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In this paper, we experimentally and analytically evaluate the reliability of two state-of-the-art neural networks for linear regression and pattern recognition (multilayer perceptron and single-layer perceptron) implemented in a system-on-chip composed of a field-programmable gate array (FPGA) and a microprocessor. We have considered, for each neural network, three different activation function complexities, to evaluate how the implementation affects FPGAs reliability. As we show in this paper, higher complexity increases the exposed area but reduces the probability of one failure to impact the network output. In addition, we propose to distinguish between critical and tolerable errors in artificial neural networks. Experiments using a controlled heavy-ions beam show that, for both networks, only about 30% of the observed output errors actually affect the outputs correctness. We identify the causes of critical errors through fault injection, and found that faults in initial layers are more likely to significantly affect the output. [ABSTRACT FROM PUBLISHER]

The doping profile of silicon-germanium heterojunction bipolar transistors (SiGe HBTs) is modified to enhance inverse-mode (IM) device operation. Device improvements are presented in this paper, along with the impact the alterations have on the radiation effects response. This investigation represents the first published occurrence of a radiation-hardening-by-process approach in a SiGe HBT technology. Results show that improving IM performance can degrade the radiation tolerance of the structure. Total ionizing dose and single-event transient (SET) results are provided along with an analysis that utilizes TCAD simulation. An additional profile modification using an implanted vertical superjunction is included in this paper to expand upon how nonradiation specific device modifications can impact SETs. [ABSTRACT FROM PUBLISHER]

At the gigahertz range of frequencies, contribution of combinational logic upsets has increased significantly to the overall single-event (SE) upset rate (SER) of sequential circuits. Most approaches for modeling and/or predicting logic SER are either pure simulation based or pure experiment based. Simulation-based approaches need a lot of computing power. Experiment-based approaches require fabrication of actual circuits. This paper presents an empirical method that uses experimental data from simple test structures for estimating SE vulnerability of any combinational logic circuit. Estimated logic SEU cross section matches well with the measured logic SEU cross section. Estimated logic SEU cross section results obtained with the proposed method are within $2\times $ average error when compared to the experimentally measured logic SEU cross section. This method only needs to be calibrated once for use at a given technology node. [ABSTRACT FROM PUBLISHER]

The May 2021 Special Issue of the IEEE Transactions on Nuclear Science (TNS) contains selected papers from the 57th annual IEEE International Nuclear and Space Radiation Effects Conference (NSREC), which was held virtually from November 29 through December 30, 2020. The 2020 IEEE NSREC was sponsored by the IEEE Nuclear and Plasma Sciences Society. More than 60 of the papers presented during NSREC are included in this year’s Special Issue. This issue is neither a conference proceedings nor a conference record. The papers that appear in this Special Issue successfully completed the regular journal review process before the special issue deadline. Several more papers presented during the conference are likely to appear in subsequent issues of the TNS. [ABSTRACT FROM AUTHOR]

Perturbations in N-well potential have been shown to strongly affect the charge collection, charge sharing, and parasitic bipolar transistor characteristics. In this paper, temporal and spatial characteristics of the well-potential modulation are characterized through 3-D TCAD simulations. Effects of well-contact layout, ion energy, and technology process parameters for a 90-nm bulk CMOS process are investigated. [ABSTRACT FROM PUBLISHER]

The ML-EM (maximum likelihood expectation maximization) algorithm is the most popular image reconstruction method when the measurement noise is Poisson distributed. This short paper considers the problem that for a given noisy projection data set, whether the ML-EM algorithm is able to provide an approximate solution that is close to the true solution. It is well-known that the ML-EM algorithm at early iterations converges towards the true solution and then in later iterations diverges away from the true solution. Therefore a potential good approximate solution can only be obtained by early termination. This short paper argues that the ML-EM algorithm is not optimal in providing such an approximate solution. In order to show that the ML-EM algorithm is not optimal, it is only necessary to provide a different algorithm that performs better. An alternative algorithm is suggested in this paper and this alternative algorithm is able to outperform the ML-EM algorithm. [ABSTRACT FROM AUTHOR]

Time-of-flight positron emission tomography requires high timing resolution. In this paper, we determined the influence of scintillation properties on the detector timing resolution for crystals with non-negligible optical transit timespread. In addition to intrinsic scintillation properties, such as the light yield, decay time constant, and scintillation rise time, we also studied the relation between the timing resolution and extrinsic scintillation properties, such as the dimensions of the crystal, the absorption probability of the reflector, the dwell time of photons inside the reflector during the reflection process, and the crystal polish. For this purpose, we developed ray-tracing software. The crystals simulated in this paper are LSO:Ce, LYSO:Ce, LSO:Ce,0.2%Ca, LYSO:0.11%Ce,0.2%Mg, and LYSO:0.2%Ce,0.2%Ca, with dimensions 3 \times 3 \times 5~\mm^3, 3 \times 3 \times 10~\mm^3, 3 \times 3 \times 20~\mm^3, and 4 \times 4 \times 22~\mm^3. We furthermore studied the optical transit timespread of photons inside polished and etched crystals, which explains the differences in timing resolution. [ABSTRACT FROM AUTHOR]

The assessment of the soft-error rate (SER) of semiconductor devices continues to be important, even with the adoption of FinFET devices which overcome some important limitations of planar MOSFETs. The study in this paper presents both theoretical and experimental results via advanced simulation techniques, to investigate the difference between planar and FinFET devices in terms of SER. Neutron test results from different facilities are presented, and the observed differences in sensitivity are explained through theoretical analysis. In the second half of the paper, the test results are validated through TCAD and TFIT simulations using a calibrated technology response model. The analysis shows that the reduction in sensitivity of FinFET devices is primarily due to an increase in the threshold LET and a reduction in the sensitive volume due the shape of the transistor. [ABSTRACT FROM AUTHOR]

This paper investigates the vulnerability of several micro- and nano-electronic technologies to a mixed harsh environment involving high total ionizing dose at MGy levels and high temperature. Such operating conditions emerge today for several applications like new security systems in existing or future nuclear power plants, fusion experiments, or deep space missions. In this work, the competing effects of ionizing radiations and temperature are characterized in elementary devices made of MOS transistors from several technologies. First, devices are irradiated using a radiation laboratory X-ray source up to MGy dose levels at room temperature. Devices are either grounded or biased during irradiation to simulate two major circuit cases: a circuit which waits for a wake up signal, representing most of the lifetime of an integrated circuit operating in a harsh environment, and a nominal circuit function. Devices are then annealed at several temperatures to discuss the post-irradiation behavior and to determine whether an elevated temperature is an issue or not for circuit function in mixed harsh environments. [ABSTRACT FROM PUBLISHER]

This paper presents a novel auto-adaptive method for pulse triggering and extraction. Pulse triggering uses a threshold that must be placed as close as possible to the noise level. We do this by means of an adaptive threshold level based on real-time noise level estimation. A dynamic estimation of the pulse length is also used for pulse selection. The proposed approach is largely insensitive to noise and enables autonomous extraction of pulses regardless of their shape, height or length. The proposed approach can be used with numerous types of detectors from an analog-to-digital converter, and can be used in conjunction with various pulse processing techniques such as spectroscopy, counting or neutron-gamma discrimination. Moreover, the proposed method enables efficient pulse pile-up detection. This paper demonstrates the feasibility of a completely generic pulse trigger and shows that it compares favorably to a representative panel of other pulse extraction approaches disclosed in the literature. [ABSTRACT FROM PUBLISHER]

Positron attenuation tomography (PAT) is a new modality for imaging the linear attenuation coefficients (LACs) of magnetically constrained \beta ^+ -ray beams in matter. A complete 3-D LAC image of an object can be made by measuring the positron annihilation rate density within it at a single orientation relative to the beam, and then applying the PAT transformation. The spatial resolution of this image is limited by the resolution of the positron emission tomography (PET), or other, system used to acquire the data as well as the scattering and gyration of the positrons around the magnetic field lines. The finite resolution of the PET system also leads to nonlinear artifacts associated with extended LAC discontinuities parallel to the beam. The mass thickness of an object that can be imaged is limited by the positron beam’s range in it. However, due to the directional nature of the imaging process as well as its discrete sampling, PAT images acquired at different view angles may each carry unique information on the object’s structure. This paper describes a forward model of PAT image formation and a backpropagation algorithm that, when used together to iteratively combine the data from multiple views, can improve the spatial resolution of PAT LAC images, extend their effective field of view, and reduce artifacts. The technique is demonstrated on measured and simulated data. [ABSTRACT FROM PUBLISHER]

This paper studies perspectives on using optical fibers and distributed fiber sensing schemes to perform real-time-distributed gamma-ray radiation sensing with high spatial resolution. The radiation-induced optical property changes of aluminum-doped fibers were studied using cobalt-60 sources. The distributed optical loss of the aluminum-doped fiber was characterized using the Rayleigh backscattering optical frequency domain reflectometry (Rayleigh OFDR). The optical loss of unprotected fiber under various gamma dose rates remains linear up to 100 grays (Gy). Using the gamma radiation-sensitive fiber, the localized optical loss measured by the Rayleigh OFDR was used to map the accumulated gamma radiation dosage on the entire surface of the cylinder with a 1-cm spatial resolution. Using electrical cables as a ubiquitous sensor platforms for fiber sensor deployment, this paper explores the potential for multifunctional distributed fiber sensor by integrating distributed fiber temperature and gamma ionizing radiation sensors in electrical cables for multifunctional measurements to improve the safety of nuclear power systems at both the component and system levels. As sensors that can readily be embedded in a wide variety of materials and structures, radiation-sensitive fibers can be low-cost and highly flexible tool to gauge the performance degradation and longevity of materials and components used in the nuclear power systems. [ABSTRACT FROM AUTHOR]

This paper shows the impact of low linear energy transfer heavy ions on the reliability of 28-nm Bulk static random access memory (RAM) cells from Artix-7 field-programmable gate array. Irradiation tests on the ground showed significant differences in the multiple bit upset cross section of configuration RAM and block RAM memory cells under various angles of incidence and rotation of the device. Experimental data are analyzed at transistor level by using the single-event effect prediction tool called multiscale single-event phenomenon prediction platform coupled with SPICE simulations. [ABSTRACT FROM PUBLISHER]

In this paper, we investigate neutron-induced errors in three implementations of sort algorithms (QuickSort, MergeSort, and RadixSort) executed on modern graphics processing units designed for high-performance computing and large server applications. We measure the radiation-induced error rate of sort algorithms taking advantage of the neutron beam available at the Los Alamos Neutron Science Center facility. We also analyze output error criticality by identifying specific output error patterns. We found that radiation can cause wrong elements to appear in the sorted array, misalign values as well as application crashes or system hangs. This paper presents results showing that the criticality of the radiation-induced output error pattern depends on the application. Additionally, an extensive fault-injection campaign has been performed. This campaign allows for better understanding of the observed phenomena. We take advantage of SASS-assembly Intrumentator Fault Injector developed by NVIDIA, which can inject faults into all the user-accessible architectural state. Comparing fault-injection results with radiation experiments data provides an understanding that not all the output errors observed under radiation can be replicated in fault injection. However, fault injection is useful in identifying possible root causes of the output errors observed in radiation testing. Finally, we take advantage of our experimental and analytical study to design efficient experimentally tuned hardening strategies. We detect the error patterns that are critical to the final application and find the more efficient way to detect them. With an overhead as low as 16% of the execution time, we are able to reduce the output error rate of sort of about one order of magnitude. [ABSTRACT FROM PUBLISHER]

This paper investigates the total ionizing dose (TID) response of nanoscaled field-effect transistors (FET) made of silicon multiple-gate nanowire (NW). The NWFET architecture relies on its remarkable electrostatic properties to push “silicon”-based technologies much deeper into device scaling than present FinFETs. However, as commonly observed when a new device or technology concept is proposed, such as shallow trench isolation and silicon-on-insulator or FinFET, TID effects reveal unexpected behaviors that can permanently modify pristine device electrical characteristics. This is why this paper discusses the impact of several parameters including the NWFET design and the transistor’s type to get thorough insights into the NWFET TID behavior. [ABSTRACT FROM PUBLISHER]

A recent model provides risk estimates for the deprogramming of initially programmed floating gates via prompt charge loss produced by an ionizing radiation environment. The environment can be a mixture of electrons, protons, and heavy ions. The model requires several input parameters. This paper extends the model to include TID effects in the control circuitry by including one additional parameter. Parameters intended to produce conservative risk estimates for the Samsung 8 Gb SLC NAND flash memory are given, subject to some qualifications. [ABSTRACT FROM PUBLISHER]

Digital signal processing techniques have been widely used in radiation spectrometry to provide improved stability and performance with compact physical size over the traditional analog signal processing. In this paper, field-programmable gate array (FPGA)-based adaptive digital pulse shaping techniques are investigated for real-time signal processing. National Instruments (NI) NI 5761 14-bit, 250-MS/s adaptor module is used for digitizing high-purity germanium (HPGe) detector’s preamplifier pulses. Digital pulse processing algorithms are implemented on the NI PXIe-7975R reconfigurable FPGA (Kintex-7) using the LabVIEW FPGA module. Based on the time separation between successive input pulses, the adaptive shaping algorithm selects the optimum shaping parameters (rise time and flattop time of trapezoid-shaping filter) for each incoming signal. A digital Sallen–Key low-pass filter is implemented to enhance signal-to-noise ratio and reduce baseline drifting in trapezoid shaping. A recursive trapezoid-shaping filter algorithm is employed for pole-zero compensation of exponentially decayed (with two-decay constants) preamplifier pulses of an HPGe detector. It allows extraction of pulse height information at the beginning of each pulse, thereby reducing the pulse pileup and increasing throughput. The algorithms for RC–CR2 timing filter, baseline restoration, pile-up rejection, and pulse height determination are digitally implemented for radiation spectroscopy. Traditionally, at high-count-rate conditions, a shorter shaping time is preferred to achieve high throughput, which deteriorates energy resolution. In this paper, experimental results are presented for varying count-rate and pulse shaping conditions. Using adaptive shaping, increased throughput is accepted while preserving the energy resolution observed using the longer shaping times. [ABSTRACT FROM PUBLISHER]

The conventional front-end electronics for PET imaging consist of an energy circuit and a timing circuit. A single channel in front-end electronics typically requires several amplifiers, an ADC and a TDC. In this paper, we present a novel front-end electronic design using 1-bit sigma-delta ( \boldsymbol \Sigma - \boldsymbol \Delta ) modulation and an FPGA. The new design requires only one analog amplifier per channel. The output of the analog amplifier is read directly by the FPGA. Both the energy and timing calculation are implemented in FPGA firmware. The scope of this paper is to introduce the novel design in detail and to evaluate its performance in energy and dark current measurements. Simulink simulations were performed to validate the design with ideal components. A one-channel prototype circuit was built to assess the design with real components. The prototype circuit was tested with different input signals, including test pulses, pulse signals from a PMT detector, DC current signals and dark current signals from an SiPM sensor. Both the simulation and experimental results show that the method is inherently stable and has excellent accuracy and linearity in energy and dark current measurements. The prototype analog board was built with discrete components cost about $ 0.5 in total. The power consumption was about 20 mW. We conclude that the new method provides a cost-efficient and power-efficient way to accurately measure the energies of analog pulses and dark currents from detectors. The timing performance of this method is currently under evaluation. [ABSTRACT FROM PUBLISHER]

1D or 2D neutron position sensitive detectors with individual wire or strip readout using discriminators have the advantage of being able to treat several neutron impacts partially overlapping in time, hence reducing global dead time. A single neutron impact usually gives rise to several discriminator signals. In this paper, we introduce an information-theoretical definition of image resolution. Two point-like spots of neutron impacts with a given distance between them act as a source of information (each neutron hit belongs to one spot or the other), and the detector plus signal treatment is regarded as an imperfect communication channel that transmits this information. The maximal mutual information obtained from this channel as a function of the distance between the spots allows to define a calibration-independent measure of position resolution. We then apply this measure to quantify the power of position resolution of different algorithms treating these individual discriminator signals which can be implemented in firmware. The method is then applied to different detectors existing at the ILL. Center-of-gravity methods usually improve the position resolution over best-wire algorithms which are the standard way of treating these signals. [ABSTRACT FROM PUBLISHER]

The single-event transient (SET) response of two different silicon-germanium (SiGe) X-band (8–12 GHz) low noise amplifier (LNA) topologies is fully investigated in this paper. The two LNAs were designed and implemented in 130nm SiGe HBT BiCMOS process technology. Two-photon absorption (TPA) laser pulses were utilized to induce transients within various devices in these LNAs. Impulse response theory is identified as a useful tool for predicting the settling behavior of the LNAs subjected to heavy ion strikes. Comprehensive device and circuit level modeling and simulations were performed to accurately simulate the behavior of the circuits under ion strikes. The simulations agree well with TPA measurements. The simulation, modeling and analysis presented in this paper can be applied for any other circuit topologies for SET modeling and prediction. [ABSTRACT FROM PUBLISHER]

To improve the reliability of pressurizer level measurement channels against sensor common cause failures (CCFs), a sensor fault detection scheme has been developed based on analytical redundancy in this paper. The fault detection mechanism has been transformed into statistical tests on a Kalman filter generated innovation sequence. An exponentially weighted moving average (EWMA) scheme has been developed to work with other sensor channels to ensure that the abnormality can be detected and isolated as quickly as possible. Because analytical redundancy does not share the same failure modes as existing sensor channels, the overall reliability of the measurement system has been improved. The paper provides a detailed procedure for formulating analytical redundancy, generating the corresponding innovation sequence, and detailing the design and implementation of the proposed detection scheme. Finally, the performance of the proposed scheme has been evaluated in a CANDU (Canada deuterium uranium) pressurizer to demonstrate its potential benefits. The speed of the fault detection is also evaluated against that of the average run length of the Shewhart control chart. It can be concluded that the proposed scheme is significantly more sensitive to sensor abnormalities at an earlier stage in their development. Even though level measurement channels in a pressurizer are considered, the methodology and design techniques can easily be extended to other systems/applications. [ABSTRACT FROM AUTHOR]

The use of protons and heavy ions for the treatment of tumors is increasing since it provides a better relative biological effectiveness (RBE) than traditional radiotherapy. Accurate knowledge of the energy deposition at submicrometric scales is paramount for RBE characterization. This paper shows the latest version of the silicon cylindrical microdosimeter array developed by the Instituto de Microelectrónica de Barcelona, Centro Nacional de Microelectrónica (IMB-CNM, Spain). The detector consists of a matrix of $11 \times 11$ cylindrical sensitive unit cells with individual readout etched within the silicon substrate available in different diameters and pitches between detectors. The detector employed in this paper had a diameter of $15~\mu \text{m}$ , a pitch of $200~\mu \text{m}$ , and a thickness of $5.5~\mu \text{m}$. The detectors were tested in the clinical facilities of Fondazione Centro Nazionale di Adronterapia Oncologica (CNAO) (Pavia, Italy) employing a 12C pencil beam at a therapeutic beam fluence rate. Microdosimetric spectra of lineal energy were measured in different depths of polymethyl methacrylate (PMMA) up to the Bragg peak. Results were then compared with Monte Carlo simulations using the FLUKA particle transport code, showing an excellent agreement between experimental and simulated microdosimetric distributions even at the high fluence rates associated with clinical beams. [ABSTRACT FROM AUTHOR]

This paper presents the effect of the photodiode implant dose on the radiation degradation of pinned photodiode (PPD) CMOS image sensors. Several custom image sensors with similar structures are manufactured using five different photodiode implant doses. Each image sensor comprises nine $32 \times 32$ pixel arrays with nine different pixel layouts. After testing the effect of the photodiode implant dose and the pixel layout on the key performances of the image sensors, they are irradiated using 50-MeV protons at ionizing doses from 10 to 100 krad. By comparing the radiation-induced performance degradation depending on the pixel layout and the implant dose, some insights can be given about the physical mechanisms responsible for the degradation and the location of the degradation sources within the pixel. Eventually, we conclude about how the photodiode implant dose should be tweaked to improve the radiation tolerance, depending on which performance criterion has to be optimized in priority. [ABSTRACT FROM AUTHOR]

Vertical Au/ZnO Schottky barrier diodes (SBDs) were fabricated on an n+ Si substrate and tested as X-ray detectors in this paper. The high-resistivity ZnO film-based SBDs had a large effective area about 0.78 cm2 and showed a notable sensitivity about 0.78 uC/Gy for X-ray illumination. The detector with linear outputs achieved an X-ray dose measurement across four orders of magnitude of the dose rate from 3.83 mGy/s to 19.00 Gy/s. The response current to switched X-ray illumination exhibited a repeatable and stable characteristic, and the response current mechanism was given and discussed. The results imply the potential of junction devices based on ZnO material for X-ray dose measurement. [ABSTRACT FROM AUTHOR]

In order to reduce the difficulty of the tuning work and improve transmission efficiency at the 320-kV heavy ion multidisciplinary research facility (IMRF), an online optimization system was developed. In this paper, the difficulties of manual tuning are analyzed amply. Various optimization-based approaches were considered and a Bayesian optimization method was selected and implemented in hardware. We have applied the online optimization system at the beamline to increase transmission efficiency. The transmission efficiency obtained by this online tuning system can reach 50%, which is better than the manual tuning 30% to 35%. The general work developed in this paper can provide a reference for the design and implementation of online tuning approaches for various complex systems, not just accelerator facilities. [ABSTRACT FROM AUTHOR]

This paper presents a solution for error detection in ARM microprocessors based on the use of the trace infrastructure. This approach uses the Program and Instrumentation Trace Macrocells that are part of ARM’s CoreSight architecture to detect control-flow and data-flow errors, respectively. The proposed approach has been tested with low-energy protons. Experimental results demonstrate high accuracy with up to 95% of observed errors detected in a commercial microprocessor with no hardware modification. In addition, it is shown how the proposed approach can be useful for further analysis and diagnosis of the cause of errors. [ABSTRACT FROM AUTHOR]

This paper describes a comparison between in-orbit single-event effects (SEE) rate measurement acquired by the CARMEN-3 experiment on-board the JASON-3 satellite (middle earth orbit, 1336 km, 66°) and an estimation using SEE rate calculation approaches from several facilities. A SRAM memory sensitive to single-event latchup (SEL) has been monitored in orbit, and the number of events per day was estimated using monoenergetic data coming from the Kernfysisch Versneller Instituut (protons) and Université Catholique de Louvain (heavy-ions) facilities as well as using mixed-field data coming from the Cern High energy AcceleRator Mixed field (CHARM) facility. A comparison of both estimations with respect to the in-flight measurement has been carried out. [ABSTRACT FROM AUTHOR]

Because of their ultrafast scintillation with subnanosecond decay time, barium fluoride (BaF2) crystals have attracted broad interest in the high energy physics and nuclear physics communities. One crucial issue, however, is its slow scintillation component with 600-ns decay time, which causes pile-up in a high rate environment. Previous studies show that the slow component can be suppressed effectively by rare earth doping. In this paper, we report investigations on a set of $\Phi \,\,18\times21$ mm3 BaF2 cylinders doped with different yttrium levels grown at Beijing Glass Research Institute (BGRI), from which the optimized yttrium doping level was determined. $\text{A}\Phi \,\,40\times160$ mm3 BaF2 ingot with 5 atomic % (at.%) yttrium doping was consequently grown at BGRI and was used to cut one $25\times 25\times100$ mm3 crystal and several thin slices. Their optical and scintillation properties were measured at Caltech. The results show that yttrium doping effectively suppresses the slow component while maintaining its ultrafast light unchanged. Research and development will continue to develop large-size BaF2:Y crystals with improved optical quality for a fast BaF2:Y crystal calorimeter for Mu2e-II. [ABSTRACT FROM AUTHOR]

In many physical experiments and applications with photomultiplier tubes (PMTs), high-speed pulse digitization is used extensively. The current pulse from a PMT has a rising time of several to a hundred nanoseconds. The current pulse shape can be used to obtain the pulse energy and discriminate between different particles. The conventional readout system with a PMT uses the discrete or integrated pulse-shaping circuits and analog-to-digital converter (ADC) boards that are based on the Nuclear Instrument Modules (NIMs) or VersaModule Eurocard (VME) system to implement the data acquisition function. In many applications, such as security instruments, there are only several PMTs used in the whole system, or in some distributed applications, long-distance analog cable with high-voltage power cable is not applicable due to the tremendous number of channels and enormous distributed space. In this paper, an integrated digitizer base is designed and interfaced with a Cs2LiYCl6 (CLYC) scintillator with a PMT. The CLYC scintillator has the ability to realize the pulse shape discrimination (PSD) between the neutron and gamma rays. There is only one Category 5 cable needed for over 700-Mb/s transmission control protocol (TCP) data throughput and more than 10-W power. The boards of high voltage supply, current-sensitive preamplifier, 500-MSPS/12-bit ADC, readout module based on ZYNQ system-on-chip (SoC), power over Ethernet, and user-interface circuits are stacked with board-to-board connectors. The gamma-ray energy resolution is ∼4.6% at 662 keV with a $20-\mu \text{s}$ pulse integral and PSD figure of merit (FOM) is ∼3.0 by using the totally recorded events of neutrons and gamma rays. This integrated digitizer base can also be interfaced with other detectors with a PMT. [ABSTRACT FROM AUTHOR]

Circular Electron and Positron Collider (CEPC) is a large experiment facility proposed by the Chinese particle physics community. One of the running options is being the Higgs factory. The calorimeter is the main part of this experiment to measure the jet energy. Semidigital hadron calorimeter (SDHCAL) is one of the options for the hadron measurement. Gas electron multiplier (GEM) detector with its high-position resolution and flexible configuration is one of the candidates for the active layer of the SDHCAL. The main purpose of this paper is to provide a feasible readout method for the GEM-based SDHCAL. A small-scale prototype is designed and implemented, including front-end board (FEB) and data interface board (DIF). The prototype electronics has been tested. The equivalent rms noise of all channels is below 0.35 fC. The dynamic range is up to 500 fC and the gain variation is less than 1%. The readout electronics is applied on a double-layer GEM detector with 1 cm $\times 1$ cm readout pad. The result indicates that the electronics works well with the detector. The detection efficiency of minimum ionization particle (MIP) is over 95% with a 5-fC threshold. [ABSTRACT FROM AUTHOR]

The Peripheral Component Interconnect Express (PCIe) Luminosity UPgrade board ($\pi $ LUP) was designed by INFN and University of Bologna as a readout interface candidate to be used after the Phase-II upgrade of the Pixel Detector of the ATLAS and CMS experiments at Large Hadron Collider (LHC). The same team in Bologna is also responsible for the design and commissioning of the readout driver (ROD) board—currently implemented in all the four layers of the ATLAS pixel detector (Insertable B-Layer, B-Layer, Layer-1, and Layer-2)—and acquired in the past years expertise on the ATLAS readout chain and the problematics arising in such experiments. Although the $\pi $ LUP was designed to fulfill a specific task, it is highly versatile and might fit a wide variety of applications, some of which will be discussed in this paper. Two seventh-generation Xilinx field-programmable gate arrays (FPGAs) are mounted on the board: a Zynq-7 with an embedded dual-core Advanced Reduced Instruction Set Computer (RISC) Machine (ARM) Processor and a Kintex-7. The latter features 16 12.5-Gbps transceivers, allowing the board to interface easily to any other electronic board, either electrically and/or optically, at the current bandwidth of the experiments for LHC. Many data-transmission protocols have been tested at different speeds; results will be discussed later in this paper. Two batches of $\pi $ LUP boards have been fabricated and tested; two boards in the first batch (version 1.0) and four boards in the second batch (version 1.1), encapsulating all the patches and improvements required by the first version. [ABSTRACT FROM AUTHOR]

Laterally diffused metal–oxide–semiconductors transistors PD-silicon on insulator 150-nm mixed technology from Microchip are irradiated with 60Co gamma rays. Those irradiations have revealed a high sensitivity of the LDnMOS and LDpMOS pointing out that the main sensitive parameter is the ON-resistance. In this paper, degradation mechanisms at play are investigated through TCAD simulation, and an explanation of the physical mechanisms for the observed degradation is proposed. [ABSTRACT FROM AUTHOR]

This paper presents remote direct memory access (RDMA) over the Ethernet protocol used for data acquisition systems, currently under development at the European Synchrotron Radiation Facility. The protocol is implemented on Xilinx Ultrascale + field-programmable gate arrays (FPGAs), thanks to the 100G hard media access controller (MAC) internet protocol (IP). The proposed protocol is fairly compared with the well-known RDMA over converged Ethernet (RoCE-V2) protocol using a commercial network adapter from Mellanox. The obtained results show the superiority of the proposed algorithm over RoCE-V2 in terms of data throughput. Performance tests on the 100G link show that it can reach a maximum stable link performance of 90 Gb/s with minimum packet sizes greater than 1 kB and 95 Gb/s for packet sizes greater than 32 kB. [ABSTRACT FROM AUTHOR]

The Circular Electron Positron Collider (CEPC) is a proposing electron–positron collider in China, which aims for generating high center-of-mass energy colliding above 250 GeV. The high-granularity electromagnetic calorimeter (ECAL) is included in a calorimeter system, which is mainly responsible for the measurement of photon. A particle flow algorithm (PFA)-based ECAL solution will utilize about 400k channels/m3. Here, we present the design and development status of readout electronics based on SPIROC2b for the CEPC ECAL with high-granularity scintillants and silicon photomultipliers (SiPMs). The readout electronics consists of front-end electronics (FEE), data interface (DIF) board, and data acquisition (DAQ) board. The front-end board (FEB) carries SiPMs (S12571-010P), scintillants (PSD), and FEB application-specific integrated circuit (ASIC) (SPIROC2b). Two electronics were designed in this paper, one is for ASIC functionality and performance only, and the other is used as a single layer of a further prototype of ECAL. Electronic test and cosmic ray test have been done to electronics. The results indicate that a charge dynamic from 62 fC to 300 pC at S/N = 2 is successfully achieved, and the minimum ionizing particles (MIPs) are separated from the pedestal. [ABSTRACT FROM AUTHOR]

The sensitivity of memory devices under proton irradiation has been extensively studied over the years. Two main mechanisms have been identified to drive the single-event upset (SEU) sensitivity in the last generation of devices: direct ionization for low proton energies and inelastic nuclear reactions for higher proton energies. Some papers have shown that the Coulomb elastic contribution should be considered. This paper supports this conclusion and proposes analyses in order to show the importance of this contribution according to the technological node studied. [ABSTRACT FROM AUTHOR]

To achieve the aim of the international thermonuclear experimental reactor (ITER) radial neutron camera diagnostic, the data acquisition prototype must be compliant with a sustained 2-MHz peak event per each channel. The data are acquired and processed using an IPFN FPGA Mezzanine Card (FMC-AD2-1600) with two digitizer channels of 12-bit resolution and a sampling rate up to 1.6 GSamples/s mounted in an peripheral component interconnect express (PCIe) evaluation board from Xilinx (KC705) installed in the host PC. The acquired data in the event-based data path are streamed to the host through the PCIe $\times 8$ direct memory access with a maximum data throughput per channel $\approx 0.5$ GB/s of raw data (event base), $\approx 1$ GB/s per digitizer, and up to 1.6 GB/s in continuous mode. The prototype architecture comprises a host PC with two KC705 modules and four channels, producing up to 2 GB/s in event mode and up to 3.2 GB/s in continuous mode. To reduce the produced data throughput from host to ITER archiving system, the real-time data compression was evaluated using the LZ4 lossless compression algorithm, which provides compression speed up to 400 MB/s per core. This paper presents the architecture, implementation, and test of the parallel real-time data compression system running in multiple isolated cores. The average space saving and the performance results for long-term acquisitions up to 30 min, using different data block sizes and different number of CPUs, are also presented. [ABSTRACT FROM AUTHOR]

In the context of achieving an efficient radiation monitoring system, while also aiming to increase the flexibility of the measurement system, the integrated digital and analog circuitries of the floating gate dosimeter (FGDOS) have been upgraded. The capability to control autonomously the recharge process and the easy access to the data allows exploiting the FGDOS in both the autonomous and passive mode. The former provides the cumulated dose measurement by a sensor coupled to a digital interface. The latter implies the reading of the dose only after the irradiation time, performing the dose detection by positioning the sensor without any supply. In this paper, the functionality and characterization of the new features of the FGDOS are demonstrated. The resolution, the dose range, and the error introduced on the measurements are discussed in detail by analyzing the results of irradiation experiments. The use of a filtering technique in different radiation environments is discussed, as well as the capability to retain the information after multiple readings and the power consumption for each configuration. [ABSTRACT FROM AUTHOR]

The compressed baryonic matter (CBM) experiment will investigate the quantum chromodynamics phase diagram at high net baryon densities and moderate temperatures. CBM time-of-flight (TOF) system is composed of super modules containing high-performance multigap resistive plate chambers (MRPCs). During the mass production, each super module assembled with MRPCs needs quality evaluation, which includes time measurement and data readout. Read out electronics encounter the challenge of reading data from a super module at a speed of about 6 Gb/s. In this paper, a read out method based on peripheral component interconnect express (PCIe) over optical fiber is proposed for CBM-TOF super module quality evaluation. The digitized data from super module will be concentrated at the front-end electronics and then be transmitted to a PCIe switch module (PSM) over optical fiber using PCIe protocol. The PSM is directly plugged into the motherboard via vertical edge card connector at the back-end data acquisition server. With this readout method, a high-speed transmission rate can be reached. Furthermore, a PSM can receive data from several super modules simultaneously, which is important to improve the evaluation efficiency. This readout method simplifies the architecture of readout electronics and supports long-distance transmission between front end and back end. [ABSTRACT FROM AUTHOR]

The detector readout architecture introduced in this paper is intended for small to medium size physics experiments that have moderate bandwidth needs and applications that only tolerate an ultimately low background radioactivity for the parts close to the detector. The first idea to simplify the readout system and minimize the material budget is to use a common fan-out structure to transport from off-detector back-end electronics to the front ends all the traffic required for the synchronization, configuration, and readout. The second idea is to use between each front-end card and the back-end electronics a point-to-point link that runs at the relatively low speed that suffices for the target application. This broadens the possible choices of physical media, e.g., glass fiber, plastic optical fiber, or copper. This paper presents a communication protocol adequate for the proposed asymmetric network. It shows the design of a back-end unit capable of controlling 32 front-end units at up to 12.8 Gb/s of aggregate bandwidth. This back-end unit uses an inexpensive commercial field-programmable gate array (FPGA) module where a large number of regular I/O pins interface to the front-end links, while the few available multigigabit per second capable transceivers are assigned to the communication with the upper stage of the data acquisition (DAQ) system. [ABSTRACT FROM AUTHOR]

This paper analyses the neutron irradiation impact on the electrical performances of unstressed, ON-state, OFF-state, and negative gate bias (NGB) stressed AlInN/GaN HEMTs. These irradiations have resulted in the creation of electron traps that are causing a decrease in the drain current and an increase in the access resistance of the unstressed, ON-state, or OFF-state stressed AlInN/GaN devices. These degradations have been correlated with gamma spectrometry measurements and transmutation reactions occurred during the thermalized neutron irradiation have been highlighted. Despite these phenomena, a rise in drain current and a reduction in access resistance have been observed when NGB stressed AlInN/GaN HEMTs were irradiated with a fluence of $1.2\times 10^{\mathbf {12}}$ neutrons/cm2. The differences between the electrical behaviors of unstressed, ON-state, OFF-state, and NGB stressed devices observed after the neutron bombardment are related to the presence of electron traps in these device structures. [ABSTRACT FROM AUTHOR]

This paper investigates the total ionizing dose (TID) responses of forward body bias (FBB) ultrathin body and buried oxide fully depleted silicon-on-insulator (UTBB FD-SOI) transistors, which are commonly used in commercial foundries. The experimental results demonstrate that TID-induced threshold voltage shift in FBB nMOSFET cannot be mitigated by applying biasing to back-gate (back-gate biasing). Bias condition dependence has also been explored, revealing that building up of the oxide-trapped charge (Not) in the buried oxide is affected by the electric field induced by the space charge. Moreover, the effect of threshold voltage option on TID responses of UTBB FD-SOI transistors with the undoped channel was first explored. Finally, the TID-enhanced back-gate biasing controlling of the threshold voltage was observed, which is a new phenomenon for the TID responses of UTBB FD-SOI transistors. [ABSTRACT FROM AUTHOR]

Traditional approaches to material control and accounting at used nuclear fuel reprocessing facilities rely in large part on laboratory-based destructive assay of periodic samples taken from key stages. These techniques are highly accurate, but limited inspection frequency may limit the size and operation of a reprocessing facility. Online monitoring techniques using in-line detectors can be applied to fuel reprocessing systems to improve the situational awareness as the facility is operating to provide additional indicators of the evolving state of the facility between normal inspection periods, potentially alerting regulators to the need for additional inspection. The multi-isotope process (MIP) monitor combines medium-resolution gamma detectors with statistical data analysis techniques to monitor reprocessing systems for anomalous conditions resulting from process control issues or malfeasance. The MIP monitor is attractive for process and safeguards monitoring because of its unsupervised approach to detection and its inherent data obfuscation. This paper presents the application of the MIP monitor to detect a notional diversion scenario in an operating aqueous reprocessing facility by analyzing gamma spectra with a combination of principal component analysis (PCA) and the sequential probability ratio test. Gamma spectra collected from the H-Canyon reprocessing facility were analyzed to demonstrate the efficacy of the MIP Monitor for detecting notional diversion scenarios. The proposed analysis successfully detected small, protracted diversions, which would alert regulators of the need for additional inspection. [ABSTRACT FROM AUTHOR]

The laser treated surface method is a novel way to mitigate electron cloud in high-energy and high-intensity particle accelerators. Aluminum alloy is a common and important material used in the vacuum system construction of particle accelerators. The influences of laser parameters, such as scanning speed and average laser power on the secondary electron yield (SEY) and surface morphology of laser processed aluminum alloy samples, were studied and explored in this paper. The as-received laser processed aluminum alloy surfaces with SEY less than 1 were obtained. The surface composition and topography were tested by the X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and laser scanning confocal microscopy (LSCM). The XPS results revealed that the surface of as-received laser processed aluminum alloys consists of aluminum oxide layer and intermetallic aluminum. The LSCM and SEM results show that the selection of appropriate laser parameters and hatched patterns was ascertained by the surface topography of the sample to obtain low-SEY surface. [ABSTRACT FROM AUTHOR]

This paper investigates the leakage currents as well as the leakage current Random Telegraph Signals (RTSs) sources in sense node floating diffusions (FDs) and their consequences on imaging performances specifically after exposure to high-energy particle radiation. Atomic displacement damage and ionization effects are separately studied thanks to neutron and X-ray irradiations. Proton irradiations have been performed to simultaneously study displacement damage dose (DDD) and total ionizing dose (TID) effects while being more representative of the space environment. The studied DDD ranges from $500\,\,\text {TeV}\cdot \text {g}^{-1}$ to $40\,\,\text {GeV}\cdot \text {g}^{-1}$ , and the TID ranges from 24 krad(SiO2) to 72 krad(SiO2). High-magnitude electric field effects, such as transfer-gate-induced leakage current, are investigated to further understand the phenomena involved in FDs while giving new insights into the Electric Field Enhancement of the charge generation mechanisms. This paper shows that FDs are very sensitive to ionizing radiation because of the presence of depleted Si/SiO2 interface with high-magnitude electric fields around the junction. On the other hand, displacement damage in the FDs is a major source of high amplitude leakage current RTSs and leakage current nonuniformity. Such radiation-induced degradations can prevent the use of CMOS image sensor with long FD retention time (e.g., global shutter operating mode or burst imagers) in radiation environments. [ABSTRACT FROM AUTHOR]