume, confirming our expectations based on smaller detector setups.

The 40 MHz bunched muon beam set up at CERN was used in May 2003 to make a full test of the drift tubes local muon trigger. The main goal of the test was to prove that the integration of the various devices located on a muon chamber was adequately done both on the hardware and software side of the system. Furthermore the test provided complete information about the general performance of the trigger algorithms in terms of efficiency and noise. Data were collected with the default configuration of the trigger devices and with several alternative configurations at various angles of incidence of the beam. Tests on noise suppression and di-muon trigger capability were performed.

During 12 months of follow-up in a randomized double-blind controlled field study, a killed whole-promastigote vaccine cocktail plus bacille Calmette-Guérin (BCG) adjuvant significantly reduced the incidence of cutaneous leishmaniasis (CL) in Ecuadorian children, compared with BCG alone. To determine how much longer protection might continue, the study was reblinded to permit 48 additional months of follow-up. During months 13–18, CL incidence remained lower in the vaccine group, compared with that in the control group (5.9% vs. 13.8%; χ2=8.8; P=.003), with vaccine efficacy calculated at 56.5% (95% confidence interval, 18.7%–76.7%); however, during months 24–60, no significant between-group differences were detected. Periodic administration of boosters may be necessary to maintain whole-parasite–vaccine protection against New World CL

We have searched for the decay of ϒ's into a monochromatic photon accompanied by other particles as a signal for the reaction ϒ→γ+Higgs. Two different methods are presented both with null result. While we are not sensitive to the branching ratios predicted by the standard model with a minimal Higgs content, we can put limits on the possible values of the lowest Higgs mass and the ratio of the vacuum expectation values for more complex models. Our results are also of interest with respect to the ξ(2.2) being a Higgs in the context of such models.

Large size detectors based on Cs2LiYCl6:Ce (CLYC) are capable of performing a combined γ-ray and neutron spectrometry and constitute a promising technology for a wide range of applications in nuclear and high energy physics. Due to their novelty, the comprehensive characterization of the performance of individual CLYC detectors is of great importance for determining their range of applicability. In this work we report on a wide series of measurements performed with a commercial 2"×2" CLYC crystal. Good energy and timing resolution values, of 4.7% (@ 662 keV) and 1340 ps (FWHM) respectively, were achieved, and a neutron/γ separation figure of merit value of 4.2 was obtained. A dedicated measurement for investigating the intrinsic background of the detector was performed at the Laboratorio Subterráneo de Canfranc (Spain). It evidenced a sizeable contamination in the detector materials which poses limits in the use of CLYC in low background experiments. In addition, detailed Monte Carlo simulations with the GEANT4 toolkit were performed for modelling the response function of the CLYC detector to γ-rays. An excellent agreement with the experimental data has been achieved.

We are developing a PET insert for existing MRI equipment to be used in clinical PET/MR studies of the human brain. The proposed scanner is based on annihilation gamma detection with monolithic blocks of cerium-doped lutetium yttrium orthosilicate (LYSO:Ce) coupled to magnetically-compatible avalanche photodiodes (APD) matrices. The light distribution generated on the LYSO:Ce block provides the impinging position of the 511 keV photons by means of a positioning algorithm. Several positioning methods, from the simplest Anger Logic to more sophisticate supervised-learning Neural Networks (NN), can be implemented to extract the incidence position of gammas directly from the APD signals. Finally, an optimal method based on a two-step Feed-Forward Neural Network has been selected. It allows us to reach a resolution at detector level of 2 mm, and acquire images of point sources using a first BrainPET prototype consisting of two monolithic blocks working in coincidence. Neural networks provide a straightforward positioning of the acquired data once they have been trained, however the training process is usually time-consuming. In order to obtain an efficient positioning method for the complete scanner it was necessary to find a training procedure that reduces the data acquisition and processing time without introducing a noticeable degradation of the spatial resolution. A grouping process and posterior selection of the training data have been done regarding the similitude of the light distribution of events which have one common incident coordinate (transversal or longitudinal). By doing this, the amount of training data can be reduced to about 5% of the initial number with a degradation of spatial resolution lower than 10%.

The ArDM experiment completed a single-phase commissioning run in 2015 with an active liquid argon target of nearly one tonne in mass. The analysis of the data and comparison to simulations allowed for a test of the crucial detector properties and confirmed the low background performance of the setup. The statistical rejection power for electron recoil events using the pulse shape discrimination method was estimated using data from a Cf-252 neutron calibration source. Electron and nuclear recoil band profiles were found to be well described by Gaussian distributions. Employing such a model we derive values for the electron recoil statistical rejection power of more than 10$^8$ in the tonne-scale liquid argon target for events with more than 50 detected photons at a 50% acceptance for nuclear recoils. The Rn-222 emanation rate of the ArDM cryostat at room temperature was found to be 65.6$\pm$0.4 $\mu$Hz/l, and the Ar-39 specific activity from the employed atmospheric argon to be 0.95$\pm$0.05 Bq/kg. The cosmic muon flux at the Canfranc underground site was determined to be between 2 and 3.5$\times 10^{-3}m^{2}s^{-1}$ . These results pave the way for the next physics run of ArDM in the double-phase operational mode.

Abstract Biometric locking systems offer a seamless integration of an individual's physiological characteristics with secure authentication. However, they suffer from limitations such as false positive and negative authentication, environmental interference, and varying disadvantages across multiple authentication methods. To address these limitations, this study develops a soft smart biopatch for a continuous cardiac biometric wearable device that can continuously gather novel biometric data from an individual's heart sound for authentication with minimal error (less than 0.5%). The device is designed to be discreet and user‐friendly, and it employs soft biocompatible materials to ensure comfort and ease of use. The patch system incorporates a miniaturized microphone to monitor sounds over long periods and multiple dimensions, enhancing the reliability of the biometric data. Furthermore, the use of machine‐learning algorithms has enabled the creation of unique identification keys for individuals based on the continuous monitoring properties of the low‐cost device. These advantages make it more effective and efficient than traditional biometric systems, with the potential to enhance the security of mobile devices and door locks.

A prototype of the CMS Barrel Muon Detector incorporating all the features of the final chambers was built using the mass production assembly procedures and tools. The performance of this prototype was studied in a muon test beam at CERN and the results obtained are presented in this paper.

A study of the dynamics of the positive charges in liquid argon has been carried out in the context of the future massive time projection chambers proposed for dark matter and neutrino physics. Given their small mobility coefficient in liquid argon, the ions spend a considerably longer time in the active volume with respect to the electrons. The positive charge density can be additionally increased by the injection, in the liquid volume, of the ions produced by the electron multiplying devices located in gas argon. The impact of the ion current on the uniformity of the field has been evaluated as well as the probability of the charge signal quenching due to the electron-ion recombination along the drift. The study results show some potential concerns for massive detectors with drift of many meters operated on surface.

In October 2001 the first produced CMS Barrel Drift Tube (DT) Muon Chamber was tested at the CERN Gamma Irradiation Facility (GIF) using a muon beam. A Resistive Plate Chamber (RPC) was attached to the top of the DT chamber, and, for the first time, both detectors were operated coupled together. The performance of the DT chamber was studied for several operating conditions, and for gamma rates similar to the ones expected at LHC. In this paper we present the data analysis; the results are considered fully satisfactory.

We are developing a PET insert for existing MRI equipment to be used in clinical PET/MR studies of the human brain. Previous results have demonstrated that our detector concept, based on monolithic scintillator crystals coupled to magnetically-compatible APD matrices with a dedicated ASIC front-end, is suitable for this application. In this work we present the final design of our PET scanner and report on the characterization of a prototype demonstrator used to validate the coincidence processing and data readout architecture.

Abstract We performed a time-resolved spectroscopic study of the VUV/UV scintillation of gaseous argon as a function of pressure and electric field, by means of a wavelength sensitive detector operated with different radioactive sources. Our work conveys new evidence of distinctive features of the argon light which are in contrast with the general assumption that, for particle detection purposes, the scintillation can be considered to be largely monochromatic at 128 nm (second continuum). The wavelength and time-resolved analysis of the photon emission reveal that the dominant component of the argon scintillation during the first tens of ns is in the range [160, 325] nm. This light is consistent with the third continuum emission from highly charged argon ions/molecules. This component of the scintillation is field-independent up to 25 V/cm/bar and shows a very mild dependence with pressure in the range [1, 16] bar. The dynamics of the second continuum emission is dominated by the excimer formation time, whose variation as a function of pressure has been measured. Additionally, the time and pressure-dependent features of electron-ion recombination, in the second continuum band, have been measured. This study opens new paths toward a novel particle identification technique based on the spectral information of the noble-elements scintillation light.

We are developing a positron emission tomography (PET) scanner based on avalanche photodiodes (APD), monolithic LYSO:Ce scintillator crystals and a dedicated readout chip. All these components allow operation inside a magnetic resonance imaging (MRI) scanner with the aim of building a PET/MRI hybrid imaging system for clinical human brain studies. Previous work verified the functional performance of our first chip (VATA240) based on a leading edge comparator and the principle of operation of our radiation sensors, which are capable of providing reconstructed images of positron point sources with spatial resolutions of 2.1 mm FWHM. The new VATA241 chip presented in this work has been designed with the aim of reducing the coincidence window of our final PET scanner by implementing an on-chip constant fraction discriminator (CFD), as well as providing a better robustness for its implementation in the full-scale PET scanner. Results from the characterization of the VATA241 chip are presented, together with the first results on coincidence performance, validating the new design for our application.

Two drift tubes (DTs) chambers of the CMS muon barrel system were exposed to a 40 MHz bunched muon beam at the CERN SPS, and for the first time the whole CMS Level-1 DTs-based trigger system chain was tested. Data at different energies and inclination angles of the incident muon beam were collected, as well as data with and without an iron absorber placed between the two chambers, to simulate the electromagnetic shower development in CMS. Special data-taking runs were dedicated to test for the first time the Track Finder system, which reconstructs track trigger candidates by performing a proper matching of the muon segments delivered by the two chambers. The present paper describes the results of these measurements.

<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">68</sup> Ga is one of the non-conventional nuclides that are being used in preclinical imaging. One disadvantage of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">68</sup> Ga versus <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> F is its larger positron range, which deteriorates the effective spatial resolution and the overall image quality. In this work we present a performance evaluation of the ARGUS small-animal positron emission tomography (PET) scanner for two positron emitters, <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">68</sup> Ga and <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> F. These experiments followed the procedure based on the National Electrical Manufacturers Association (NEMA) NU 4-2008 standard. We show how the use of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">68</sup> Ga may affect the NEMA performance of the system in terms of image quality and spatial resolution. The recovery coefficients (RC) measured in the image-quality phantom ranged from 0.17 to 0.72 for <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">68</sup> Ga and from 0.28 to 0.92 for <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> F, using iterative image reconstruction methods and applying all corrections. Under the same conditions the image noise (%STD) in a uniform region was 17.0% for <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">68</sup> Ga and 15.1% for <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> F. The respective spillover ratios (SOR) were 0.13 and 0.09 in air, and 0.21 and 0.12 in water. Attenuation correction yielded an improvement of the SOR close to 50% for both radionuclides in the air-filled region. This work evaluates the image reconstruction methods and corrections available in the ARGUS PET for <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">68</sup> Ga and <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> F to assess the influence of their physical properties on the NEMA parameters.

Gamma detectors based on monolithic scintillator blocks coupled to APDs matrices have proved to be a good alternative to pixelated ones for PET scanners. They provide comparable spatial resolution, improve the sensitivity and make easier the mechanical design of the system. In this study we evaluate by means of Geant4-based simulations the possibility of replacing the APDs by SiPMs. Several commercial matrices of light sensors coupled to LYSO:Ce monolithic blocks have been simulated and compared. Regarding the spatial resolution and linearity of the detector, SiPMs with high photo detection efficiency could become an advantageous replacement for the APDs.

We are developing a positron emission tomography (PET) insert based on avalanche photodiode (APD) arrays and monolithic LYSO:Ce scintillators for human brain functional studies to be used inside a clinical magnetic resonance imaging (MRI) equipment. In a previous work [1], we demonstrated the performance of our detectors by implementing an experimental setup consisting of two monolithic blocks working in coincidence, which were read out by the first version of an application-specific integrated circuit (ASIC), VATA240, followed by external coincidence and digitalization modules. This preliminary demonstrator showed good spatial resolution at detector level on the order of 2.2 mm full-width at half-maximum (FWHM) and good imaging qualities, which achieved reconstructed images of 22Na point sources with spatial resolutions of 2.1 mm FWHM. Nevertheless, we detected image distortions and compressions due to the non-linearities close to the edge of the crystals and the simplicity of that demonstrator with the absence of neighbor blocks [1]. In this work we have implemented a larger scale PET demonstrator, which is based on the new updated ASIC (VATA241) [2] and is formed by two sectors of four monolithic detector blocks placed face-to-face. This new prototype demonstrator has been built for validating the data readout architecture, the coincidence processing implemented in a Xilinx Virtex 5 field programmable gate array (FPGA), as well as the continuous neural networks (NN) training method required to determine the points of entrance over the surface of our monolithic detector blocks.

We are developing a positron emission tomography (PET) insert for existing magnetic resonance (MR) equipment, aiming at hybrid MR–PET imaging. Our detector block design is based on trapezoid-shaped LYSO:Ce monolithic scintillators coupled to magnetically compatible Hamamatsu S8550-02 silicon avalanche photodiode (APD) matrices with a dedicated ASIC front-end readout from GammaMedica-Ideas (Fornebu, Norway). The detectors are position sensitive, capable of determining the incidence point of 511 keV gammas with an intrinsic spatial resolution on the order of 2 mm by means of supervised learning neural-network (NN) algorithms. These algorithms, apart from providing continuous coordinates, are also intrinsically corrected for depth of interaction effects and thus parallax-free. Recently we have implemented an advanced prototype featuring two heads with four detector blocks each and final front-end and readout electronics, improving the spatial resolution of reconstructed point source images down to 1.7 mm full width at half maximum (FWHM). Presently we are carrying out operational tests of components and systems under magnetic fields using a 3 T MR scanner. In this paper we present a description of our project, a summary of the results obtained with laboratory prototypes, and the strategy to build and install the complete system at the nuclear medicine department of a collaborating hospital.

Given their small mobility coefficient in liquid argon with respect to the electrons, the ions spend a considerably longer time in a sensitive detector volume instrumented with an electric field. We studied the effects of the positive ion current in a liquid argon time projection chamber, in the context of massive argon experiments for neutrino physics. The constant recombination between free ions and electrons produces a quenching of the charge signal and a constant emission of photons, uncorrelated in time and space to the physical interactions. The predictions evidence some potential concerns for multi-ton argon detectors, particularly when operated on surface.

Abstract The barrel muon chambers of the CMS detector consist of three sets of four layers of rectangular drift tubes. The performance of several prototypes was measured in a muon beam for various experimental conditions. Special emphasis was given to study performance aspects related to the trigger capability of the chambers.

The drift tubes based CMS barrel muon trigger, which uses self-triggering arrays of drift tubes, is able to perform the identification of the muon parent bunch crossing using a rather sophisticated algorithm. The identification is unique only if the trigger chain is correctly synchronized. Some beam test time was devoted to take data useful to investigate the synchronization of the trigger electronics with the machine clock. Possible alternatives were verified and the dependence on muon track properties was studied.

This paper shows how the use of resistive films inside of a quad-ridge horn can be utilized to reduce the sidelobes and help equalize the E-plane and H-plane beamwidths. This extends the upper frequency limit, thereby enabling the antenna range to use fewer feed horns. The resistive films also tend to reduce the gain, however, in an antenna test range, the reduced gain is an acceptable trade-off for achieving reduced sidelobes and increased bandwidth.

A 144 channel measurement IC for CdZnTe detectors, used for PET, is presented. Each channel consists of a charge sensitive amplifier, a fast and a slow shaper, a peak sampler for the energy acquisition and an event detector based on a time to digital converter to generate an accurate time stamp for each event. The channels are multiplexed to a fast pipeline ADC on demand. Measurement results for the ASIC showed a noise equivalent input charge of 800 e− rms and a time resolution of 737 ps rms. Evaluation results with a CdZnTe detector yielded an energy resolution of 4.4% full width half maximum at 662 keV with a 137Cs radiation source. The IC is implemented on a 180 nm CMOS process with a total chip size of 100 mm2.

Author(s): Haranczyk, M; Amsler, C; Badertscher, A; Boccone, V; Bourgeois, N; Bueno, A; Carmona-Benitez, MC; Chorowski, M; Creus, W; Curioni, A; Daw, E; Degunda, U; Dell'Antone, A; Droge, M; Epprecht, L; Haller, C; Horikawa, S; Kaufmann, L; Kisiel, J; Knecht, L; Laffranchi, M; Lagoda, J; Lazzaro, C; Lightfoot, P; Lozano, J; Lussi, D; Maire, G; Mania, S; Marchionni, A; Mavrokoridis, K; Melgarejo, A; Mijakowski, P; Natterer, G; Navas-Concha, S; Otiougova, P; Piotrowska, A; Polinski, J; De Prado, M; Przewlocki, P; Ravat, S; Regenfus, C; Resnati, F; Robinson, M; Rochet, J; Romero, L; Rondio, E; Rubbia, A; Scotto-Lavina, L; Spooner, N; Viant, T; Trawinski, A; Ulbricht, J; Zalewska, A | Abstract: The aim of the ArDM project is the development and operation of a one ton double-phase liquid argon detector for direct Dark Matter searches. The detector measures both the scintillation light and the ionization charge from ionizing radiation using two independent readout systems. This paper briefly describes the detector concept and presents preliminary results from the ArDM RaD program, including a 3 l prototype developed to test the charge readout system.

ArDM-1t is the first operating ton-scale liquid argon detector for direct search of Dark Matter particles. Developed at CERN as Recognized Experiment RE18, the experiment has been approved in 2010 to be installed in the Spanish underground site LSC (Laboratorio Subterraneo de Canfranc). Under the label of LSC EXP-08-2010 the ArDM detector underwent an intensive period of technical completion and safety approval until the recent filling of the target vessel with almost 2 ton of liquid argon. This report describes the experimental achievements during commissioning of ArDM and the transition into a stage of first physics data taking in single phase operational mode. We present preliminary observations from this run. A first indication for the background discrimination power of LAr detectors at the ton-scale is shown. We present an outlook for completing the detector with the electric drift field and upgrade of the scintillation light readout system with novel detector modules based on SiPMs in order to improve the light yield.

The drift chambers in the barrel region of the CMS detector are exposed to magnetic stray fields. To study the performance of the muon reconstruction and the drift time-based muon trigger, prototypes were tested under the expected magnetic field conditions at the H2 test facility at CERN. The results indicate that the overall chamber performance will not be affected. Only the bunch crossing identification capability in the small region near η=1.1, corresponding to the border of the solid angle region covered by the barrel, will be weakened.

The L3 detector is designed to measure the muon momentum with a 2% resolution at p = 45 GeV/c. We discuss here the systems we developed to reach the required accuracy and control the mechanical alignment at running time. We also report on the test done on the muon spectrometer with UV lasers and cosmic rays.

The L3 muon spectrometer is presented. Characteristics, useful for experiments at future accelerators, are highlighted. Particular emphasis is given to the systems envisaged to keep the error on the relative alignment of detectors below 30 μm and so reach a momentum resolution Δpp = 2% at p = 45 GeV/c.

In this paper we investigate the energy calibration methods of a high spatial resolution CdZnTe pixel detector, across a wide energy range, along with a fine estimation of the depth of interaction (DOI). A 24 × 24 CdZnTe detector (160 μm pixel size, 300 μm pitch) is successfully calibrated in energy, from 32 keV to 662 keV, dealing with three effects, which have a strong impact on the acquired data: charge sharing, dependence with the DOI and incomplete charge induction. The CdZnTe detector is bump-bonded to a VATA210P ASIC, which outputs the induced charge on the square of nine pixels and on the common cathode. The ASIC noise is characterized by an automatic adjustment of the internal threshold available for every pixel. The channels are linearized in charge units in order to improve the resolution when the complete induced charge is computed as the sum of the adjacent pixel contributions. For energy calibration, the variation of the photopeak histogram with the cathode-to-pixel ( C/P) ratio is analyzed. Two calibration profiles are generated for 32 and 662 keV for a complete <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">137</sup> Cs histogram. The obtained resolution, full width at half maximum (FWHM), is 24% for 32 keV (7.9 keV) and 4% for 662 keV (30 keV). The higher charge sharing for 662 keV events into many pixels explains the different energy resolutions. The DOI calibration is performed using simulation tools. A linear function with an exponential term is found suitable to characterize the DOI. Finally, the parametric fit obtained by simulation is applied to the experimental data with good results.

The BrainPET scanner is a magnetically-compatible human PET insert based on APDs and LYSO:Ce monolithic scintillators, which is currently under development at CIEMAT, intended for the operation inside magnetic resonance imaging (MRI) equipment. An ASIC called VATA241 was specifically designed for the BrainPET project. This ASIC includes a constant fraction discriminator (CFD) in its architecture and presents a better robustness and reliability with respect to the first leading-edge-based ASIC [1], which was successfully utilized in our first BrainPET demonstrator for validating the principle of operation of our detector blocks [2]. In this work we have characterized the VATA241 in terms of noise, time walk, jitter, linearity and operation with detector blocks. Moreover, we have carried out its optimization performance by adjusting the corresponding different bias currents. Based on the characterization carried out by CIEMAT, manufacturer Gamma Medica-Ideas (GM-I) has performed the tuning of the simulation model of this ASIC as well as the optimization of the timing performance for the fabrication of the final VATA241.2 ASIC, which will be used in our full-ring PET scanner.

We have analyzed the performance of a PET demonstrator formed by two sectors of four monolithic detector blocks placed face-to-face. Both front-end and read-out electronics have been evaluated by means of coincidence measurements using a rotating <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sup> Na source placed at the center of the sectors in order to emulate the behavior of a complete full ring. A continuous training method based on neural network (NN) algorithms has been carried out to determine the entrance points over the surface of the detectors. Reconstructed images from 1 MBq <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sup> Na point source and <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sup> Na Derenzo phantom have been obtained using both filtered back projection (FBP) analytic methods and the OSEM 3D iterative algorithm available in the STIR software package [1]. Preliminary data on image reconstruction from a <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sup> Na point source with ∅ = 0.25 mm show spatial resolutions from 1.7 to 2.1 mm FWHM in the transverse plane. The results confirm the viability of this design for the development of a full-ring brain PET scanner compatible with magnetic resonance imaging for human studies.

The age and stroke-associated decline in musculoskeletal strength degrades the ability to perform daily human tasks using the upper extremities. Although there are a few examples of exoskeletons, they need manual operations due to the absence of sensor feedback and no intention prediction of movements. Here, we introduce an intelligent upper-limb exoskeleton system that uses cloud-based deep learning to predict human intention for strength augmentation. The embedded soft wearable sensors provide sensory feedback by collecting real-time muscle signals, which are simultaneously computed to determine the user's intended movement. The cloud-based deep-learning predicts four upper-limb joint motions with an average accuracy of 96.2% at a 200-250 millisecond response rate, suggesting that the exoskeleton operates just by human intention. In addition, an array of soft pneumatics assists the intended movements by providing 897 newton of force and 78.7 millimeter of displacement at maximum. Collectively, the intent-driven exoskeleton can augment human strength by 5.15 times on average compared to the unassisted exoskeleton. This report demonstrates an exoskeleton robot that augments the upper-limb joint movements by human intention based on a machine-learning cloud computing and sensory feedback.

The widespread emergence of the COVID-19 pandemic has transformed our lifestyle, and facial respirators have become an essential part of daily life. Nevertheless, the current respirators possess several limitations such as poor respirator fit because they are incapable of covering diverse human facial sizes and shapes, potentially diminishing the effect of wearing respirators. In addition, the current facial respirators do not inform the user of the air quality within the smart facepiece respirator in case of continuous long-term use. Here, we demonstrate the novel smart N-95 filtering facepiece respirator that incorporates the humidity sensor and pressure sensory feedback-enabled self-fit adjusting functionality for the effective performance of the facial respirator to prevent the transmission of airborne pathogens. The laser-induced graphene (LIG) constitutes the humidity sensor, and the pressure sensor array based on the dielectric elastomeric sponge monitors the respirator contact on the face of the user, providing the sensory information for a closed-loop feedback mechanism. As a result of the self-fit adjusting mode along with elastomeric lining, the fit factor is increased by 3.20 and 5 times at average and maximum respectively. We expect that the experimental proof-of-concept of this work will offer viable solutions to the current commercial respirators to address the limitations.

El desarrollo de módulos y componentes libres de errores o bugs es uno de los objetivos medulares de la construcción de sistemas. Esto forma parte de entregar y/o liberar en ambientes de producción, sistemas de calidad, libres de problemas o vicios ocultos que impidan cubrir los requerimientos de los usuarios y que eviten cumplir los objetivos del sistema. Se exponen algunas estrategias y herramientas que el programador puede utilizar para depurar los sistemas de información, basados tanto en cambios de metodologías o paradigmas, como es la aplicación de Scrum, como en el uso de la Inteligencia Artificial para encontrar rutinas de código probadas, o incluso para la refactorización del código. Asimismo se ha observado útil la integración de técnicas como el Test Driven Development (TDD), que propone automatizar las pruebas de módulos individuales, además del uso de herramientas propias de Laravel/Livewire, como sus archivos de depuración, la herramienta Tinker y la barra de depuración de Laravel, o bien el uso de extensiones integradas al editor de código Visual Studio Code.

In this paper, we analyse the impact of gender equality in managerial positions on wages and the gender wage gap in 22 European countries. We draw on the employer–employee microdata from the European Structure of Earnings Survey (E-SES) for the year 2018, which allows us to include firm fixed effects in our econometric specifications, thus controlling for both observed and unobserved heterogeneity at the firm level. The analysis is carried out not only at the mean but also across the wage distribution through unconditional quantile regressions. The results on the impact of gender equality in management on wages are mixed. However, we find that gender equality has a predominantly positive effect in the upper part of the wage distribution, and a negative effect in the middle and lower parts. The results on the impact on the gender wage gap show that in many cases, a more gender-equal management reduces the gender wage gap. Furthermore, gender equality in management reduces the gender wage gap mainly in the middle and lower part of the wage distribution.

The Information and Communication Technologies (ICT) have a great potential to transform the field of engineering, and their use is increasingly widespread. In this context, the software (simulator) consists of three calculation modules: two of them focus on the simulation and evaluation of a shell-and-tube heat exchanger, and the third one centers on thermal-hydraulic design. The choice of the module to be used within the program depends on the user's needs. The freely accessible software allows teachers and students to adjust parameters, perform parametric sensitivity analyses, enabling a better understanding of the effects of variables involved in the equipment's performance. The software incorporates equations, graphs, and theoretical support for in-depth analysis of variables, as well as potential adjustments that can be made to meet the thermal-hydraulic requirements of the heat exchange unit. This makes it an educational tool that facilitates comprehensive analysis of the different variables involved. It aids in designing potential configurations for the required service of the shell-and-tube heat exchanger.

The data collected by the L3+C muon spectrometer at the CERN Large Electron-Positron collider, LEP, have been used to search for short duration signals emitted by cosmic point sources.A sky survey performed from July to November 1999 and from April to November 2000 has revealed one single flux enhancement ðchance probability ¼ 2:6 Â 10 À3 Þ between the 17th and 20th of August 2000 from a direction with a galactic longitude of (265.02 ± 0.42)°and latitude of (55.58 ± 0.24)°.The energy of the detected muons was above 15 GeV.

A high sensitivity experimental set up for luminescence decay measurements is described. Luminescence light decay in ZnS: Ag after excitation by a pulsed N2 laser is measured in the 0.1 μs to 1 s time range. Spectral evolution in the first 15 μs is investigated and a strong violet emission at zero time is observed. A comparison is made of the experimental results with donor–acceptor pair theory. Dans cet article on fait la decription d'un equipement experimental pour la mesure du decroissement de la luminescence avec le temps. La luminescence du ZnS: Ag, excitée par laser a N2, a été mesurée dans l'intervalle compris entre 0,1 μs à 1 s. L'évolution de l'espectre de luminescence pendant les premières 15 μs a été mesurée, et on a trouvé une forte emisión violet pendant les instantes initiales. On a fait un comparison entre les resultats experimentales et la théorie de pairs donateur accepteur.

Abstract SaG4n is a code fully based on Geant4 that we have developed to calculate neutron yields. The code is available in http://win.ciemat.es/SaG4n and works for Geant4.10.6 or superior. The improvements to the ( α ,n) yields introduced by the use of a single Monte Carlo code, fully developed in Geant4, are presented. Neutrons are a potential source of background for all rare-event searches, and is specially relevant for WIMP searches with liquid argon, where they are the only source of irreducible background together with the yet-negligible coherent neutrino scattering. The precision of the neutron yield is critical to evaluate the discovery potential of coming experiments and to reduce systematic effects in current data. We present the result of evaluating the neutron yield for three different cases and show the sizable effect of interfaces between materials with high ( α ,n) cross section and materials with small mass which contribution to the neutron budget is often considered negligible.

Nowadays, Dark Matter search constitutes one of the most challenging scientific activity. During the last decades several detectors have been developed to evidence the signal of interactions between Dark Matter and ordinary matter. The Argon Dark Matter detector, placed in the Canfranc Underground Laboratory in Spain is the first ton-scale liquid-Ar experiment in operation for Dark Matter direct detection. In parallel to the development of other engineering issues, computational methods are being applied to maximize the exploitation of generated data. In this work, two algorithms based on decision trees —Generalized Boosted Regression Models and Random Forests— are employed to reconstruct the position of the interaction in Argon Dark Matter detector. These two algorithms are confronted to a Montecarlo data set reproducing the physical behaviour of Argon Dark Matter detector. In this work, an in-depth study of the position reconstruction of the interaction is performed for both algorithms, including a study of the distribution of errors.

We report on a measurement of the attenuation length for the scintillation light in the tonne size liquid argon target of the ArDM dark matter experiment. The data was recorded in the first underground operation of the experiment in single-phase operational mode. The results were achieved by comparing the light yield spectra from 39-Ar and 83m-Kr to a description of the ArDM setup with a model of full light ray tracing. A relatively low value close to 0.5 m was found for the attenuation length of the liquid argon bulk to its own scintillation light. We interpret this result as a presence of optically active impurities in the liquid argon which are not filtered by the installed purification systems. We also present analyses of the argon gas employed for the filling and discuss cross sections in the vacuum ultraviolet of various molecules in respect to purity requirements in the context of large liquid argon installations.

The Argon Dark Matter (ArDM) experiment consists of a liquid argon (LAr) time projection chamber (TPC) sensitive to nuclear recoils resulting from scattering of hypothetical Weakly Interacting Massive Particles (WIMPs) on argon targets. With an active target of 850 kg, ArDM represents an important milestone in the quest for Dark Matter with LAr. We present the experimental apparatus currently installed underground at the Laboratorio Subterraneo de Canfranc (LSC), Spain. We show first data recorded during a single-phase commissioning run in 2015 (ArDM Run I), which overall confirm the good and stable performance of the ton-scale LAr detector.

The CSTD project aims at developing a high resolution pixel gamma detector based on CdZnTe for Compton imaging applications. Our research group has been working recently on the design and characterization of a new pixel detector with specifications focused at high energy SPECT for medical imaging applications. The detector pitch, 0.3 mm, and its thickness, 5 mm, allows to reach high spatial resolution and high detector efficiency. Non-ideal performance appears with more strength in small pixel pitch CdZnTe detectors, below 1 mm, affecting at the spectroscopic results. In order to recuperate the shared charge, the customized ASIC simultaneously collects the charge in the triggering pixel and its eight neighboring pixels per event. The detector design, readout electronics, acquisition software and data analysis have been completed at CIEMAT. Data has been taken by irradiating the CdZnTe detector with high and low energy gamma-ray sources. The high energy events of the <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">137</sup> Cs source suffer from a great proportion of charge sharing in the neighboring pixels. Two <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">137</sup> Cs spectra, with and without energy correction, are shown and compared. To obtain the corrected spectra offline, the collected charge at the neighboring pixels is added to the trigger pixel collected charge. The corrected spectra show that the 662 keV photopeak is reconstructed. Interaction depth correction follows to improve the energy resolution by data segmentation of the 662 keV energy peak according to fifty cathode to pixel ratios. The computed interaction depth correction profile is the inverse of the charge collection efficiency. Energy resolution can be improved discarding the segmented data which do not achieve an acceptable energy resolution. Several interaction depth correction profiles at 81, 356 and 662 keV are shown and reveal a second correlation between the charge collecting efficiency and the collecting energy.

The aim of the ArDM project is the development and operation of a one ton double-phase liquid argon detector for direct Dark Matter searches. The detector measures both the scintillation light and the ionization charge from ionizing radiation using two independent readout systems. This paper briefly describes the detector concept and presents preliminary results from the ArDM R&amp;D program, including a 3 l prototype developed to test the charge readout system.

Abstract The development of the barrel drift chambers for the CMS muon detector at the CERN Large Hadron Collider is supported by a variety of simulation calculations, based on the GARFIELD drift chamber simulation program and the GEANT detector simulation package. This study surveys the results influencing the actual chamber design. The dependence of the drift cell performance on shape and position of the cell electrodes as well as on the mechanical tolerances is shown. The results obtained for space-time relation and spatial resolution are in good agreement to test beam measurements on prototypes.

Measurements of cosmic rays in the L3 multisampling chambers are presented. The study of tracks with polar angles from 30° < θ < 130° w.r.t. the wires show increasing pulse height like 1/sin θ. Using inclined tracks, we find a ±1.5 cm region of reduced accuracy near the glass supports of the 5.4 m long wires.

The calculation of physics parameters of semiconductor compounds is of great interest in order to evaluate their potential use in a wide class of optoelectronics devices. Different methods have been developed for these calculations, based on the Hartree-Fock Hamiltonian and on the Density Functional ones. Here, a theoretical study by using Crystal 06 software and ab initio Density Functional Theory and Hartree-Focks method with different basis functions was carried out in order to calculate the lattice energy and the energy gap of the MnGa$_2$Se$_4$ magnetic semiconductor compound. It is shown that it is possible to calculate physics parameters of MnGa$_2$Se$_4$ with the mentioned software but due to the multiple values reported in literature for the same parameter, it is not possible to determinate which of the bases used is more effective.

We have characterized a PET prototype based on monolithic scintillator detectors. The prototype has a modular design with 8 identical detector cassettes, each housing 4 monolithic blocks. The cassettes are mounted on a gantry in 2 groups of 4 cassettes facing each other, totaling 32 detectors. Each detector block is composed of a trapezoidal LYSO:Ce scintillator glued to a pair of Hamamatsu S8550-02 APD matrices, which are read out by dedicated VATA 241 ASICs from Gamma Medica Ideas. The ASIC collects and amplifies the charge pulses from the 64 photosensors in each detector block, sums them into 8 rows and 8 column outputs and generates a trigger signal whenever the charge in a channel is above a user-defined threshold. Positioning algorithms based on supervised training neural networks are used for the detector blocks. A rotating platform with precise movement control is aligned with the system axis allowing acquisition of coincidence data along different projection angles. Using this system, Na22 point sources and a NEMA NU4-2008 image quality phantom filled with F18-FDG have been imaged and the images obtained have been characterized and compared with those from a Sedecal Argus PET/CT small-animal scanner, used as reference. Results show that the data acquisition system performs according to specifications and that PET imaging based on a large number of monolithic detector blocks is an alternative to designs based on segmented detectors.

This paper describes a new software tool developed for designing and characterizing CdZnTe γ-ray detectors. The tool includes three major components. The Geant4 toolkit is used for simulating gamma ray interactions and charge generation in the detector. A standard software package (ANSYS) is used for electrostatic field calculation inside the detector. The output of both codes is used as input in a custom developed charge transport simulation code. Drift and diffusion processes are simulated by solving Fokker-Planck equations, a method formally equivalent to the drift-diffusion equations of the carriers in the detector. Together, the three software packages allow to investigate time and spectrometric detector features. Therefore we can optimize the detector design for each specific application. The code has been validated by comparing simulation results with spectrum and waveforms measured from real detectors.

A time projection chamber, usually applied to high energy physics, was designed to accurately detect 511 keV gammas in coincidence, using liquefied Xenon as active media. The possibility of having 3D location of the interaction points, and its relatively large active volume make this detector a candidate for a PET scanner, with high energy resolution and high detection efficiency expectations. Its behavior was simulated using Monte Carlo methods with GAMOS software -a GEANT4 based framework-, including its geometry, materials, shielding and the main parameters expected of the system. The simulated device was tested using protocols based on the recommendations of NEMA standards for PET scanners, in the matter of spatial resolution, sensitivity, scatter fraction, count losses and random coincidence studies. The results show good overall behavior, as well as certain design flaws that can be compensated. This work presents the complete results of the NEMA characterization.

Transport studies require, as a preliminary step, conducting a survey process to a sample of the universe of users of the transportation system. The statistical reliability of the data determines the goodness of the results and conclusions that can be inferred from the analyses and models generated. In this communication a methodology, based on the techniques of bootstrapping, to the robust statistical estimation of freight transport matrices is presented; this allows to generate the confidence intervals of travel between origin-destination (OD) pairs defined by each cell of the OD matrix derived from a freight transport survey. The techniques of bootstrapping originated in the 70's, although widely used during the 90's, have not been fully exploited in the field of freight transport studies. To address this study a data set from a statistically reliable freight transport study conducted in Spain at the level of multi-province regions has been used.

Ga is one of the non-conventional nuclides that are being used in preclinical imaging. One disadvantage of 68 Ga versus 18 F is its larger positron range, which deteriorates the effective spatial resolution and the overall image quality. In this work we present a performance evaluation of the ARGUS small- animal positron emission tomography (PET) scanner for two positron emitters, 68 Ga and 18 F. These experiments followed the procedure based on the National Electrical Manufacturers Association (NEMA) NU 4-2008 standard. We show how the use of 68 Ga may affect the NEMA performance of the system in terms of image quality and spatial resolution. The recovery coefficients (RC) measured in the image-quality phantom ranged from 0.17 to 0.72 for 68 Ga and from 0.28 to 0.92 for 18 F, using iterative image reconstruction methods and applying all corrections. Under the same conditions the image noise (%STD) in a uniform region was 17.0% for 68 Ga and 15.1% for 18 F. The respective spillover ratios (SOR) were 0.13 and 0.09 in air, and 0.21 and 0.12 in water. Attenuation correction yielded an improvement of the SOR close to 50% for both radionuclides in the air-filled region. This work evaluates the image reconstruction methods and corrections available in the ARGUS PET for 68 Ga and 18 F to assess the influence of their physical properties on the NEMA parameters.

Light emitted in radiation detection by an argon-methane proportional counter has been studied by the delayed coincidence method. The experiment yields the light pulse shape in a time range up to 12 μsec. The time between photoelectric satellite pulses that arose at sufficiently large tensions was 820 ± 20 nsec for 2.7 kV applied voltage. The total light emitted during the discharge was found to be proportional to the detector gain.

The dynamics of the positive ions created by particle interactions inside argon time projection chambers plays an important role in characterizing the next generation of massive detectors planned for the direct search for dark matter and the study of neutrino properties. We have constructed a 1 L liquid argon chamber (ARION: ARgon ION experiment) with a high voltage pulse generator capable of injecting, in a controlled manner, a sizeable ion current into the drift region. This chamber is capable of reproducing a volume charge similar to that found in large detectors, allowing its effects to be studied systematically. New experimental results regarding ion dynamics in the liquid and direct demonstration of ion feedback from the gas to the liquid are discussed in this paper. In addition, a novel technique to measure the drift velocity of argon ions is introduced along with preliminary results obtained in gas.

Some of the main neutrino oscillation and dark matter experiments have chosen time projection chambers (TPC) filled with liquid argon (LAr) as their technology for the next generation of detectors. Because of its typical drift length of several meters, relatively large cathode voltages are desirable to provide a sizeable drift field. Current designs are based on feedthroughs with high voltages (HV) limited to several hundred kV. The present work proposes a novel method to produce higher voltages inside the detector. It is based on a Van de Graaff HV generator where the charge transporting belt is replaced by a cryogenic LAr flow. Negative charge is injected in liquid by means of a grounded sharp point facing a positive voltage electrode with a high speed LAr stream in between. The LAr flow transports the charge to the cathode through an electrically insulating pipe. In the cathode the charge is extracted with a metallic mesh. The LAr flux is driven by a cryogenic helium pump with unidirectional valves assuring a continuous flow. The LAr operational temperature is maintained by a pressurized liquid nitrogen deposit with automatic filling. The whole system is installed within a dewar container that will be filled with LAr reproducing the typical TPC conditions. This design has no mobile parts, so it is very robust and can be easily embedded within the structural support of a TPC cathode. A prototype of this HV generator has been constructed at CIEMAT (Madrid), and is currently being characterized. This R&D is presented and the preliminary results are discussed.