M. Meschini

The characteristics of the L3 hadron calorimeter as realized in the observation of hadronic jets and other events from e+e− collisions at LEP are presented and discussed. The pattern-recognition algorithm utilizing the fine granulatiry of the calorimeter is described, and the observed overall resolution of 10.2% for hadron jets from Z decay is reported. The use of the calorimeter in providing information on muon energy losses is also noted.

This paper covers the main technological and design aspects relevant to the development of a new generation of thin 3D pixel sensors with small pixel size aimed at the High-Luminosity LHC upgrades.

3D pixel sensors aimed at the upgrades of the ATLAS and CMS experiments at the High Luminosity LHC have small pixel size and pretty dense layouts. In addition, modified 3D designs with small pixel size and trenched electrodes in place of columnar electrodes are being developed to optimize the pixel timing performance in view of the LHCb upgrade. The fabrication of these advanced 3D pixels is challenging from the lithographical point of view. This motivated the use of stepper lithography at Fondazione Bruno Kessler in place of a standard mask aligner. The small minimum feature size and high alignment accuracy of stepper allow a good definition of the sensor geometries also in the most critical layouts, so that a higher fabrication yield can be obtained. In this paper, we will present the main design and technological issues and discuss their impact on the electrical characteristics of 3D pixel sensors of different geometries.

A new development of Plastic Streamer Tubes is obtained making use of the electrodeless drift chamber idea, This leads to a simplified construction, while performance remains practically unaffected. There are no relevant limitations on operating conditions.

We report on the 3-year INFN ATLAS–CMS joint research activity in collaboration with FBK, started in 2014, and aimed at the development of new thin pixel detectors for the High Luminosity LHC Phase-2 upgrades. The program is concerned with both 3D and planar active-edge pixel sensors to be made on 6" p-type wafers. The technology and the design will be optimized and qualified for extreme radiation hardness (2×1016 neq cm−2). Pixel layouts compatible with present (for testing) and future (RD53 65 nm) front-end chips of ATLAS and CMS are considered. The paper covers the main aspects of the research program, from the sensor design and fabrication technology, to the results of initial tests performed on the first prototypes.

Results of an extensive R&D program aiming at radiation hard, small pitch, 3D pixel sensors are reported. The CMS experiment is supporting this R&D in the scope of the Inner Tracker upgrade for the High Luminosity phase of the CERN Large Hadron Collider (HL-LHC). In the HL-LHC the Inner Tracker will have to withstand an integrated fluence up to 2.3×1016neq/cm2. A small number of 3D sensors were interconnected with the RD53A readout chip, which is the first prototype of 65 nm CMOS pixel readout chip designed for the HL-LHC pixel trackers. In this paper results obtained in beam tests before and after irradiation are reported. The irradiation of a single chip module was performed up to a maximum equivalent fluence of about 1×1016neq/cm2. The analysis of the collected data shows excellent performance: the spatial resolution in not irradiated sensors can reach about 3 to 5 μm, for inclined tracks, depending on the pixel pitch. The measured hit detection efficiencies are close to 99% measured both before and after the above mentioned irradiation fluence.

Interstrip and backplane capacitances on silicon microstrip detectors with p+ strip on n substrate of 320μm thickness were measured for pitches between 60 and 240μm and width over pitch ratios between 0.13 and 0.5. Parametrisations of capacitance w.r.t. pitch and width were compared with data. The detectors were measured before and after being irradiated to a fluence of 4×1014protons/cm2 of 24GeV/c momentum. The effect of the crystal orientation of the silicon has been found to have a relevant influence on the surface radiation damage, favouring the choice of a 〈100〉 substrate. Working at high bias (up to 500 V in CMS) might be critical for the stability of detector, for a small width over pitch ratio. The influence of having a metal strip larger than the p+ implant has been studied and found to enhance the stability.

A Higgs particle produced in association with a Z boson and decaying into two photons is searched for in the data collected by the L3 experiment at LEP. All possible decay modes of the Z boson are investigated. No signal is observed in 447.5 pb^-1 of data recorded at centre-of-mass energies up to 209 GeV. Limits on the branching fraction of the Higgs boson decay into two photons as a function of the Higgs mass are derived. A lower limit on the mass of a fermiophobic Higgs boson is set at 105.4 GeV at 95% confidence level.

3D type of pixel sensors is a promising option for the innermost pixel layer at the High-Luminosity LHC. However, the required very high hit-rate capabilities, finer pixel granularity, extreme radiation hardness and reduced material budget call for a downscale of the pixel size as compared to existing 3D sensors, involving smaller pitch (e.g. 50 × 50 or 25×100μm2), shorter inter-electrode spacing (∼30μm), narrower electrodes (∼6μm diameter), and reduced active thickness (∼100–150μm). Within a joint R&D effort with INFN, FBK has produced a new generation of 3D pixel sensors with these challenging features. In this talk preliminary results from the electrical and functional characterisation of the first prototypes are reported, included their behaviour after large radiation fluence, close to the ones expected in the High Luminosity LHC environment. Prospects for the next prototypes are also presented.

Test beam results obtained with 3D pixel sensors bump-bonded to the RD53A prototype readout ASIC are reported. Sensors from FBK Italy and IMB-CNM (Spain) have been tested before and after proton-irradiation to an equivalent fluence of about 1 × 1016 ≠cm-2 (1 MeV equivalent neutrons). This is the first time that one single collecting electrode fine pitch 3D sensors are irradiated up to such fluence bump-bonded to a fine pitch ASIC. The preliminary analysis of the collected data shows no degradation on the hit detection efficiencies of the tested sensors after high energy proton irradiation, demonstrating the excellent radiation tolerance of the 3D pixel sensors. Thus, they will be excellent candidates for the extreme radiation environment at the innermost layers of the HL-LHC experiments.

We report on measurements of mass and total decay width of the W boson and of triple-gauge-boson couplings, γWW and ZWW, with the L3 detector at LEP. W-pair events produced in e+e− interactions between 161 GeV and 172GeV centre-of-mass energy are selected in a data sample corresponding to a total luminosity of 21.2 pb−1. The mass and total decay width of the W boson are determined to be MW = 80.75−0.27+0.26(exp.) ± 0.03 (LEP) GeV and ΓW = 1.74−0.78+0.88(stat.) ± 0.25(syst.)GeV, respectively. Limits on anomalous triple-gauge-boson couplings, γWW and ZWW, are determined, in particular −1.5 < δZ < 1.9 (95% CL), excluding vanishing ZWW coupling at more than 95% confidence level.

Abstract Making use of electrons extracted by UV photons on aluminum cathodes, the ionization threshold of the streamer mode has been measured, and a fully efficient operation range for single ionization electrons has been found. Operation conditions have been investigated for Ar-isobutane and He-isobutane gas mixtures, and 50 and 100 μm wire diameters.

Results obtained with 3D columnar pixel sensors bump-bonded to the RD53A prototype readout chip are reported. The interconnected modules have been tested in a hadron beam before and after irradiation to a fluence of about 1×1016 neq cm−2 (1 MeV equivalent neutrons). All presented results are part of the CMS R&D activities in view of the pixel detector upgrade for the High Luminosity phase of the LHC at CERN (HL-LHC) . A preliminary analysis of the collected data shows hit detection efficiencies around 97% measured after proton irradiation.

We report on the ATLAS and CMS joint research activity, which is aiming at the development of new, thin silicon pixel detectors for the Large Hadron Collider Phase-2 detector upgrades. This R&D is performed under special agreement between Istituto Nazionale di Fisica Nucleare and FBK foundation (Trento, Italy). New generations of 3D and planar pixel sensors with active edges are being developed in the R&D project, and will be fabricated at FBK. A first planar pixel batch, which was produced by the end of year 2014, will be described in this paper. First clean room measurement results on planar sensors obtained before and after neutron irradiation will be presented.

Due to the large expected instantaneous luminosity, the future HL-LHC upgrade sets strong requirements on the radiation hardness of the CMS detector Inner Tracker. Sensors based on 3D pixel technology, with its superior radiation tolerance, comply with these extreme conditions. A full study and characterization of pixelated 3D sensors fabricated by FBK is presented here. The sensors were bump-bonded to RD53A readout chips and measured at several CERN SPS test beams. Results on charge collection and efficiency, for both non-irradiated and irradiated up to 1016 neq/cm2 samples, are presented. Two main studies are described: in the first the behaviour of the sensor is qualified as a function of irradiation, while kept under identical conditions; in the second the response is measured under typical operating conditions.

We report the results of two beam tests performed in July and September 1995 at CERN using silicon microstrip detectors of various types: single sided, double sided with small angle stereo strips, double sided with orthogonal strips, double sided with pads. For the read-out electronics use was made of Preshape32, Premux128 and VA1 chips. The signal to noise ratio and the resolution of the detectors was studied for different incident angles of the incoming particles and for different values of the detector bias voltage. The goal of these tests was to check and improve the performances of the prototypes for the CMS Central Detector.

We have measured the probability, n(g->cc~), of a gluon splitting into a charm-quark pair using 1.7 million hadronic Z decays collected by the L3 detector. Two independent methods have been applied to events with a three-jet topology. One method relies on tagging charmed hadrons by identifying a lepton in the lowest energy jet. The other method uses a neural network based on global event shape parameters. Combining both methods, we measure n(g->cc~)= [2.45 +/- 0.29 +/- 0.53]%.

The High Luminosity upgrade of the CERN Large Hadron Collider (HL-LHC) calls for new high radiation-tolerant solid-state pixel sensors, capable of surviving irradiation fluences up to a few 1016 neq/cm2 at ∼3 cm from the interaction point. The INFN ATLAS-CMS joint research activity, in collaboration with Fondazione Bruno Kessler, is aiming at the development of thin n+ on p type pixel sensors to be operated at the HL-LHC. The R&D covers both planar and 3D pixel devices made on substrates obtained by the Direct Wafer Bonding technique. The active thickness of the planar sensors studied in this paper is 100μm or 130μm, that of 3D sensors 130μm. First prototypes of hybrid modules, bump-bonded to the present CMS readout chips (PSI46 digital), have been characterized in beam tests. First results on their performance before and after irradiation up to a maximum fluence of ∼5×1015 neq/cm2 are reported in this article.

The experiments at the planned 14 TeV proton-proton collider LHC will need a good identification and measurement of muons with energies of up to about 800 GeV. The production of electromagnetic secondaries by muons of energy from 10 to 300 GeV has been measured at the RD5 experiment at CERN using various detector types proposed for LHC experiments. It is demonstrated that the detectors can recognize the presence of individual hits from em secondaries, and that the muon measurement would be seriously compromised if these hits are not suppressed.

Abstract The parallel plate chamber technique is summarized together with recent results of tests concerning efficiency, time resolution, high rate capability and radiation resistance.

We present results obtained with full-size wedge silicon microstrip detectors bonded to APV6 (Raymond et al., Proceedings of the 3rd Workshop on Electronics for LHC Experiments, CERN/LHCC/97-60) readout chips. We used two identical modules, each consisting of two crystals bonded together. One module was irradiated with 1.7×1014neutrons/cm2. The detectors have been characterized both in the laboratory and by exposing them to a beam of minimum ionizing particles. The results obtained are a good starting point for the evaluation of the performance of the “ensemble” detector plus readout chip in a version very similar to the final production one. We detected the signal from minimum ionizing particles with a signal-to-noise ratio ranging from 9.3 for the irradiated detector up to 20.5 for the non-irradiated detector, provided the parameters of the readout chips are carefully tuned.

3D sensors are a promising option for the innermost pixel layers at the High Luminosity LHC.However, the required very high hit-rate capabilities, increased pixel granularity, extreme radiation hardness, and reduced material budget call for a device downscale as compared to existing 3D sensors, involving smaller pitch (e.g., 50×50 or 25×100 µm 2 ), shorter inter-electrode spacing (~30 µm), narrower electrodes (~5 µm), and reduced active thickness (~100 µm).The development of a new generation of 3D pixel sensors with these challenging features is under way by many research groups, in collaboration with processing facilities like FBK, CNM, and SINTEF.This paper talk will review the lessons learned from existing 3D detectors, and will address the main design and technological issues for small pitch 3D devices.Preliminary results from the electrical and functional characterization of the first prototypes will be reported and compared to TCAD simulations.

Among the several existent proposals for the cosmic antimatter search, the Wi#x005A-0304;ard project for the U.S. Space Station Freedom shows the greatest interest. A possible upgrading of the Wi#x005A-0304;ard apparatus, called Wi#x005A-0304;ard 2, is presented in order to sensibly improve the capability of detecting antihelium nuclei in the cosmic radiation.

The luminosity of the Large Hadron Collider (LHC) at CERN will be upgraded to 7.5 × 10 34 cm -1 s -2 .The increased luminosity leads to an increased particle fluence and ionizing dose in the detectors.The tracking detectors of the CMS experiment will be upgraded in order to cope with the new operating conditions.Prototype hybrid pixels sensors for the CMS Inner Tracker upgrade with rectangular 100 µm × 25 µm pixels produced by three different manufacturers and readout by the RD53A chip were characterized before and after irradiation to fluences up to Φ eq = 2.0 × 10 16 cm -2 .The characterization results presented in this paper demonstrate that all sensors meet the requirements for operation at the high-luminosity LHC.

This paper describes the main achievements in the development of radiation resistant silicon detectors to be used in the CMS tracker. After a general description of the basic requirements for the operation of large semiconductor systems in the LHC environment, the issue of radiation resistance is discussed in detail. Advantages and disadvantages of the different technological options are presented for comparison. Laboratory measurements and test beam data are used to check the performance of several series of prototypes fabricated by different companies. The expected performance of the final detector modules are presented together with preliminary test beam results on system prototypes.

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.

To cope with the harsh environment foreseen at the high luminosity conditions of HL- LHC, the ATLAS pixel detector has to be upgraded to be fully efficient with a good granularity, a maximized geometrical acceptance and an high read out rate. LPNHE, FBK and INFN are involved in the development of thin and edgeless planar pixel sensors in which the insensitive area at the border of the sensor is minimized thanks to the active edge technology. In this paper we report on two productions, a first one consisting of 200 {\mu}m thick n-on-p sensors with active edge, a second one composed of 100 and 130 {\mu}m thick n-on-p sensors. Those sensors have been tested on beam, both at CERN-SPS and at DESY and their performance before and after irradiation will be presented.

One “wedge” Double Sided Silicon Detector prototype for the CMS forward inner tracker has been tested both in laboratory and on a high energy particle beam. The results obtained indicate the most reliable solutions for the strips geometry of the junction side. Three different designs of “wedge” Double Sided detectors with different solutions for the ohmic side strip geometry are presented.

Following initial work done by some of us on the readout of the L3 silicon microvertex detector, we have developed a complete data acquisition system for silicon microstrip detectors for use both in our home institute and at the various test beam facilities at the CERN laboratory. The system uses extensive decoupling schemes allowing a fully floating connection to the detector. This feature has many advantages especially in the readout of the latest double-sided silicon microstrip detectors.

The tracking detector of ATLAS, one of the experiments at the Large Hadron Collider (LHC), will be upgraded in 2024–2026 to cope with the challenging environment conditions of the High Luminosity LHC (HL-LHC). The LPNHE, in collaboration with FBK and INFN, has produced 130μm thick n−on−p silicon pixel sensors which can withstand the expected large particle fluences at HL-LHC, while delivering data at high rate with excellent hit efficiency. Such sensors were tested in beam before and after irradiation both at CERN-SPS and at DESY, and their performance are presented in this paper. Beam test data indicate that these detectors are suited for all the layers where planar sensors are foreseen in the future ATLAS tracker: hit-efficiency is greater than 97% for fluences of Φ≲7×1015neq∕cm2 and module power consumption is within the specified limits. Moreover, at a fluence of Φ=1.3×1016neq∕cm2, hit-efficiency is still as high as 88% and charge collection efficiency is about 30%.

The High Luminosity upgrade of the CERN Large Hadron Collider (HL–LHC) calls for an upgrade of the CMS tracker detector to cope with the increased radiation levels while maintaining the excellent performance of the existing detector. Specifically, new high-radiation tolerant solid-state pixel sensors, capable of surviving irradiation fluences up to 1.9×1016neq/cm2 at 3 cm from the interaction point, need to be developed. For this purpose an R&D program involving different vendors have been pursued, aiming at the development of thin n-in-p type pixel sensors. The R&D covers both planar (manufactured by Fondazione Bruno Kessler, FBK; Hamamatsu Photonics, HPK and LFoundry) and single-sided 3D columnar (manufactured by FBK and Centro Nacional de Microelectronica, CNM) pixel devices. The target active thickness is 150μm while two different pixel cell dimensions are currently investigated (25 × 100 and 50×50μm2). Sensors presented in this article have been bump-bonded to the RD53A readout chip (ROC), the first prototype towards the development of a ROC to be employed during HL–LHC operation. Test beam studies, both of thin planar and 3D devices, have been performed by the CMS collaboration at the CERN, DESY and Fermilab test beam facilities. Results of modules performance before and after irradiation (up to 2.4×1016neq/cm2) are presented in this article.

The CMS experiment at the LHC will comprise a large silicon strip tracker. This article highlights some of the results obtained in the R&D studies for the optimization of its silicon sensors. Measurements of the capacitances and of the high voltage stability of the devices are presented before and after irradiation to the dose expected after the full lifetime of the tracker.

This paper describes the proton irradiation campaign, performed at the INFN “Laboratori Nazionali del Sud” (LNS), on a silicon microstrip detector. The irradiated module is identical to the ones which are used to assemble the tracker inner barrel of the CMS experiment at the CERN Large Hadron Collider (LHC). The aim of the test was to verify the radiation resistance of the detector module to the LHC environment by checking its behavior with increasing fluence.

In this paper we present a Monte Carlo study of a calorimeter response for an experiment to equip the magnetic facility of the USA space station. Main purpose in the design of such a calorimeter is the efficient discrimination between eloctromagnetic and hadronic showers. The estimated rejection power results to be better than 1·10−3 p/e+ for incident particles with energy between 10 GeV and 100GeV.

Tracker Inner Barrel half-cylinders and Tracker Inner Disks of the CMS tracker have been integrated in three INFN sites. Integrated structures are submitted to an extensive set of tests whose main aim is to validate the functioning of the structures in CMS-like conditions. The tests have furthermore proven to be a great opportunity to study several aspects of the performance in detail. In this note the tests are described in some detail and an overview of the results is presented.

This paper reports on the INFN (Istituto Nazionale di Fisica Nucleare, Italy) research activity in collaboration with FBK foundry, which is aiming at the development of new pixel detectors for the LHC Phase-2 upgrades. The R&D covers both planar pixel devices and 3D detectors built using columnar technology. All sensors are low thickness n-in-p type, as this is the general direction envisaged for the High Luminosity LHC pixel detector upgrades. Hybrid modules with 100 $$\upmu $$ m and 130 $$\upmu $$ m active thickness, connected to the PSI46dig readout chip, have been tested on beam test experiments. Selected preliminary results from test beams are described for both planar and 3D devices. The results on the 3D pixel sensors before irradiation are very satisfactory and support the conclusion that columnar devices are very good candidates for the inner layers of the upgrade pixel detectors.

This paper describes the development of new 3D and planar silicon pixel sensors designed for the Compact Muon Solenoid (CMS) Phase-2 Upgrade at High Luminosity LHC (HL-LHC).The project is funded by INFN and sensors are produced in collaboration with the FBK foundry.The HL-LHC will operate at an instantaneous luminosity approximately 5 times larger than the original LHC design, significantly increasing the number of concurrent collisions per bunch crossing, the integrated luminosity delivered to the experiments and, as a consequence, the radiation dose that the detectors will have to sustain.In order to cope with these future conditions, upgrades to the detectors are required.This is necessary for the pixel tracker that is the closest to the interaction point and will be replaced.In this paper, the results, from beam tests performed at Fermilab Test Beam Facility, of thin (100 µm and 130 µm thick) n-in-p type sensors, assembled into hybrid single chip modules bump bonded to the PSI46dig readout chip, will be presented.A comparison of the performances obtained with planar sensors before and after proton irradiation up to 3 × 10 15 n eq /cm 2 will be also discussed.The paper will also report the results obtained with the first 3D pixel sensors 130 µm thick with columnar electrodes for different pixel cell prototypes.The novelty of the 3D prototypes is their small pixel cell size, ranging form the standard 100 µm × 150 µm, down to 50 µm × 50 µm and 25 µm × 100 µm, which are the preferred dimensions in the high pile-up environment of the HL-LHC.

A prototype of the barrel Tracking Detector of the Compact Muon Solenoid (CMS) experiment proposed for LHC was built and tested in a beam and in a magnetic field of up to 3 T. It contained six microstrip gas chambers, 25 cm long, and three double-sided silicon microstrip detectors, 12.5 cm long. We report some preliminary results on the performance of the chambers.

The High Luminosity upgrade of the CERN Large Hadron Collider (HL-LHC) calls for new highly radiation tolerant silicon pixel sensors, capable of withstanding fluences up to 2.3 × 1016 neq/cm2 (1 MeV equivalent neutrons). In this paper results obtained in beam test experiments with 3D and planar pixel sensors interconnected with the RD53A readout chip are reported. RD53A is the first prototype in 65 nm technology issued by the RD53 collaboration for the future readout chip to be used in the upgraded pixel detectors. The interconnected modules have been tested in an electron beam at DESY, before and after irradiation, which was performed at the CERN IRRAD facility for the 3D sensors or at the KIT Irradiation Center for the planar sensors, up to an equivalent fluence of 1 × 1016 neq/cm2. The sensors were made by FBK foundry in Trento, Italy, and their development was done in collaboration with INFN (Istituto Nazionale di Fisica Nucleare, Italy). The analysis of the collected data shows hit detection efficiencies around 99% measured after irradiation. All results are obtained in the framework of the CMS R&D activities.

The CMS Silicon tracker consists of 70m2 of microstrip sensors which design will be finalized at the end of 1999 on the basis of systematic studies of device characteristics as function of the most important parameters. A fundamental constraint comes from the fact that the detector has to be operated in a very hostile radiation environment with full efficiency. We present an overview of the current results and prospects for converging on a final set of parameters for the silicon tracker sensors.

Abstract Radiation effects on silicon microstrip detectors have been investigated on sensors similar to the ones that will be installed in the forward tracker of CMS. Sensors have been built starting from a high resistivity (about 6 kΩ cm ) n-type substrate, 〈1 1 1〉 crystal lattice orientation. Some of the wafers have been exposed to a neutron beam with a 1 MeV equivalent neutron fluence of 1.1×10 14 neutron / cm 2 . Depletion voltage, reverse current, bulk and interstrip capacitance have been measured in laboratory before and after irradiation, directly on the full size structures. Detectors built with these structures have then been tested with a 90 Sr source in laboratory. Device properties and performances with respect to signal to noise ratio are presented, emphasizing their dependence on irradiation.

An iron/gas parallel plate volume calorimeter prototype, working in the avalanche mode, has been tested using electrons of 20 to 150 GeV/c momentum with high voltages varying from 5400 to 5600 V (electric fields ranging from 36.0 to 37.3 kV/ cm), and a gas mixture of CF4/ CO2 (80%/20%). The collected charge has been measured as a function of the high voltage and of the electron energy. The energy resolution has also been measured. Comparisons have been made with Monte Carlo predictions. Agreement between data and simulation allows the calculation of the expected performance of a full size calorimeter.

For the construction of the silicon microstrip detectors for the Tracker of the CMS experiment, two different substrate choices were investigated: A high-resistivity (6 k cm) substrate with (111) crystalorientation and a low-resistivity (2k cm) one with (100) crystalorientation. The interstrip and backplane capacitances were measured before and after the exposure to radiation in a range of strip pitches from 60 μm to 240 μm and for values of the width-over-pitch ratio between 0.1 and 0.5.

The radiation hardness of silicon microstrip detectors has been investigated on full-size prototypes similar to the ones that will be installed in the forward tracker of CMS, where a very intense radiation environment is envisaged. Silicon detectors were exposed to a neutron beam with 3 different fluences up to 2.4 × 1014 neutrons/cm2, more than those foreseen at LHC after 10 years of operation. Degradation effects of the device properties regarding reverse current, depletion voltage, bulk and interstrip capacitance has been measured in laboratory as function of bias voltage, temperature and neutron fluence.

Abstract A large quantity of silicon microstrip detectors is foreseen to be used as part of the CMS tracker. A specific research and development program has been carried out with the aim of defining layouts and technological solutions suitable for the use of silicon detectors in high radiation environment. Results presented here summarise this work on many research areas such as techniques for device manufacturing, pre- and post-irradiation electrical characterization, silicon bulk defects analysis and simulations, system performance analytical calculations and simulations and test beam analysis. As a result of this work we have chosen to use single-sided, AC-coupled, poly silicon biased, 300 μm thick, p + on n substrate detectors. We feel confident that these devices will match the required performances for the CMS tracker provided they can be operated at bias voltages as high as 500 V. Such high-voltage devices have been succesfully manufactured and we are now concentrating our efforts in enhancing yield and reliability.

The breakdown performance of CMS barrelmodule prototype detectors and test devices with single and multi-guard structures were studied before and after neutron irradiation up to 2·1014 1 MeV equivalent neutrons. Before irradiation avalanche breakdown occurred at the guard ring implant edges. We measured 100–300 V higher breakdown voltage values for the devices with multi-guard than for devices with single-guard ring. After irradiation and type inversion the breakdown was smoother than before irradiation and the breakdown voltage value increased to 500–600 V for most of the devices.

Ceramic parallel plate chambers were irradiated with gamma rays and neutrons. Results on radiation resistance are presented after 60 Mrad gamma and 0.5 × 1016 neutrons per cm2 irradiation of the detector surface. Results of activation analysis of chambers made of two different ceramic materials are also presented.

The baseline option for the very forward calorimetry in the CMS experiment is an iron/gas calorimeter based on parallel plate chambers. A small prototype module of such a calorimeter, has been tested using electrons of 5 to 100 GeV/c momentum with various high voltages and two gases: CO2 (100%) and CF4CO2 (8020), at atmospheric pressure. The collected charge has been measured as a function of the high voltage and of the electron energy. The energy resolution has also been measured. Comparisons have been made with Monte-Carlo predictions. Agreement between data and simulation allows to make an estimation of the expected performance of a full size calorimeter.

The decision taken by the CMS experiment to build a tracker entirely based on silicon detectors has made necessary the use of thicker sensors instead of the usual 300-/spl mu/m sensors for the outer part of the detector. We first present results on the performance of 500-/spl mu/m-thick detectors, before and after neutron irradiation, bonded to the CMS tracker front-end electronics. Laboratory measurements show that the total collected charge scales linearly with thickness when compared with a 300-/spl mu/m module, and the measured noise is in good agreement with expectations. The results obtained confirm the feasibility of large-area silicon trackers.

Abstract The CMS experiment at the CERN Large Hadron Collider has collected data during year 2011 for an integrated luminosity exceeding 5 fb−1 at 7 TeV center of mass energy. The detector performed excellently, with very good data taking efficiency since the very beginning. The operational experience will be described, including the first part of 2012, focusing on some relevant technical aspects. New challenges dictated by the planned luminosity increase are ahead for CMS. A general overview of the upgrade plans to cope with increased luminosity scenarios will be given, including both medium and long term range.

This paper investigates the performance of 500μm thick silicon microstrip detectors before and after heavy irradiation. Prototype sensors, produced by STMicroelectronics, have been extensively studied using laboratory measurements, a radioactive source and a beam of minimum ionising particles. The comparison with a standard 300μm sensor shows that the collected charge in thick devices scales linearly with thickness. By over-depleting the irradiated devices, the pre-irradiated charge collection efficiency is fully recovered. The measured noise is in good agreement with expectations. Although more work is needed, the paper shows that 500μm thick devices are a promising technology for very large tracking systems.

This paper describes the Silicon microstrip Tracker of the CMS experiment at LHC. It consists of a barrel part with 5 layers and two endcaps with 10 disks each. About 10 000 single-sided equivalent modules have to be built, each one carrying two daisy-chained silicon detectors and their front-end electronics. Back-to-back modules are used to read-out the radial coordinate. The tracker will be operated in an environment kept at a temperature of T=−10°C to minimize the Si sensors radiation damage. Heavily irradiated detectors will be safely operated due to the high-voltage capability of the sensors. Full-size mechanical prototypes have been built to check the system aspects before starting the construction.

The High Luminosity upgrade of the CERN-LHC (HL-LHC) demands for a new high-radiation tolerant solid- state pixel sensor capable of surviving fluencies up to a few 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">16</sup> particles cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at ∼3 cm from the interaction point. To this extent the INFN ATLAS-CMS joint research activity, in collaboration with Fondazione Bruno Kessler, is aiming at the development of thin n-in-p type pixel sensors for the HL-LHC. The R & D covers both planar and single-sided 3D columnar pixel devices made with the Si-Si Direct Wafer Bonding technique, which allows for the production of sensors with 100µm and 130µm active thickness for planar sensors, and 130µm for 3D sensors, the thinnest ones ever produced so far. First prototypes of hybrid modules bump-bonded to the present CMS readout chips have been tested in beam tests. Preliminary results on their performance before and after irradiation are presented.

We demonstrate the feasibility of 10.7 Gb/s error-free (BER < 10 -12) optical transmission on distances up to 2 km using a recently developed ultra-low-voltage commercial Electro-Optic Modulator (EOM) that is driven by 0.6 Vpp and with an optical input power of 1 mW. Given this low voltage operation, the modulator could be driven directly from the detectors' board signals without the need of any further amplification reducing significantly the power dissipation and the material budget.

The inner portion of the CMS microstrip Tracker consists of 3540 silicon detector modules; its construction has been under full responsibility of seven INFN (Istituto Nazionale di Fisica Nucleare) and University laboratories in Italy. In this note procedures and strategies, which were developed and perfected to qualify the Tracker Inner Barrel and Inner Disks modules for installation, are described. In particular the tests required to select highly reliable detector modules are illustrated and a summary of the results from the full Inner Tracker module test is presented. 1) INFN sez. di Catania and Universita di Catania, Italy 2) INFN sez. di Perugia and Universita di Perugia, Italy 3) INFN sez. di Pisa and Scuola Normale Superiore di Pisa, Italy 4) INFN sez. di Pisa and Universita di Pisa, Italy 5) INFN sez. di Pisa, Italy 6) INFN sez. di Torino and Universita di Torino, Italy 7) INFN sez. di Torino, Italy 8) INFN sez. di Firenze, Italy 9) INFN sez. di Bari and Dipartimento Interateneo di Fisica di Bari, Italy 10) INFN sez. di Bari, Italy 11) INFN sez. di Padova, Italy 12) INFN sez. di Firenze and Universita di Firenze, Italy 13) INFN sez. di Padova and Universita di Padova, Italy 14) INFN sez. di Perugia, Italy a) On leave from ISS, Bucharest, Romania b) On leave from IFIN-HH, Bucharest, Romania c) Corresponding Author

The momentum and angular distributions of punchthrough muons have been measured after a 10 λ calorimeter using an iron toroid magnet with 1.5 T as spectrometer. The calorimeter was inside a variable magnetic field of 0 to 3 T. The incident momentum of the π− beam ranged from 20 to 300 GeV/c. Measurements were also done at some beam momenta for π+, K+ and p. The results are compared with Monte Carlo predictions. A parameterization for the momentum spectrum of punchthrough muons was derived from the data.

Abstract A prototype module of an iron/gas calorimeter based on parallel plate chambers, has been tested using high energy electrons and pions, at two high voltages, using CF 4 CO 2 ( 80 20 ) at atmospheric pressure. The collected charge and energy resolution have been measured as a function of the beam energy for both electrons and pions and compared with Monte Carlo predictions.

Abstract A large use of silicon microstrip detectors is foreseen for the intermediate part of the CMS tracker. A specific research and development program has been carried out with the aim of finding design layouts and technological solutions for allowing silicon microstrip detectors to be reliably used on a high radiation level environment. As a result of this work single sided, AC-coupled, polysilicon biased, 300 μ m thick, p + on n substrate detectors were chosen. Irradiation tests have been performed on prototypes up to fluence 2×10 14  n/cm 2 . The detector performances do not significantly change if the detectors are biased well above the depletion voltage. S / N is reduced by less than 20%, still enough to insure a good efficiency and space resolution. Multiguard structures has been developed in order to reach high voltage operation (above 500 V).

During the last few years a large number of silicon microstrip detectors has been especially designed and tested in order to study and optimize the performances of the tracking devices to be used in the forward–backward part of the CMS (Technical proposal, CERN/LHCC 94-38 LHCC/P1, 15 December 1994) experiment. Both single and double sided silicon detectors of a trapezoidal (“wedge”) shape and with different strip configurations, including prototypes produced with double metal technology, were characterized in the laboratory and tested using high-energy beams. Furthermore, due to the high-radiation environment where the detectors should operate, particular care was devoted to the study of the characteristics of heavily irradiated detectors. The main results of detector performances (charge response, signal to noise ratio, spatial resolution etc.) will be reviewed and discussed.

We report the results of test beams performed at CERN using irradiated microstrip silicon detectors. The detectors were single- and double-sided devices, produced by different manufacturers and irradiated with neutrons at various fluences up to 3.6 × 1013 n/cm2. Signal-to-noise ratio, resolution and efficiency were studied for different values of the incidence angle, of the detector temperature and of the read-out pitch, as a function of the detector bias voltage. The goal of these tests was to optimize the design of the final prototypes for the CMS Silicon Strip Tracker.

In view of the LHC upgrade for the High Luminosity phase (HL-LHC), the ATLAS experiment plans to replace the Inner Detector with an all-silicon system. The n-on-p silicon technology is a promising candidate to achieve a large area instrumented with pixel sensors, since it is radiation hard and cost effective. The paper reports on the performance of thin 100 and 130μm n-in-p planar pixel sensors produced by FBK-CMM with active-edge technology in collaboration with LPNHE and INFN. Beam-test results are presented, with focus on the hit efficiency at the detector edge of a novel design consisting of a staggered deep trench.

The High Luminosity upgrade of the CERN LHC collider (HL-LHC) demands for a new, highradiation tolerant solid-state pixel sensor capable of surviving fluencies up to a few 10 16 n eq /cm 2 at ∼ 3 cm from the interaction point.To this extent the INFN ATLAS-CMS joint research activity, in collaboration with Fondazione Bruno Kessler (FBK), is aiming at the development of thin n-in-p type pixel sensors for the HL-LHC.The R&D covers both planar and single-sided 3D columnar pixel devices made with the Si-Si Direct Wafer Bonding technique, which allows for the production of sensors with 100 µm and 130 µm active thickness for planar sensors, and 130 µm for 3D sensors, the thinnest ones ever produced so far.Prototypes of hybrid modules, bumpbonded to the RD53A readout chip, have been tested on beam.First results on their performance before and after irradiation are presented.

A two-coil toroid magnet is proposed for the ASTROMAG facility on the NASA space station. This field fulfils the requirement of zero net dipole moment and the magnet is designed to fit the boundary conditions connected with the use in space. In this paper the magnetic field of the twocoil toroid for the ASTROMAG facility is discussed and compared with that of an equivalent ideal continuous toroid. The volumes of the magnetic field regions are equal for these two extreme cases of toroid, in spite of the deformed shape in case of the two-coil design.

In this article we describe the outer part (Muon Filter) of the Hadron Calorimeter of the L3 detector. Construction and performance of the brass chambers, which form the sensitive part of the detector, are reviewed. We also report the results from data taken on two beam tests, at CERN.

We are developing a new generation of 3D pixel sensors, based on columnar electrodes and trenched electrodes, and aimed at the upgrades of the major detector experiments at the High Luminosity LHC. These 3D sensors have small pixel size with downscaled geometries, and their layout is much denser than in previous devices, that is a challenge for lithography equipment. Mask aligners are not favored to be used in these conditions, so we have started to use stepper lithography, which yields a much smaller minimum feature size and higher alignment accuracy. We report on the initial results obtained from the first stepper batches, which confirm the feasibility of advanced 3D sensors with a good fabrication yield.

Dopo che, tra il luglio e l’agosto del 1209, la crociata «albigese » voluta da Innocenzo III ebbe conquistato Béziers e Carcassonne, la viscontea Trencavel venne assegnata a Simone di Montfort. L’autore indaga le ragioni che indussero i legati pontifici a scegliere il Montfort per proseguire la lotta in Linguadoca ; le risorse e le condizioni di svolgimento di quell’esperienza politico-militare ; la fine dei Trencavel ; le previsioni, i tentativi di apertura verso il Midi e alcuni errori da parte dei comandanti della crociata, con particolare ma non esclusivo riferimento ai primi tempi della nuova dominazione. Ne risulta una più complessa e «causale » lettura di quegli eventi, contro quella «casualistica » oggi più diffusa. Infine, sulla scorta di questo tipo di analisi, vengono poste alcune questioni che si ritengono ancora aperte e valide per tutto il periodo della crociata «albigese » .

In this work, we have exploited the possibility of swapping the functionalities of the two stages of fast frontend electronics based on the usual preamplifier and shaper structure. Measurements on a prototype of the CMS frontend chip (APV6) confirm what expected from general considerations: invariance of the output shape and amplitude, and tolerance to very high particle rates. The noise may increase marginally because of the different impedance of the first stage, which depends on the peaking time.

We report selected results of laboratory measurements and beam tests of heavily irradiated microstrip silicon detectors. The detectors were single-sided devices, produced by different manufacturers and irradiated with different sources, for several total ionizing doses and fluences up to 4 /spl times/10/sup 14/ 1-MeV-equivalent neutrons per cm/sup 2/. Strip resistance and capacitance, detector leakage currents and breakdown performance were measured before and after irradiations. Signal-to-noise ratio and detector efficiency were studied in beam tests, for different values of the detector temperature and of the read-out pitch, as a function of the detector bias voltage. The goal of these test is to optimise the design of the final prototypes for the Silicon Strip Tracker of the CMS experiment at the CERN LHC collider.

The decision-taken by the CMS experiment to build a tracker entirely based on silicon detectors has made necessary the use of thicker sensors instead of the usual 300 /spl mu/m ones for the outer part of the detector. We present first results on the performance of 500 /spl mu/m thick detectors, before and after neutron irradiation, bonded to the CMS tracker front-end electronics. Laboratory measurements show that the total collected charge scales linearly with thickness when compared with a 300 /spl mu/m module and the measured noise is in good agreement with expectations. The results obtained confirm the feasibility of large area silicon trackers.

This note is intended to describe the main features of the first engineered versions of the basic singlesided detector modules for the barrel and forward silicon tracker of CMS.

A prototype module of an iron-gas sampling calorimeter based on parallel-plate chambers, full-size depth, has been tested using high-energy muons, electrons and pions. The module was equipped with more than 1000 active cells read out individually. Experimental measurements at the test beam and their comparison with Monte-Carlo simulations are presented. Expected performance for a calorimeter suitable for low-angle regions in LHC experiments are derived.

Abstract The new silicon tracker layout (V4) is presented. The system aspects of the construction are discussed together with the expected tracking performance. Because of the high radiation environment in which the detectors will operate, particular care has been devoted to the study of the characteristics of heavily irradiated detectors. This includes studies on performance (charge collection, cluster size, resolution, efficiency) as a function of the bias voltage, integrated fluence, incidence angle and temperature.

The CMS silicon strip tracker involves about 70 m2 of instrumented silicon, with approximately 18500 microstrip detectors read out by 5 × 106 electronics channels. It has to satisfy a set of stringent requirements imposed by the environment and by the physics expected at the LHC: low cell occupancy and good resolution, radiation hardness aided by adequate cooling, low mass combined with high stability. These conditions have been incorporated in a highly modular design of the detector modules and their support structures, chosen to facilitate construction and to allow for easy assembly and maintenance.

The paper describes the Silicon Tracking System of the Compact Muon Solenoid (CMS) experiment that is foreseen to collect events from p–p collision at the Ecm=14 TeV at the CERN future Large Hadron Collider (LHC). The proposed system consists of four layers of silicon microstrip detectors placed between the two inner layers of the pixel detector and the outer microstrip gas chamber system. The barrel part covers the η region up to 1.8, instrumenting the central radial region between 20 and 50 cm. The forward–backward disks extend the coverage up to η=2.6. This paper will review the main characteristics and performances of the system, the actual status of the R&D activities that we are carrying on, and the status of the milestones we have to fulfill in view of the Technical Design Report expected at the end of the year.

Results on the radiation resistance test of ceramic parallel-plate chambers after nearly 1 Grad gamma irradiation are presented.

Silicon microstrip devices to be installed in Large Hadron Collider (LHC) tracking detectors will have to operate in a high radiation environment.We report on performance studies of silicon microstrip detectors irradiated with neutrons or protons, up to fluences comparable to the first ten years of running at LHC. Obtained results show that irradiated detectors can still be operated with satisfactory signal-to-noise ratio,and in the case of inhomogeneously type inverted detector a very good position resolution is achieved regardless of the zone crossed by the particle.

We describe a completely optically decoupled DAQ system, using a single optical fiber for feeding fast trigger and control signals to the front end electronics. Its main use is foreseen in the general environment of silicon microstrip detectors, with both single and double side readout. It has been shown to be very helpful, especially in case of double sided heavily irradiated silicon detectors where the bias operation voltage is around 500 V in order to get overdepletion and an optimal signal to noise ratio.

This paper describes the silicon microstrip tracker of the CMS experiment at the future LHC. The silicon tracker consists of a barrel part with 5 layers and two endcaps with 10 disks each. About 6500 modules will have to be built, each one carrying two daisy-chained silicon sensors and their front-end electronics. The modules have been designed to be as simple and robust as possible. Radiation damage in the silicon sensors is minimized by cooling the whole system down to -10°C. Safe operation after heavy irradiation will be possible due to the high-voltage capability of the sensors. We expect the sensors to have a signal-to-noise ratio of 10 at the end of 10years of LHC running, which still gives an efficiency of almost 100%.

We present results on the measurements of the spark probability with CO2 and CF4/CO2 (80/20) mixture, at atmospheric pressure, using 1.5 mm gas gap parallel plate chambers, working at a gas gain ranging from 4.5 × 102 to 3.3 × 104.

Abstract Making use of electrons extracted by UV photons on aluminum cathodes, the ionization threshold of the streamer mode has been measured, and a fully efficient operation range for single ionization electrons has been found. Operation conditions have been investigated for Ar-isobutane and He-isobutane gas mixtures, and 50 and 100 μm wire diameters.

Present status of Parallel Plate Chambers (PPC) is reviewed. After a description of this detector, results from tests concerning PPC efficiency uniformity, radiation hardness, and behaviour in electromagnetic calorimetry are presented. Some possible utilizations in LHC experiments are mentioned.

The total punchthrough probability of showers produced by negative pions, positive pions, positive kaons and protons, has been measured as a function of depth in an absorber in a magnetic field ranging from 0 to 3 Tesla. The incident particle momentum varied from 10 to 300 GeV/c. The lateral shower development and particle multiplicity at several absorber depths have been determined. The measurements are compared with the predictions of Monte Carlo simulation programs.