Table of contents

The vibrating wire monitor proposed herein is based on the strong dependence of the frequency of the pinched wire on its temperature. This dependence allows the measurement of a particle/X-ray/gamma-ray beam that deposits part of its energy on the wire. A wide measured temperature range from fractions of mK to hundreds of degrees allows the detection of beam properties at a given position of the wire in space. It also enables preparing profiling of a beam in a large dynamic range by scanning the wire through the beam. This review paper presents information on various applications of a vibrating wire, including the method of resonance target and the use of wire oscillations as a scanner for the profiling of thin beams.

Mechanisms of charging-up and charging-down of Gas Electron Multiplier (GEM) have been studied. Experimental investigations have been carried out on both dielectric polarization and radiation charging of GEMs. Environmental parameters, such as pressure and temperature have been monitored to normalize their effects on the charging-up and charging-down measurements. Variation in gain due to the combined, as well as individual, effects of the mentioned parameters, have been illustrated.

The ICARUS T600 liquid argon (LAr) time projection chamber (TPC) underwent a major overhaul at CERN in 2016–2017 to prepare for the operation at FNAL in the Short Baseline Neutrino (SBN) program. This included a major upgrade of the photo-multiplier system and of the TPC wire read-out electronics. The full TPC wire read-out electronics together with the new wire biasing and interconnection scheme are described. The design of a new signal feed-through flange is also a fundamental piece of this overhaul whose major feature is the integration of all electronics components onto the signal flange. Initial functionality tests of the full TPC electronics chain installed in the T600 detector at FNAL are also described.

The Liquid Argon Time Projection Chamber (LArTPC) is an advanced neutrino detector technology widely used in recent and upcoming accelerator neutrino experiments. It features a low energy threshold and high spatial resolution that allow for comprehensive reconstruction of event topologies. In current-generation LArTPCs, the recorded data consist of digitized waveforms on wires produced by induced signal on wires of drifting ionization electrons, which can also be viewed as two-dimensional (2D) (time versus wire) projection images of charged-particle trajectories. For such an imaging detector, one critical step is the signal processing that reconstructs the original charge projections from the recorded 2D images. For the first time, we introduce a deep neural network in LArTPC signal processing to improve the signal region of interest detection. By combining domain knowledge (e.g., matching information from multiple wire planes) and deep learning, this method shows significant improvements over traditional methods. This work details the method, software tools, and performance evaluated with realistic detector simulations.

We developed a positron emission tomography (PET) system for multiple-isotope imaging. Our PET system, named multiple-isotope PET (MI-PET), can distinguish between different tracer nuclides using coincidence measurement of prompt γ-rays, which are emitted after positron emission. In MI-PET imaging with a pure positron emitter and prompt-γ emitter, because of the imperfectness of prompt γ-ray detection, an image for a pure positron emitter taken by MI-PET is superposed by a positron-γ emitter. Therefore, in order to make isolated images of the pure positron emitter, we developed image reconstruction methods based on data subtraction specific to MI-PET. We tested two methods, subtraction between reconstructed images and subtraction between sinogram data. In both methods, normalization for position dependence of the prompt γ-ray sensitivity is required in addition to detector sensitivity normalization. For these normalizations, we performed normalization scans using cylindrical phantoms of the positron-γ emitters ^44mSc (prompt γ-ray energy: 1157 keV) and ²²Na (prompt γ-ray energy: 1274 keV) . A long period measurement using the activity decay of ^44mSc (T_1/2 = 58.6 hours) elucidated that the acquisition ratio between the prompt γ-rays coincided with PET event and pure PET event changes on the basis of object activities. Therefore, we developed a correction method that involves subtraction parameters dependent on the activities, i.e., the counting rate. We determined that correction for sensitivity normalization in variation of activity can be performed using only the triple-coincidence rate as an index, even if using a different nuclide from that used for normalization. From analysis of dual-tracer phantom images using ¹⁸F and ^44mSc or ¹⁸F and ²²Na, data subtraction in the sinogram data with sensitivity correction gives a higher quality of isolated images for the pure positron emitter than those from image subtractions. Furthermore, from dual-isotope (¹⁸F-FDG and ^44mSc) mouse imaging, we concluded that our developed method can be used for practical imaging of a living organism.

The ntCT nano tomography system is a geometrically magnifying X-ray microscopy system integrating the recent Excillum NanoTube nano-focus X-ray source and a CdTe photon counting detector from Dectris. The system's modulation transfer function (MTF) and corresponding point spread function (PSF) are characterized by analyzing the contrast visibility of periodic structures of a star pattern featuring line width from 150 nm to 1.5 μm. The results, which can be attributed to the characteristics of the source spot, are crosschecked by scanning the source's electron focus over an edge of the structured transmission target in order to obtain an independent measurement of its point spread function. For frequencies above 1000 linepairs/mm, the MTF is found to correspond to a Gaussian PSF of 250 nm full width at half maximum (FWHM) . The lower frequency range down to 340 linepairs/mm shows an additional Gaussian contribution of 1 μm FWHM . The resulting resolution ranges at 3200 linepairs/mm, which is consistent with the visual detectability of the smallest 150 nm structures within the imaged star pattern.

The operation of a novel large area micro-patterned gaseous electron multiplier, made from a 125 micron thick copper claded kapton foil, the COBRA_125, is presented. The COBRA_125 is equiped with 3 independent electrodes which allow to establish 2 independent multiplication regions in a single micro-patterened gaseous electron mutiplier. We report on the operation of a COBRA_125 with an active area of 100×100 mm². Charge gains above 10⁴ and energy resolutions in the range 18%–20% were achieved in a mixture of Ar-CH₄ (90%–10%) by irradiation with X-rays from ⁵⁵Fe source. Gain and energy resolutions were stable over the detector area, with maximum deviation from the average values of 8% and 15%, respectively.

The new generation of synchrotron radiation sources sets advanced requirements in the performance of hybrid pixel detectors. A critical point in the design of such detectors is the choice of the sensor material. Chromium-compensated Gallium Arsenide (GaAs:Cr) is a promising candidate for use in pixel detectors, targeting imaging applications in the intermediate energy range 20–50 keV. In this work, thick GaAs:Cr sensors grown recently using the Liquid Encapsulated Czochralski (LEC) method were bonded to Timepix chips. The performance of the sensors was characterised by using various X-ray sources in view of imaging applications. The uniform illumination of the sensors reveals inhomogeneities due to the presence of crystal defects in the microscopic level. Using a micro-focused X-ray beam we extract sensitivity maps and the mobility-lifetime product at the pixel level. The results obtained confirm that the non-uniformities observed at the sensor level are directly linked with the microscopic defects. Overall, the efficient use of such sensors in X-ray imaging applications relies on their stability over irradiation-time.

A network of ten GaAs:Cr semiconductor Timepix detectors with GaAs:Cr sensors was installed in the ATLAS cavern at CERN's LHC during the shutdown periods 2015–2016 and 2016–2017 in the framework of a cooperation between ATLAS and the Medipix2 Collaboration. The purpose was to augment the existing system of measuring and characterising the radiation environment in the ATLAS cavern that is based on ATLAS-TPX devices with pixelated silicon sensors. The detectors were in continuous operation during 13 TeV proton-proton collisions in 2017–2018. Data were recorded during proton-proton bunch crossings, and during times without bunch crossings (LHC physics runs) as well as between the physics runs. The overall level of particle radiation as well as the ratio between neutral and charged particles were measured. The detectors recorded all interactions of charge particles, neutrons and photons in GaAs sensors, in which the signal was higher than 6.5 keV in individual pixels. This made it possible to register clusters (tracks) of individual radiation particles interacting in the detectors sensors. During LHC beam-beam collisions, these were all particles represented in the radiation field. In the periods without beam-beam collisions, these were photons and electrons resulting from radioactivity induced during previous collisions in GaAs detectors and in surrounding construction materials, namely by neutrons.

We present results of a toy model study of performance of the Time-of-Flight detectors integrated into forward proton detectors. The goal of the ToF device is to suppress effects of additional soft processes (so called pile-up) accompanying the hard-scale central diffractive event, characterized by two tagged leading protons, one on each side from the interaction point. The method of mitigation of the pile-up effects exemplified in this study is based on measuring a difference between arrival times of these leading protons at the forward proton detectors and hence estimate the z-coordinate of the production vertex. We evaluate effects of the pile-up background by studying in detail its components, and estimate the performance of the ToF method as a function of the time and spatial resolution of the ToF device and of the number of pile-up interactions per bunch crossing. We also propose a new observable with a potential to efficiently separate central diffractive signal from the harsh pile-up environment.

The capacitance of the charge collection node of a sensor system is an important parameter for the design of the analog front-end electronics. The analog front-end of high-granularity sensors like for example hybrid pixel detectors need to be optimized for timing resolution, power consumption, and electronics noise—parameters which all depend on the pixel capacitance. Current pixel detector developments for the HL-LHC upgrade typically use silicon sensors with a pixel size in the order of 50 × 50 μm² which have a pixel capacitance of several tens of fF, depending on the sensor geometry. We have developed a dedicated integrated circuit to be bump-bonded to a pixel sensor, which enables a precise pixel capacitance measurement by using the charge-based capacitance measurement method. In this paper, we will describe the measurement method and the implementation of the capacitance measurement chip (Pixcap65) and show measurement results of a planar pixel sensor whose pixel capacitance is influenced by variations of the implant geometry.

The subject of space charge in ionisation detectors is reviewed, with particular attention to the case of liquid argon time projection chambers. Analytical and numerical description of the effects on the reconstructed coordinates along the drift and the transverse directions are presented. The cases of limited electron lifetime, of dual-phase detectors with ion feedback, and of detectors with small and comparable ratio between drift length and width are considered. Two design solutions that mitigates the effects are discussed.

Compton camera is capable of visualizing the distribution of radioactivity based on the Compton scattering kinematics, and can be applied in nuclear accident emergency response, radioactivity decontamination, homeland security and etc. A prototype of Compton camera has been constructed consisting of two 4×4 SiPM-Ce: GAGG scintillator arrays. The signals of a SiPM array were converted into 4 position-weighted outputs with capacitive network circuit and collected by a CAEN digitizer. Two-dimensional flood images and energy responses of two detector modules were obtained. The average energy resolution of single elements of the two detector modules was 6.6% FWHM at 662 keV. Imaging performance of the prototype camera was evaluated with a ¹³⁷Cs point source and a ²²Na point source. Efficiency of the prototype for the ¹³⁷Cs point source located right in front was measured to be 0.09%. The angular resolution of a ¹³⁷Cs point source placed right in front of the camera was 7.2° FWHM. Isotopic images of the two gamma-ray sources were obtained with spatial resolutions of 8.2° FWHM for ¹³⁷Cs and 8.8° FWHM for ²²Na.

AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory to complement the study of ultra-high-energy cosmic rays (UHECR) by measuring the muon content of extensive air showers (EAS). It consists of an array of 61 water Cherenkov detectors on a denser spacing in combination with underground scintillation detectors used for muon density measurement. Each detector is composed of three scintillation modules, with 10 m² detection area per module, buried at 2.3 m depth, resulting in a total detection area of 30 m². Silicon photomultiplier sensors (SiPM) measure the amount of scintillation light generated by charged particles traversing the modules. In this paper, the design of the front-end electronics to process the signals of those SiPMs and test results from the laboratory and from the Pierre Auger Observatory are described. Compared to our previous prototype, the new electronics shows a higher performance, higher efficiency and lower power consumption, and it has a new acquisition system with increased dynamic range that allows measurements closer to the shower core. The new acquisition system is based on the measurement of the total charge signal that the muonic component of the cosmic ray shower generates in the detector.

The continued desire for X-ray pixel detectors with higher frame rates will stress the ability of application-specific integrated circuit (ASIC) designers to provide sufficient off-chip bandwidth to reach continuous frame rates in the 1 MHz regime. To move from the current 10 kHz to the 1 MHz frame rate regime, ASIC designers will continue to pack as many power-hungry high-speed transceivers at the periphery of the ASIC as possible. In this paper, however, we present new strategies to make the most efficient use of the off-chip bandwidth by utilizing data compression schemes for X-ray photon-counting and charge-integrating pixel detectors. In particular, we describe a novel in-pixel compression scheme that converts from analog to digital converter units to encoded photon counts near the photon Poisson noise level and achieves a compression ratio of > 1.5× independent of the dataset. In addition, we describe a simple yet efficient zero-suppression compression scheme called "zeromask" (ZM) located at the ASIC's edge before streaming data off the ASIC chip. ZM achieves average compression ratios of > 4×, > 7×, and > 8× for high-energy X-ray diffraction, ptychography, and X-ray photon correlation spectroscopy datasets, respectively. We present the conceptual designs, register-transfer level block diagrams, and the physical ASIC implementation of these compression schemes in 65 nm CMOS. When combined, these two digital compression schemes could increase the effective off-chip bandwidth by a factor of 6–12×.

In this study, we present results of initial trials of a scintillator-over-fiber detector system with a silicon photomultiplier readout designed at Budker Institute of Nuclear Physics. The results demonstrate that the proposed system, using a pair of boron-enriched and boron-free scintillators, could be successfully used for monitoring of thermal neutron flux and estimation of irradiation dose. Nevertheless, it is necessary to optimize the design of the detector head components to ensure long time detector stability with heavy radiation background.

Systematic and random errors are often introduced in white-beam neutron Computed Tomography (CT) due to the nature of the neutron source, neutron-matter interactions or limitations in hardware. These errors can cause bias in measured linear attenuation coefficients (LACs) and artifacts in the reconstructed images, reducing image quality and impeding quantitative analysis. Three sources of error in neutron tomography were investigated and quantified that are particularly pertinent to spallation source facilities. These include detector to sample stage misalignment, beam fluctuations and undersampling due to missing CT projections. Quantitative analyses of the grayscale biases and misalignment artifacts were performed on the reconstructed data using ImageJ. Furthermore, the efficacy of classical iterative reconstruction algorithms for the suppression of missing projection artifacts was explored. Several image qualifying metrics were used to compare Filtered Back Projection (FBP) and iterative algorithms quantitatively. We show that beam intensity fluctuations if left uncorrected provide a minimal bias even when exaggerated across a stack of projections. In addition, detector-sample stage misalignment causes a geometrical misalignment blur when not corrected for and severe ring artifacts despite image rotation correction. We suggest that iterative algorithms are more favourable in suppressing missing projection neutron artifacts, however they inaccurately reproduce the LACs for missing-wedge reconstructions compared to FBP.

The response of a Timepix3 detector (256 × 256 pixels, pixel pitch 55 μm) with a 300 μm thick silicon sensor was studied in relativistic charged particle beams at the Super-Proton-Synchrotron at CERN . The detector was irradiated at different angles in a 400 GeV/c primary proton beam and in a mixed beam created by a 330 GeV/c Pb beam hitting a beryllium target. We present and discuss energy deposition spectra and particle track features for relativistic particles of different stopping power. The proton data shows that a relative energy resolution of approximately 9 % can be achieved. Analysis of deposited energy spectra and tracks in the detector produced by heavier ions are carried out with the aim to investigate the capabilities of the Timepix3 detector for decomposing the mixed beam. Using spectrum stripping technique by iterative Landau curve fitting charge discrimination could be done up to Z = 7 for impact angle of 60 degrees (with respect to the sensor normal). For smaller impact angles the particle charge separation is decreased due to the saturation of the pixel electronics (∼600 keV) . Previous works describing the 3D track reconstruction for minimally ionizing particles (Z = 1) were extended in the present work by adding the methodology of heavier ions track reconstruction in 3D.

This paper presents two digital quasi-Gauss filters, the first of which is a digital CR-RC^m filter with the function of pole-zero cancellation (digital CR_PZC-RC^m filter) and the second a digital Sallen-Key filter (digital S-K filter). The digital filters are established according to the differential equations of an analog CR_PZC-RC^m circuit and an analog S-K circuit, respectively. Characteristics including frequency response, noise suppression and stability for both digital filters are discussed and improved algorithm cascade structures are obtained to reduce the resources consumption of field programmable gate arrays (FPGAs). To compare the two digital filters, the energy resolution (@Cs-137, 662 keV) for LaBr₃(Ce) and NaI(Tl) detectors is calculated for the digital spectroscopy system and the analog spectroscopy system from CANBERRA. The results prove that the two digital filters exhibit similar performance in frequency response, noise suppression and energy resolution improvement. Further, the optimum energy resolution (@Cs-137, 662 keV) for both digital filters is slightly superior to that of CANBERRA. The digital S-K filter consumes fewer FPGA resources compared to the digital CR_PZC-RC^m filter due to its simpler algorithm cascade structure, though the digital S-K filter becomes unstable when its gain (K) exceeds a certain threshold.

To reduce the exposure doses of workers and to establish decontamination plans, it is important to understand and visualize the distribution of radioactive substances at the Fukushima Daiichi Nuclear Power Station in Japan, where an accident occurred on the 11th of March, 2011. In this decommissioning work environment, radioactive substances adhered to various objects, such as rubble and equipment, and it was necessary to visualize the distribution of these contaminants in all three dimensions. The technology used to automatically and remotely acquire data to visualize the distribution of radioactive substances in three dimensions was useful for reducing the exposure dose of the workers and to shorten the survey time. We constructed an automatic data acquisition system that consisted of a Compton camera and a 3D-light detection and ranging sensor mounted on an autonomously moving robot. We also evaluated the system feasibility using radiation sources and succeeded in automatically acquiring the data required for visualizing the radiation sources. For this data acquisition, the operator did not need to operate the system after the measurements were started. The effects of the imaging parameters of the Compton camera and the accuracy of the self-position estimation of the system on the radiation-imaging accuracy are also discussed.

Artificial intelligence plays an important role in the classification of medical images for computerized diagnosis of the disease. The computer-aided medical imaging analysis system is developed for breast tissue density classification in mammogram images. Mammogram density is considered as significant predictive markers for breast cancer detection, treatment and management. Recently, deep learning techniques achieved impressive results in computer-assisted disease diagnosis. The deep learning technique such as the convolution neural network (CNN) is used for automated classification of mammogram density as fatty, dense and glandular. This study investigates how computer-aided medical imaging analysis system provides a reliable classification of mammogram density. The proposed methodology is evaluated using a mini-MIAS (Mammogram Image Analysis Society) database. We obtained an average accuracy of 98.5%. So, the proposed CAD system aids the clinicians in the classification of mammogram density.

The liquid xenon (LXe) time projection chamber (TPC) technology is probing a wide range of dark matter masses from sub-GeV to a few TeV. To further improve its sensitivity to sub-GeV dark matter and its application in reactor neutrino monitoring via coherent elastic neutrino-nucleus scattering (CEνNS), more understanding and suppression of single/few electrons background rate are needed. Here we report on the design and performance of a sealed LXeTPC with a graphene-coated fused silica window as the cathode. The purpose of the sealed TPC is for isolating the liquid xenon target volume from the majority of out-gassing materials in the detector vessel, thus improving the liquid xenon purification efficiency and reducing the impurity-induced single/few electrons background. We investigated the out-gassing rate and purification efficiency using the data from the sealed TPC with a simple purification model. The single electron signals from the photoionization of impurities in LXe are obtained and their correlation with the LXe purity is investigated. The photo-electron emission rate on the graphene-coated electrode is compared to that from stainless steel, the electrode material typically used in LXe detectors. We discuss the possible further improvement and potential applications of the sealed TPC for the next generation liquid xenon experiments for dark matter and neutrino physics.

Two modules of the AD detector have been studied with the test beam at the T10 facility at CERN. The AD detector is made of scintillator pads read out by wave-length shifters (WLS) coupled to clean fibres that carry the produced light to photo-multiplier tubes (PMTs). In ALICE the AD is used to trigger and study the physics of diffractive and ultra-peripheral collisions as well as for a variety of technical tasks like beam-gas background monitoring or as a luminometer.

The position dependence of the modules' efficiency has been measured and the effect of hits on the WLS or PMTs has been evaluated. The charge deposited by pions and protons has been measured at different momenta of the test beam. The time resolution is determined as a function of the deposited charge. These results are important ingredients to better understand the AD detector, to benchmark the corresponding simulations, and very importantly they served as a baseline for a similar device, the Forward Diffractive Detector (FDD), being currently built and that will be in operation in ALICE during the LHC Runs 3 and 4.

JUNO is a multi-purpose neutrino experiment currently under construction in Jiangmen, China. It is primarily aiming to determine the neutrino mass ordering. Moreover, its 20 kt target mass makes it an ideal detector to study neutrinos from various sources, including nuclear reactors, the Earth and its atmosphere, the Sun, and even supernovae. Due to the small cross section of neutrino interactions, the event rate of neutrino experiments is limited. In order to maximize the signal-to-noise ratio, it is extremely important to control the background levels. In this paper we discuss the potential of particle identification in JUNO, its underlying principles and possible areas of application in the experiment. While the presented concepts can be transferred to any large liquid scintillator detector, our methods are evaluated specifically for JUNO and the results are mainly driven by its high optical photon yield of 1,200 photo electrons per MeV of deposited energy. In order to investigate the potential of event discrimination, several event pairings are analysed, i.e. α/β, p/β, e⁺/e⁻, and e⁻/γ. We compare the discrimination performance of advanced analytical techniques based on neural networks and on the topological event reconstruction keeping the standard Gatti filter as a reference. We use the Monte Carlo samples generated in the physically motivated energy intervals. We study the dependence of our cuts on energy, radial position, PMT time resolution, and dark noise. The results show an excellent performance for α/β and p/β with the Gatti method and the neural network. Furthermore, e⁺/e⁻ and e⁻/γ can partly be distinguished by means of neural network and topological reconstruction on a statistical basis. Especially in the latter case, the topological method proved very successful.

This paper describes the basic design of electron accelerator using co-axial cavity. Theoretical calculations and simulation results are presented. Simulations are carried out using CST Particle studio, final energy ∼ 9 MeV is obtained. Nine Dipole magnets with magnetic field 0.07 T to 0.2 T are used to bend electron beam through 180 deg. Calculated values and simulation results are matching well.

A phase contrast imaging (PCI) diagnostic has been developed for the Wendelstein 7-X (W7-X) stellarator. The PCI diagnostic provides a line-integrated measurement of turbulent electron density fluctuations, which is essential for understanding high performance scenarios that can lead to improved confinement at fusion-relevant temperatures and densities. The PCI system is also sensitive to coherent fluctuations, which arise from Alfvén eigenmodes or other MHD activity. This paper provides an overview of the hardware and the optical system and presents an example PCI measurement from the W7-X OP1.2b experimental campaign.

The resistive wall impedance is one of the expected main drivers of transverse beam instabilities in the proposed Future Circular Collider hadron-hadron option (FCC-hh). We obtain the resistive wall impedance for the FCC-hh beam screen from a two-dimensional finite element solver. The impedances and resulting growth rates are compared to the LHC, using similar models for the resistivity of the copper layer. Similar to the LHC and in addition to active feedback, dedicated octupole magnets together with a finite chromaticity should be employed for Landau damping, as a cure against transverse beam instabilities. The stability boundary provided by an LHC-like octupoles configuration in combination with an electron lens is obtained from a dispersion relation including the two-dimensional tune spreads. The prediction from the simple dispersion relation are compared to the corresponding beam transfer function and to the stability boundaries reconstructed using particle tracking with an effective impedance. The electron cloud induced tune spreads and their scaling with higher energy and smaller beam pipe radius are estimated. Besides the important estimation of growth rates and stability threshold for FCC-hh we also try to improve the understanding of the scaling of coherent instabilities and their thresholds with energy towards a possible highest-collider limit, using the example of two high-energy colliders, the existing LHC and the proposed FCC-hh.

A resource-saving dual channel time-to-digital converter (TDC) in field programmable gate array (FPGA) is presented in this paper. The presented TDC is formed by cascading a channel waveform generator (CWG) and a tapped delay line. Specifically, the CWG can generate six types of waveforms with different transition edges to propagate on tapped delay line according to the different assertion times of two hit signals. Besides, a pipelined encoding module is designed to detect the positions of multiple transition edges on tapped delay line precisely so that the six types of waveforms can be identified and the two hit signals can be distinguished and measured. Since the measurements of two hit signals share one tapped delay line, the TDC based on CWG (CWG-TDC) is a resource-saving dual channel TDC. To evaluate the performance of CWG-TDC, time intervals from 10ns to 200ns were measured on a Xilinx's 40nm Virtex-6 development board. In CWG-TDC, channel 1 and channel 2 can achieve LSB of 9ps, the highest RMS precision of 6.2ps. The consistency between experimental results and theoretical analysis shows that the presented CWG-TDC can not only achieve high RMS precision but also achieve resource-saving.

With recent advances in the growth of CdZnTe (CZT) sensors, high-flux photon-counting detectors (PCDs) have begun to see more use commercially in non-destructive testing (NDT). One such application is food inspection, where radiography is currently used to detect undesirable contaminants introduced in the production and packaging processes. PCDs can offer better detection than conventional radiography due to the preservation of energy data by analyzing the pulse height of each x-ray detection and sorting the x-ray into one of a number of energy bins. However, there are a number of parameters that must be explored in order to offer efficient and efficacious detection of contaminants. Here, two such parameters were investigated in a phantom study with an 8×24 mm² CZT detector for a number of common contaminant materials. The detectability of contaminants was evaluated based on their contrast-to-noise ratio (CNR) in 2D transmission images. First, the energy bin demonstrating the highest CNR for each contaminant material was found by adjusting the threshold energies defining the edges of the bin. Second, various pixel binning schemes were utilized to lower noise and investigate the effect on the detectability based on the size of contaminants. CNR was maximized for pixel binning that corresponded to the approximate size of the contaminant objects in x-ray images.

The simulation and analysis of High Energy Physics experiments require a realistic simulation of the detector material and its distribution. The challenge is to describe all active and passive parts of large scale detectors like ATLAS in terms of their size, position and material composition. The common method for estimating the radiation length by weighing individual components, adding up their contributions and averaging the resulting material distribution over extended structures provides a good general estimate, but can deviate significantly from the material actually present. A method has been developed to assess its material distribution with high spatial resolution using the reconstructed scattering angles and hit positions of high energy electron tracks traversing an object under investigation. The study presented here shows measurements for an extended structure with a highly inhomogeneous material distribution. The structure under investigation is an End-of-Substructure-card prototype designed for the ATLAS Inner Tracker strip tracker—a PCB populated with components of a large range of material budgets and sizes. The measurements presented here summarise requirements for data samples and reconstructed electron tracks for reliable image reconstruction of large scale, inhomogeneous samples, choices of pixel sizes compared to the size of features under investigation as well as a bremsstrahlung correction for high material densities and thicknesses.

In positron emission tomography (PET) image reconstruction, the accurate system response matrix (SRM) is one of the key factors for reconstructing high-quality images. To reduce the influence of various factors on the spatial resolution, this paper focuses on calculating the SRM based on Monte Carlo (MC) simulation and proposes a method based on system geometric symmetry to reduce the simulation time. We split the symmetry into two types: intra-ring symmetry and inter-axis symmetry, a total of 208 times the symmetry is used. According to the standards formulated by the American National Electrical Manufacturers Association (NEMA), the spatial resolution and image quality are assessed by simulation experiments. Results of point source measurement show that the full width at half maximum (FWHM) range in each direction is about 1.1–1.3 mm, the average value is about 1.2 mm. In Derenzo phantom imaging, the MC method can clearly distinguish the 1.2 mm rods. To assess image quality, we calculated the uniformity of the image, contrast recovery coefficients (CRC), and coefficient of variation (COV). At the same time, we compared with the ray tracing (RT) and pixel drive (PD) models. In general, the MC method achieves better results in simulation experiments than RT and PD methods.

Design and development of an Arduino based control system and a Majority Logic Unit have been presented, which can perform different logic operations in remote as well as in manual mode. Performances of this unit viz. time jitter, minimum overlap time, maximum operating frequency, double pulse resolution and module delay have been measured which are found to be comparable with the commercially available modules. This work presents a low cost up-gradation of the commercially available manually controlled Majority Logic Units.

Luminescence of water during irradiation with particles having energies below the Cerenkov-light threshold was recently found for various types of radiations. However, the relation between the intensities of Cerenkov light and of the luminescence of water at the beam energy below the Cherenkov threshold is not well known. To clarify this point, we measured the produced light irradiating a water sample with electron beams having maximum energies above and below the Cerenkov-light threshold. The intensities of light during irradiation of electron beams with different energies increased rapidly at higher energy than ∼260 keV while very small intensity was observed at the beam energy below the Cerenkov-light threshold. We conclude that the intensities of light produced in water during irradiation of electron beams with energies below the Cherenkov threshold from the luminescence of water are much lower than those of Cerenkov light.

The natural electric field at the depth of 0 ∼ 1500 m in high seas of South China Sea is obtained by using a new type of measuring device. The electric field data in the 0.01 ∼ 0.5 Hz and 0.5 ∼ 30 Hz frequency range are analyzed respectively. The results show that the induced electric field generated by the surface wave (about 0.14 Hz in the experiment) is obvious at the depth of 50 m but can be ignored at the depth greater than 100 m. When the depth increases from 50 m to 1500 m, the peak-to-peak value of the natural electric field gradually decreases. At the depth of 1000 m, the peak-to-peak values are 0.04 ∼ 0.08 μV/m in the 0.01 ∼ 0.5 Hz range, and 0.07 ∼ 0.1 μV/m in the 0.5 ∼ 30 Hz range. At last, the natural electric field in coastal water near Sanya City, where the water depth is 15 m, is measured by means of a sinking device. The results show that the peak-to-peak values are about 2 ∼ 4 μV/m in the 0.01 ∼ 0.5 Hz range and 2 μV/m in the 0.5 ∼ 30 Hz range. By comparing the natural electric field in high seas with that of coastal water, we find the latter has a larger peak-to-peak value at nearly the same water depth. In addition, line spectrum noise often occurs in coastal water, while it is rarely observed in high seas when the water depth is more than 50 m.

A high-precision intra-bunch-train beam orbit feedback correction system has been developed and tested in the ATF2 beamline of the Accelerator Test Facility at the High Energy Accelerator Research Organization in Japan. The system uses the vertical position of the bunch measured at two beam position monitors (BPMs) to calculate a pair of kicks which are applied to the next bunch using two upstream kickers, thereby correcting both the vertical position and trajectory angle. Using trains of two electron bunches separated in time by 187.6 ns, the system was optimised so as to stabilize the beam offset at the feedback BPMs to better than 350 nm, yielding a local trajectory angle correction to within 250 nrad. The quality of the correction was verified using three downstream witness BPMs and the results were found to be in agreement with the predictions of a linear lattice model used to propagate the beam trajectory from the feedback region. This same model predicts a corrected beam jitter of c. 1 nm at the focal point of the accelerator. Measurements with a beam size monitor at this location demonstrate that reducing the trajectory jitter of the beam by a factor of 4 also reduces the increase in the measured beam size as a function of beam charge by a factor of c. 1.6.

Although light emission from an acrylic block during irradiation of carbon ions at lower energy than the Cerenkov-light threshold was found recently, the origins and fractions of the light in the images have not yet been clarified. Since light spectra may provide information to estimate the origins and fractions of the light emission, we conducted optical imaging of an acrylic block during irradiation of carbon ions using a charge-coupled device (CCD) camera with optical filters. We measured the light images of the acrylic block with optical filters of different wavelengths using an ultraviolet (UV)-sensitive CCD camera during carbon-ion irradiation with slightly higher energy to produce secondary electrons to emit Cerenkov light (241 MeV/u). From the images, we derived depth profiles with different wavelengths and calculated the spectra of the emitted light from the acrylic block. The depth profiles showed higher intensity due to Cerenkov light at the shallow area distributed in the images of longer wavelengths. By calculating between the depth profiles of different wavelengths, we could derive the depth profiles for possible origins of the produced light: luminescence, Cerenkov light, and scintillation of the acrylic block. Using the derived fractions of these components, we could estimate their depth profiles at different wavelengths.

In this paper we demonstrate that it is possible to produce low cost neutron-sensitive detectors using stereo-lithography additive manufacturing. A curable scintillating resin is made by mixing BN/ZnS with a commercially available UV resin. This resin is used to print several small area neutron detectors made of arrays of BN/ZnS cones that can be directly coupled to a photo-multiplier tube.

The application of shielding is one of the main protective measures in ionizing radiation safety. This paper addresses the influence of erbium oxide (Er₂O₃) amount fraction on shielding properties of the glass system with compound formula 75TeO₂-10Nb₂O₅-10ZnO-5PbO (TNZP). Addition of Er₂O₃portions increased samples densities from 5.57 to 5.65 g/cm³. The attenuation properties for the different TNZP-Er₂O₃samples were simulated using Phy-X/PSD software at vary wide energy ranged from 0.015 to 15 MeV . Various radiation shielding parameters were evaluated including; linear (LAC) and mass (MAC) attenuation coefficients, the half (HVL)- and tenth (TVL)-value layers, the mean (MFP) free path, the total atomic (ACS) and electronic (ECS) cross-sections and fast (FNRCS) neutron-removal cross-section. These parameters were also verified by a comparison with the currently available shielding materials such as RS-253-G18, RS-360, RS-520 and, Chromite, Ferrite, Magnetite, and Barite. Morover the strong green and weak red emission estimated in the prepared glasses under excited 980 nm. Results show that TNZP with high Er₂O₃constituents is not merely an effective shield for photons but also a good candidate for neutrons protection and theraputic surgery for medical diagnostic applications. The provided esults showed lower FNRCS values compared to the Chromite, Ferrite, and Magnetite. Nevertheless, it can be noticed that the partially added density of Er₂O₃enhanced FNRCS.

This study simulated and measured the attenuation in signal propagation in a Resistive-Plate Chamber (RPC) and analysed it as a loss of signal charge during propagation along the readout strip. The measurement results revealed a strong correlation between the quantified rate of attenuation in charge and the surface resistivity of the graphite layer of the RPC . The rates of attenuation in amplitude and frequency of the signal were also measured, following which the mechanism of attenuation in signal propagation was discussed. Potential methods to mitigate its effects were studied using simulations.

The event plane detector (EPD), installed in the Solenoid Tracker at the Relativistic Heavy-Ion Collider located at the Brookhaven National Laboratory, is a plastic scintillator-based device that measures the reaction centrality and event plane in the forward region of the relativistic heavy-ion collisions. We used silicon photomultiplier (SiPM) arrays to detect the photons produced in the scintillator via the fiber connection. Signals from the SiPM arrays were amplified by the front-end electronic (FEE) board and sent to the analog-to-digital converter (ADC) boards for further processing via the receiver (RX) board. The full EPD system consisted of 24 super-sectors (SSs); each SS was equipped with two SiPM boards, two FEE boards and two RX boards, and they corresponded to 744 readout channels. All these boards were mass produced at the University of Science and Technology of China, with dedicated quality assurance (QA) procedures applied to identify any problems before deployment. This article describes the details of the QA method and the related test system. The QA test results are presented along with the discussions.

A stop-timing microchannel detector with an integrated fast amplifier has been developed and its mechanical and electronic structure described in detail. A typical output amplitude of 1.1 V, rise time of 10 ns, noise amplitude of 2.5 mV_rms and timing jitter of 23 ps of the detector have been obtained. The detector has tested with ¹³³Cs¹⁺ ions in the multi-reflection time-of-flight mass analyzer at the Spectrometer for Heavy Atom and Nuclear Structure (SHANS) and a mass resolving power of 19500 has been achieved for a total time-of-flight of 5.85 ms.

A low power preamplifier solution for use with the rs-p4-0332-203r4 resistive charge distribution neutron detectors is presented in this work. The effects of the ground input impedance caused by the chip and the ground signal undershoot caused by the blocking capacitance are evaluated via simulations. For reference, a reasonable parameter configuration in the structure of a passive filter is sufficient to suppress the effects of both the input impedance and the undershoot. The power per channel in the preamplifier is limited to a maximum of 39 mW. Finally, measurement resolution of 6.8 mm is obtained for the detector.

This paper reports about complete characterization of a small volume, cylindrical (1'' × 1'') CeBr₃ crystal. The measurements include determination of energy and timing resolutions, absolute photo-peak detection efficiency, internal activity and linearity of response up to 4.43 MeV gamma-ray energy. The results, so obtained, have been compared with the performance of NaI(Tl) and LaBr₃:Ce crystals of similar volume. Realistic Monte Carlo simulations were carried out using GEANT4 package to reproduce the experimental spectra and photo-peak detection efficiency. We have obtained best energy resolution of 4.7% at 662 keV for −800 V using a 2'' ET9266B tube. A somewhat better value of 4.3% is obtained using Hamamatsu R10233 tube. On the timing front we have obtained a resolution of 310 ps at Co energy. We have determined the absolute photo-peak efficiency of the crystal for 662 keV to be 13.2%, in very close conformity with our Geant4 simulated value of 13.8%. We have estimated from the measurements the actual internal activity of the crystal to be less than 0.045 counts cm⁻³ s⁻¹. It has been concluded that while CeBr₃ is just marginally inferior to LaBr₃:Ce in terms of energy and timing resolutions, it scores over LaBr₃:Ce in terms of internal activity. Unlike LaBr₃:Ce, CeBr₃ is much purer and has no significant gamma and beta activity.

This report describes a concept of an EIC cooling system, based on a proven induction-linac technology with a DC electron beam. The system would operate in a full energy range of proton beams (100–270 GeV) and would provide 50–100 A electron beams, circulating in a cooler ring for 5 ms. Every 5 ms a new electron pulse would be injected into the cooler ring to provide continuous cooling at collisions. Operations with a 10-ms cycle is possible but it will reduce the cooling rates by ∼30%. The system is capable of delivering the required performance in the entire EIC energy range with emittance cooling times of less than 1–2 hours.

The electron beam path in a planar undulator is usually chosen at the undulator magnetic center in both the vertical and horizontal directions. In the case of the vertical-gap undulators of x-ray free-electron lasers, best efforts are paid to align the vertical magnetic center to the reference electron beam path. The twenty undulator segments are aligned vertically within 50 μm to obtain the target K-values of the undulator segments in the PAL-XFEL hard X-ray beamline. Besides K-value, undulator phase error and beam trajectory deflection are also concerned when the undulator is misaligned to the beam path. In some cases, an off-set in the vertical direction is applied intentionally when a transverse field gradient is required. In this report, we present the systematic measurements of the phase error and trajectory deflection at vertical off-axes of a PAL-XFEL hard X-ray undulator.

The performance of a Thick-COBRA (THCOBRA) gaseous detector is studied using an optical readout technique. The operation principle of this device is described, highlighting its operation in a gas mixture of Ar/CF₄ (80/20 %) for visible scintillation light emission. The contributions to the total gain from the holes and the anode strips as a function of the applied bias voltage were visualized. The preservation of spatial information from the initial ionizations was demonstrated by analyzing the light emission from 5.9 keV X-rays of an ⁵⁵Fe source. The observed non-uniformity of the scintillation light from the holes supports the claim of a space localization accuracy better than the pitch of the holes. The acquired images were used to identify weak points and sources of instabilities in view of the development of new optimized structures.

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