Showing papers in "Nuclear instruments and methods in physics research in 2022"

First gadolinium loading to Super-Kamiokande

Abstract: In order to improve Super-Kamiokande’s neutron detection efficiency and to thereby increase its sensitivity to the diffuse supernova neutrino background flux, 13 tons of Gd2(SO4)3⋅8H2O (gadolinium sulfate octahydrate) was dissolved into the detector’s otherwise ultrapure water from July 14 to August 17, 2020, marking the start of the SK-Gd phase of operations. During the loading, water was continuously recirculated at a rate of 60 m3/h, extracting water from the top of the detector and mixing it with concentrated Gd2(SO4)3⋅8H2O solution to create a 0.02% solution of the Gd compound before injecting it into the bottom of the detector. A clear boundary between the Gd-loaded and pure water was maintained through the loading, enabling monitoring of the loading itself and the spatial uniformity of the Gd concentration over the 35 days it took to reach the top of the detector. During the subsequent commissioning the recirculation rate was increased to 120 m3/h, resulting in a constant and uniform distribution of Gd throughout the detector and water transparency equivalent to that of previous pure-water operation periods. Using an Am–Be neutron calibration source the mean neutron capture time was measured to be 115±1 μs, which corresponds to a Gd concentration of 111±2 ppm, as expected for this level of Gd loading. This paper describes changes made to the water circulation system for this detector upgrade, the Gd loading procedure, detector commissioning, and the first neutron calibration measurements in SK-Gd.

DGFRS-2—A gas-filled recoil separator for the Dubna Super Heavy Element Factory

Abstract: The main goal of development of the new Dubna Gas-Filled Recoil Separator (DGFRS-2) is to sufficiently improve the efficiency of studies on heavy and superheavy nuclei at the Super Heavy Element Factory of the Flerov Laboratory of Nuclear Reactions (FLNR) at the Joint Institute for Nuclear Research. The use of beams with the intensity up to 6×1013 s−1 (10 pμA) delivered by the DC280 cyclotron requires an effective setup providing high suppression of background reaction products. The described gas-filled separator is optimized for synthesis and study of heavy isotopes produced in complete fusion reactions of massive nuclei. Basic characteristics of DGFRS-2, as well as the results of the first test experiments, are presented. In comparison to the DGFRS-1, the transmission efficiency was doubled, and the background was reduced by a factor 200.

Quantifying spatial resolution in a fast neutron radiography system

Abstract: Neutron imaging is a powerful nondestructive examination modality that has been employed in various applications. Fast neutrons provide advantages over lower energy neutrons, such as examining thicker samples and inducing negligible activation and transmutations. However, fast neutrons interact mostly via elastic scattering with both the neutron detector and the object, causing degradation in spatial resolution. This study explores the quantification of spatial resolution caused by the testing target itself and suggests proper candidate materials for characterizing spatial resolution in terms of modulation transfer function. Knife-edge radiographs of 3 mm, 6 mm, and 5 cm thick Tantalum (Ta) foils, and a 2.54 cm Tungsten (W) cube were acquired using a CCD-based imaging system and a Polyvinyl Toluene (PVT) scintillator at the Ohio State Research Reactor (OSURR)’s fast neutron beam facility. The spatial resolutions calculated were 195 ± 20 μ m , 224 ± 22 μ m , 248 ± 25 μ m , and 435 ± 44 μ m for 3 mm, 6 mm, and 5 cm Ta foils, and 2.54 cm W cube, respectively. The results showed a worsening spatial resolution with increasing target thickness. Simulations and calculations estimate that elastic scattering kinematics between neutrons and protons in the PVT medium also limits spatial resolution, and it sets a lower limit of ∼ 44 μ m on the spatial resolution for 2 MeV neutrons.

Reconstructing the kinematics of deep inelastic scattering with deep learning

Abstract: We introduce a method to reconstruct the kinematics of neutral-current deep inelastic scattering (DIS) using a deep neural network (DNN). Unlike traditional methods, it exploits the full kinematic information of both the scattered electron and the hadronic-final state, and it accounts for QED radiation by identifying events with radiated photons and event-level momentum imbalance. The method is studied with simulated events at HERA and the future Electron–Ion Collider (EIC). We show that the DNN method outperforms all the traditional methods over the full phase space, improving resolution and reducing bias. Our method has the potential to extend the kinematic reach of future experiments at the EIC, and thus their discovery potential in polarized and nuclear DIS.

Power-efficient high-frequency readout concepts of SiPMs for TOF-PET and HEP

Abstract: Recent SiPM developments, together with improved readout electronics, opened new doors in time of flight positron emission tomography (TOF-PET) and high energy physics (HEP) research with a focus on prompt photon detection with inorganic scintillators . For instance, the relatively high Cherenkov yield of Bismuth Germanate (BGO) upon 511 keV gamma interaction has triggered a lot of interest, especially for its use in total-body PET scanners due to the relatively low production costs of BGO. However, especially in TOF-PET, the electronic readout for BGO still poses unsolved problems. Lab experiments have shown the benefit of Cherenkov detection, with coincidence time resolutions (CTRs) < 200 ps FWHM achieved, but lack system integration due to an unacceptably high power consumption ( ≫ 30 mW) of the used amplifiers. Therefore it becomes necessary to investigate different readout concepts of modern analog SiPMs, for which we tested several high-bandwidth amplifiers, commercially available, small in dimension, cheap and with a power consumption ranging from 288 mW to only 17 mW. We found that all tested amplifiers showed similar CTR performance of ∼ 100 ps FWHM coupling 3 × 3 × 3 mm 3 LYSO:Ce cubes from EPIC-crystals to S14160-3050HS Hamamatsu SiPMs with 3 × 3 mm 2 active area. The CTR performance with BGO is comparable for all tested amplifiers and the noise contribution to the CTR is found negligible. The results obtained lead to the conclusion that power-efficient SiPM readout solutions can be found, also suitable for Cherenkov light detection with BGO, which opens the door for their implementation in application-specific integrated circuits (ASICs) and systems.

Improvement of Geant4 Neutron-HP package: From methodology to evaluated nuclear data library

Abstract: An accurate description of interactions between thermal neutrons (below 4 eV) and materials is key to simulate the transport of neutrons in a wide range of applications such as criticality-safety, reactor physics, compact accelerator-driven neutron sources, radiological shielding or nuclear instrumentation, just to name a few. While the Monte Carlo transport code Geant4 was initially developed to simulate particle physics experiments, %-with a large emphasis given on modeled cross-sections for all known particles at all conceivable energies-, its use has spread to neutronics applications, requiring evaluated cross-sections for neutrons and gammas between $0$ and $20$ MeV (the so-called neutron High Precision -HP- package), as well as a proper offline or on-the-flight treatment of these cross-sections. In this paper we will point out limitations affecting Geant4 (version 10.07.p01) thermal neutron treatment and associated nuclear data libraries, by using comparisons with the reference Monte Carlo neutron transport code \tripoli, version 11, and we will present the results of various modifications of the Geant4 neutron-HP package, required to overcome these limitations. Also, in order to broaden the support of nuclear data libraries compatible with Geant4, a nuclear processing tool has been developed and validated allowing the use of the code together with ENDF-BVIII.0 and JEFF-3.3 libraries for example. These changes should be taken into account in an upcoming Geant4 release.

Pulse characteristics of CLYC and piled-up neutron–gamma discrimination using a convolutional neural network

Abstract: A method of describing the characteristics of Cs2 LiYCl 6 scintillator pulses is proposed by fitting all individual pulses with multiple exponential functions. Simulated pulses under very high counting rates (e.g., 2–40 Million counts per second) are generated by sampling from fitted parameter distributions, which include the non piled-up neutron (n) and gamma (g) pulses as well as piled-up gamma + neutron (g + n), neutron + gamma (n + g), neutron + neutron (n + n), and gamma + gamma (g + g) pulses. A fully connected neural network (FCNN) model can discriminate n and g signals clearly and demonstrates a discrimination performance similar to the traditional charge comparison method. A model trained with experimental data demonstrated very good prediction accuracy on simulated data, and a model trained with simulated data demonstrated good prediction accuracy on experimental data as well, indicating all characteristic of CLYC had been simulated. A convolutional neural network (CNN) model could discriminate between the six pulse types more effectively than a FCNN model, producing a discrimination error lower than 0.22% for n, g, n + g, and n + n pulses, and an error lower than 3.61% for g + g and g + n pulses. These results indicate that a CNN model is very suitable for complicated n–g discrimination under a piled-up condition.

NJOY+NCrystal: An open-source tool for creating thermal neutron scattering libraries with mixed elastic support

Abstract: In this work we present NJOY+NCrystal, a tool to generate thermal neutron scattering libraries with support for coherent and incoherent elastic components for crystalline solid materials. This tool, which is a customized version of NJOY, was created by modifying the nuclear data processing program NJOY to call the thermal scattering software library NCrystal, and includes a proposed change in the ENDF-6 format to store both the coherent and incoherent elastic components. Necessary changes to enable this format in NJOY, as well as to sample it in the OpenMC Monte Carlo code, are detailed here. Examples of materials that are coherent–dominant, incoherent–dominant, and mixed elastic scatterers are presented, as well as the creation of novel libraries for MgH2 and MgD2, that are under consideration as advanced neutron reflectors in the HighNESS project at the European Spallation Source. NJOY+NCrystal greatly simplifies the process to generate thermal scattering libraries (TSL) and this is exemplified with 213 new and updated TSL evaluations.

Mo/4H-SiC Schottky diodes for room temperature X-ray and γ-ray spectroscopy

Abstract: Mo/4H-SiC Schottky diodes were investigated as detectors for their suitability in photon counting X-ray and γ-ray spectroscopy. The Schottky diodes, with a 35μm thick n− epitaxial layer, were treated with a phosphorus pentoxide surface passivation, which had been previously shown to improve the homogeneity of the metal–semiconductor interface and suppress leakage current. One device was coupled to a low-noise charge sensitive preamplifier and standard onwards readout electronics; the resultant spectrometer was used to accumulated X-ray and γ-ray spectra. The spectrometer had an energy resolution of 1.67 keV ± 0.08 keV (97 e− rms ± 5 e− rms) at 5.9 keV and 1.6 keV ± 0.1 keV (93 e− rms ± 6 e− rms) at 59.54 keV. Despite the moderate energy resolution achieved, the results suggested that the leakage current of the Mo/4H-SiC Schottky diode detector was not the dominant source of noise limiting the energy resolution of the spectrometer at the optimum operating conditions at room temperature; lossy dielectrics in close proximity to the input of the preamplifier (including stray dielectrics) and the relatively large average electron–hole pair creation energy of 4H-SiC (an inherent property) were the main contributors to the achieved energy resolution in energy terms.

Front-end electronics for silicon strip trackers: Architectures and evolution

Abstract: Tracking detectors based on segmented semiconductor sensors have been present in high-energy physics experiments for more than 40 years. The development of these sensors was always strongly linked to advances in CMOS technologies that offer features supporting the design of specialized ASICs for readout purposes. While in the beginning, the front-end electronics only provided simple signal reception and amplification, sending out the raw analog data, growing demands from the experiments lead designers to begin directly integrating more advanced features for data processing and storage, power management, calibration functions, amongst others, on-chip. This development was, and continues to be, possible due to CMOS technology evolution, in particular the scaling. Besides higher speed and better transconductance, today’s sub-micron processes offer intrinsic ionizing radiation tolerance which, together with Single Event Effect (SEE) hardening techniques, allows design for reliable operation in a harsh radiation environment. Despite the enhanced functionality and greater number of transistors, higher time resolution and, in consequence, faster analog shaping and readout speed, the power consumption of typical front-end electronics measured per area of tracking detector remains of the order of a few tens of mW per square centimeter. The basic architecture of the input stage has also remained practically the same over the last 40 years. The optimal solution providing wide bandwidth and high open-loop gain at minimum power is the cascode: a cascade of common-source and common-gate amplifiers. Although each particular implementation differs slightly depending on the specific requirements and process used, the core of the preamplifier remains the same since its conception.

Performance of portable TDCR systems developed at LNE-LNHB

Abstract: The triple to double coincidence ratio (TDCR) liquid scintillation measurement technique is commonly used in national metrology institutes (NMIs) to perform standardization of pure beta emitters. The LNE-LNHB historical device, RCTD1, is a quite large device, which has been developed and commonly used over the past 30 years with its associated electronics for measurements of various radionuclides. During the last 4 years LNE-LNHB has developed two new portable TDCR devices. Such portable instrumentation gives end-users access to a reference measurement method that can be used for a large number of radionuclides. It addresses a wide range of industrial and medical applications for radionuclide metrology, including calibrations of solutions containing short-lived radionuclides, avoidance of radioactive source transportation, and performing on-site comparison to promote radionuclide metrology harmonization. In this paper, we will present the newly developed portable TDCR liquid scintillation measurement systems. Two kinds of devices have been developed and designed at LNE-LNHB and built using fused deposition modelling (FDM) 3D printing: a mini-TDCR (25 cm diameter, 10 cm height) and a micro-TDCR (16 cm diameter, 10 cm height). After a detailed discussion of the design and the possibilities offered by 3D printing for their conception, this paper will present the performance of the devices obtained for several radionuclides. The results will be compared with the RCTD1 in order to validate the performance of the new devices. They exhibit improved performance, such as higher detection efficiency, and include various useful tools for proper on-site metrology. The first tests, which were performed in Orsay Hospital (CEA/SHFJ) and in another laboratory (IRSN), allowed us to show the very good overall performance of the systems including their outstanding linearity, which was tested in the range from 430 000 s −1 down to 160 s −1 in the double coincidences channel. Applications of the developed systems for high and low activity measurements are also discussed. Finally, the portable device has been used for half-life measurements in order to check for impurities in a radio-pharmaceutical solution.

A feasibility study of extruded plastic scintillator embedding WLS fiber for AMoRE-II muon veto

Abstract: AMoRE-II is the second phase of the Advanced Molybdenum-based Rare process Experiment aiming to search for the neutrino-less double beta decay of 100Mo isotopes using ∼200 kg of molybdenum-containing cryogenic detectors. The AMoRE-II needs to keep the background level below 10−5 counts/keV/kg/year with various methods to maximize the sensitivity. One of the methods is to have the experiment be carried out deep underground free from the cosmic ray backgrounds. The AMoRE-II will run at Yemilab with ∼1,000 m depth. However, even in such a deep underground environment, there are still survived cosmic muons, which can affect the measurement and should be excluded as much as possible. A muon veto detector is necessary to reject muon-induced particles coming to the inner detector where the molybdate cryogenic detectors are located. We have studied the possibility of using an extruded plastic scintillator and wavelength shifting fiber together with SiPM as a muon veto system. We found that the best configuration is two layers of plastic scintillators (PSs, 150 cm × 25 cm × 1.2 cm) with two WLS fibers per groove, which could separate radiogenic gammas well with muon detection efficiency above 99.4% along the length of the PS. Based on the expected flux from a prototype measurement at a 700 m deep underground, we found that the dead time of the muon veto system for AMoRE-II at the Yemilab with a 1 ms veto window is 0.6% of whole muon events.

Interaction chamber for laser Compton slant-scattering in SLEGS beamline at Shanghai Light Source

Abstract: Energy-variable gamma-rays are produced in the laser Compton slant-scattering in the Shanghai laser electron gamma source (SLEGS) beamline of the Shanghai Light Source. An interaction chamber composed of the rotating laser optical system, shielding finger, and reference-target insertion device was developed to ensure slant scattering in the angular range of 20–160°, producing gamma-rays in the energy range of 0.66–21.1 MeV with a flux of 4.8 × 105–1.5 × 107 photons/s. SLEGS is the first slant-scattering beamline which systematically produces energy-variable gamma-ray beams and continuously tune the gamma-ray energy in the laser Compton slant-scattering. We report on designed performance of the slant-scattering and results of a test run.

4D tracking: Present status and perspective

Abstract: The past ten years have seen the advent of silicon-based precise timing detectors for charged particle tracking. The underlying reason for this evolution is a design innovation: the Low-Gain Avalanche Diode (LGAD). In its simplicity, the LGAD design is an obvious step with momentous consequences: low gain leads to large signals maintaining sensors stability and low noise, allowing sensor segmentation. Albeit introduced for a different reason, to compensate for charge trapping in irradiated silicon sensors, LGAD found fertile ground in the design of silicon-based timing detectors. Spurred by this design innovation, solid-state-based timing detectors for charged particles are going through an intense phase of R&D, and hybrid and monolithic sensors, with or without internal gain, are being explored. This contribution offers a review of this booming field.

The DESPEC setup for GSI and FAIR

Abstract: The DEcay SPECtroscopy (DESPEC) setup for nuclear structure investigations was developed and commissioned at GSI, Germany in preparation for a full campaign of experiments at the FRS and Super-FRS. In this paper, we report on the first employment of the setup in the hybrid configuration with the AIDA implanter coupled to the FATIMA LaBr3(Ce) fast-timing array, and high-purity germanium detectors. Initial results are shown from the first experiments carried out with the setup. An overview of the setup and function is discussed, including technical advancements along the path.

Heavy-ion beam test of a monolithic silicon pixel sensor with a new 130 nm High-Resistivity CMOS process

Abstract: The Topmetal-M is a newly designed monolithic silicon pixel sensor for charged particle tracking based on a novel detector structure and implemented in a new 130 nm High-Resistivity (>1 kΩ cm) CMOS process. This sensor integrates the functionality of the Monolithic Active Pixel Sensor (MAPS) and the Topmetal sensor. It has a matrix of 512 × 400 pixels with the pitch of 40μm×40μm. Heavy-ion campaigns with a 181Ta35+ beam have been performed to study the performance of this Topmetal-M sensor. The test results demonstrate it has an excellent response to particle energy deposition. Furthermore,this sensor is still fully functional after exposure to ∼14.1 krad, and no Single Event Latch-up (SEL) occurred. In addition, the baseline, the Equivalent Noise Charge (ENC), and the number of bad pixels show relatively good performance.

Bandgap engineering of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="d1e627" altimg="si1.svg"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cd</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub><mml:ms

Abstract: CdZnTe (CZT) detectors with more than 10% zinc content did not show any remarkable improvement in the detector performance due to the additional defects introduced by the higher zinc content. However, recent research showed that the formation of defects was suppressed effectively by adding a small amount of selenium (at. 2%) in CZT. On this basis, we attempted to enhance the detector performance through the bandgap engineering by increasing the zinc content up to 25%, while adding 2% of selenium. Multiple CdZnTeSe (CZTS) ingots with Zn = 10, 12.5, 15, and 20%, while keeping the Se contents at 2%, were grown by the Bridgman method. The bandgap of CZTS for the different Zn and Se contents was analyzed and then introduced modified equation for predicting more accurately the bandgap of other alloy compositions. Also, the crystallinity of CZTS was evaluated by photoluminescence measurements. The pulse height spectra for Am-241 and Co-57 sources were used to evaluate the detector performance for the CZTS samples.

A High-Granularity Timing Detector for the ATLAS Phase-II upgrade

Abstract: The increase of the particle flux at the HL-LHC with instantaneous luminosities up to L=7.5 × 10 34 cm −2 s −1 will have a severe impact on the ATLAS detector reconstruction and trigger performance. The end-cap and forward region where the liquid Argon calorimeter has coarser granularity and the inner tracker has poorer momentum resolution will be particularly affected. A High Granularity Timing Detector will be installed in front of the liquid Argon end-cap calorimeters to help in charged-particle reconstruction and luminosity measurement. This low angle detector is introduced to augment the new all-silicon Inner Tracker in the pseudo-rapidity range from 2.4 to 4.0. Two silicon-sensor double-sided per end-cap will provide precision timing information for minimum-ionizing particles with a resolution as good as 30 ps per track in order to assign each particle to the correct vertex. Readout cells have a size of 1.3 mm × 1.3 mm, leading to a highly granular detector with 3.7 million channels. The Low Gain Avalanche Detectors technology has been chosen as sensor as it provides excellent timing performance. The requirements and overall specifications of the High Granularity Timing Detector are presented as well as the technical design and the project status. The on-going R&D effort carried out to study the sensors, the readout ASIC, and the other components, supported by laboratory and test beam results, are also presented.

SPring-8 LEPS2 beamline: A facility to produce a multi-GeV photon beam via laser Compton scattering

Abstract: We have constructed a new laser-Compton-scattering facility, called the LEPS2 beamline, at the 8-GeV electron storage ring, SPring-8. This facility provides a linearly polarized photon beam in a tagged energy range of 1.3--2.4 GeV. Thanks to a small divergence of the low-emittance storage-ring electrons, the tagged photon beam has a size (sigma) suppressed to about 4 mm even after it travels about 130 m to the experimental building that is independent of the storage ring building and contains large detector systems. This beamline is designed to achieve a photon beam intensity higher than that of the first laser-Compton-scattering beamline at SPring-8 by adopting the simultaneous injection of up to four high-power laser beams and increasing a transmittance for the long photon-beam path up to about 77%. The new beamline is under operation for hadron photoproduction experiments.

Pulse-shape discrimination in water-based scintillators

Abstract: This work describes a class of liquid scintillators that contain mostly water (>50 wt% of the entire composition) and can discriminate between interactions induced by neutrons and gamma rays. By balancing the interface interactions between the components of the formulation, these scintillators form emulsions that can be thermodynamically stable. This approach, which considers a quantity known as the hydrophilic–lipophilic difference, requires consideration of the salinity and temperature as well as characterization of the surfactants and oil phase. Emulsions comprised of water and various oils were characterized first. Then, the effect of scintillating dyes in the oil phase was considered, followed by the construction of partial phase diagrams of the emulsions. For transparent oil-in-water emulsions with a single phase, the scintillation light yield and metrics related to pulse-shape discrimination were measured. The best performing scintillators contained 33 wt% of a scintillating oil phase and exhibited a light yield that was as high as 18% of the light yield of a commercially available liquid scintillator that does not contain water (EJ-309). These water-based liquid scintillators exhibited a figure of merit of neutron/gamma ray discrimination as high as 1.79 at about 1500 keVee.

The methodology for validation of cross sections in quasi monoenergetic neutron field

Abstract: Dosimetry cross sections are fundamental quantities for proper determination of the neutron fluences in points of interest under heavy radiation load. One of the critical applications is the Reactor Pressure Vessel aging management, related to the correct estimation of its residual lifetime or for many non-reactor applications including neutron dosimetry of accelerator-based fields or space applications. The neutron flux of neutrons above 12 MeV in reference to fission spectra is below 1%. Therefore, new reference neutron fields with average energy above 5 MeV should be developed for the validation of neutron dosimetry cross sections up to 60 MeV. This paper presents the testing of a new methodology for the use of quasi monoenergetic neutron fields, where different sensitivity allows validations of the dosimetry cross section at energies much higher than the average energy of around 2 MeV typical of fission spectra. The exact shape of the neutron spectrum in the tested fields is measured by stilbene spectrometry. The total flux is determined from Ni and Al flux monitors. The developed methodology was applied to the validation of selected reactions from the IRDFF-II library showing satisfactory agreement.

Femtosecond laser studies of the Single Event Effects in Low Gain Avalanche Detectors and PINs at ELI Beamlines

Abstract: A feasibility study conducted at the laser facility ELI Beamlines confirms that fs-laser pulses can produce Single Event Effect (SEE), Single Event Upset (SEU) and Single Event Burnout (SEB) conditions in irradiated Low Gain Avalanche Detectors (LGADs) and the corresponding PIN diodes. A comprehensive and systematic study on PIN and LGAD mortality has been conducted to experimentally determine the stability, instability, and irreversible damage thresholds for LGADs and PINs exploiting a fs-laser system. Thresholds are given as sets of two parameters: bias voltage and laser pulse energy (energy deposition threshold). Using the Two-Photon Absorption (TPA) - Transient Current Technique (TCT) to study the mechanism that triggers SEU/SEB conditions in LGADs, as a function of illumination position establishes this technique as a promising tool for more advanced explorations of SEE, not only in LGADs but also in other Si-based sensors. To achieve these results, a highly flexible and versatile fs-laser-based TCT experimental setup has been developed at ELI Beamlines, allowing two TCT modalities with the same setup: Single Photon Absorption (SPA) at 800 nm laser wavelength and TPA at 1550 nm.

ELIGANT-GN — ELI Gamma Above Neutron Threshold: The Gamma-Neutron setup

Abstract: Here we present the ELI Gamma Above Neutron Threshold setup recently implemented at the Extreme Light Infrastructure – Nuclear Physics. The main goals of the detector array are presented, as well as the mechanical design and the performance of the individual detectors. In addition, we have performed Geant4 simulations for realistic beam conditions. Finally, we show the performance of the array as a whole and outline the analysis procedure for complex experimental measurements by reproducing the angular correlations of neutrons following spontaneous fission of a 252Cf source.

Quality control of mass-produced GEM detectors for the CMS GE1/1 muon upgrade

Abstract: The series of upgrades to the Large Hadron Collider, culminating in the High Luminosity Large Hadron Collider, will enable a significant expansion of the physics program of the CMS experiment. However, the accelerator upgrades will also make the experimental conditions more challenging, with implications for detector operations, triggering, and data analysis. The luminosity of the proton–proton collisions is expected to exceed 2–3×1034 cm−2s−1 for Run 3 (starting in 2022), and it will be at least 5×1034 cm−2s−1 when the High Luminosity Large Hadron Collider is completed for Run 4. These conditions will affect muon triggering, identification, and measurement, which are critical capabilities of the experiment. To address these challenges, additional muon detectors are being installed in the CMS endcaps, based on Gas Electron Multiplier technology. For this purpose, 161 large triple-Gas Electron Multiplier detectors have been constructed and tested. Installation of these devices began in 2019 with the GE1/1 station and will be followed by two additional stations, GE2/1 and ME0, to be installed in 2023 and 2026, respectively. The assembly and quality control of the GE1/1 detectors were distributed across several production sites around the world. We motivate and discuss the quality control procedures that were developed to standardize the performance of the detectors, and we present the final results of the production. Out of 161 detectors produced, 156 detectors passed all tests, and 144 detectors are now installed in the CMS experiment. The various visual inspections, gas tightness tests, intrinsic noise rate characterizations, and effective gas gain and response uniformity tests allowed the project to achieve this high success rate.

Neutron diagnostic system at the Globus-M2 tokamak

Abstract: A neutron diagnostic system was developed at the Ioffe Institute as part of the Globus-M2 tokamak to optimize NBI heating conditions and evaluate heating efficiency. The system contains two compact neutron spectrometers based on the liquid organic scintillator BC-501A and two gas-discharge counters based on a 10B isotope. The BC-501A spectrometers were calibrated by measuring neutron emission produced in a 9Be(α,n)12C nuclear reaction on the cyclotron facility at the Ioffe Institute. In addition, in situ calibrations of the system, including the neutron spectrometers and the gas-discharge counters, was carried out using an Am–Be neutron source to provide accurate measurements of the total neutron yield from the plasma of the Globus-M2 tokamak. During the plasma experiments at the Globus-M2 tokamak, a deuterium beam was injected into the deuterium plasma that causes a yield of the DD-neutrons with ∼2.45 MeV energy. The neutron spectrometry diagnostic system was used to provide neutron measurements and detect the DD-neutrons in these experiments. The neutron yield and the DD-reaction rate during plasma discharges were evaluated. The energy distributions of neutrons emitted from plasma during discharges with neutron beam injection were reconstructed from the measured neutron spectra.

A muon–ion collider at BNL: The future QCD frontier and path to a new energy frontier of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="d1e450" altimg="si4.svg"><mml:mrow><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>μ</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math> colliders

Abstract: We propose the development and construction of a novel muon-ion collider (MuIC) at Brookhaven National Laboratory (BNL) in the USA as an upgrade to succeed the electron-ion collider (EIC) that is scheduled to commence in the early 2030s, by a joint effort of the nuclear and particle physics communities. The BNL facility could accommodate a muon storage beam with an energy up to about 1~TeV with existing magnet technology. When collided with a 275~GeV hadron beam, the MuIC center-of-mass energy of about 1~TeV will extend the kinematic coverage of deep inelastic scattering physics at the EIC (with polarized beams) by more than an order of magnitude in $Q^2$ and $x$, opening a new QCD frontier to address many fundamental scientific questions in nuclear and particle physics. This coverage is comparable to that of the proposed Large Hadron-Electron Collider (LHeC) at CERN, but with complementary lepton and hadron kinematics and beam polarization. Additionally, the developmentof a MuIC at BNL will focus the worldwide R\&D efforts on muon collider technology and serve as a demonstrator toward a future muon-antimuon collider at {$\mathcal O$}(10)~TeV energies, which is an attractive option to reach the next high energy frontier in particle physics at an affordable cost and a smaller footprint than a future circular hadron collider. We discuss here the possible design parameters of the MuIC, kinematic coverage, science cases, and detector design considerations including estimates of resolutions on DIS kinematic variables. A possible road map toward the future MuIC and muon-antimuon colliders is also presented.

Universal drive unit for detector velocity modulation in Mössbauer spectroscopy

Abstract: A multifunctional transducer for applications in Mössbauer spectrometry has been developed. The transducer design and performance is presented in detail. The described transducer is able to carry an object weighing up to approximately 1.5 kg. Thus it is able to operate while being loaded with a scintillation detector. This ability offers a number of interesting measuring configurations, with the most beneficial being the possibility of measuring several Mössbauer spectra while using a single radiation source. The capabilities of our transducer are demonstrated by acquiring spectra of 12 μ m α -Fe in different velocity ranges and at different operational frequencies using a triangular and saw velocity profile. The linewidth obtained under optimal conditions was 0.21 mm/s. • Detail description of the construction of Doppler transducer for Mössbauer spectroscopy. • Possibilities of moving with heavy objects including scintillation detector. • Twice more efficient usage of a radioactive source. • New configuration of setups for transmission, emission and resonant Mössbauer spectroscopy. • Opening new possibilities in manipulation with source, detector and absorber, suitable for gamma optics experiments.

Implementation of the trigger system of the ICARUS-T600 detector at Fermilab

Abstract: The ICARUS-T600 liquid argon (LAr) time projection chamber (TPC) detector is currently deployed as a far detector of the Short Baseline Neutrino (SBN) program at Fermilab (USA) to search for a possible LSND-like sterile neutrino signal at Δm2≈1 eV2 with the Booster (BNB) and Main Injector (NuMI) Neutrino Beams [1]. A global physical event rate of ≈0.6Hz, including the genuine neutrino interactions in LAr, beam halos and cosmic interactions inside the proton pulse time windows, is expected, roughly corresponding to ≈4 PB of data for the total 6.6×1020 protons on target exposure if the full ICARUS-T600 detector is read-out (≈200 MB event size). The designed trigger system described here would collect the genuine neutrino interactions with a ≈95% expected efficiency.

Effect of front, lateral and back dead layer thicknesses of a HPGe detector on full energy peak efficiency

Abstract: As well known, High Purity Germanium (HPGe) detectors have a wide range of applications in every area where radiation detection and measurements are involved. One of the most important parameters in this respect is the determination of the full energy peak (FEP) efficiency. There are certain parameters affecting the so-called FEP efficiency. Perhaps the most important one is the thickness of dead layers of the crystal itself. In the current study, we investigated the effects of the thickness of front, lateral and back dead layer thicknesses of the detector crystal on the FEP efficiencies for the energy range 30 keV–5 MeV using EGS4 Monte Carlo simulation package. It was shown that the change in the thickness of the front dead layer has significant effect on the efficiency values for the energy interval 30–400 keV. The change in the thickness of the lateral and back dead layer was shown to have significant effects on the efficiencies for the energy intervals 2–3 MeV and 3–5 MeV, respectively. The results were checked using GEANT4 and a good agreement was observed.

Gain reduction mechanism observed in Low Gain Avalanche Diodes

Abstract: Low Gain Avalanche Diodes (LGADs) is one of the candidate sensing technologies for future 4D-tracking applications and recently have been qualified to be used in the ATLAS and CMS timing detectors for the CERN High Luminosity Large Hadron Collider upgrade. LGADs can achieve an excellent timing performance by the presence of an internal gain that improves the signal-to-noise ratio leading to a better time resolution. These detectors are designed to exhibit a moderate gain with an increase of the reverse bias voltage. The value of the gain strongly depends on the temperature. Thus, these two values must be kept under control in the experiments to maintain the gain within the required values. A reduction in the reverse bias or an increase in the temperature will reduce the gain significantly. In this paper, a mechanism for gain reduction in LGADs is going to be presented. It was observed, that the gain measured in these devices depends on the charge density projected into the gain layer, generated by a laser or a charged particle in their bulk. Measurements performed with different detectors showed that ionizing processes that induce more charge density in the detector bulk lead to a decrease in the detector’s measured gain. Measurements conducted with an IR-laser and a Sr-90 in the lab, modifying the charge density generated in the detector bulk, confirmed this mechanism and will be presented here.