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The IEEE Transactions on Nuclear Science (TNS) Best Paper Award is an annual award recognizing the most significant paper published in the Transactions in a given year. The Award is sponsored by the IEEE Nuclear and Plasma Sciences Society and the winning paper is selected according to its quantifiable usefulness to the community. The authors of the papers published in the Transactions in the third year prior to the year of the award are eligible for consideration. The 2021 award is, therefore, awarded to the paper published in the calendar year 2018, judged to be the most useful to our community based on metrics calculated for the years 2018–2020.

The IEEE Transactions on Nuclear Science Best Paper Award is an annual award recognizing the most significant paper published in the Transactions in a given year. The Award is sponsored by the IEEE Nuclear and Plasma Sciences Society and the winning paper is selected according to its quantifiable usefulness to the community. The authors of the papers published in the Transactions in the third year prior to the year of the award are eligible for consideration. The 2020 award is, therefore, awarded to the paper published in the calendar year 2017, judged to be the most useful to our community based on metrics calculated for the years 2017–2019.

IEEE Transactions on Nuclear Science (TNS) is pleased to announce that Prof. Gian-Franco Dalla Betta (S’94–M’98–SM’06) was appointed as Senior Editor receiving papers on Radiation Instrumentation in June 2020. He replaced Prof. Arnold Burger who had served in this position since early 2016. Prof. Burger handled over 1600 original papers and revisions during his tenure, and we are grateful for his service.

IEEE Transactions on Nuclear Science (TNS) is pleased to announce that Prof. Yuntao Wu was appointed Associate Editor, receiving papers on radiation instrumentation in November 2020.

The IEEE Transactions on Nuclear Science Best Paper Award is an annual award to recognize the best paper published in the Transactions in a given year. The Award is sponsored by the IEEE Nuclear and Plasma Sciences Society and the winning paper is selected according to its quantifiable usefulness to the community. The authors of papers published in the Transactions in the third year prior to the year of the award are eligible for consideration. The 2019 award is, therefore, awarded to the paper published in calendar year 2016 judged to be the most useful to our community based on metrics calculated for the years 2016, 2017, and 2018.

This conference presents the recipients of the Outstanding Conference Paper Award from the 2015 IEEE Nuclear and Space Radiation Effects Conference.

IEEE Transactions on Nuclear Science is pleased to announce that Dr. Sang-Ho Kim has been appointed as an Associate Editor for Accelerator Technology papers.

The recipients of the 1994 NSREC Outstanding Conference Paper Award are Gordon Hopkinson of SIRA Ltd., Isobel Hopkins of SIRA/UCL Postgraduate Centre, and Bengt Johlander of ESA/ESTEC, for their paper entitled, "Proton-Induced Charge Transfer Degradation in CCDs for Near-Room Temperature Applications." The paper describes an innovative optical technique for measuring charge transfer inefficiency in CCDs operated in the near-room-temperature-range of -30°C to 30°C. The optical spot technique enables the measurement of CTD dependence on signal size, background charge, and clock waveform shape, as well as trap emission times, as a function of these variables. The technique involves spot illumination of the CCD, followed by repeated charge transfer regimes. It is applicable to any CCD and yields improved accuracy over the x-ray method. The paper reflects strong current interest in CCD hardness issues as these devices become more pervasive in space applications

In recent months a number of suggestions have been made to improve the appearance and readability of author-prepared papers appearing in some issues of our journal. Since all contributed papers are now published in a typeset format, it is worthwhile to consider changes to update the preparation of author-prepared papers as well.

This paper updates and complements a previously published evaluation of computational methods for total and partial cross sections, relevant to modeling the photoelectric effect in Monte Carlo particle transport. It examines calculation methods that have become available since the publication of the previous paper, some of which claim improvements over previous calculations; it tests them with statistical methods against the same sample of experimental data collected for the previous evaluation. No statistically significant improvements are observed with respect to the calculation method identified in the previous paper as the state of the art for the intended purpose, encoded in the EPDL97 data library. Some of the more recent computational methods exhibit significantly lower capability to reproduce experimental measurements than the existing alternatives., To be published in IEEE Trans. Nucl. Sci, DOI 10.1109/TNS.2020.2971173

Throughout the last decade, the Advanced Telecommunications Computing Architecture (ATCA) solidified its position as one of the main switched-based crate standards for advanced Physics instrumentation, offering not only highly performant characteristics in data throughput, channel density or power supply/dissipation capabilities, but also special features for high availability (HA), required for latest and upcoming large-scale endeavours, as is the case of ITER. Hot Swap is one of the main HA features in ATCA, allowing for Boards to be replaced in a crate (Shelf), without powering off the whole system. Platforms using the Peripheral Component Interconnect Express (PCIe) protocol on the Fabric Interface must be complemented, at the software level, with the PCIe Hot Plug native feature, currently not specified for the ATCA form-factor. From a customised Hot Plug support implementation for ATCA Node Boards, the paper presents an implementation extension for Hub Boards, allowing Hot Plug of PCIe switching devices, without causing bus enumeration problems. This paper further addresses the main issues concerning an eventual standardization of PCIe Hot Plug support in ATCA, such as the implementability of Hot Plug Elements and the generation and management of Hot Plug Events, aiming to stimulate the discussion within the PICMG community towards a long overdue standardized solution for Hot Plug in ATCA., 4 pages, 3 figures, 21st IEEE Real Time Conference - Colonial Williamsburg 9-15 June 2018 Woodlands Conference Center

A front-end board (FEB) configuration test board is developed for examining the configuration interfaces of various application-specific integrated circuits (ASICs) developed for the ATLAS New Small Wheel project. In this paper, we present the development of a FEB configuration test board, and some functions are developed in terms of configurations of the key chips on the FEB-VMM3 and trigger data serializer (TDS2) using giga-bit transceiver-slow control adapter (GBT-SCA). Additionally, the protocols provided by GBT-SCA and the front-end board ASICs are used to verify the whole data link. The board provides technical reference for prototyping the FEB key chip configuration and data readout, as well as the final system configuration. The FEB(front end board) configuration test board is developed aiming at meeting the requirement of testing the new generation ASIC(application-specific integrated circuit) chips and its configuration system for ATLAS NSW(New Small Wheel) upgrade, In this paper, some functions are developed in terms of the configurations of the key chips on the FEB, VMM3 and TDS2 using GBT-SCA. Additionally, a flexible communication protocol is designed, verifying the whole data link. It provides technical reference for prototype FEB key chip configuration and data readout, as well as the final system configuration.

The data compression technology now is fully developed and widely used in many fields such as communication, multi-media, image information processing and so on. The large physical experiments, especially the ones with Micro-pattern Gas Detectors (MPGD), which always have many readout channels and have a lot of data to be transferred and saved, are however relatively seldom use this technology. In this paper, the real-time lossless data compression method is proposed for a general-purposed MPGD readout system. The lossless data compression can reduce the data transmission bandwidth of the system as well as keep all information of the data. The compression method discussed in the paper mainly consists of two steps. The first step is to pre-process the data according to different characteristics of different signals and the second step is to compress the pre-processed data using common lossless compression algorithm. Besides, the whole compression method is implemented in the Field-Programmable Gate Array (FPGA) and able to run real-timely. The system is then used to readout two different kinds of signals and the compression rate can reach as high as 43% and 30% respectively.

Commercial off-the-shelf microcontrollers can be useful for noncritical processing on spaceborne platforms. These microprocessors can be inexpensive and consume small amounts of power. However, the software running on these processors is vulnerable to radiation upsets. In this paper, we present a fully automated, configurable, software-based tool to increase the reliability of microprocessors in high-radiation environments. This tool consists of a set of open-source LLVM compiler passes to automatically implement software-based mitigation techniques. We duplicate or triplicate computations and insert voting mechanisms into software during the compilation process, allowing for runtime error correction. While the techniques we implement are not novel, previous work has typically been closed source, processor architecture dependent, not automated, and not tested in real high-radiation environments. In contrast, the compiler passes presented in this paper are publicly available, highly customizable, and are platform independent and language independent. We have tested our modified software using both fault injection and through neutron beam radiation on a Texas Instruments MSP430 microcontroller. When tested by a neutron beam, we were able to decrease the cross section of programs by $17-29\times $ , increasing mean-work-to-failure by $4-7\times $ .

The image classification accuracy of a TaO x ReRAM-based neuromorphic computing accelerator is evaluated after intentionally inducing a displacement damage up to a fluence of 1014 2.5-MeV Si ions/cm2 on the analog devices that are used to store weights. Results are consistent with a radiation-induced oxygen vacancy production mechanism. When the device is in the high-resistance state during heavy ion radiation, the device resistance, linearity, and accuracy after training are only affected by high fluence levels. The findings in this paper are in accordance with the results of previous studies on TaO x -based digital resistive random access memory. When the device is in the low-resistance state during irradiation, no resistance change was detected, but devices with a 4- $\text{k}\Omega $ inline resistor did show a reduction in accuracy after training at 1014 2.5-MeV Si ions/cm2. This indicates that changes in resistance can only be somewhat correlated with changes to devices’ analog properties. This paper demonstrates that TaO x devices are radiation tolerant not only for high radiation environment digital memory applications but also when operated in an analog mode suitable for neuromorphic computation and training on new data sets.

This paper describes a recent effort to develop and benchmark a simulation tool for the analysis of radio frequency (RF) transients and their compensation in an H-linear accelerator. Existing tools in this area either focus on electron linear accelerators (LINACs) or lack fundamental details about the low level radio frequency system that are necessary to provide realistic performance estimates. In this paper, we begin with a discussion of our computational models followed by benchmarking with existing beam-dynamics codes and measured data. We then analyze the effect of RF transients and their compensation in the Proton Improvement Plan-II LINAC, followed by an analysis of calibration errors and how Newton’s method-based feedback scheme can be used to regulate the beam energy to within the specified limits.

It is a long-standing tradition of the IEEE Nuclear and Space Radiation Effects Conference (NSREC) to recognize the Outstanding Conference Paper, the Outstanding Data Workshop Presentation, and the best paper presented and first-authored by an IEEE Student Member. In addition to recognizing authors for particularly high quality and relevant work, the awards process also encourages all authors to produce presentations and manuscripts of high technical quality, clarity of presentation, and significance to the community.

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.

International audience; A comprehensive approach is developed for the simulation of Single Particle Displacement Damage in silicon, from the incident particle interaction in silicon, to the resulting electrical effect observed experimentally. The different steps of the global approach are described. The paper then focuses on the first step corresponding to Monte Carlo simulation of the primary interaction. The characteristics of the Primary Knock-On Atom (PKA) generated by neutron- or proton-silicon interactions for different energies are explored, analyzing in particular the PKA range in energies and species. This leads to the selection of 1 and 10 keV silicon atoms as good candidates to best represent the displacement cascades generated by all PKA. These PKA characteristics will be used as input in the following Molecular Dynamics simulation step, developed in a separate paper to simulate the displacement cascade generation and evolution. Monte Carlo simulations are also performed in a geometry representative of an image sensor, analyzing the distribution of non-ionizing deposited energy. The obtained distributions appear very similar for incident neutrons from 3 to 18 MeV and incident protons of 200 MeV, in agreement with similarities observed in experimentally measured dark current distributions in image sensors. The effect of geometric parameters on these distributions is finally explored.

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.

The work presented in this paper has been performed in the framework of a joint research program between Aix-Marseille University and CEA Cadarache. The aim is to develop a mass spectrometer (MS) device for the MERARG facility. MERARG is devoted to the study of fission gas release measurement, from nuclear fuels submitted to annealing tests in high activity laboratory such as LECA-STAR, thanks to gamma spectrometry. The mass spectrometer will then extend the measurement capability from the $\gamma $ -emitting gases to all the gases involved in the release in order to have a better understanding of the fission gas release dynamics from fuel during thermal transients. Furthermore, the mass spectrometer instrument combines the capabilities and performances of both on-line (for release kinetic) and off-line implementations (for delayed accurate analysis of capacities containing total release gas). The paper deals with two main axes: 1) the modelling of gas sampling inlet device and its performance and 2) the preliminary MS qualification/calibration results. The inlet device samples the gas and also adapts the pressure between MERARG sweeping line at 1.2 bar and mass spectrometer chamber at high vacuum. It is a two-stage device comprising a capillary at inlet, an intermediate vacuum chamber, a molecular leak inlet and a two-stage pumping device. Pressure drops, conductance and throughputs are estimated both for mass spectrometer operation and for exhaust gas recovery. The time constant for gas renewal is very low and estimated at about 1 s. Possible gas segregation is also estimated and device modification is proposed to attain a more accurate calibration. Preliminary experimental results obtained from a standard gas bottle show that the quantitative analysis at a few ppm level can be achieved for all isotopes of Xe as well as masses 2 and 4 u.

Recently we developed a Bayesian-FBP (Filtered Backprojection) algorithm for CT image reconstruction. This algorithm is also referred to as the FBP-MAP (FBP Maximum a Posteriori) algorithm. This non-iterative Bayesian algorithm has been applied to real-time MRI, in which the k-space is under-sampled. This current paper investigates the possibility to extend this Bayesian-FBP algorithm by introducing more controlling parameters. Thus, our original Bayesian-FBP algorithm became a special case of the extended Bayesian-FBP algorithm. A cardiac patient data set is used in this paper to evaluate the extended Bayesian-FBP algorithm, and the result from a well-establish iterative algorithm with ${{\rm L}_1}$ -norms is used as the gold standard. If the parameters are selected properly, the extended Bayesian-FBP algorithm can outperform the original Bayesian-FBP algorithm.

This paper will address dosimetry and monitoring techniques for total ionizing dose (TID) testing of electronics devices. We will first discuss the basic principles of dosimetry, as well as the most common dosimetric quantities and units, used for the determination of the energy deposited in a given medium by ionizing radiation. In Section III , we will give an overview of the available dosimetry techniques for ionizing radiation, along with the basic mechanisms exploited for their operation. In Section IV , we will address issues and factors affecting the dosimetry measurements, as well as we will give some practical “hints” about the selection and use of the presented techniques. Finally, a synthesis of the existing radiation test facilities, focusing on the one for TID testing, will be given in Section V . Their interest, limitations, and some practical aspects involving the organization of radiation test campaigns will also be discussed in this paper.

It is a long-standing tradition of the IEEE Nuclear and Space Radiation Effects Conference (NSREC) to recognize the Outstanding Conference Paper, the Outstanding Data Workshop Presentation, and the best paper presented and first-authored by an IEEE Student Member. In addition to recognizing authors for particularly high-quality and relevant work, the awards process also encourages all authors to produce presentations and manuscripts of high technical quality, clarity of presentation, and significance to the community.

Large scientific projects present new technological challenges, such as the distributed control over a communication network. In particular, the middleware Experimental Physics and Industrial Control System (EPICS) is the most extended communication standard in particle accelerators. The integration of modern control architectures in these EPICS networks is becoming common, as for example for the PXI/PXIe and xTCA hardware alternatives. In this paper, a different integration procedure for PXI/PXIe real-time controllers from National Instruments is proposed, using LabVIEW as the design tool. This methodology is considered and its performance is analyzed by means of a set of laboratory experiments. This control architecture is proposed for achieving the implementation requirements of fast controllers, which need an important amount of computational power and signal processing capability, with a tight real-time demand. The present paper studies the advantages and drawbacks of this methodology and presents its comprehensive evaluation by means of a laboratory test bench, designed for the application of systematic tests. These tests compare the proposed fast controller performance with a similar system implemented using an standard EPICS IOC provided by the CODAC system.

This paper investigates some potential methods for few-view tomography, and investigates the cause and remedy of the staircase artifacts. This paper also discusses whether there is any benefit to use edge-preserving filters in emission tomography. We formulate a general Green’s one-step-late algorithm, so that it can incorporate any linear or non-linear filters. We argue that the derivative of the penalty function can be “artificially” created, not naturally derived from a penalty function. We have gained more insight into constrained image reconstruction especially with edge-preserving constraints. Our numerical results show that the bilateral method can have better performance than the TV method, and higher order methods may not be necessary for non-piecewise-constant objects.

The unique capabilities of neutrons to penetrate materials opaque to X-rays and at the same time to interact with hydrogen make neutron radiography a technique of choice for the quantification of hydrogen-containing substances. However, the interaction of neutrons with hydrogen is through scattering, not absorption and unwanted scattered neutrons can be responsible for a considerable fraction of the registered events, reducing the accuracy of hydrogen quantification, especially in imaging experiments where the sample has to be placed close to the detector to avoid image blurring due to the finite beam divergence. Various post-experiment data processing techniques were developed to correct and mitigate the effects of scattering. Another complementary 'hardware' solution described in this paper, is to simply eliminate the detrimental scattering component from the detected signal through the use of neutron collimators. Development of compact polycapillary collimators, merely a few mm thick, now enables accurate, high spatial resolution quantification of a wide range of materials which tend to strongly scatter neutrons. This paper demonstrates how it is now possible to substantially improve the accuracy of the measured water content in cement samples. A compact polycapillary neutron collimator (2 mm thick, 5 cm diameter, with ∼8 µm pores hexagonally packed on ∼10 µm centers) used for scatter rejection in our experiments. The water content within the 1×1×2 cm3 cement samples is measured by neutron transmission radiography, performed with sub-100 µm spatial resolution. The measurement of water concentration is markedly improved through the use of this collimator, proving those can be attractive for the experiments where samples must be placed in quite close proximity (e.g., only few centimeters or closer), from the neutron detector active surface.

The recipients of the 2014 NSREC Outstanding Conference Paper Award are Nathaniel A. Dodds, James R. Schwank, Marty R. Shaneyfelt, Paul E. Dodd, Barney L. Doyle, Michael Trinczek, Ewart W. Blackmore, Kenneth P. Rodbell, Michael S. Gordon, Robert A. Reed, Jonathan A. Pellish, Kenneth A. LaBel, Paul W. Marshall, Scot E. Swanson, Gyorgy Vizkelethy, Stuart Van Deusen, Frederick W. Sexton, and M. John Martinez, for their paper entitled "Hardness Assurance for Proton Direct Ionization-Induced SEEs Using a High-Energy Proton Beam." For older CMOS technologies, protons could only cause single-event effects (SEEs) through nuclear interactions. Numerous recent studies on 90 nm and newer CMOS technologies have shown that protons can also cause SEEs through direct ionization. Furthermore, this paper develops and demonstrates an accurate and practical method for predicting the error rate caused by proton direct ionization (PDI).

This paper presents a non-uniform object-space pixelation (NUOP) approach for image reconstruction using the penalized maximum likelihood methods. This method was developed for use with a single photon emission microscope (SPEM) system that offers an ultrahigh spatial resolution for a targeted local region inside mouse brain. In this approach, the object-space is divided with non-uniform pixel sizes, which are chosen adaptively based on object-dependent criteria. These include (a) some known characteristics of a target-region, (b) the associated Fisher Information that measures the weighted correlation between the responses of the system to gamma ray emissions occurred at different spatial locations, and (c) the linear distance from a given location to the target-region. In order to quantify the impact of this non-uniform pixelation approach on image quality, we used the modified uniform Cramer-Rao bound (MUCRB) to evaluate the local resolution-variance and bias-variance tradeoffs achievable with different pixelation strategies. As demonstrated in this paper, an efficient object-space pixelation could improve the speed of computation by 1-2 orders of magnitude, whilst maintaining an excellent reconstruction for the target-region. This improvement is crucial for making the SPEM system a practical imaging tool for mouse brain studies. The proposed method also allows rapid computation of the first and second order statistics of reconstructed images using analytical approximations, which is the key for the evaluation of several analytical system performance indices for system design and optimization.

This paper reports the experimental qualification of an original uranium characterization method based on fluorescence X-rays induced by the spontaneous gamma emission of bituminized radioactive waste drums. The main 661.7 keV gamma ray following the 137Cs decay produces by Compton scattering in the bituminized matrix an intense photon continuum around 100 keV, i.e. in the uranium X-ray fluorescence region. “Self-induced” X-rays produced without using an external source allow a quantitative assessment of uranium as 137Cs and uranium are homogeneously mixed and distributed in the bituminized matrix. The paper presents the experimental qualification of the method with real waste drums, showing a detection limit well below 1 kg of uranium in 20 min acquisitions while the usual gamma rays of 235U (185 keV) or 238U (1001 keV of 234mPa in the radioactive decay chain) are not detected. The relative uncertainty on the uranium mass assessed by self-induced X-ray fluorescence (SXRF) is about 50%, with a 95% confidence level, taking into account the correction of photon attenuation in the waste matrix. This last indeed contains high atomic numbers elements like uranium, but also barium, in quantities which are not known for each drum. Attenuation is estimated thanks to the peak-to-Compton ratio to limit the corresponding uncertainty. The SXRF uranium masses measured in the real drums are in good agreement with long gamma-ray spectroscopy measurements (1001 keV peak) or with radiochemical analyses.

Organic scintillators are often chosen as radiation detectors for their fast decay time and their low Z, while inorganic ones are used when high light ields are required. In this paper we show that a para-terphenyl based detector has a blend of properties of the two categories that can be optimal for energy and position measurements of low energy charged particles. On 0.1% diphenylbutadiene doped para-terphenyl samples we measure a light yield 3.5+-0.2 times larger than a typical organic scintillator (EJ-200), and a rejection power for 660 keV photons, with respect to electrons of the same energy, ranging between 3-11%, depending on the signal threshold. We also measure a light attenuation length = 4.73+-0.06 mm and we demonstrate that, with the measurements performed in this paper, a simulation based on FLUKA can properly reproduce the measured spectra.

This issue of the IEEE Transactions on Nuclear Science (TNS) is devoted to the 21st IEEE-NPSS Real Time Conference (RT2018) on Computing Applications in Nuclear and Plasma Sciences held in Williamsburg, VA, USA, in June 2018. A total of 98 papers presented at the conference have been submitted for possible publication in TNS. The conference accepted 54 papers as oral and 149 as poster presentations in 13 tracks.

The 2018 RADECS Workshop and 2nd International Conference on Radiation Effects of Electronic Devices (ICREED) were held on May 16–18, 2018, at the Fengda International Hotel, Beijing, China. The workshop and conference were hosted by the China Academy of Aerospace Electronics Technology, organized by the Beijing Microelectronics Technology Institute and the Harbin Institute of Technology, and attended by more than 260 researchers from 15 countries and more than 70 institutions. Six papers presented at ICREED are included in the June 2019 issue of the IEEE Transactions on Nuclear Science. These papers highlight active research on radiation effects on microelectronics in China. Additional papers based on work presented at ICREED appear in other issues of the transactions.

The January 2019 special issue of the IEEE Transactions on Nuclear Science (TNS) contains selected papers from the 55th annual IEEE International Nuclear and Space Radiation Effects Conference (NSREC) held on July 16–20, 2018, in Kona, Hawaii. The 2018 IEEE NSREC was sponsored by the IEEE Nuclear and Plasma Sciences Society. Eighty-three of the 102 papers presented at the 2018 IEEE NSREC were submitted for consideration for this year’s special issue. This issue is neither a conference proceeding 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 at the Conference are likely to appear in subsequent issues of the Transactions.

Modern low-level radio frequency (LLRF) control systems of linear accelerators are designed to achieve extremely precise field amplitude and phase regulation inside superconducting cavities. One of the crucial components of the feedback loop is a vector modulator used to drive the high-power RF chain supplying the accelerating cavities. The LLRF control systems for the Free Electron Laser in Hamburg (FLASH) and European X-ray Free Electron Laser (XFEL) are based on the emerging Micro-Telecommunications Computing Architecture (MTCA.4) platform offering numerous advantages for high-performance control systems. This paper describes the concept, design, and performance of the first vector modulator (uVM) module dedicated for RF controls compliant with the MTCA.4 specification developed by PCI Industrial Computer Manufacturers Group (PICMG). The uVM module has been built as a double-width, mid-size rear transition module (RTM) that is accessed by an advanced mezzanine card (AMC). The uVM module incorporates digital, analog, and diagnostic subsystems. The digital part is based on Xilinx Spartan 6 family field-programmable gate array (FPGA), with several fast gigalink connections to a control module. The uVM module is equipped with an intelligent platform management interface (IPMI) circuit required by the MTCA.4 standard. The FPGA controls the analog part, which includes fast, high-precision digital-to-analog converters (DACs), In-phase and quadrature modulator chips, programmable attenuators, power amplifiers, and fast RF gates for an external interlock system. The RF chain can be adopted to different carrier frequencies covering a frequency range from 50 MHz to 6 GHz. The design has been carefully optimized for high linearity and low-output signal phase noise. The diagnostic system of the RF chain allows monitoring of input and output power levels and failure detection in the RF circuits. A low-noise and high-performance clocking system makes the uVM a universal device, extending the scope of applications beyond the LLRF control systems. Extensive tests of the board were performed, and the measurement results are presented and discussed in this paper.

Studies over the past 25 years have shown that heavy ions can trigger catastrophic failure modes in power MOSFETs [e.g., single-event gate rupture (SEGR) and single-event burnout (SEB)]. In 1996, two papers were published in a special issue of the IEEE Transaction on Nuclear Science [Johnson, Palau, Dachs, Galloway and Schrimpf, “A Review of the Techniques Used for Modeling Single-Event Effects in Power MOSFETs,” IEEE Trans. Nucl. Sci., vol. 43, no. 2, pp. 546-560, April. 1996], [Titus and Wheatley, “Experimental Studies of Single-Event Gate Rupture and Burnout in Vertical Power MOSFETs,” IEEE Trans. Nucl. Sci., vol. 43, no. 2, pp. 533-545, Apr. 1996]. Those two papers continue to provide excellent information and references with regard to SEB and SEGR in vertical planar MOSFETs. This paper provides updated references/information and provides an updated perspective of SEB and SEGR in vertical planar MOSFETs as well as provides references/information to other device types that exhibit SEB and SEGR effects.

Task-based assessments of image quality constitute a rigorous, principled approach to the evaluation of imaging system performance. To conduct such assessments, it has been recognized that mathematical model observers are very useful, particularly for purposes of imaging system development and optimization. One type of model observer that has been widely applied in the medical imaging community is the channelized Hotelling observer (CHO). Since estimates of CHO performance typically include statistical variability, it is important to control and limit this variability to maximize the statistical power of image-quality studies. In a previous paper, we demonstrated that by including prior knowledge of the image class means, a large decrease in the bias and variance of CHO performance estimates can be realized. The purpose of the present work is to present refinements and extensions of the estimation theory given in our previous paper, which was limited to point estimation with equal numbers of images from each class. Specifically, we present and characterize minimum-variance unbiased point estimators for observer signal-to-noise ratio (SNR) that allow for unequal numbers of lesion-absent and lesion-present images. Building on this SNR point estimation theory, we then show that confidence intervals with exactly-known coverage probabilities can be constructed for commonly-used CHO performance measures. Moreover, we propose simple, approximate confidence intervals for CHO performance, and we show that they are well-behaved in most scenarios of interest.