Search

Cosmic ray muon has strong penetrating power and no ionizing radiation hazards, which makes it an ideal probe for detecting special nuclear materials (SNMs). In this article, a high spatial resolution muon tomography system based on Micromegas detectors is proposed to optimize the imaging time and quality. The proposed system includes eight Micromegas detectors based on the thermal bonding technique and a scalable readout system. In addition, a multiplexing method based on position encoding is developed to reduce the number of electronics channels by order of magnitude. The spatial resolution of the proposed system with encoding readout can reach a value of hundred micrometers. Finally, a tomography test is performed, and test results show that this proposed system can image 2-cm objects and distinguish different materials. [ABSTRACT FROM AUTHOR]

We present a field-programmable gate array (FPGA)-based technique for the on-line identification of highly ionizing particles in a liquid xenon (LXe) detector. The method was developed and successfully exploited to select $\alpha $ particles emitted by 241Am sources submerged in LXe in an overwhelming, mostly beam-related, $\gamma $ -ray background. After revising the main features of xenon and other liquid noble gases as ultra-violet (UV) scintillating media, we describe the algorithm idea and its firmware implementation. We then present the results in terms of efficiency and background suppression for the real-time $\alpha $ -particle tagging and the limits of the MEG trigger configuration. Finally, we show that in MEG II we are going to overcome the main issues and further improve the performances. [ABSTRACT FROM AUTHOR]

The Mu2e experiment at the Fermilab Muon Campus will search for the coherent neutrinoless conversion of a muon into an electron in the field of an aluminum nucleus with a sensitivity improvement by a factor of 10 000 over existing limits. Such a charged lepton flavor-violating reaction probes new physics at a scale unavailable with direct searches at either present or planned high-energy colliders. The Mu2e Trigger and Data Acquisition (TDAQ) system exploits otsdaq as its online Data Acquisition System (DAQ) solution. Developed at Fermilab, otsdaq integrates both the artdaq DAQ and the art analysis frameworks for event transfer, filtering, and processing. otsdaq is an online DAQ software suite with a focus on flexibility and scalability and provides a multi-user, web-based, interface accessible through a web browser. The read out controllers (ROCs) stream out zero-suppressed data continuously from the detector subsystems to the data transfer controllers (DTCs). The data stream is then read over the peripheral component interconnect express (PCIe) bus to a software filter algorithm that selects events which are combined with the data flux coming from a cosmic-ray veto (CRV) system. The detector control system (DCS) has been developed using the experimental physics and industrial control system (EPICS) open source platform for monitoring, controlling, alarming, and archiving. The DCS has been integrated into otsdaq. A prototype of the TDAQ system and the DCS has been built at Fermilab’s Feynman Computing Center. In this article, we report on the progress of the integration of this prototype in the online otsdaq software. [ABSTRACT FROM AUTHOR]

J-PARC E16 is an experiment to examine the origin of hadron mass through a systematic measurement of spectral changes of vector mesons in nuclei. The measurement of $e^{+}e^{-}$ pairs from the decay of vector mesons will provide the information of the partial restoration of the chiral symmetry in a normal nuclear density. To resolve a pulse pile-up and achieve good discrimination of $e^{+}$ and $e^{-}$ from the background of a reaction rate of an order of 10 MHz, the data acquisition (DAQ) system uses waveform sampling chips of APV25 and DRS4. The trigger rate and data rate are expected to be 1 kHz and 120–330 MiB/s, respectively. The DAQ system for readout of APV25 and DRS4 were developed, where events were synchronized by common trigger and tag data. The first commissioning in beam, called Run-0a, was performed in June 2020 with about 1/4 of the designed setup. The DAQ worked with a trigger rate of 300 Hz in the Run-0a and the main bottleneck was a large data size of APV25. Further optimization of the DAQ system will improve the performance. [ABSTRACT FROM AUTHOR]

The CMS experiment at the LHC selects events with a two-level trigger system, the Level-1 (L1) trigger, and the high-level trigger (HLT). The HLT reduces the rate from 100 to about 1 kHz and has access to the full detector readout and runs a streamlined version of the offline event reconstruction. During LHC Run-2, the peak instantaneous luminosity reached values up to $2.0\times 10^{34}$ cm−2s−1, posing a challenge to the online event selection. An overview of the HLT system at CMS, the online physics object reconstruction, and the main triggers using those physics objects in 2016–2018 proton collision data-taking period is presented. The performance of a representative set of physics triggers is also discussed. [ABSTRACT FROM AUTHOR]

The COherent Muon to Electron Transition (COMET) experiment aims to search for the neutrinoless muon to electron transition process with new sensitivity levels. The online trigger system is an integral part of achieving the sensitivity levels required and will be subject to an expected neutron fluence of up to $10^{12}\,\,n \cdot \mathrm {cm}^{-2}$ within regions inside the detector solenoid. Consequently, a significant number of soft errors in the logic of the onboard field programmable gate arrays (FPGAs) can occur, requiring error correction for single event upsets and firmware reprogramming schemes for unrecoverable soft errors. We studied the radiation tolerance of the COMET Phase-I front-end trigger system, called COMET TRIgger (COTTRI), subject to neutron fluence on order $10^{12}\,\,n \cdot \mathrm {cm}^{-2}$ with multiple error correcting codes and automatic firmware reconfiguration. The regions measured were the configuration random access memory (RAM), block RAM (BRAM) and also in a multigigabit transfer link using copper cables that will be used for communication between different trigger boards during Phase-I. The resulting cross sections observed suggest the most significant impact to the experiment will come from unrecoverable soft errors in configuration RAM (CRAM), with dead time expected to be 4.2% ± 1.3%. The effect of multibit errors in BRAM was found to be almost negligible in COMET Phase-I. In addition, multiple solutions have already been proposed in order to suppress these errors further. Soft errors observed in the multigigabit transfer links were measured to be of two orders of magnitude less impact compared to the unrecoverable errors in CRAM. We concluded that the COTTRI system meets the trigger requirement in COMET Phase-I. [ABSTRACT FROM AUTHOR]

Ground-level cosmic ray muon detections have various potential applications in the predictions of space and Earth weather variations and muon tomography. However, in order to push its practical applications, a low-power, low-cost, high-accuracy, and portable ground-level cosmic ray muon detection system needs to be developed. In this article, we present a high time-resolution and low-power readout integrated circuit (ROIC) for portable ground-level cosmic ray muon detection. The ROIC comprises preamplifiers, comparators, encoding modules, a delay-locked loop (DLL), and a data transfer module. The preamplifiers amplify the weak signals produced by the muon detector. The comparators convert the amplified signals into digital signals. The encoding modules extract and store the time information of the input pulses produced by the comparator, and the data transfer module transmits them to a microcontroller unit (MCU). A pulse edge detecting method using DLL clocks is employed to improve the time-resolution and limit the power consumption of the ROIC. A 32-channel prototype of the ROIC was designed and fabricated in a 0.18- $\mu \text{m}$ mixed-signal CMOS process. The main chip size is 11.4 mm2. A one-channel double-layer plastic scintillator muon detector was used to test the performance of the ROIC. A time-resolution of 1.0 ns was achieved with a system clock of 50 MHz, and the ROIC power consumption was measured at 1.9 mW/channel. Compared with existing muon readout electronics systems, the system using the proposed ROIC achieves high time-resolution and accuracy, with low power consumption and a smaller size, making it suitable for portable real-time cosmic ray muon detection. [ABSTRACT FROM AUTHOR]

The Belle II experiment at the SuperKEKB collider at KEK, Tsukuba, Japan has successfully started taking data with the full detector in March 2019. Belle II is a luminosity frontier experiment of the new generation to search for physics beyond the Standard Model of elementary particles, from precision measurements of a huge number of $B$ and charm mesons and tau leptons. To read out the events at a high rate from the seven subdetectors of Belle II, we adopt a highly unified readout system, including a unified trigger-timing distribution system (TTD), a unified high-speed data link system (Belle2link), and a common backend system to receive Belle2link data. Each subdetector frontend readout system has a field-programmable gate array (FPGA) in which unified firmware components of the TTD receiver and Belle2link transmitter are embedded. The system is designed for data taking at a trigger rate up to 30 kHz with a dead-time fraction of about 1% in the frontend readout system. The trigger rate is still much lower than our design. However, the background level is already high because of the initial vacuum condition and other accelerator parameters, and it is the most limiting factor of the accelerator and detector operation. Hence, the occupancy and radiation effects to the frontend electronics are rather severe, and they cause various kinds of instabilities. We present the performance of the system, including the achieved trigger rate, dead-time fraction, and stability, and discuss the experience gained during the operation. [ABSTRACT FROM AUTHOR]

The Mu3e experiment aims to find or exclude the lepton flavor violating decay μ+ → e+e−e+$ with a sensitivity of one in 1016 muon decays. The first phase of the experiment is currently under construction at the Paul Scherrer Institute (PSI, Switzerland), where beams with up to 108 muons per second are available. The detector will consist of an ultra-thin pixel tracker made from High-Voltage Monolithic Active Pixel Sensors (HV-MAPS), complemented by scintillating tiles and fibers for precise timing measurements. The experiment produces about 100Gbit/s of zero-suppressed data, which are transported to a filter farm using a network of field programmable gate arrays (FPGAs) and fast optical links. On the filter farm, tracks and three-particle vertices are reconstructed using highly parallel algorithms running on graphics processing units, leading to a reduction of the data to 100 Mbyte/s for mass storage and offline analysis. This article introduces the system design and hardware implementation of the Mu3e data acquisition and filter farm. [ABSTRACT FROM AUTHOR]

The large Hadron collider (LHC) is expected to increase its center-of-mass energy from 13 to 14 TeV for Run 3 scheduled from 2022 to 2024. After Run 3, upgrades for the high-luminosity-LHC (HL-LHC) program are planned and the operation will start in 2027, increasing the instantaneous luminosity to 5.0–7.5 times its nominal luminosity. Continuous upgrades of the ATLAS trigger system are planned to cope with the high event rate and to keep the physics acceptance. During the long shutdown period before Run 3, new detectors will be installed to improve the trigger performance. A new trigger logic, combining information from detectors located outside of the magnetic field and new detectors installed inside the magnetic field, will be introduced for Run 3 to reduce the trigger rate. In order to handle data from the various detectors, a new trigger processor board has been developed and the design is presented. During the upgrade for HL-LHC, the trigger and readout systems of the first level hardware-based part are planned to be upgraded. Full-granularity information will be transferred to the trigger processor board which enables more OFF-line like track reconstruction in the hardware-based system. To handle the full-granularity information and perform the hardware-based track reconstruction, the trigger processor board will be equipped with a field programmable gate array (FPGA) with hundreds of transceivers and a large memory. Expected performance for the hardware-based endcap muon trigger in Run 3 and HL-LHC will also be presented. [ABSTRACT FROM AUTHOR]

Arrays of superconducting transition-edge sensor (TES) microcalorimeters are attractive for some X-ray experiments where the combination of higher collection efficiency than crystal spectrometers and much better energy resolution than semiconductor detectors is enabling. For hard X-ray (>2 keV) applications, a TES is often integrated with an extra absorber to extend its dynamic range, quantum efficiency and collecting area. For >100 keV applications, millimeter size absorbers have been manually attached to TES pixels after fabrication. At lower energies, the absorber size needs to be much smaller, because a large heat capacity degrades energy resolution. In that case, the absorber is directly electroplated or evaporated on the TES during the fabrication process. In this work, we present TES microcalorimeters optimized for the intermediate hard X-ray energy region (20 keV ∼ 100 keV) that have thick absorbers directly deposited during the TES fabrication process. This microcalorimeter is designed to measure high-resolution muonic atom transition X-ray spectra as a method to study quantum electrodynamics (QED) effects. The absorber is comprised of evaporated gold and electroplated bismuth layers and is designed to optimize dynamic range, collecting efficiency, and energy resolution in the 20 keV to 45 keV energy range. A prototype with pure gold absorbers has been fabricated and characterized, in order to obtain a first experimental reference in the detector development process. [ABSTRACT FROM AUTHOR]

A new silicon-strip readout chip named “SliT” has been developed for the measurement of the muon anomalous magnetic moment and electric dipole moment (EDM) of the muon at Japan Proton Accelerator Research Complex (J-PARC). The SliT chip is designed in the Silterra 180-nm CMOS technology with mixed-signal integrated circuits. An analog circuit incorporates a conventional charge-sensitive amplifier, shaping amplifiers, and two distinct discriminators for each of the 128 identical channels. A digital part includes storage memories, an event building block, a serializer, and low voltage differential signaling (LVDS) drivers. A distinct feature of the SliT is utilization of the zero-crossing architecture, which consists of a CR– RC filter followed by a CR circuit as a voltage differentiator. This architecture allows generating hit signals with subnanosecond amplitude-independent time walk, which is the primary requirement for the experiment. The test results show a time walk of 0.38 ± 0.16 ns between 0.5 and 3 MIP signals. The equivalent noise charge is 1547 ± 75 e− (rms) at Cdet =33 pF as a strip-sensor capacitance. SliT128C satisfies all requirements of the J-PARC muon g−2/EDM experiment. [ABSTRACT FROM AUTHOR]

The trigger selection capabilities of the ATLAS detector have been significantly enhanced for the Large Hadron Collider (LHC) Run-2 in order to cope with the higher event rates and with a large number of simultaneous interactions (pile-up) per proton–proton bunch crossing. A new hardware system, designed to analyze real-time event-topologies at level-1, came to full use in 2017. A hardware-based track reconstruction system, expected to be used real time in run-3, is designed to provide track information to the high-level software trigger at its full input rate. The high-level trigger (HLT) selections largely rely on off-line-like reconstruction techniques and in some cases multivariate analysis methods. Despite the sudden change in LHC operations during the second half of 2017, which caused an increase in pile-up and, therefore, also in CPU usage of the trigger algorithms, the set of triggers (so-called trigger menu) running online has undergone only minor modifications thanks to the robustness and redundancy of the trigger system and the use of a leveling luminosity scheme in agreement with LHC and other experiments. This article gives a brief yet comprehensive review of the real-time performance of the ATLAS trigger system in 2017. Considerations will be presented on the most relevant parameters of the trigger (efficiency to collect signal and output data rate) and details on some aspects of the algorithms which are run real time on the HLT CPU farm will be presented. [ABSTRACT FROM AUTHOR]

This article describes a series of experimental measurements and calculations designed to quantify the scattering and albedo effects on neutron spectra and their consequences on single-event effect (SEE) sensitivities. An experimental approach was proposed to investigate the scattering and albedo neutron spectra using a 252Cf facility and for several scene topologies. A highly sensitive neutron spectrometer based on a Bonner sphere system (BSS) is used, allowing to measure neutron energy from thermal to tens of megaelectron-volts. To complete previous SEE measurements on 45 nm, the soft error rate (SER) was recorded on 28-nm technology. A second part considers complex topologies including concrete walls and high-density polyethylene (HDPE) blocks to represent a design facility and the shielding to protect some parts of the SEE test board, respectively. The results showed that devices are more impacted by the presence of materials, especially HDPE. Indeed, almost 25% of the events are due to the secondary neutrons. Orders of magnitude are not critical, nevertheless, they warn about taking into account the albedo contributions and how to add materials in the vicinity of measurement devices. [ABSTRACT FROM AUTHOR]

The planned upgrade of the A Large Ion Collider Experiment (ALICE) inner tracking system (ITS) aims at improving the ALICE performance in terms of spatial resolution and data rate readout. The new ITS will be a low-material-budget, high-granularity detector. It comprises seven concentric layers of monolithic active pixel sensors (MAPS), called ALPIDE, which are based on the TowerJazz 180-nm CMOS technology. In this article, we report on detection performance and radiation hardness studies of ALPIDE sensors. We show that these sensors keep having high detection efficiency for minimum ionizing particles (MIPs) (>99%) and low fake-hit rate while being radiation hard to some ${ 1.7} \times { 10}^{ 13}\,\,1$ MeV $\text{n}_{\text {eq}}$ cm−2 of nonionizing energy loss (NIEL) and 2.7 Mrad of total ionization dose (TID), which exceeds the expected radiation load during the detector lifetime ten times. ALPIDE sensors thus completely fulfill the design requirements. In addition, we show that measured cluster shape frequencies obtained at different operating points (thresholds, bias voltages) are well described with the state-of-the-art ALICE Monte Carlo simulation. [ABSTRACT FROM AUTHOR]

An experiment to measure an invariant mass of $\phi $ mesons in nuclear medium is planned as the J-PARC E16 experiment. A trigger merging module (TRG-MRG) has been developed to detect leading-edges from 256 channels of discriminator-output signals and transmit those serialized hit data to trigger decision module with four optical links. The result of the test shows enough performance of the TRG-MRG as 1-ns time-to-digital converter (TDC) and data multiplexer with four 6.25 Gb/s transceivers. [ABSTRACT FROM AUTHOR]

The Level-1 barrel trigger of the ATLAS experiment is based on the resistive plate chambers (RPCs) detectors. The on-detector trigger electronics identifies muons with specific values of transverse momentum, by using coincidences between different layers of detectors. Trigger data are then transferred from on-detector to off-detector trigger electronics boards. Data are processed by a complex system, which combines trigger data from the barrel and the end-cap regions and provide the combined muon candidate to the central trigger processor (CTP). The system has been performing well for almost a decade. However, in order to cope with continuously increasing large hadron collider luminosity and more demanding requirements on trigger efficiency and performance, various upgrades for the full-trigger system were already deployed and others are foreseen in the next years. Most of the trigger upgrades are based on the state-of-the-art technologies and allow designing more complex trigger menus, increasing processing power and data transfer bandwidth in order to send more trigger candidates, to perform topological selections, and to support new physics studies. In this paper, we describe the design of the first prototype of the barrel interface board, designed around a Xilinx field-programmable gate array, which transfers RPC trigger data to the CTP system; the board supports the optical transmission of trigger data with fixed latency and new trigger algorithms. We discuss the design strategies, the hardware implementation, and the results of the first functional and integration tests. [ABSTRACT FROM AUTHOR]

The design and performance of a new front-end acquisition system is presented in this paper. It was developed to be used with muon array with resistive plate chamber (RPCs) for tagging air showers (MARTA’s) RPC detectors that measure the muonic component of cosmic ray air showers. The system is hybrid and capable of counting active channels and performing a charge measurement. It is low power (1.43 W per 64 channels), compact ($21.6 \times 14.4\,\,\mathrm {cm^{2}}$ per 64 channels), stable, and reliable to comply with the strict demands of field operation associated with experiments that measure air showers. The front-end is based on an application-specified integrated circuit [Multi Anode Read-Out Chip (MAROC)] with 64 input channels, which is responsible for the digitization of the RPC signals. While a simple threshold measurement is applied after a fast shaper to count particles, the charge measurement is performed by an analog to digital converter that reads the peak of a slow shaper. An field-programmable gate array is responsible for control of all the digital part which includes storing the MAROC outputs and sending them to a Central Unit [via low voltage differential signal (LVDS)] or PC (via USB). Both the count and charge measurement performance are assessed. The threshold efficiency curve is measured for different temperatures. For all the conditions tested, the efficiency is 100% for charges higher than 52 fC. The overall efficiency to detect muons is studied by placing an RPC between a hodoscope and comparing the efficiency of the front-end with another established data acquisition system. The efficiency results are consistent within the statistical uncertainties of the measurements showing that the MARTA front-end does not introduce unwanted inefficiencies in the setup. The charge measurement is tested in the laboratory using a signal generator. Different shaping conditions and input charges are used to study the waveform of the slow shaper. A linear dependence between input charge and the value measured by the MAROC was found and taken as the calibration curve for the particular channel tested. [ABSTRACT FROM AUTHOR]

The increase in atmospheric CO2 concentrations has initiated research into carbon sequestration methods. One possibility is to store CO2 in subsurface porous reservoirs. Monitoring the injected CO2 plume is vital because escaping CO2 poses health and environmental risks. Typically, seismic reflection methods are used to determine the change in density due to the replacement of brine by CO2 in the reservoir but this is expensive and not continuous. A potential alternative is to use cosmic muon tomography to measure density changes in the reservoir as a function of time. This paper describes the development of a muon detector that will be capable of being deployed in boreholes. The detector will be designed to have the required dimensions, an angular resolution of approximately 2°, and be mechanically robust. The prototype design is based on alternating layers of scintillating rods, which can provide 4-D reconstruction of the overburden to detect small changes in density at depths up to approximately 2 km. Geant4, a Monte Carlo simulation code, is being used to develop models to guide the design of the physical configuration. Preliminary testing and measurements have been performed to validate the simulation predictions and optimize physical performance parameters. The simulated and preliminary experimental results are presented here. [ABSTRACT FROM AUTHOR]

A portable muography detector was developed for measuring infrastructure degradation and its performance was tested. The detector consists of two muon position sensitive detectors (mu-PSDs) of the area of 140 mm $\times \,\, 140$ mm, placed in a compact light-shielding box. Each mu-PSD consists of plastic scintillating fibers connected to multipixel photon counters (MPPCs). To suppress the gain deviation of the MPPCs, the box was heat insulated and its inner air temperature was maintained by Peltier cooling–heating modules. The mu-PSD pixel size was 8.75 mm $\times \,\, 8.75$ mm and the distance between the two mu-PSDs was set to 100 mm in order to achieve a solid angle resolution of 8 msr when measuring typical pieces of infrastructure at thicknesses of several tens of centimeters. The intensity of cosmic-ray muons was measured as a function of zenith angle on the ground and was found to be in good agreement with the well-known empirical formula for muon intensity at Earth’s surface. The structural interior of a seven-story concrete building was then successfully imaged with the muography detector placed in the building’s basement. [ABSTRACT FROM AUTHOR]

The Mu2e experiment at Fermilab searches for the charged-lepton flavor violating (CLFV) conversion of a negative muon into an electron in the field of an aluminum nucleus, with a distinctive signature of a monoenergetic electron of energy slightly below the muon rest mass (104.967 MeV). The Mu2e goal is to improve by four orders of magnitude the search sensitivity with respect to the previous experiments. Any observation of a CLFV signal will be a clear indication of new physics. The Mu2e detector is composed of a tracker, an electromagnetic calorimeter, and an external veto for cosmic rays surrounding the solenoid. The calorimeter plays an important role in providing particle identification capabilities, a fast online trigger filter, a seed for track reconstruction while working in vacuum, in the presence of 1-T axial magnetic field and in a harsh radiation environment. The calorimeter requirements are to provide a large acceptance for 100-MeV electrons and reach at these energies: 1) a time resolution better than 0.5 ns; 2) an energy resolution <10%; and 3) a position resolution of 1 cm. The calorimeter design consists of two disks, each one made of 674-undoped cesium iodine crystals read by two large area arrays of UV-extended silicon photomultipliers (SiPMs). We report here the construction and the test of the Module-0 prototype. The Module-0 has been exposed to an electron beam in the energy range around 100 MeV at the Beam Test Facility in Frascati. Preliminary results of timing and energy resolution at normal incidence are shown. A discussion of the technical aspects of the calorimeter engineering is also reported in this paper. [ABSTRACT FROM AUTHOR]

Time measurements play a crucial role in trigger and data acquisition systems of high-energy physics experiments, where synchronization between system elements, signal calibration, and phase-measurement accuracy is often required. In this paper, we present a fully digital time-to-digital converter (TDC) architecture and its application, based on a synthesizable digitally controlled oscillator (DCO), where the TDC is used to measure the phase relationship between a timing signal and a 40-MHz reference clock. The DCO design is technology independent; it is described by means of a hardware description language and it can be placed and routed with automatic tools. The TDC will be used in the new readout chip that is under development for the muon detector electronic upgrade in Large Hadron Collider beauty experiment at CERN. The TDC presented in this paper has the fundamental task of measuring, with a resolution of about 1.5 ns, the phase difference between the 40-MHz LHC machine clock and a digital signal coming from the muon detector. [ABSTRACT FROM PUBLISHER]

Neutrinos play a fundamental role in the understanding of the origin of ultrahigh-energy cosmic rays. They interact through charged and neutral currents in the atmosphere generating extensive air showers. However, the very low rate of events potentially generated by neutrinos is a significant challenge for detection techniques and requires both sophisticated algorithms and high-resolution hardware. Air showers initiated by protons and muon neutrinos at various altitudes, angles, and energies were simulated in CORSIKA and the Auger OffLine event reconstruction platforms, giving analog-to-digital convertor (ADC) patterns in Auger water Cherenkov detectors on the ground. The proton interaction cross section is high, so proton “old” showers start their development early in the atmosphere. In contrast to this, neutrinos can generate “young” showers deeply in the atmosphere relatively close to the detectors. Differences between “old” proton and “young” neutrino showers are visible in attenuation factors of ADC waveforms. For the separation of “old” proton and “young” neutrino ADC traces, many three-layer artificial neural networks (ANNs) were tested. They were trained in MATLAB (in a dedicated way -only “old” proton and “young” neutrino showers as patterns) by simulated ADC traces according to the Levenberg–Marquardt algorithm. Unexpectedly, the recognition efficiency is found to be almost independent of the size of the networks. The ANN trigger based on a selected 8-6-1 network was tested in the Cyclone V E FPGA 5CEFA9F31I7, the heart of prototype front-end boards developed for testing new algorithms in the Pierre Auger surface detectors. [ABSTRACT FROM AUTHOR]

The KOTO experiment at J-PARC, Japan, aims to observe the rare neutral kaon decay mode KL\rightarrow \pi ^{0}\nu \bar {\nu } . After the first experimental run in May 2013 at a 24-kW beam power, the KOTO data acquisition (DAQ) system was upgraded in 2015 to provide efficient and reliable data collection at higher beam intensities. Lossless data compression in the analog-to-digital converter modules was implemented to reduce the size of data packets, resulting in a threefold increase in data collection rate. A new software trigger on a 47-node cluster was designed to use Infiniband hardware with message passing interface protocol to establish a mesh network inside the computer clusters for parallel data processing. The upgrade to the KOTO DAQ system was commissioned in 2015 and successfully collected data with a beam intensity of up to 42 kW. In preparation for increasing beam intensities in future runs, the hardware trigger upgrades using the reconfigurable clustering element platform technology are under development. [ABSTRACT FROM AUTHOR]

The operation of the compact muon solenoid drift tubes (DTs) muon detectors at the high-luminosity large hadron collider will be possible only with an upgrade of the current readout and trigger electronics, which are based on very old technology and directly exposed to radiation, hence particularly sensitive to aging. A new level 1 trigger primitive generator, based on the use of an original compact Hough transform (CHT) algorithm, is being designed with the goal of its implementation in the state-of-the-art field programmabla gate array (FPGA) devices. The algorithm can identify the muon track segment parameters and must be combined with a majority mean-timer in order to assign the muon to its parent bunch crossing. The algorithm is expected to be deployed on FPGAs and has a few \mu \texts latency for decision taking, with efficiency and resolution equal or higher with respect to the ones provided by the currently running algorithm. The major challenges are parallelization of the algorithm, fast readout of the CHT parameter matrix, the capability of handling data from a large array of DTs in the minimal number of FPGAs, and coping with the latency requirements. These issues will be addressed proposing constructive solutions. [ABSTRACT FROM AUTHOR]

For the 2016 physics data runs, the L1 trigger system of the compact muon solenoid (CMS) experiment underwent a major upgrade to cope with the increasing instantaneous luminosity of the CERN LHC whilst maintaining a high event selection efficiency for the CMS physics program. Most subsystem specific trigger processor boards were replaced with powerful general purpose processor boards, conforming to the MicroTCA standard, whose tasks are performed by firmware on an field-programmable gate array of the Xilinx Virtex 7 family. Furthermore, the muon trigger system moved from a subsystem centered approach, where each of the three muon detector systems provides muon candidates to the global muon trigger (GMT), to a region-based system, where muon track finders (TFs) combine information from the subsystems to generate muon candidates in three detector regions that are then sent to the upgraded GMT. The upgraded GMT receives up to 108 muons from the processors of the muon TFs in the barrel, overlap, and endcap detector regions. The muons are sorted in two steps and duplicates are identified for removal. The first step treats muons from different processors of a TF in one detector region. Muons from TFs in different detector regions are compared in the second step. An isolation variable is calculated, using energy sums from the calorimeter trigger and added to each of the best eight muons before they are sent to the upgraded global trigger (GT) where the final trigger decision is made. The upgraded GMT algorithm is implemented on a general purpose processor board that uses optical links at 10 Gb/s to receive the input data from the muon TFs and the calorimeter energy sums, and to send the selected muon candidates to the upgraded GT. [ABSTRACT FROM AUTHOR]

A front-end electronics prototype for the ATLAS small-strip Thin Gap Chamber (sTGC) based on gigabit Ethernet has been developed. The prototype is designed to read out signals of pads, wires, and strips of the sTGC detector. The prototype includes two VMM2 chips developed to read out the signals of the sTGC, a Xilinx Kintex-7 field-programmable gate array (FPGA) used for the VMM2 configuration and the events storage, and a gigabit Ethernet transceiver PHY chip for interfacing with a computer. The VMM2 chip is designed for the readout of the Micromegas detector and sTGC detector, which is composed of 64 linear front-end channels. Each channel integrates a charge-sensitive amplifier, a shaper, several analog-to-digital converters, and other digital functions. For a bunch-crossing interval of 25 ns, events are continuously read out by the FPGA and forwarded to the computer. The interface between the computer and the prototype has been measured to reach an error-free rate of 900 Mb/s, therefore making a very effective use of the available bandwidth. Additionally, the computer can control several prototypes of this kind simultaneously via the Ethernet interface. At present, the prototype will be used for the sTGC performance test. The features of the prototype are described in detail. [ABSTRACT FROM AUTHOR]

We present first results from a trigger based on the discrete cosine transform (DCT) operating in new front-end boards with a Cyclone V E field-programmable gate array (FPGA) deployed in seven test surface detectors in the Pierre Auger Test Array. The patterns of the ADC traces generated by very inclined showers (arriving at 70° to 90° from the vertical) were obtained from the Auger database and from the CORSIKA simulation package supported by the Auger OffLine event reconstruction platform that gives predicted digitized signal profiles. Simulations for many values of the initial cosmic ray angle of arrival, the shower initialization depth in the atmosphere, the type of particle, and its initial energy gave a boundary on the DCT coefficients used for the online pattern recognition in the FPGA. Preliminary results validated the approach used. We recorded several showers triggered by the DCT for 120 Msamples/s and 160 Msamples/s. [ABSTRACT FROM AUTHOR]

Effective longitudinal segmentation of shashlik calorimeters can be achieved taking advantage of the compactness and reliability of silicon photomultipliers. These photosensors can be embedded in the bulk of the calorimeter and are employed to design very compact shashlik modules that sample electromagnetic and hadronic showers every few radiation lengths. In this paper, we discuss the performance of a calorimeter made up of 12 such modules and able to sample showers every \sim 4X0 . In summer 2016, this prototype has been exposed to electrons, muons, and hadrons at CERN PS (East Area T9 beamline). The performances in terms of energy resolution, linearity, response to minimum ionizing particles, and reconstruction of the shower profile are discussed. [ABSTRACT FROM PUBLISHER]

Micromegas (MICRO MEsh GAseous Structure) chambers are Micro-Pattern Gaseous Detectors designed to provide a high spatial resolution in highly irradiated environments. In 2007 an ambitious long-term R&D activity was started in the context of the ATLAS experiment, at CERN: the Muon ATLAS Micromegas Activity (MAMMA). After years of tests on prototypes and technology breakthroughs, Micromegas chambers were chosen as tracking detectors for an upgrade of the ATLAS Muon Spectrometer. These novel detectors will be installed in 2018 and 2019 during the second long shutdown of the Large Hadron Collider, and will serve as precision detectors in the innermost part of the ATLAS Muon Spectrometer. Eight layers of Micromegas modules of unprecedented size, up to 3~\boldsymbol m^2 , will cover a surface of 150~\boldsymbol m^2 for a total active area of about 1200~\boldsymbol m^2 . This upgrade will be crucial to ensure high quality performance for the ATLAS Muon Spectrometer in view of the third run of the Large Hadron Collider and of the High-Luminosity LHC, as the luminosity of the collider will significantly exceed the one the machine was originally designed for. To meet the demanding performance requirements of the ATLAS Muon Spectrometer, Micromegas chambers are required to achieve a single plane resolution of 100~\boldsymbol \mu \mathbf m with an efficiency better than 95% for tracks up to an inclination of 32° and in a magnetic field up to 0.3 T. A thorough test program on Micromegas prototypes has been performed during the past years and is still ongoing, with the goal of driving the design of the ATLAS Micromegas chambers and of fully characterising and certifying their performance. These tests produced excellent results, proving that the prototypes fully meet the performance requirements. The methodology and the results of this activity will be reviewed in this paper. [ABSTRACT FROM PUBLISHER]

Cosmic ray muons passing through matter lose energy from inelastic collisions with electrons and are deflected from nuclei due to multiple Coulomb scattering. The strong dependence of scattering on atomic number Z and the recent developments on position sensitive muon detectors indicate that multiple Coulomb scattering could be an excellent candidate for spent nuclear fuel imaging. Muons present significant advantages over existing monitoring and imaging techniques and can play a central role in monitoring nuclear waste and spent nuclear fuel stored in dense well shielded containers. The main purpose of this paper is to investigate the applicability of multiple Coulomb scattering for imaging of spent nuclear fuel dry casks stored within vertical and horizontal commercial storage dry casks. Calculations of muon scattering were performed for various scenarios, including vertical and horizontal fully loaded dry casks, half loaded dry casks, dry casks with one row of fuel assemblies missing, dry casks with one fuel assembly missing and empty dry casks. Various detector sizes (1.2 m \times 1.2 m, 2.4 m \times 2.4 m and 3.6 m \times 3.6 m) and number of muons ( , 5\cdot 10^{5} , 10^{6}$ and 10^{7} ) were used to assess the effect on image resolution. The Point-of-Closest-Approach (PoCA) algorithm was used for the reconstruction of the stored contents. The results demonstrate that multiple Coulomb scattering can be used to successfully reconstruct the dry cask contents and allow identification of all scenarios with the exception of one fuel assembly missing. In this case, an indication exists that a fuel assembly is not present; however, the resolution of the imaging algorithm was not enough to identify exact location. [ABSTRACT FROM AUTHOR]

The Semi-Digital Hadronic CALorimeter (SDHCAL) is one of the two hadronic calorimeter options proposed by the International Large Detector (ILD) project for the future International Linear Collider (ILC) experiments. It is a sampling calorimeter with 48 active layers made of Glass Resistive Plate Chambers (GRPCs) and their embedded electronics. A fine lateral segmentation is obtained thanks to pickup pads of 1 cm2. This ensures the high granularity required for the application of the Particle Flow Algorithm (PFA) in order to improve the jet energy resolution in the ILC experiments. The performance of the SDHCAL technological prototype was tested successfully in several beam tests at CERN. The main point to be discussed here concerns the energy reconstruction in SDHCAL. Based on Monte Carlo simulation of the SDHCAL prototype using the GEANT4 package, we present different energy reconstruction methods to study the energy linearity and resolution of the detector response to single hadrons. In particular, we highlight a new technique based on the Artificial Neural Network giving promising results compared to analytic methods. [ABSTRACT FROM AUTHOR]

Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. A total surface area of about 150~\text m^2 of the forward regions (pseudo-rapidity coverage, 1.3 \,\, < \,\, \eta \,\, < \,\, 2.7 ) of the Muon Spectrometer of the ATLAS detector at LHC will be equipped with 8-layer Micromegas modules. Each module extends over a surface from 2 to 3~\text m^2 for a total active area of 1200~\text m^2 . Together with the small strip Thin Gap Chambers they will compose the two New Small Wheels (NSW), which will replace the innermost stations of the ATLAS endcap muon tracking system in the 2018/19 shutdown. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, in addition to an excellent intrinsic position resolution, the mechanical precision of each plane of the assembled module must be 30 microns along the precision coordinate and 80 microns perpendicular to the chamber. All readout planes are segmented into strips with a pitch of 450 microns for a total of 8180 strips per plane and more than 2 million channels for the NSW. In two of the four planes the strips are inclined by ±1.5° and provide a measurement of the second coordinate. The design and construction procedure of the Micromegas modules are presented, as well as the design for the assembly of modules onto the NSW. Emphasis is given on the methods developed to achieve the challenging mechanical precision. Measurements of deformation on chamber prototypes as a function of thermal gradients, gas over-pressure and internal stress (mesh tension and module fixation on supports) are also shown and compared to simulation. These tests were essential in the development of the final design in order to minimize the effects of deformations. During installation and operation all deformations and relative misalignments will be monitored through an optical alignment system and compensated in the tracking software. [ABSTRACT FROM AUTHOR]

The performance of hadronic calorimeters will be a key parameter at the next generation of High Energy Physics accelerators. A detector combining fine granularity with excellent timing information would prove beneficial for the reconstruction of both jets and electromagnetic particles with high energy resolution. In this work, the space and time structure of high energy showers is studied by means of a Geant4-based simulation toolkit. In particular, the relevant time scales of the different physics phenomena contributing to the energy loss are investigated. A correlation between the fluctuations of the energy deposition of high energy hadrons and the time development of the showers is observed, which allows for an event-by-event correction to be computed to improve the energy resolution of the calorimeter. These studies are intended to set the basic requirements for the development of a new-concept, total absorption time-imaging calorimeter, which seems now within reach thanks to major technological advancements in the production of fast scintillating materials and compact photodetectors. [ABSTRACT FROM AUTHOR]

A large volume scintillator detector has been used to measure the terrestrial stopping muon rate under different conditions of location, altitude, shielding and weather to determine the range of variation of the low energy muon flux. About 1 year of data has been collected under different conditions. This data can then be used to compare with cosmic ray muon simulations and to estimate the soft error rate due to direct ionization of muons. [ABSTRACT FROM PUBLISHER]

The NA62 experiment refid="ref1"/ at CERN SPS (Super Proton Synchrotron) accelerator aims at studying Kaon decays with high precision. The high resolution Liquid Krypton (LKr) calorimeter, built for the NA48 refid="ref2"/ experiment, is a crucial part of the photon-veto system; to cope with the demanding NA62 requirements, its back-end electronics had to be completely renewed. The new readout system is based on the Calorimeter REAdout Module (CREAM) refid="ref3"/, a 6U VME board whose design and production was sub-contracted to CAEN refid="ref4"/, with CERN NA62 group continuously supervising the development and production phase. The first version of the board was delivered by the manufacturer in March 2013 and, as of June 2014, the full board production is ongoing. In addition to describing the CREAM board, all aspects of the new LKr readout system, including its integration within the NA62 TDAQ scheme, will be treated. [ABSTRACT FROM AUTHOR]

We have developed a novel algorithm based on Markov random fields that uses cosmic ray muons to detect high-Z material, such as special nuclear material, in large-scale volumes, such as cargo containers. Since the amount of muon scattering is approximately dependent on the Z and the density of the material traversed, strong scattering in a localized area is indicative of high-Z material being present. For scanning purposes in freight harbors and similar, a decision should be made in \sim 1 minute. The performance of our algorithm has been evaluated on a variety of scenarios reflecting the composition of real-life cargo, using simulations tuned with our detector performance; we show that the algorithm can clear 64% of these containers using 60 seconds of cosmic muon exposure, and 88% using 90 seconds, with a run-time of the algorithm between 1 and 5 seconds. [ABSTRACT FROM AUTHOR]

The performances of the OFFSET3 tracker (Optical Fiber Folded Scintillating Extended Tracker) are presented. It exploits a novel system for particle tracking, designed to achieve real-time particle imaging and tracking, large detection areas, and a high spatial resolution especially suitable for applications in medical diagnostics. The tracker is composed by two 288 \times 288~\mm^2 FOV position detectors stacked by 10 cm, made by 500 micron square scintillating fiber ribbons for both directions. The track position information is extracted in real-time in an innovative way, using a reduced number of readout channels, by means of which it is possible to obtain the large detection area with moderate cost and complexity. The architecture has been patented by the Istituto Nazionale di Fisica Nucleare (INFN). The performances of the tracker were investigated by beta sources, cosmic rays, 60 MeV-250 MeV proton and 400 MeV/A carbon clinical beams. [ABSTRACT FROM PUBLISHER]

The increase in center-of-mass energy and luminosity for Run-II of the Large Hadron Collider poses new challenges for the trigger systems of the experiments. To keep triggering with a similar performance as in Run-I, the CMS muon trigger is currently being upgraded. The new algorithms will provide higher resolution, especially for the muon transverse momentum and will make use of isolation criteria that combine calorimeter with muon information already in the level-1 trigger. The demands of the new algorithms can only be met by upgrading the level-1 trigger system to new powerful FPGAs with high bandwidth I/O. The processing boards will be based on the new \mu TCA standard. We report on the planned algorithms for the upgraded Global Muon Trigger (\muGMT) which sorts and removes duplicates from boundaries of the muon trigger sub-systems. Furthermore, it determines how isolated the muon candidates are based on calorimetric energy deposits. The \muGMT will be implemented using a processing board that features a large Xilinx Virtex 7 FPGA. Up to 72 optical links at 10 Gb/s will be used to receive muon candidates and energy sums from the calorimeter trigger. Muon candidates will be received directly from the sector processors of the upgraded trigger, absorbing the final sorting stage of each muon sub-system and thus minimizing the latency of the trigger. [ABSTRACT FROM PUBLISHER]

The iron calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) will be used to measure neutrino mass hierarchy. The magnet in the ICAL detector will be used to distinguish the \mu ^- and \mu ^+ events induced by \nu \mu and anti- \nu \mu , respectively. Due to the importance of the magnet in ICAL, an electromagnetic simulation has been carried out to study the $B$ -field distribution in iron using various designs. The simulation shows better uniformity in the portion of the iron layer between the coils, which is bounded by regions that have lesser field strength as we move to the periphery of the iron layer. The ICAL magnet was configured to have a tiling structure that gave the minimum reluctance path, while keeping a reasonably uniform field pattern. This translates into less ampere-turns needed for generation of the required magnetic field. At low ampere-turns, a larger fractional area with $|B|\ge 1$ T can be obtained using a soft magnetic material. A study of the effect of the magnetic field on muon trajectories has been carried out using GEANT4. For muons up to 20 GeV, the energy resolution improves as the magnetic field increases from 1.1 to 1.8 T. The charge identification efficiency for muons was found to be >90% except for large zenith angles. [ABSTRACT FROM PUBLISHER]

High-energy physics experiments at the high-intensity frontier place ever-greater demands on detectors, and in particular on tracking devices. In order to compare the performance of many possible small-size tracking prototypes, a high-resolution cosmic ray tracker may be used as an external track reference. We have constructed a telescope by assembling four spare ladders of the external layers of the Silicon Vertex Tracker of the BaBar experiment. This test facility, operating at INFN Sezione di Pisa, provides the detector under test with an external track with an intrinsic resolution of 15–30 ~\mu\m. The DAQ originally used in the BaBar experiment was replaced by custom-designed boards coupled with an acquisition front-end personal computer through commercial field-programmable gate array evaluation boards. We show that the facility is operative, and we present the performance in terms of tracking resolution and efficiency. A first device has been characterized, and some plots from the analysis demonstrating the telescope performance are shown. [ABSTRACT FROM PUBLISHER]

We have tested a time-of-propagation (TOP) counter, which is a ring-image Cherenkov counter utilizing the position and propagation time of the Cherenkov light produced by particles moving in a quartz radiator. Position-sensitive photomultipliers (PMTs) are attached to the end of the quartz bar to detect the produced Cherenkov-ring image. The velocity of the charged particle was determined by comparing the time-of-propagation spectra of the Cherenkov light with the results of Monte Carlo simulation. From analysis of the test experiment using the 1.22-GeV/c electron beam at SPring-8, we determined the velocity of the electron beam to be 1.001 with a resolution of 0.002. On the basis of this study, we suggest a full setup for the detector for separating pions and kaons in the momentum region from 1.5 to 2.0 GeV/c for a beam angle of less than 6^\circ, by more than four standard deviations. [ABSTRACT FROM PUBLISHER]

The Mu2e experiment at Fermilab is designed to explore charged lepton flavor violation by searching for muon-to-electron conversion. The magnetic field generated by a system of solenoids is a crucial component of Mu2e and requires accurate characterization to detect any potential flaws and to produce a detailed field map. In order to design and build a precise field mapping system consisting of Hall and NMR probes, tolerances and precision for such a system need to be evaluated. To generate a final magnetic field map of the Mu2e solenoids, a continuous field has to be extracted from a discrete set of measurement points. A design for the Mu2e field mapping hardware, and results from simulations to specify parameters for Hall and NMR probes are presented. A fitting procedure for the analytical treatment of our expected magnetic measurements is introduced. [ABSTRACT FROM PUBLISHER]

The Mu2e experiment at Fermilab has been approved by the Department of Energy to proceed with the development of the preliminary design. Integral to the success of Mu2e is the superconducting solenoid system. One of the three major solenoids is the detector solenoid that houses the stopping target and the detectors. The goal of the detector solenoid team is to produce detailed design specifications that are sufficient for vendors to produce the final design drawings, tooling and fabrication procedures and proceed to production. In this paper we summarize the reference design of the detector solenoid. [ABSTRACT FROM PUBLISHER]

The ATLAS Tile hadronic calorimeter (TileCal) provides highly-segmented energy measurements for incident particles. Information from TileCal’s last radial layer can assist in muon tagging and has been considered for inclusion in an upgraded Level-1 trigger. It can assist in the rejection of fake muon triggers arising from background radiation without degrading the efficiency of the trigger. This paper addresses the additional muon discrimination obtained by using a new receiver for the TileCal signals which interfaces with the current ATLAS Level-1 muon trigger. The design and performance of the receiver are also described. [ABSTRACT FROM PUBLISHER]

The paper describes the prototype of a synchronous (Master/Slave) data acquisition system for underground muon counters triggered by surface detectors. A water Cherenkov surface detector (Master) when hit by extensive air showers generates and transmits the trigger to the underground system (Slave) to register the muon fraction of the showers which survived the propagation through 3 m layer of soil. The surface and underground segments are built on the Altera field-programmable gate array (FPGA) CycloneIII/CycloneIV platforms, respectively. Both FPGAs are equipped with NIOS processors, which makes previously used external microcontrollers unnecessary. They also generate necessary interfaces: SDRAM controller, UART, SPI, DMA; interfaces which were previously implemented by means of logic elements. Moving several time-consuming tasks from the logic block (coded in the Altera Hardware Description Language) to the NIOS (coded in “C”) dramatically simplifies the system and increases its flexibility. The time margin for all processes managed by the soft-core NIOS for the 100 Hz T1 trigger rate remains sufficient. NIOS processors communicate with each other via UART protocol and by the RS485 standard. The underground CycloneIV FPGA is programmed remotely via additional MAXII CPLD with nonvolatile programmable memory. Tests have shown that a full string of data processing goes smoothly. The above-mentioned string involves the following processes: the transfer of the trigger with a time stamp from the surface detector into the underground segment via a dedicated line with a galvanic barrier, freezing data from 64 channels at 320 MHz sampling in internal DPRAMs, writing/reading data into/from external SDRAM, extracting physical data identified by GPS time stamps sent from Central Data Acquisition System (CDAS) and the data transfer from the underground NIOS via the surface NIOS to CDAS. [ABSTRACT FROM PUBLISHER]

The upcoming Belle II experiment is designed to work at a luminosity of 8\times 10^35 cm^-2s^-1, 40 times higher than its predecessor. The pixel detector of Belle II with its \sim8 million channels will deliver ten times more data than all other sub-detectors together. A data rate of 22 Gbytes/s is expected for a trigger rate of 30 kHz and an estimated pixel detector occupancy of 3%, which is by far exceeding the specifications of the Belle II event builder system. Therefore a realtime data reduction of a factor > 30 is needed. [ABSTRACT FROM AUTHOR]

The NA62 RICH detector is used for the separation of pions and muons in the momentum range 15–35 GeV/c and is expected to provide a muon suppression factor better than 10^-2. A prototype of the final detector equipped with about 400 PMs (RICH-400 prototype) was built and tested in a dedicated run in 2009. The \pi-\mu separation was tested, as well as the effect of the contamination of the neon radiator with different amounts of oxygen and CO2. The \mu misidentification probability is about 0.7% and the time resolution better than 100 ps in the whole momentum range. We did not observe any absorption of the light due to the contamination of the radiator, however an effect on the ring radius is clearly observed due to the change of the refractive index of the medium. The conclusion of the studies is that the amount of CO2 in the final detector should be known at the 10^-3 level of precision or the quality of the pion identification could be seriously compromised. [ABSTRACT FROM PUBLISHER]

A muon tracking system consisting of four 9 cm \times\,10 cm sized bulk Micromegas detectors with 128 \mum amplification-gap and two 10 cm \times\,10 cm triple GEM detectors is foreseen for high-precision tracking of 160 GeV muons at the H8 beamline at CERN with a readout rate above 10 kHz and an overall resolution below 20 \mum. Signal studies of both detector types have been performed by recording cosmic muon and 5.9 keV X-ray signals. The analysis of the complete signal-cycles allows for the determination of rise times, pulse heights, timing fluctuations and discrimination of background, resulting in a FWHM energy resolution of about 20% and detection efficiencies of 98% and more. Models for signal formation in both detector types will be presented. A single detector spatial resolution of 75 \mum was measured for cosmic muons using a fast Gassiplex based strip readout with readout strips of 150 \mum width and a pitch of 250 \mum. Multiple scattering of low energy cosmic muons deteriorates the observable spatial detector resolution by more than 20 \mum. Additionally, we report on the sensitivity to gamma- and neutron background and on the behavior of spatial resolution as a function of background rates. [ABSTRACT FROM AUTHOR]

With the tenfold luminosity increase envisaged at the HL-LHC, the background (i.e., photons, neutrons, \ldots) and the event pileup probability are expected to highly increase in proportion in the different experiments, especially in the forward regions, for instance the muons chambers of the ATLAS detector. Detectors based on the Micromegas principle should be good alternatives for the detector upgrade in the HL-LHC framework because of its good spatial (< 100\mu\m) and time (few ns) resolutions, high-rate capability, radiation hardness, good robustness, and the possibility to build large areas. The aim of this study is to demonstrate that it is possible to reduce the discharge probability and protect the electronics by using a resistive anode plane in a high-flux hadrons environment. Several prototypes of 10 \times 10~\cm^2, with different pitches (0.5–2 mm) and different resistive layers have been tested at CERN (\pi^+@SPS). Several tests have been performed with a telescope at different voltages to assess the performance of the detectors in terms of position resolution and efficiency. The spark behavior in these conditions has also been evaluated. Resistive coating has been shown to be a successful method to reduce the effect of sparks on the efficiency of micromegas. A good spatial resolution (\sim 80\ \mu\m) can be reached with a resistive strip coating detector of 1-mm pitch, and a high efficiency ( > 98\%) can be achieved with resistive-anode micromegas detector. An X-rays irradiation has also been performed, showing no ageing effect after more than 21 days exposure and an integrated charge of almost 1C. [ABSTRACT FROM AUTHOR]