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This paper describes an equipment for continuous measurement and identification of gamma radioactivity in aerosols developed by the Nuclear Engineering Research Group (NERG) at the Technical University of Catalonia (UPC) and Raditel Serveis i Subministraments Tecnològics, Ltd. A spectrometric analysis code has been specially designed for it. Spectrum analysis identifies and determines activity concentration of aerosol emitters captured by a fiberglass paper filter. This new equipment is currently operating in three radioactivity monitoring stations of the Environmental Radiological Surveillance Network of the Generalitat of Catalunya (local Catalan government): two near Ascó and Vandellòs Nuclear Power Plants in the province of Tarragona and one in the city of Barcelona. Two more monitors are expected to be deployed at Roses, Girona, Spain, and Puigcerdà, Barcelona, Spain. Measurements and evolution analysis results of emitters identified at these stations were also provided. [ABSTRACT FROM PUBLISHER]

This paper uses the meteorological conditions to predict neutron background counts as measured by a neutron detector. Such counts occur due to cosmic-ray interactions and temporal variations that are primarily dependent on meteorological factors. This paper presents a marginal autoregressive (AR) model constructed from eight months of hourly meteorological data that accurately predicts neutron background without being susceptible to the presence of source material. Nonmeteorological factors impacting neutron background (including cosmic-ray intensity) are not readily measurable in real time in a validated format, so a conditional AR model is also presented that can compensate for phenomena not included in the model while maintaining some independence from potential sources. This paper shows that the conditional AR model is more effective than the moving average, with lower susceptibility to source contamination, ensuring a consistent level of sensor effectiveness. [ABSTRACT FROM PUBLISHER]

The radiation environment of the Galileo spacecraft is severe and poorly characterized. The Galileo orbit takes the spacecraft through the heart of the outer radiation belt, while the low levels of geomagnetic shielding throughout the orbit expose the spacecraft to intermittent intense fluxes of protons during solar energetic particle events. In the Galileo constellation, two environmental monitoring units (EMUs) are currently flying in two different orbital planes. These units monitor the radiation environment and provide critical information related to hazards for the host spacecraft and its payload. In this paper, we present the results from the analysis of the surface charge collecting plates and the proton telescope sensors. The performed numerical calibration of the EMU sensors and the application of novel unfolding and in-flight cross-calibration techniques allow the calculation of high-quality proton and electron differential fluxes. The creation of a high-quality, long-term EMU electron flux data set, is a step forward toward the improved characterization of medium earth orbit (MEO) environment through the update of the existing or the development of new radiation environment models. [ABSTRACT FROM AUTHOR]

JUICE, the Jupiter Icy Moons Explorer, ESA’s next L-class mission to the Jovian system, will carry a radiation hard electron monitor (RADEM). It will be the first mission since Galileo to perform long-term measurements of the Jovian radiation environment. RADEM has challenging low mass and power constraints which required novel detector concepts. In this paper, we present a RADEM directionality detector and describe its capability to measure radiation angular variability. [ABSTRACT FROM AUTHOR]

This paper presents our achievement in the development of new types of advanced composite scintillators (CSs) based on the single crystalline films (SCFs) of Lu3Al5O12 (LuAG) garnet, doped with Pr3+ and Sc3+ ions, and substrate from single crystals (SCs) of Ce3+-doped LuAG using the technology of liquid phase epitaxy. We show the possibility of the simultaneous registration of $\alpha$ -particles and $\gamma$ -quanta by means of separation of the decay kinetics of SCF and crystal parts of such CSs. Namely, the significant differences in the scintillation decay kinetics of LuAG:Pr SCF/LuAG:Ce SC and LuAG:Sc SCF/LuAG:Ce SC CSs under excitation by $\alpha$ -particles of 241Am (5.5 MeV) source and $\gamma$ -quanta of 137Cs (662 keV) source are observed. Thus, such types of CSs can be successfully applied for separation of the signals coming from their film and crystal parts at the registration of the mixed radiation fluxes of $\alpha$ -particles and $\gamma$ -quanta. [ABSTRACT FROM AUTHOR]

In this paper, we report the rise time of three silicon reach-through avalanche photodiodes (APD) when measuring alpha particles and low-energy ions in the energy range from 50 to 300 keV. The APDs were custom manufactured by Hamamatsu Photonics and differ by their doping manufacturing method (p-type or n-type) and their depletion layer thickness (30 or $150~\mu \text{m}$ ). Our findings are summarized as follows: 1) the rise time is largely a function of detector drift layer thickness and 2) the rise time is mostly independent of ion species. The measured rise time values were comparable to ~1.5 ns for the two $30~\mu \text{m}$ APDs at the operational bias voltages. In combination with the timing electronics, such as constant fraction discriminators, a less than 1-ns response time resolution will be achievable for these APDs. These new findings are valuable for applying APDs for suprathermal particle measurements in space physics, enabling simplified time-of-flight and energy systems, and high count rate applications. [ABSTRACT FROM AUTHOR]

A complete, general solution for collecting and processing data from gaseous tracking detectors in high-rate applications has been developed. The readout chain consists of front-end modules equipped with PASTTREC ASIC chips and trigger readout boards version 3 (TRBv3) as a readout platform. The platform is accompanied by dedicated control, monitoring, and data quality assessment software. The entire system has been evaluated with a tracking system based on straw detectors in laboratory and in-beam experiments. In this paper, we present key elements of the system as well as results of various tests. The measured PASTTREC operation characteristics and the TRBv3 specification used for the readout allow us to adapt and to integrate it to the existing HADES spectrometer and the PANDA detector, an experiment under construction, both located at the FAIR facility in Darmstadt. [ABSTRACT FROM PUBLISHER]

A bipolar-transistor-based sensor technique has been used to compare silicon displacement damage from known and unknown neutron energy spectra generated in nuclear reactor and high-energy-density physics environments. The technique has been shown to yield 1-MeV(Si) equivalent neutron fluence measurements comparable to traditional neutron activation dosimetry. This paper significantly extends previous results by evaluating three types of bipolar devices utilized as displacement damage sensors at a nuclear research reactor and at a Pelletron particle accelerator. Ionizing dose effects are compensated for via comparisons with 10-keV X-ray and/or cobalt-60 gamma ray irradiations. Nonionizing energy loss calculations adequately approximate the correlations between particle and device responses and provide evidence for the use of one particle type to screen the sensitivity of the other. [ABSTRACT FROM PUBLISHER]

Compact environmental anomaly sensor risk reduction (CEASE-RR) is a new sensor designed for anomaly attribution due to the space radiation environment. It does this using two solid-state particle telescopes that have been designed to measure proton and electron fluxes that are the drivers for three of the four primary space environment effects (event total dose, deep-dielectric charging, and single event effects). These telescopes are integrated into a compact package along with space reserved for a planned electrostatic analyzer being developed for the final CEASE 3 design (covering the fourth primary space environment effect—surface charging). The sensors themselves will measure a wider dynamic range in particle flux, provide higher energy resolution, have better out-of-band contamination rejection, and improved diagnostic capability compared to previous CEASE instruments. The CEASE-RR instrument is planned to be launched in 2018 to geostationary orbit as part of an Air Force Research Laboratory flight experiment. The sensor design, calibration, and planned flight experiment objectives are described in this paper. [ABSTRACT FROM PUBLISHER]

In order to provide benchmark data sets for radiation detector and algorithm development, a particle transport test bed has been created using experimental data as model input and validation. A detailed radiation measurement campaign at the Combined Arms Collective Training Facility in Fort Indiantown Gap, PA (FTIG), USA, provides sample background radiation levels for a variety of materials present at the site (including cinder block, gravel, asphalt, and soil) using long dwell high-purity germanium (HPGe) measurements. In addition, detailed light detection and ranging data and ground-truth measurements inform model geometry. This paper describes the collected data and the application of these data to create background and injected source synthetic data for an arbitrary gamma-ray detection system using particle transport model detector response calculations and statistical sampling. In the methodology presented here, HPGe measurements inform model source terms while detector response calculations are validated via long dwell measurements using 2” $\times 4$ ” $\times 16$ ” NaI(Tl) detectors at a variety of measurement points. A collection of responses, along with sampling methods and interpolation, can be used to create data sets to gauge radiation detector and algorithm (including detection, identification, and localization) performance under a variety of scenarios. Data collected at the FTIG site are available for query, filtering, visualization, and download at muse.lbl.gov. [ABSTRACT FROM PUBLISHER]

This paper reports a series of measurements that characterize the directional dependence of the scintillation response of crystalline anthracene to incident DT neutrons, DD neutrons, ^137Cs gamma rays, and, for the first time, cosmic ray muons. The neutron measurements give the amplitude and pulse shape dependence on the proton recoil direction over one hemisphere of the crystal, confirming and extending previous results in the literature. In similar measurements using incident gamma rays, no directional effect is evident, and any anisotropy with respect to the electron recoil direction is constrained to have a magnitude of less than a tenth of that present in the proton recoil events. Cosmic muons are measured at two directions, and no anisotropy is observed. This set of observations indicates that high $dE/dx$ is necessary for an anisotropy to be present for a given type of scintillation event, which in turn could be used to discriminate among different hypotheses for the underlying causes of the anisotropy, which are not well understood. [ABSTRACT FROM PUBLISHER]

This paper reports on the preparation and growth of Eu-doped strontium iodide (SrI2) single crystals by modified micro-pulling-down method. Influence of the Eu^2 + and Eu^3 + (introduced in form of EuI2 and EuCl3) on the luminescence and scintillation properties is analyzed. Sufficient optical quality of prepared single crystals was obtained allowing further characterization of their absorption, radio- and photoluminescence spectra. Photoluminescence and scintillation decay time of grown SrI2 crystals irradiated under \gamma -ray source were evaluated as well. [ABSTRACT FROM AUTHOR]

Nuclear decay data measurements were performed in the frame of a EURAMET project. Two specific goals were addressed: (1) High-precision measurements of ^238U alpha-particle emission probabilities and (2) experimental characterization of the shape of beta spectra using cryogenic detectors. In the paper, specific lessons learned from the metrological work are highlighted. This includes effects of source preparation on the quality of alpha and beta spectrometry, the influence of exchange effects on beta spectra and the use of a magnet system to eliminate coincidence effects by conversion electrons in alpha-particle spectra. [ABSTRACT FROM PUBLISHER]

This paper presents an enhanced approach to extract as much as possible information from raw measurements of a given solid-state detector. Here we focus on the benefits of a singular value decomposition approach applied to the special case of the CNES–JASON 2 mission. It allows us to extract more information from the sensor than a more traditional technique. Refined differential fluxes instead of only coarse integral and differential ones are now obtained and to get an improved resolution for both protons (40–500 MeV) and electrons (825 keV to 8 MeV). Finally, thanks to the combination of all the information embedded into the different response functions of the ICARE-NG instrument, we are now able to: 1) estimate the uncertainty of our measurements, and 2) automatically filter contamination from both proton and electron in restored fluxes channels. [ABSTRACT FROM PUBLISHER]

An extension to space environment data analysis proposed by COSPAR/PRBEM in 2008 is proposed in this paper. By correlating two channels available on the same vehicle, it is shown that the definition of regions or times when protons or electrons dominate radiation monitor measurements can be given. This is of particular interest when the response function of the instrument is such that proton and electron events are mixed. Taking the advantage of having well-defined radiation monitor response functions, a detailed analysis of count rate data is applied to PROBA-1/SREM. It is then possible to sort proton count rates and electrons count rates from a given channel and found well-known general trends of electron and proton short-term and long-term dynamics. [ABSTRACT FROM PUBLISHER]

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 yields 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. Using 0.1% diphenylbutadiene doped para-terphenyl samples we measured a light attenuation length \lambda = 4.73 \pm 0.06~\mm, a quenching factor for \alpha particles Q_\alpha = (10.7 \pm 0.6), and a rejection power ranging between 3 - 11\% for 660 keV photons, with respect to electrons of the same energy, depending on the signal threshold. A simulation based on FLUKA properly reproduces the experimental data distributions. [ABSTRACT FROM AUTHOR]

An experiment named AMMON is dedicated to the analysis of the neutron and photon physics of the Jules Horowitz Reactor (JHR). AMMON, performed in the EOLE zero-power experimental reactor at CEA Cadarache, is finished since April 2013. Photon heating measurements were performed with both Thermoluminescent Dosimeters (TLD-400s) and Optically-Stimulated Dosimeters (OSLDs) in three AMMON configurations. The objective is to provide data for the experimental validation of the JHR photon calculation tool. The first analysis of the photon heating measurements of the reference configuration (AMMON/REF) is presented in this paper. The reference configuration consists of an experimental zone of 7 JHR assemblies with U3Si_2 - Al 27% ^235U enriched fuel curved plates surrounded by a driver zone with 623 standard PWR UOx fuel pins. The photon heating has been measured in the aluminum follower of the central and peripheral assemblies, and in aluminum fillers in the rack between assemblies. The measurement analysis is based on Monte Carlo TRIPOLI-4 ® version 8.1 calculations modeling the core exact three-dimensional geometry. The JEFF nuclear data library is used for the calculation of the neutron transport and the photon emission in the AMMON/REF experiment. The photon transport is made on the basis of the EPDL97 photo-atomic library. The prompt and delayed doses deposited in dosimeters have been estimated separately. The transport of 4 (neutrons, photons, electrons and positrons) or 3 particles (photons, electrons and positrons) is simulated in the calculations for the AMMON/REF analysis, depending whether the prompt or delayed dose is calculated. The TRIPOLI-4.8.1 ® calculations makes it possible the modeling of the electromagnetic cascade shower with both electrons and positrons. The delayed dose represents about 25% of the total photon energy deposition in the dosimeters. The comparison between Calculation and Experiment brings into relief a slight systematic underestimation of the calculated global photon energy deposition: (C - E)/E = - 8\% \pm 4.5\% (1\sigma ). A special care has been directed towards the determination of the uncertainty associated with the (C-E)/E values. The slight underestimation could be probably explained by an underestimation in the photon emission with the JEFF library. [ABSTRACT FROM PUBLISHER]

Inferring the ON/OFF operational state of a reactor facility using measurements from an independent monitoring system is critical to the assessment of its compliance to agreements. We consider the problem of inferring the ON/OFF state of a reactor facility using the measurements of Ar-41, Cs-138, and Xe-138 gas effluence types collected at the facility’s off-gas stack. We present classifiers based on thresholding measurements of individual effluence types, and then present fusers that combine their outputs or measurements. We present five fusers based on the simple majority rule, Chow’s pattern recognition function, Fisher’s combined ${p}$ -value statistic, the physics-based Poisson radiation counts model, and the correlation coefficient (CC) method. In addition, we also test five machine learning methods based on nonlinear classifiers, which are available as R packages. Our results show that: 1) these gas effluence measurements are effective in inferring the ON/OFF state of a reactor facility, for example, best fusers achieve ~97% detection at ~1% false alarm rate and 2) fusers that combine all effluence types based on physics-based models, CC, and Fisher’s method outperform the simple majority rule, Chow’s fusers, and the machine learning methods, as well as when they are applied to individual and pairs of effluence types. [ABSTRACT FROM AUTHOR]

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

Irradiation experiments of positive and negative muon were conducted for 65-nm bulk CMOS static random-access memory. The experimental results reveal that parasitic bipolar action (PBA) contributes to negative muon-induced upsets. We observe an increase in single event upset (SEU) cross section at higher operation voltage under negative muon irradiation while positive muon shows an opposite decreasing tendency. Also, the proportion of multiple-cell upset (MCU) events to all the negative muon-induced upset events is up to 66, and more than a 20-bit MCU is observed. Furthermore, Monte Carlo simulation of particle and heavy ion transport code system (PHITS) is performed for explaining the difference in SEU between positive and negative muons. We also discuss the charge threshold that triggers PBA-induced MCU using measurement and simulation results with different momentum muons. The estimated threshold is much larger than the charge that the positive muons can deposit, which well explains that no PBA-induced MCUs are observed under positive muon irradiation. [ABSTRACT FROM AUTHOR]

In this paper, the soft error rate (SER) induced by neutrons in 65-nm 10T static random access memory (SRAM) is measured over a wide range of supply voltages from 1.0 to 0.3 V. The results show that the neutron-induced SER at 0.3 V is around eight times that at 1.0 V. The dependence of multiple cell upsets (MCUs) on the supply voltage and on the distance between well ties is also investigated. The dependence of the MCU rate on the supply voltage between 1.0 and 0.5 V is small and increases as the voltage is reduced below 0.5 V. This is because the effect of another mechanism, such as charge-sharing, becomes larger in the subthreshold region, rather than the parasitic bipolar effect, which is considered the dominant mechanism causing MCUs in SRAM at the nominal supply voltage in our design. [ABSTRACT FROM AUTHOR]

Recently (IEEE Trans. Nucl. Sci., Vol. 60, No. 3, pp. 1876-1911, 2013), Reed published an anthology of contributions from different research groups, each developing and/or applying Monte Carlo-based radiation transport tools to simulate a variety of effects that result from energy transferred to a semiconductor material by a single particle event. The Tool suIte for rAdiation Reliability Assessment (TIARA) simulation platform and its development by STMicroelectronics and Aix-Marseille University is described in this paper as a complement to this anthology. [ABSTRACT FROM AUTHOR]

It was demonstrated in the previous work that various threat materials could be detected inside the sea going cargo container by measuring the three variables, carbon and oxygen concentration and density of investigated material. Density was determined by measuring transmitted neutrons, which is not always practical in terms of setting up the instrument geometry. In order to enable more geometry flexibility, we have investigated the possibility of using the scattered neutrons in cargo material identification. For that purpose, the densities of different materials were measured depending on the position of neutron detectors and neutron generator with respect to the target position. One neutron detector was put above the target, one behind and one in front of the target, above the neutron generator. It was shown that all three positions of neutron detectors can be successfully used to measure the target density, but only if the detected neutrons are successfully discriminated from the gamma rays. [ABSTRACT FROM PUBLISHER]

In this paper, high-altitude measurements of both radiation environment and effects are described. Measurements are made using a neutron spectrometer and CCD camera. MUSCA SEP3 software is used to correlate both measurement approaches. Analyses of the charge levels in pixels induced by radiation events are proposed. Then, cross-comparison analyses based on a CCD camera and HERMEIS neutron spectrometer are performed to investigate radiation dynamic properties, including neutron/proton and muon contributions. [ABSTRACT FROM PUBLISHER]

In this paper are described measurements at high-altitude of both radiation environment and effects. These measurements comprise cosmic ray neutrons and SBU/MCU on nanoscales devices. Results obtained at Pic-du-Midi, France, and in the city of Puno, Peru, are presented and analyzed. Analyses and cross comparisons based-on MUSCA SEP^3 calculations show a good agreement between experimental data and modeling, thus illustrating the importance of the knowledge of the radiation field for a reliable prediction. [ABSTRACT FROM AUTHOR]

A phoswich detector with Compton suppression capability has been developed and tested for measuring xenon radioisotopes via a beta-gamma coincidence measurement technique. The phoswich detector has been designed with three scintillation layers. Beta-gamma coincidence events from radioxenon isotopes are identified when a coincidence energy absorption is detected in the first (BC-400) and second (CsI(Tl) crystal) scintillation layers. To identify and reject scattered photons from the CsI(Tl) crystal, the crystal is surrounded by a BGO scintillation layer. Our measurements show that the Compton suppression mechanism reduces the Compton continuum from 662 keV photons by 20–50% in the low-energy region of spectrum. Our beta-gamma coincidence measurements with ^135Xe and ^133Xe radioisotopes show energy resolutions (FWHM) of 13%, 46% and 24% for 250 keV, 30 keV and 80 keV gamma-ray peaks, respectively. In this paper, the detector design, assembly steps, digital pulse shape discrimination technique, and our recent measurements with radioactive lab sources and xenon radioisotopes are discussed. [ABSTRACT FROM PUBLISHER]

A Kalman-filter-based method is proposed to address challenges in nuclear signal processing, including pileup events and noise cancelation. The state-transition equation is established on the basis of suitable pulse shape models. By regarding the output signal of particle detectors as a measurable variable, the measurement equation is also introduced to correct dynamic processes of the state transition. A linear Kalman filter with $n$ tunnels is constructed to separate pileup events and maintain the original waveforms of pulses. In addition, two terms are defined and addressed for separation operations, namely, Availability, which is used to prepare for upcoming events, and Clearance Mechanism, which is given to remove thumbnail information from the previous events and make occupied tunnels available to subsequent nuclear events. Simulation and field experiments demonstrate that the proposed method can handle critical situations of pulse pileup and minimize count loss and dead time in the X-ray energy spectrum while maintaining the original pulse shapes. [ABSTRACT FROM AUTHOR]

The radon exhalation rate from the medium surface is commonly derived using a scheme involving a radon detector and an accumulation chamber. The accumulation chamber accumulates the radon gas to make its concentration level inside the chamber detectable by the radon detector in the scheme. The common calculation method for deriving the exhalation rate is based on an assumption that the radon concentrations in the detector's internal cell and that in the accumulation chamber become equal with sufficient accumulation time. However, based on our recent experiments, this method tends to underestimate the actual exhalation rates as generated by our simulation facility. To correct this, we develop a new method for computing the exhalation rate based on the non-equilibrium concept. This paper presents the new method. [ABSTRACT FROM AUTHOR]

The formation of clusters in the data analysis of position-sensitive detectors is traditionally based on signal-to-noise ratio thresholds. For detectors with a very low signal-to-noise ratio, e.g., as a result of radiation damage, the total collected charge obtained from the clusters is biased to the greater signal values resulting from the thresholds. In this paper an unbiased method to measure the charge collection of a silicon strip detector in a test beam environment is presented. The method is based on constructing the clusters on test detectors around the impact point of the reference track. [ABSTRACT FROM AUTHOR]

We have performed an irradiation test of low-energy positive and negative muons on 65-nm ultra-thin body and thin buried oxide silicon-on-insulator static random access memories. The single event upset (SEU) cross sections were measured systematically as a function of incident muon momentum and operating supply voltage. The experimental results show that the negative muon SEUs occur at about three times higher rate than the positive muon ones at the supply voltage of 0.5 V when the incident muons stop near the sensitive volume (SV). A Monte-Carlo simulation with the particle and heavy ion transport code system (PHITS) was carried out using a simple SV model. The simulation based on the PHITS using the SV model is found to reproduce generally well the momentum dependence of the measured SEU cross sections for both positive and negative muons. From the simulation, the charged particles and secondary ions having significant influence on SEUs are specified and the differences between negative and positive muons are discussed. [ABSTRACT FROM AUTHOR]

The Gd3(Al,Ga)5O12:Ce single-crystalline films were grown by a liquid phase epitaxy (LPE) technique from BaO-B2O3-BaF2 flux. The scintillation characteristics were investigated and compared to the bulk Gd3(Al2.7Ga2.3)O12:Ce single crystal (SC) grown by the Czochralski technique. The light yield (LY) and energy resolution were measured using an R6231 photomultiplier. At 5.5-MeV $\alpha$ -particles, the LY value of 7100 photons/MeV obtained for Gd3Al2.62Ga2.38O12:Ce-LPE sample is lower than that of 9310 photons/MeV for the Gd3(Al2.7Ga2.3)O12:Ce-SC sample, whereas an energy resolution of the LPE sample is better (5.9% versus 6.6%). The ratio of LY value under excitation with $\alpha$ - and $\gamma$ -rays ($\alpha /\gamma$ ratio) was also determined. Faster scintillation decay time and lower slow-component content were obtained for LPE samples with respect to Gd3(Al2.7Ga2.3)O12:Ce-SC one. [ABSTRACT FROM AUTHOR]

A network of Timepix (TPX) devices installed in the ATLAS cavern measures the Large Hadron Collider (LHC) luminosity as a stand-alone system. The data were recorded from 13-TeV proton–proton collisions in 2016. Using two TPX devices, the number of hits created by particles passing the pixel matrices was counted. Absolute luminosity is determined with the van der Meer scan technique by separating the LHC proton beams and measuring the widths of the beams in low-intensity LHC proton–proton collisions. The exact determination of the activation background contributes to the overall precision of the TPX luminosity measurements. The activation background varies in time due to induced radioactivity at the different positions of the TPX devices in the ATLAS cavern. The activation at a given time depends on the history of the LHC operation. A detailed study of induced radioactivity has been performed to reduce the uncertainty on both the relative and absolute luminosity measurements. [ABSTRACT FROM AUTHOR]

Data from ground-level radiation monitors and cosmogenic nuclides are combined to give a probability distribution for severe radiation events related to the well quantified event of February 23, 1956. Particle fluxes, single event effects rates, and dose rates are calculated for ground level and aerospace systems. The event of February 1956 would provide a challenge to air safety while more extreme events seen in historical records would challenge safety-critical ground systems. A new space weather hazard scale based on this event could be used to give rapid assessment of the radiation hazard using high-latitude neutron monitor data. [ABSTRACT FROM PUBLISHER]

An extension of the point kinetics model is developed to describe the neutron multiplicity response of a bare uranium object under interrogation by an associated particle imaging deuterium–tritium (D-T) measurement system. This extended model is used to estimate the total neutron multiplication of the uranium. Both MCNPX-PoliMi simulations and data from active interrogation measurements of highly enriched and depleted uranium geometries are used to evaluate the potential of this method and to identify the sources of systematic error. The detection efficiency correction for measured coincidence response is identified as a large source of systematic error. If the detection process is not considered, results suggest that the method can estimate total multiplication to within 13% of the simulated value. Values for multiplicity constants in the point kinetics equations are sensitive to enrichment due to ( $n$ , xn) interactions by D-T neutrons and can introduce another significant source of systematic bias. This can theoretically be corrected if isotopic composition is known a priori. The spatial dependence of multiplication is also suspected of introducing further systematic bias for high multiplication uranium objects. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the relation between gamma nonproportionality and alpha particle nonproportionality. First, we collected literature data on the $\alpha/\beta$ ratio of almost all commonly used scintillators. Second, we extended the literature review with our own measurements of LaBr3:Ce $\alpha/\beta$ ratio in function of Ce3+ concentration. A strong influence of codoping on the $\alpha/\beta$ ratio of LaBr3:Ce has been observed. Finally, we conclude that the gamma nonproportionality, gamma intrinsic energy resolution, and $\alpha$ particle response are closely related to each other, and they are due to quenching in the high density part of ionization tracks. Though it still needs to be tested for a larger group of scintillators, $\alpha/\beta$ can be used as a single value characterizing intensity of light quenching processes in scintillators. [ABSTRACT FROM AUTHOR]

Single-event transients (SETs) induced by alpha particles and heavy ions are measured and analyzed with subthreshold voltage SET characterization circuits. Using a Schmitt trigger inverter target chain fabricated in a 65-nm bulk CMOS process, SET pulse widths are captured from an operating voltage down to 0.32 V. At nominal voltages, the Schmitt trigger inverter chain is immune to SETs, but at subthreshold voltages energetic particles can induce SET pulse widths that range up to and over a microsecond. Additionally, the results show that at subthreshold voltages the 28-nm node offers a significant improvement in the SET response over the 65-nm node. [ABSTRACT FROM PUBLISHER]

The detection efficiency of an ionization counter and the resulting energy spectra of samples can be dependent on the sample geometry. This is especially important for samples that are large compared to the size of the detector since some of the alpha particles emitted near the edge of the samples might not be collected if their trajectories fall outside the active area of the detector. We examine this effect in detail by measuring the alpha particles detected for rings and disks of various sizes, and compare the results to analytical and Monte Carlo models. [ABSTRACT FROM PUBLISHER]

The upper atmosphere is a transition region between the neutron-dominated aviation environment and satellite environment where primary protons and ions dominate. We report high altitude balloon measurements and model results characterising this radiation environment for single event effects (SEE) in avionics. Our data, from the RaySure solid-state radiation monitor, reveal markedly different altitude profiles for low linear energy transfer (LET) and high LET energy depositions. We use models to show that the difference is caused by the influence of primary cosmic ray particles, which induce counts in RaySure via both direct and indirect ionization. Using the new Model of Atmospheric Ionizing Radiation Effects (MAIRE), we use particle fluxes and LET spectra to calculate single event upset (SEU) rates as a function of altitude from ground level to the edge of space at 100 km altitude. The results have implications for a variety of applications including high altitude space tourism flights, UAVs and missions to the Martian surface. [ABSTRACT FROM PUBLISHER]

Two real-time tritium monitors are installed at the stack of HANARO, a 30 MW research reactor, to measure the tritium concentrations in the discharged air from the reactor hall and reactor concrete island region. The tritium monitor adopts coincidence and anticoincidence coupling to detect the very low energy beta particles from tritium. Since the tritium level in the air released from the reactor hall is very low during normal operation of HANARO, tritium concentration measurements are easily affected by the noble gas signal contribution and background. Thus, a method to remove the noble gas contribution and the tritium background is established. The noble gas contribution is verified and removed using reliable noble gas measurements by a third detection method. The tritium background is deduced using the bubbling method. The tritium concentration is determined using the newly established method, and it is compared with bubbling data. The two measurement methods produce mutually consistent data. Thus it can be concluded that our evaluation method provides useful data processing for the real-time measurement of extremely low tritium levels. [ABSTRACT FROM AUTHOR]

With a software-based approach using commercial off-the-shelf CMOS imaging sensors to detect ionizing particles, a low-cost radiation monitor is published to improve fault tolerance of nanosatellites with commodity hardware. We achieve this by segmenting image artifacts caused by radiation effects simultaneously within the original capturing images. For this purpose, a two-step segmentation method was developed using already acquired images from a miniaturized limb sounding spectrometer that derives atmospheric temperature profiles. The method covers bad pixel elimination and particle flux determination by a minimalized amount of additional computational costs. This allows the determination of the radiation environment close to the imaging instruments inside the satellite. We present the segmented results and compare it with simulated as well as measured data from a reference radiation monitor experiment. The detected particle flux is up to a factor of five lower than the simulated flux. These effective particle flux values will be used to improve measurement time by triggering mitigation measures on demand and expand their life time. [ABSTRACT FROM AUTHOR]

New metrological facilities for high temperature measurements of thermophysical properties have been recently developed by European National Metrology Institutes (NMIs). This work, performed in the framework of the joint research project “MetroFission”, aims to provide reliable measurements up to 2000^\circ C for materials having thermal properties similar to those required for design of new generations of fission reactors. This will enable to improve the traceability to the International System of Units (SI) of measurements performed by nuclear research laboratories. The validation of these reference apparatuses was done at high temperature by measuring the thermal diffusivity and normal spectral emissivity of an isostatic graphite and pure tungsten. [ABSTRACT FROM PUBLISHER]

A follow-up alpha emissivity study was conducted to examine the wide variability observed in previous work that was hypothesized to be due to differences in the pulse height discrimination threshold among participant’s equipment. Two samples, one mixed energy and one monoenergetic, were prepared and sequentially circulated to all participants for counting. Analysis of the data demonstrates that only a small portion of the variability is explained by this mechanism. The role of the sample to entrance window gap for some counters was analyzed post hoc using the same data set and may be responsible for a large amount of the variability. The results of this large-scale study demonstrate the continuing uncertainty for these measurements and the importance of interpreting their results appropriately when estimating soft error rates. [ABSTRACT FROM PUBLISHER]

We present a study of the radiation field at various locations in the ATLAS experiment, using compact detector systems based on pixelated silicon sensors assembled with Timepix readout chips. The hodoscope design of the ATLAS-Timepix (TPX) detectors includes neutron converters in between two sensors, allowing the characterization of both neutron and charged particle fields on a track by track basis. Thermal and fast neutrons are discriminated by segmenting the sensor area with dedicated sensitive materials. Using specific pattern recognition algorithms, clusters from electrons and photons above ~10 keV, minimum ionizing particles (MIPs), and highly ionizing particles are classified. A coincidence method using the time-over-threshold mode of the chip is developed to extract stopping power and directional information of energetic charged particles. Thermal neutron fluences are obtained for each ATLAS-TPX unit, illustrating the effect of detector material and shielding in the experimental cavern. Reconstructed trajectories of energetic charged particles point out radiation coming from the interaction point and other hot spots. [ABSTRACT FROM AUTHOR]

The approach of calibrating neutron environments through well-known Single Event Upset (SEU)-based SRAM memories is applied to a neutron spallation and mixed-field facility. Implications on the Soft Error Rate (SER) induced by intermediate energy neutrons are evaluated comparing operational environments, such as ground level and accelerator shielded areas, with those reproducible by facilities. Moreover, the energy hardness of the spectra is assessed through Single Event Latch-up (SEL) measurements with commercial components and FLUKA Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

A network of Timepix (TPX) devices installed in the ATLAS cavern has the unique capability of measuring the luminosity with thermal neutron counting in Large Hadron Collider proton-proton collisions at 13 TeV. Compared with the hit-counting method, the method of thermal neutron counting has the advantage that it is not affected by induced radioactivity. The results of the luminosity determination are presented for several independently operated TPX detectors. The long-term time stability measurements of the luminosity are presented for individual devices and between different devices. The high-statistics data sets allow a detailed comparison between neutron counting and hit-counting luminosity determinations. [ABSTRACT FROM AUTHOR]

We have developed a cryogenic heat and light detection system to investigate phonon and scintillation properties of scintillating crystals for rare event search experiments. The detector setup is designed to utilize a $1 \times 1\times 1$ cm3 scintillating crystal as a target material. A $1.5\times 1.5\times 0.05$ cm3 Ge wafer is used as the absorber of the light detection. Metallic magnetic calorimeters are employed to measure heat and scintillation-light signals of the scintillating crystal, simultaneously, at millikelvin temperatures. This measurement setup is motivated to characterize various types of scintillation crystals in a standard coupon size for a final selection of the crystal compounds to be used for a rare event search experiment. We present the first measurement for a calcium molybdate crystal doped with niobium in the test setup of heat–light detection. Clear particle identification was obtained in comparison of relative amplitude ratios of the phonon and scintillation signals. Moreover, alpha- and electron-induced events showed difference in their pulse shapes of phonon and scintillation signals. We discuss the usage of this setup for the AMoRE $0\nu \beta \beta $ search experiment. [ABSTRACT FROM PUBLISHER]

The design of a trapezoidal pulse shaper requires the definition of four parameters ( k , l , m1 , and m2 ) whose values are defined based on the characteristics of the input signal (timing, noise, etc.). A radiation detector and the data acquisition electronics provide this signal. The detector degenerates after high doses of radiation and its output no longer meets the original requirements. This behavior may lead to erroneous measurements of particle characteristics (energy, mass, charge, etc.). We present a method to adapt the shaper’s parameters to the degenerated behavior of the system based on the pulse height spectrum. It calculates, in real time, the new parameter values that recover the original detection specification under the new detector characteristics. We introduce the implementation of the system on a field programmable gate array as well. The implementation allows the autonomous recovery of the shaper in real time. Finally, we present the experimental results after testing the performance of this proposal using real data from the Castilla-La Mancha neutron monitor. [ABSTRACT FROM PUBLISHER]

A network of Timepix (TPX) devices installed in the ATLAS cavern measures the LHC luminosity as a function of time as a stand-alone system. The data were recorded from 13-TeV proton–proton collisions in 2015. Using two TPX devices, the number of hits created by particles passing the pixel matrices was counted. A van der Meer scan of the LHC beams was analyzed using bunch-integrated luminosity averages over the different bunch profiles for an approximate absolute luminosity normalization. It is demonstrated that the TPX network has the capability to measure the reduction of LHC luminosity with precision. Comparative studies were performed among four sensors (two sensors in each TPX device) and the relative short-term precision of the luminosity measurement was determined to be 0.1% for 10-s time intervals. The internal long-term time stability of the measurements was below 0.5% for the data-taking period. [ABSTRACT FROM AUTHOR]

In this work, the expected SEE rate in a generic model of a state-of-the-art SRAM memory was studied as a function of the critical charge in different radiation environments. The FLUKA Monte Carlo code was used to evaluate the SEE mono-energetic cross section for different particles as well as the SEE rate in different mixed field environments through an energy deposition analysis. Mono-energetic cross sections for protons and both positively and negatively charged muons were evaluated in the 0.1–1000 MeV energy range. The SEE rate was calculated for different mixed radiation field environments such as the terrestrial environment, commercial flight altitude, LHC critical areas for electronics and CERN’s CHARM test facility. Results show that direct ionization from charged particles becomes predominant between 0.2-1.1 fC compared to indirect neutron energy deposition. Finally the CHARM facility was demonstrated to be able to reproduce with a good approximation both the atmospheric and accelerator environments, particularly with regard to avionics, ground level applications and LHC. [ABSTRACT FROM PUBLISHER]

A new multi-pinhole Faraday cup (MPFC) device was designed, fabricated and tested to measure ion beam uniformity over a range of centimeters. There are 32 collectors within the device, and each of those is used as an individual Faraday cup to measure a fraction of the beam current. Experimental data show that the device is capable of measuring a charged particles distribution - either in the form of a raster scanned focused beam or a defocused beam. [ABSTRACT FROM PUBLISHER]