Table of contents

CMOS Monolithic Active Pixel Sensors (CPS) are ultra-light and highly granular silicon pixel detectors suited for highly sensitive charged particle tracking. Being manufactured with cost efficient standard CMOS processes, CPS may integrate sensing elements together with analogue and digital data processing circuits into one monolithic chip. This turns into 50 μm thin sensors, which provide an outstanding typical spatial resolution of fewμm and a detection efficiency for minimum ionizing particles above 99.9%. The radiation tolerance of CPS was initially constrained by the limits of the CMOS processes used for their production but has been improved by orders of magnitudes during the last years.

This work reviews the related R&D on the radiation tolerance of traditional CPS with partially depleted active medium as pioneered by the MIMOSA-series developed by the IPHC Strasbourg. Procedures for assessing radiation damage in those non-standard pixels are discussed and the major mechanisms of radiation damage are introduced. Techniques for radiation hardening are shown. Moreover, recent results on next generation CPS featuring fully depleted sensors based on improved CMOS processes are summarized.

The novel matrix-based real-time ultrasonic imaging using an ultrasonic camera for immersion application has been proposed in this paper. The proposed ultrasonic camera provides real-time images of mechanical components and the image size is equal to the field of view of the developed matrix-based transducer assembly. For the matrix-based ultrasonic imaging, the addressing-based analog multiplexing scheme has been proposed in such a way that all channels of the specific row are selected simultaneously such as the transducer excitation, data acquisition, data processing and transferring operations are performed concurrently. Similarly, the same operations are performed for remaining all rows sequentially. The developed ultrasonic camera further supports dynamic on-line reconfiguration of the analog front-end hardware, real-time hardware/software-based data processing and data transfer operation. For the experimentation, the entire matrix-based (5 × 5) ultrasonic imaging system for immersion applications has been designed, developed and evaluated in the laboratory. Here we present the performance evaluation of the developed matrix-based ultrasonic camera system by acquiring the real-time images of the water-immersed mechanical objects.

To ensure the quality of material, nondestructive testing is necessary, and radiography testing is the nondestructive technique most commonly used today. For inspection, the quality of a radiographic image is critical, and there are many image artifacts that can reduce inspection accuracies such as noise or blurring. The deterioration in spatial resolution caused by blur in both the X-ray imaging itself and the noise reduction process are particular problems. To tackle them, we implemented a non-blind deconvolution method that employs the alternating direction method of multipliers (ADMM) after noise reduction. Experimental results confirm that the proposed algorithm effectively restores edge sharpness. The 50% modulation transfer function of the restored image of a slit-camera was about 3.54 line-pairs per mm, which is about 2.5 times higher than that of the denoised image. Moreover, the edge preservation index values are about 0.82, 0.54, and 0.75 for the restored, denoised, and acquired images, respectively. Consequentially, the proposed method has the potential to increase inspection efficiency in industrial applications.

The muon detector of LHCb, which comprises 1368 multi-wire-proportional-chambers (MWPC) for a total area of 435 m², is the largest instrument of its kind exposed to such a high-radiation environment. In nine years of operation, from 2010 until 2018, we did not observe appreciable signs of ageing of the detector in terms of reduced performance. However, during such a long period, many chamber gas gaps suffered from HV trips. Most of the trips were due to Malter-like effects, characterised by the appearance of local self-sustained high currents, presumably originating from impurities induced during chamber production. Very effective, though long, recovery procedures were implemented with a HV training of the gaps in situ while taking data. The training allowed most of the affected chambers to be returned to their full functionality and the muon detector efficiency to be kept close to 100%. The possibility of making the recovery faster and even more effective by adding a small percentage of oxygen in the gas mixture has been studied and successfully tested.

To provide a general design method for a CCD timing drive, a simple CCD driving circuit design is presented. First, the internal structure and working mode of area array CCD485 are introduced, and its basic driving circuit design is given. Then, through the analysis of the driving sequence diagram of area array CCD485, the normal operation of a full-frame large-area array CCD is analyzed. A design method for a universal full-frame array CCD driving timing generator based on time sequence subdivision and a finite state machine is proposed. By grouping the driving timing of the CCD, each group of timing waveforms is divided into several basic output states. In this manner, the driving sequence needed in each working stage of the CCD can be obtained by combining the basic states, which are described by a Moore finite state machine, and the timing driver is modularized. A timing generator supporting the normal operation of a full-frame area array CCD is designed. The specific design of each module for generating the timing is given. The design process of the generator is simple. Finally, a CCD driving timing generator is designed by using Xilinx's Virtex-II Pro series FPGA-XC2VP20 and Xilinx's ISE software platform, and the waveform is simulated and analyzed. The output signal fully meets the driving timing requirements of the 485 chip, which proves the validity of the design method.

Spectral distortions exist widely due to the broadening effects of spectrometer. In this paper, a spectral deconvolution method using genetic algorithm is proposed to solve this problem. In the Bayesian framework, the spectral deconvolution model is constructed with Gaussian noise and Poisson noise hypothesis, and the prior term is constructed with adaptive Gauss-Markov priori. Genetic algorithm is employed to optimize the spectral deconvolution model to obtain the corrected spectrum. To verify the effectiveness of the proposed method, simulated degraded LED spectra with different colour temperature are corrected by the proposed method, Richardson-Lucy method and Levenberg-Marquardt method. Experimental results show that the proposed method can correct the spectra effectively.

This paper presents a fast approach to simulating muons produced in interactions of the SPS proton beams with the target of the SHiP experiment. The SHiP experiment will be able to search for new long-lived particles produced in a 400 GeV/c SPS proton beam dump and which travel distances between fifty metres and tens of kilometers. The SHiP detector needs to operate under ultra-low background conditions and requires large simulated samples of muon induced background processes. Through the use of Generative Adversarial Networks it is possible to emulate the simulation of the interaction of 400 GeV/c proton beams with the SHiP target, an otherwise computationally intensive process. For the simulation requirements of the SHiP experiment, generative networks are capable of approximating the full simulation of the dense fixed target, offering a speed increase by a factor of (10⁶). To evaluate the performance of such an approach, comparisons of the distributions of reconstructed muon momenta in SHiP's spectrometer between samples using the full simulation and samples produced through generative models are presented. The methods discussed in this paper can be generalised and applied to modelling any non-discrete multi-dimensional distribution.

A superconducting electron linac (e-Linac) photo-fission driver is under construction at VECC for the upcoming rare isotope beam facility called ANURIB. The first stage consists of an injector linac based on 1.3 GHz superconducting radio frequency technology designed for accelerating 10 MeV, 2 mA CW electron beam. An rf modulated thermionic electron gun (E-Gun) has been developed and tested for this injector linac. The E-Gun will allow continuous beam operation up to 300 keV with around 3 pC charge per pulse at 650 MHz. Electron beam with RF modulation is extracted from the gun and intensity, energy, size of the DC beam as well as trans-conductance of the electron source are measured. The design of some major components for the electron gun and low energy beam transport line is discussed and results of beam tests are presented.

This paper presents a new and compact printed monopole antenna with broadband circular polarization (CP). The wide axial ratio bandwidth is achieved by placing and feeding a monopole on the side of an FR4 dielectric. In addition, a conventional horizontal ground plane is modified by shortening its width and adding a vertical extension. Experimental results show an |S₁₁| and axial ratio (AR) of 123.5% fractional bandwidth (2.6–11 GHz) and 70% fractional bandwidth (3–6.2 GHz), respectively. The presented antenna is compact with an area of 36 mm × 19.5 mm, simple to design and fabricate, and can achieve broadband AR without using: parasitic elements, and perturbations in terms of creating multiple slots and stubs.

The Muon g−2 experiment, E989, is currently taking data at Fermilab with the aim of reducing the experimental error on the muon anomaly by a factor of four and possibly clarifying the current discrepancy with the theoretical prediction. A central component of this four-fold improvement in precision is the laser calibration system of the calorimeters, which has to monitor the gain variations of the photo-sensors with a 0.04% precision on the short-term (∼ 1 ms). This is about one order of magnitude better than what has ever been achieved for the calibration of a particle physics calorimeter. The system is designed to monitor also long-term gain variations, mostly due to temperature effects, with a precision below the per mille level. This article reviews the design, the implementation and the performance of the Muon g−2 laser calibration system, showing how the experimental requirements have been met.

Future generations of liquid scintillator neutrino experiments will require stably loading tons of candidate isotopes into kiloton-scale detectors while controlling the scintillator's optical properties. Nanoparticles' unique structural properties allow them to be used as highly-tunable wavelength shifters, which can be used to enhance double beta decay detection and background discrimination. Additionally, these nanoparticles can be made with double beta decay isotopes, which offers a promising method for isotope loading. Perovskite nanocrystals are particularly attractive due to the reliability of their crystal structure and their easily-scalable synthesis. We present here the first study of lead-based perovskite nanocrystals in a liquid scintillator experiment, demonstrating their properties as wavelength shifters and the scintillator cocktail's behavior under increasing nanocrystal mass-loading.

The single electron track-reconstruction efficiency is calibrated using a sample corresponding to 1.3 fb⁻¹ of pp collision data recorded with the LHCb detector in 2017. This measurement exploits B⁺→ J/ψ(e⁺e⁻)K⁺ decays, where one of the electrons is fully reconstructed and paired with the kaon, while the other electron is reconstructed using only the information of the vertex detector. Despite this partial reconstruction, kinematic and geometric constraints allow the B meson mass to be reconstructed and the signal to be well separated from backgrounds. This in turn allows the electron reconstruction efficiency to be measured by matching the partial track segment found in the vertex detector to tracks found by LHCb's regular reconstruction algorithms. The agreement between data and simulation is evaluated, and corrections are derived for simulated electrons in bins of kinematics. These correction factors allow LHCb to measure branching fractions involving single electrons with a systematic uncertainty below 1%.

A new detector, based on an optical-readout glass gas electron multiplier was developed for a soft X-ray CT scanner. Soft X-ray imaging (<20 keV) provides high-contrast images of low-Z elements, such as soft tissues. We model a three-dimensional (3D) copy of a low-Z object with a high-resolution gaseous detector and a 3D printer. The detector was used to acquire high-resolution images to reconstruct a 3D computed tomography (CT) image. As an example, a fine 3D X-ray CT image of a hornet was reconstructed with high contrast. The 3D CT data were converted into 3D computer-automated design data, and a copy of the scanned object was printed with a commercial 3D printer. Overall, this work demonstrates a new use of gaseous detectors, rapid and precise soft X-ray 3D scanning, and modeling of soft tissues.

We demonstrate, for the first time, the operation of a bubble-assisted Liquid Hole Multiplier (LHM) in liquid argon. The LHM, sensitive to both radiation-induced ionization electrons and primary scintillation photons, consists of a perforated electrode immersed in the noble liquid, with a stable gas-bubble trapped underneath. Electrons deposited in the liquid or scintillation-induced photoelectrons emitted from a photocathode on the electrode's surface, are collected into the holes; after crossing the liquid-gas interface, they induce electroluminescence within the bubble. After having validated in previous works the LHM concept in liquid xenon, we provide here first preliminary results on its operation in liquid argon. We demonstrate the bubble containment under a Thick Gas Electron Multiplier (THGEM) electrode and provide the detector response to alpha particles, recorded with SiPMs and with a PMT—under electroluminescence and with modest gas multiplication; the imaging capability is also demonstrated.

The Iron Calorimeter (ICAL) is a neutrino physics experiment proposed by the India-based Neutrino Observatory (INO) collaboration to measure the oscillation parameters. The mini Iron Calorimeter (mICAL) detector is a small-scale prototype of ICAL built at the Inter-Institutional Centre for High Energy Physics (IICHEP), Madurai, India. In this paper, we present the simulation study of machine learning-based predictions of directionality and charge of cosmic muons using the mICAL detector geometry.

The purpose of the present paper is to compare the various computer codes used in fast-neutron spectroscopy for spectrum unfolding and calculation of the response of the organic scintillation detectors. For neutron spectrum unfolding, the Fredholm integral equation is solved using iterative and soft computing algorithms. In the present paper, the Modified Least SQuaRe (MLSQR) method (iterative algorithm) and some soft computing algorithms are presented. The latter comprise Artificial Neural Network (ANN), Support Vector Machine (SVM) and Adaptive Group of Ink Drop Spread (AGIDS) methods. Furthermore, a MCNPX based algorithm for calculating the neutron response of organic scintillation detectors is presented which is used for Time-Of-Flight based fast-neutron spectroscopy (nTOF) . To this end, the ability for simulating the emission and tracking of two simultaneously emitted particles as well as the light production and light transport in the scintillator were added to the MCNPX computer code. Also, a post-processing software was developed to analyze the massive amounts of data in the output of the PTRAC card. The presented techniques are benchmarked with a published spectrum from an ²⁴¹Am-⁹Be neutron source. The results obtained from the calculation using the proposed methods have an acceptable agreement with the standard ISO-8592 spectrum of the ²⁴¹Am-⁹Be neutron source. However, the accuracy of the calculation using the SVM and AGIDS is better than the accuracy of the other presented methods.

We report measurements of the charged daughter fraction of ²¹⁸Po as a result of the ²²²Rn alpha decay, and the mobility of ²¹⁸Po⁺ ions, using radon-polonium coincidences from the ²³⁸U chain identified in 532 live-days of DarkSide-50 WIMP-search data. The fraction of ²¹⁸Po that is charged is found to be 0.37 ± 0.03 and the mobility of ²¹⁸Po⁺ is (8.6 ± 0.1) × 10⁻⁴ cm²/Vs.

A cryogenic apparatus is described that enables a new experiment, nEDM@SNS, with a major improvement in sensitivity compared to the existing limit in the search for a neutron Electric Dipole Moment (EDM). This apparatus uses superfluid ⁴He to produce a high density of Ultra-Cold Neutrons (UCN) which are contained in a suitably coated pair of measurement cells. The experiment, to be operated at the Spallation Neutron Source at Oak Ridge National Laboratory, uses polarized ³He from an Atomic Beam Source injected into the superfluid ⁴He and transported to the measurement cells where it serves as a co-magnetometer. The superfluid ⁴He is also used as an insulating medium allowing significantly higher electric fields, compared to previous experiments, to be maintained across the measurement cells. These features provide an ultimate statistical uncertainty for the EDM of 2−3× 10⁻²⁸ e-cm, with anticipated systematic uncertainties below this level.

Fusion experiments rely heavily on the measurement of the line-integrated electron density by interferometry for density feed-back control. In recent years the discharge length has increased dramatically and is continuing to rise, resulting in environmentally induced phase drifts to become an increasingly worrisome subject, since they falsify the interferometer's measurement of the density. Especially in larger Tokamaks the loss of density control due to uncontrolled changes in the optical path length can have a disastrous outcome. The control of environmental parameters in large diagnostic/experimental halls is costly and sometimes infeasible and in some cases cannot be retro-fitted to an existing machine. In this report we present a very cheap (ca. €100), easily retro-fitted, real-time capable phase compensation scheme for interferometers measuring dispersive media over long time scales. The method is not limited to fusion, but can be applied to any continuously measuring interferometer measuring a dispersive medium. It has been successfully applied to the Wendelstein 7-X density feed-back interferometer.

The reconstruction of top-quark pair-production (t) events is a prerequisite for many top-quark measurements. We use a deep neural network, trained with Monte-Carlo simulated events, to reconstruct t decays in the lepton+jets final state. Comparing our approach to a widely-used kinematic fit, we find significant improvements in the correct assignment of jets to the partons from the decay, and we study the reconstruction performance of several kinematic top-quark properties. We document our workflow for the optimisation of the hyperparameters of the deep neural network. This workflow can be followed by experimental collaborations to retrain the network taking into account their detailed detector simulations.

The muon identification system of the ALICE experiment at the CERN LHC is based on Resistive Plate Chamber (RPC) detectors. These RPCs are operated in the so-called maxi-avalanche mode with a gas mixture made of tetrafluoroethane (C₂H₂F₄), sulfur hexafluoride (SF₆) and isobutane (i-C₄H₁₀). All of these components are greenhouse gases: in particular, the first gas is already phasing out of production, due to recent European Union regulations, and its cost is expected to increase in the near future. Therefore, finding a new eco-friendly gas mixture has become extremely important in order to reduce the impact of the RPC operation on the environment, and for economic reasons. Due to the similar chemical structure, hydrofluoroolefins appear appropriate candidates to replace C₂H₂F₄ thanks to their very low GWPs, especially tetrafluoropropene (C₃H₂F₄) with the trade name HFO1234ze(E). In order to identify an eco-friendly gas mixture fulfilling the requirements for operation in the ALICE environment in the coming years, a dedicated experimental set-up has been built to carry out R&D studies on promising gas mixtures. Measurements have been performed with a small-size RPC equipped with the front-end electronics, providing signal amplification, developed for ALICE operation at high luminosity after the LHC Long Shutdown 2. HFO1234ze(E)-based mixtures with the addition of CO₂ are discussed in this paper as well as the role of i-C₄H₁₀, as quencher, and SF₆, as strong electronegative gas, in such mixtures.

Sterile neutrinos emerge in minimal extensions of the Standard Model which can solve a number of open questions in astroparticle physics. For example, sterile neutrinos in the keV-mass range are viable dark matter candidates. Their existence would lead to a kink-like distortion in the tritium β-decay spectrum. In this work we report about the instrumentation of the Troitsk nu-mass experiment with a 7-pixel TRISTAN prototype detector and measurements in both differential and integral mode. The combination of the two modes is a key requirement for a precise sterile neutrino search, as both methods are prone to largely different systematic uncertainties. Thanks to the excellent performance of the TRISTAN detector at high rates, a sterile neutrino search up to masses of about 6 keV could be performed, which enlarges the previous accessible mass range by a factor of 3. Upper limits on the neutrino mixing amplitude in the mass range < 5.6 keV (differential) and < 6.6 keV (integral) are presented. These results demonstrate the feasibility of a sterile neutrino search as planned in the upgrade of the KATRIN experiment with the final TRISTAN detector and read-out system.

To linearly estimate the decay time and pulse height of a scintillation detector with low power consumption, a dual time-over-threshold (dual-ToT) method is proposed in this paper. The results of comparative experiments conducted using a 3× 3× 3 mm³ LYSO crystal and 3× 3 mm² MPPC with 50 μm cells indicated that the resolution of the estimated decay time using the dual-ToT method was 3.8 ns standard deviation (SD), whereas 3.5 ns SD was obtained using fully digitized waveforms. Additionally, a linear relationship between the dual-ToT-based and the analog-to-digital converter (ADC)-based pulse height was successfully observed. The estimated pulse height resolution using the dual-ToT method and post analysis technique was 12–13% FWHM at 511 keV, which is comparable to that of the ADC-based measurement. These capabilities potentially indicate that the dual-ToT method could be an alternative to the ADC method, with the advantage of lower power consumption and being applicable to the phoswich detector and particle identification applications.

In radiation protection, the protection quantity for whole-body exposure is effective dose E. Effective dose cannot be measured and operational quantities have been introduced for dose measurement and calibration of dosimeters and survey instruments. To overcome some shortcomings of the presently used operational quantities, ICRU Report Committee 26 introduces two new quantities for whole body exposure, ambient dose H^* for prospective dose assessment and personal dose H_p(α) for retrospective measurements with personal dosimeters. Dosimeters and survey instruments are calibrated in reference fields, realised with radioisotopes and with well-defined X-ray spectra. In this paper, the spectrum-averaged conversion coefficients from kerma in air K_a to the new quantities ambient dose and personal dose are calculated and compared with the published coefficients for the present operational quantities. Especially at low energies (E_ph < 40 keV), the new quantities are significantly lower than the present ones, thus correcting a strong overestimate of effective dose.

A compact single layer coaxial probe-fed microstrip antenna with frequency tuning capability is proposed in this paper. The proposed antenna occupies a compact size of only 35 × 35 × 1.6 mm³. The proposed antenna consists of a rectangular defected microstrip structure (DMS) embedded at the rectangular patch and narrow rectangular slot loaded modified ground plane structure (MGS) to create a lower order resonance at 1.85 GHz, which corresponds to 90% miniaturization of the proposed antenna. The lower resonant frequency of the proposed antenna can be adjusted from 4.35 GHz down to 1.85 GHz with 3.59% fractional bandwidth by increasing the length of the slot embedded in the ground plane. The design structure yields an independent control of the desired resonant frequency, gain, fractional bandwidth and compactness of the antenna. By changing the dimension of the ground plane slot, the same antenna geometry supports any wireless communication applications in the frequency range of 1.85 to 4.35 GHz such as 1.92 GHz PCS, 1.9 GHz PHS, 2.4 GHz Bluetooth, 2.6 GHz extended UMTS, 2.8 GHz IMT, 2.4/3.6 GHz WLAN and 2.5/3.5 GHz Wi–MAX etc.

Conventional searches for new phenomena at collider experiments tend to focus on prompt particles, produced at the interaction point and decaying rapidly. New physics models including long-lived particles that travel a substantial distance in the detectors before decaying provide an interesting alternative, especially in light of the lack of new phenomena at the current LHC experiments, and could solve unanswered questions of the Standard Model. Long-lived particles have characteristic experimental signatures that, while making them clearly distinct from other processes, also could make them potentially invisible to current data-acquisition methods. Specific trigger strategies need to be in place to target long-lived particles. In this paper, we investigate the use of tracker information at trigger level to identify displaced signatures. We propose two methods that can be implemented at hardware-level: one based on the Hough transform, and another based on pattern matching with patterns trained on displaced tracks.

A monolithic pixelated silicon detector designed for high time resolution has been produced in the SG13G2 130 nm SiGe BiCMOS technology of IHP. This proof-of-concept chip contains hexagonal pixels of 65 μm and 130 μm side. The SiGe front-end electronics implemented provides an equivalent noise charge of 90 and 160 e⁻ for a pixel capacitance of 70 and 220 fF, respectively, and a total time walk of less than 1 ns. Lab measurements with a ⁹⁰Sr source show a time resolution of the order of 50 ps. This result is competitive with silicon technologies that integrate an avalanche gain mechanism.

There is rising interest in organic scintillators with low scattering length for future neutrino detectors. Therefore, a new scintillator system was developed based on admixtures of paraffin wax in linear alkyl benzene. The transparency and viscosity of this gel-like material can be tuned by temperature adjustment. Whereas it is a colorless transparent liquid at temperatures around 40^oC, it has a milky wax structure below 20^oC. The production and properties of such a scintillator as well as its advantages compared to transparent liquids are described.

This article is devoted to the design, analysis and fabrication of conventional and MTM (MTM) leaky wave antennas. The effects of utilizing composite right/left handed structure on bandwidth, gain and beam steering are reflected. The structures with MTM cells conduct wider bandwidth of operation. Three different configurations of MTM unit cell structures are used. The mushroom ground structure is addressed as a cell which provides MTM features on Rogers 5880, traditional square patches and two reconfigurable rows sandwiched between the ground and the radiated arrays. The conventional antenna dimensions are (50 × 70) mms, and is implemented using Rogers RT 5880 substrate, with a relative dielectric constant (2.2), thickness (3.18) mm and loss tangent of (0.002). The overall dimensions of the MTM antenna outlines the same dimensions of the conventional antenna, but its thickness is varying. The antennas are simulated by the CST microwave studio, fabricated on Roger 5880 and measured using the network analyser (Rohde & Schwarz ZVB20). The antenna conducts a gain of (9.8 dB) and a bandwidth between 7.2 GHz and 18.4 GHz. The structure adopted in this paper achieves a novelty of applying different reconfigurable structures of MTM unit cells. This type of antenna can be used a radar sensor control in industrial production lines, or those with high gain could be used for target detection. There is a good agreement between the measured and simulated results.

Pulse-shape discrimination (PSD) is essential to separate neutrons from other particles in space, given the complex radiation environment. As the SiPM array coupled Cs₂LiYCl₆:Ce³⁺ (CLYC) detector delivers slow charge signals resulting from the large parasitic capacitance of SiPMs, the PSD performance conducted by the traditional charge-comparison method can be significantly sub-optimal. In this study, a method combining a digital shaping algorithm and traditional charge-comparison method is developed to improve the PSD performance of the detector. The current pulse of CLYC is extracted from the slow charge output by the shaping algorithm, and the optimized PSD figure-of-merit (FoM) value improves 13.70% by using this method. Moreover, the piled-up events at high count rate will be lessened because the shaping algorithm reduces the pulse width. Also, this method can be applied to other detectors with charge outputs.

Current research in High Energy Cosmic Ray Physics touches on fundamental questions regarding the origin of cosmic rays, their composition, the acceleration mechanisms, and their production. Unambiguous measurements of the energy spectra and of the composition of cosmic rays at the "knee" region could provide some of the answers to the above questions. So far only ground based observations, which rely on sophisticated models describing high energy interactions in the Earth's atmosphere, have been possible due to the extremely low particle rates at these energies. A calorimetry based space experiment that could provide not only flux measurements but also energy spectra and particle identification, would certainly overcome some of the uncertainties of ground based experiments. Given the expected particle fluxes, a very large acceptance is needed to collect a sufficient quantity of data, in a time compatible with the duration of a space mission. This in turn, contrasts with the lightness and compactness requirements for space based experiments. We present a novel idea in calorimetry which addresses these issues whilst limiting the mass and volume of the detector. In this paper we report on a four year R&D program where we investigated materials, coatings, photo-sensors, Front End electronics, and mechanical structures with the aim of designing a high performance, high granularity calorimeter with the largest possible acceptance. Details are given of the design choices, component characterisation, and of the construction of a sizeable prototype (Calocube) which has been used in various tests with particle beams.

The SoLid experiment aims to measure neutrino oscillation at a baseline of 6.4 m from the BR2 nuclear reactor in Belgium. Anti-neutrinos interact via inverse beta decay (IBD), resulting in a positron and neutron signal that are correlated in time and space. The detector operates in a surface building, with modest shielding, and relies on extremely efficient online rejection of backgrounds in order to identify these interactions. A novel detector design has been developed using 12800 5 cm cubes for high segmentation. Each cube is formed of a sandwich of two scintillators, PVT and ⁶LiF:ZnS(Ag), allowing the detection and identification of positrons and neutrons respectively. The active volume of the detector is an array of cubes measuring 80× 80× 250 cm (corresponding to a fiducial mass of 1.6 T), which is read out in layers using two dimensional arrays of wavelength shifting fibres and silicon photomultipliers, for a total of 3200 readout channels. Signals are recorded with 14 bit resolution, and at 40 MHz sampling frequency, for a total raw data rate of over 2 Tbit/s. In this paper, we describe a novel readout and trigger system built for the experiment, that satisfies requirements on: compactness, low power, high performance, and very low cost per channel. The system uses a combination of high price-performance FPGAs with a gigabit Ethernet based readout system, and its total power consumption is under 1 kW. The use of zero suppression techniques, combined with pulse shape discrimination trigger algorithms to detect neutrons, results in an online data reduction factor of around 10000. The neutron trigger is combined with a large per-channel history time buffer, allowing for unbiased positron detection. The system was commissioned in late 2017, with successful physics data taking established in early 2018.

The results of investigation of detector made of cadmium zinc telluride (CdZnTe or CZT) crystal with a working volume of 1500 mm³ are presented. The detector is shown to have good spectrometric characteristics in registering gamma radiation from ²⁴¹Am, ⁵⁷Co, ¹³⁷Cs and ⁶⁰Co sources and can be effectively used for low-background measurements.

The quality of pulsed μSR spectra are affected by several factors, namely beam time structure, the time width of detector signals, signal processing methods. A Monte Carlo simulation code—"MuSS" (Musr Signal Simulation) has been developed to investigate the influences of all these factors. Simulations show that both beam time width and external transverse field decrease the observable asymmetry. The asymmetry reduces quickly with larger beam time width under strong filed (> 100 Gauss). The deadtime calculated by leading-edge or constant fraction discrimination method shows no big differences. Bias voltage setup in the constant fraction discriminator should be small (in the range (−10, 10) mV). A figure of merit is used to quantify the maximum tolerable event rate of μSR detectors. Using a proper pole-zero circuit, the deadtime of the Chinese μSR detector can be reduced from ∼ 14 to ∼ 7 ns. Therefore the maximum tolerable event rate can be increased from 8 to 12 events/frame/detector.

A highly performing muon system has been fundamental to achieve many of the physics results obtained by CMS during the LHC Run-2. The CMS muon spectrometer presently consists of three detector technologies covering different regions of pseudorapidity. Drift Tube (DT) chambers equip the CMS muon system barrel, whereas Cathode Strip Chambers (CSC) are installed at the CMS endcaps; both are used for offline tracking and provide trigger capabilities. In addition, Resistive Plate Chambers (RPC) complement DT and CSC in both barrel and endcaps, and are mostly used in the trigger. Finally, at different stages of the CMS upgrade programme, the endcaps of the muon spectrometer will be equipped with multiple layers Gas Electron Multiplier (GEM) chambers. A slice test consisting of 10 GEM chambers was successfully operated in 2018, in parallel to the rest of the muon system, to gain experience in view of the installation of the first complete GEM layer, planned to happen during the second LHC long shutdown (LS2). In this report, the performance of the different detectors comprising the CMS muon system, together with the muon trigger performance, evaluated using data collected at a centre-of-mass energy of 13 TeV during the LHC Run-2, will be presented. The experience from the integration and commissioning of the GEM slice tests will also be discussed, and the status and plans towards the installation of the first complete layer of GEM detector, happening over LS2, will be highlighted.

Detector read-out electronics for Physics Experiments as for example Compressed Baryonic Matter experiment at FAIR, Darmstadt, Germany, should meet tight requirements concerning noise (ENC < 1000 e⁻ rms to guarantee event reconstruction), power consumption (< 10 mW/channel) and average input hit frequency of 250 kHit/s/channel. The ICs design should take into account not only the charge processing parameters but also the impact of the environmental and system-level conditions like radiation, noisy power supply, and temperature to ensure reliable and stable operation during an experiment in a system built with tens of thousands of devices. The operation with gaseous detectors requires particularly effective protection of the inputs against electrostatic discharge. The ESD protection circuit (in particular based on MOS transistors), together with the sensor itself, or AC-coupling capacitors (after irradiation) can be however a source of additional leakage current flowing into the first stage of charge processing chain and affecting the performance. The read-out electronics (in particular first stage—charge sensitive amplifier, CSA) and detector-related noise can be mitigated using proper filtration and signal shaping. However, noise introduced by external sources, like power supply interference, can not be limited only via proper shaping and filtration. When LC filtering is not possible (due to high magnetic fields), it may be beneficial to use differential or pseudo-differential signal processing. The purpose of this work was to test several ideas to improve noise performance and to make the architecture of charge processing chain configurable to better adapt to different target radiation imaging applications. The ASIC comprises four single-ended and four pseudo-differential signal processing channels. In both types of channels configurable slow shaper configuration is used—it is switchable CR-RC² type shaper and complex conjugate poles 3rd order shaper. CSA feedback in single-ended architecture can be selected between MOS transistor working in a linear region and double-polarity Krummenacher circuit for leakage current compensation capability. The chip was designed and fabricated in Q4 2018 using 180 nm process. Front-end single-ended and differential channels occupy the area from 950 × 60 μm² up to 1150 × 125 μm² and consume 5 mW up to 12 mW of power respectively. The work presents design and measurements results.

MIDAS is a miniature detector developed with purpose to assess the radiation field parameters near to an astronaut. Part of the device is a spectrometer for fast neutrons. In missions outside the geomagnetic field, fast neutrons are secondary products of the interaction of Galactic Cosmic Ray heavy ions with the materials in the spaceship or even the astronaut body. The Relative Biological Effectiveness of fast neutrons is high. The neutron spectrometer first prototype has been developed, calibrated and used for measuring ²⁵²Cf spectra.

The MYTHEN detector is a single photon counting microstrip detector with 50 μm pitch developed at Paul Scherrer Institute for powder diffraction experiments at the Swiss Light Source. After more than ten years of operation of MYTHEN II, a new readout chip MYTHEN III was designed in 110 nm UMC technology to upgrade the current detector. It is designed to improve all aspects, specifically noise performance, count rate capability, threshold dispersion and frame rate. Each strip in the MYTHEN III chip features a dual polarity front end consisting of a charge sensitive amplifier and a shaper with variable gain and shaping time, as well as three comparators and three gateable 24-bit counters. The internal counting logic allows for different modes of operation: energy-windowing, charge sharing suppression, count rate improvement and pump-probe with multiple time slots. The architecture of the chip and its characterisation results will be presented. The first two prototypes have been tested in the lab and at the synchrotron. The RMS noise is reduced to 178 electrons (−24% compared to MYTHEN II) and thanks to the three thresholds in the chip, we can detect multiple analog signals in the shaper at high photon flux and thereby reach a count rate of 25 MHz per strip. Based on these results, a full scale chip with 128 channels was developed and sent to production.

The conceptual design of the heavy ion beam probe (HIBP) for T-15MD tokamak (R = 1.5 m, a = 0.67 m, B_t = 2 T, I_pl = 2 MA) is presented. The location of the HIBP injection and detection points is chosen based on the probing beam trajectory calculations. Observation area covers the whole radial interval 0 < r < a for B_t = 1 T, I_pl = 1 MA with the beam energy E_b <260 keV for Tl⁺ probing ions. It allows to measure two-dimensional maps of plasma parameters in an area which covers a large fraction in the upper right quarter of the plasma cross-section. In order to provide the measurements in a wide range of plasma density, high intensity long-focusing probing beam is needed. To develop such a beam a high voltage test bench is designed. It will allow to study the ion-optics system of the HIBP injector and the properties of the thermionic emitters and their lifetime.

Proper choice of a contact material leads to the reduction of leakage current, an increase of X-ray penetration coefficient when so-called transparent contacts are used, and an increase of the Signal-to-Noise ratio. This work is dedicated to the investigation of quasi-ohmic contact behaviour in the "Me-GaAs:Cr-Me" system. AuGe contact was made by means of electron-beam deposition as a metallization layer (Me) to form the "Me-GaAs:Cr-Me" system. Chromium compensated GaAs samples of different thicknesses in the range of 250–1000 μm were tested. The investigation was carried out under various temperature conditions. The results of current-voltage dependence measurement give an overview of the current transport model in such structures and allow us to calculate the concentration of deep-level impurities.

The Advanced Telecommunications Computing Architecture (ATCA) instrumentation platform for fusion control and diagnostics developed at IST, is being extended with a Micro Telecommunications Computing Architecture (MTCA) control and data acquisition platform, still able to maintain performance characteristics in speed, channel density and availability of ATCA, at a cost suitable for smaller systems. Software and firmware have been ported to MTCA using mostly in-house developed hardware, preserving many of ATCA's benefits in performance in a smaller form-factor. The first instance of the proposed platform comprises a MTCA 1U shelf with 6 Advanced Mezzanine Card (AMC) slots, MTCA Carrier Hub (MCH) module, AMC to Field-programmable Gate Array (FPGA) Mezzanine Card (FMC) carrier modules, 500 MSPS to 2 GSPS ADC FMC modules, timing and synchronization input/output (IO) module, or other Commercial Off-The-Shelf (COTS) modules. Data is handled by the MCH, featuring PCIe Gen 3 switching to a host computer, as well as performing clock distribution and Intelligent Platform Management Interface (IPMI) based hardware management for high availability. This compact, flexible and autonomous or scalable platform may either integrate a large-experiment system infrastructure, as well as being configured as a lower-cost, self-contained platform for smaller experiments or development and testbench purposes. The focus of this paper is the development of the MCH MTCA.0 module, which is key to introduce the platform architecture.

Recently developed three-frame complex-interferometry system driven by a Ti:Sa laser with 40 fs pulse has been installed at the PALS (Prague Asterix Laser System) laser facility. This unique diagnostic allows for the first time to perform simultaneous measurements of B-field in the coil region of the capacitor-coil targets (CCT) and the self-generated B-field (SMF) of the diode plasma in between the CCT-plates. CCT were irradiated by the PALS iodine laser (λ = 1315 nm) with energy in the range 250–500 J and pulse duration of 350 ps at full width at half maximum. The operation of this diagnostic system and methodologies for quantitative data analysis are presented in this study, including: (i) obtaining information about the induction of the magnetic field in the CCT coil based on measurements of the Faraday effect in the TGG (Terbium Gallium Garnet) paramagnetic crystal at the coil vicinity and (ii) determining magnetic field and current density distributions in the capacitor region of the CCT by analysis of the complex interferograms. The preliminary measurements confirmed the high potential of the reported setup for optimization studies of CCT targets.

In COMPASS tokamak, the ordinary mode (O-mode) microwave reflectometry diagnostic has been equipped with an upgraded acquisition system and dedicated computational node running the Multi-Threaded Application Real-Time executor (MARTe). This upgrade aims at the deployment of a real-time (RT) plasma position reflectometry (PPR) diagnostic system for future application in closed-loop plasma position control experiments. The system is synchronized with COMPASS MARTe main controller slow cycle, running at 500 μs, and allows a maximum measurement delivery latency of 450 μs. The RT signal processing algorithms, used to reconstruct the O-mode density profiles are the most time consuming step in the control cycle. This is due to the computation of a large number of Fast Fourier Transforms (FFT) over long data arrays, produced for each reflectometry profile measurement. MARTe is a software control framework that allows the integration of external C/C++ libraries and code such as the FFTW3 C library, a highly optimized and performant implementation of the FFT algorithm into the real-time designs. The framework also provides a set of tools to handle the execution of parallel threads, which can be used to expedite the execution of computationally demanding signal processing algorithms. Herein, we present the processing architecture implemented for the multi-threaded reflectometry density profile reconstruction on MARTe framework, using the FTTW3 library. Consistent systematic results have shown that the implemented solution satisfies COMPASS slow control cycle maximum data latency requirement. Moreover, the obtained reduced latency opens the possibility to either increase the number of processed measurements, leading to a more robust plasma position estimate or even to provide multiple position measurements during each control cycle.

The Multigap Resistive Plate Chambers (MRPC) are used as a timing detector in several particle physics and cosmic ray experiments. The gas mixture of MRPC at current experiments is a mixture containing C₂F₄H₂ and in some cases SF₆. C₂F₄H₂ and SF₆ have a Global Warming Potential (GWP) of 1430 and 23900 respectively, therefore they are classified as greenhouse gases. The studies to reduce the amount of emission of the greenhouse gas in high energy experiments are underway; the present contribution has been performed as part of this effort. The results have been obtained from the beam test of a small MRPC which has 6 gaps of 220 μm and a sensitive area of 20 × 20 cm². It has been operated with the ecological HFO-1234ze gas (C₃F₄H₂), and with the C₂F₄H₂/SF₆ mixture. We have found that the ecological gas can substitute for the C₂F₄H₂-based gas mixture without significantly compromising the current level of performance.

Some new progress has been made to develop the multi-point Thomson scattering (TS) diagnostic for the HL-2A tokamak physics experiments. Hardware of silicon avalanche photodiode detector electronics, motorized stages to control the laser beam for beam alignment, 3 modules of fast digitizers with more than 100 channels to record the time evolution of the TS pulses at 2.5 GS/s with 12-bit resolution, and 15 polychromators for 15-point measurements of core plasma electron temperature. The data processing code is further adjusted to manage the digitized raw data. The TS intensity is obtained by direct summing method and by Gaussian-function fitting, respectively, and then different value of electron temperature is derived by the technique of weighted least-squares regression. As to the latter, the electrical noise and perturbations of the TS signal is significantly reduced, the resulting value of electron temperature has a better quality than that of the former. New processing code is in development.

Uncertainties and errors in magnetic equilibrium reconstructions are a wide-spread problem in interpreting experimental data measured in the tokamak edge. This study demonstrates errors in EFIT++ reconstructions performed on the COMPASS tokamak by comparing the outer midplane separatrix position to the Velocity Shear Layer (VSL) position. The VSL is detected as the plasma potential peak measured by a reciprocating ball-pen probe. A subsequent statistical analysis of nearly 400 discharges shows a strong systematic trend in the reconstructed separatrix position relative to the VSL, where the primary factors are plasma triangularity and the magnetic axis radial position. This dependency is significantly reduced after the measuring coils positions as recorded in EFIT input are optimised to provide a closer match between the "synthetic" coil signal calculated by the Biot-Savart law in a vacuum discharge and the actual coil signal. In conclusion, we suggest that applying this optimisation may lead to more accurate and reliable reconstructions of the COMPASS equilibrium, which would have a positive impact on the accuracy of measurement analysis performed in the edge plasma.

The paper presents results of numerical modelling for the ITER Divertor Neutron Flux Monitor (DNFM) detector modules life time activation. In particular, the rigorous-2-step (R2S) computational methodology was implemented. In addition to MCNP and FISPACT codes the special integration framework MCKIT was applied. The MCKIT provides models preparation and data processing tools. To provide appropriate performance we replaced direct FISPACT inventory calculations with the superposition method described below. The activation characteristics (DPA, contact dose, etc.) were obtained and compared with our results for the previous DNFM design.

In spite of its very high reliability, LIDAR Thomson Scattering (LIDAR-TS) has so far only been installed on JET. The new Divertor Tokamak Test (DTT) facility at Frascati will be similar in size to JET and thus is clearly suited for a LIDAR-TS system. The proposal here follows the concept of a no vignetting region, which circumvents the need for relative density calibrations and provides much better signals than those on the JET system, particularly at the outer boundary. The scattered spectrum reaches the spectrometer through a train of relay lenses. The spectrometer uses fast MCP-PMTs for detection of the scattered signal. The fast detectors are generally limited to a spectral range below 900 nm. Hence, a laser at a single wavelength slightly below 900 nm would be ideal. Here we investigate using an Nd:YAG laser, emitting simultaneously both the fundamental and the second harmonic wavelength. The expected performance is analyzed in a simulation program, confirming the ability of this choice to cover the full temperature range. The spatial resolution of the system on JET was about 7 cm. For DTT it is possible to improve this value both by using more modern hardware and by deconvoluting the measured signals. Using a commercially available Nd:YAG two wavelength system with 100 ps pulses in combination with 180 ps MCP-PMTs a resolution of less than 4 cm is achieved. Deconvolution works well at the outer boundary of an H-mode plasma. With deconvolution of the spectral channel signals, the effective spatial resolution in this region can be reduced to ∼2 cm.

FMCW reflectometry density profile measurements will be used to complement or replace magnetic measurements for plasma position control in future plasma fusion reactors, such as ITER and DEMO. Although FMCW reflectometry is a well established diagnostic technique, on present experimental devices with short discharges (typically of a few seconds), on-line measurement quality validation and correction is not a common practice. One of the technique's main requirements is to ensure that the microwave sources always produce a linear frequency sweep within the probing frequency range. Failing to do so leads to inaccurate density profile reconstruction and, hence, to erroneous plasma position feedback to the tokamak control loops. Traditionally, static calibrations are used to build the voltage ramps driving the reflectometer's VCO (Voltage Controlled Oscillator) sources. By using extra signals like frequency markers or calibrated delay lines, the experimental reflectometry measurements can be further calibrated, off-line, to minimize frequency sweep linearity related distortions. We herein propose a technique to monitor and re-calibrate in real-time the linearity of the frequency sweeps of FMCW reflectometers. It can be applied in the long duration discharges of future devices either to correct thermal or electronic drifts of the probing frequency sources or to generate alarm signals when measurement anomalies or fundamental diagnostic malfunctions are detected. Experimental data is presented showing the benefits of the proposed technique.

This paper reports the signal and noise in the detection of OH radicals by evanescent-wave laser-induced fluorescence (EW-LIF) spectroscopy. We adopted this method to detect OH radicals, which were produced within an atmospheric-pressure argon plasma jet, in the vicinity of a quartz surface. The dominant noise was the stray laser light which could not be eliminated by using a monochromator and an interference filter. This was because the detection optics looked at the total reflection point of the laser beam in the EW-LIF spectroscopy. It was impossible to detect the LIF signal in the duration of the laser pulse because of the intense stray light. On the other hand, thanks to the slow decay of the LIF intensity, we succeeded in detecting the LIF signal after the laser pulse. The intensity ratio between the LIF signal originated from the bulk plasma and the one induced by EW near the surface was 5000–10000, which can be explained by the difference in the observation volumes. The proportionality between the LIF intensities from the bulk plasma and the surface vicinity, when changing the discharge conditions, suggests that the surface loss probability of OH on the quartz surface was not affected by these changes.

A Thomson scattering diagnostic system comprises four subsystems: a laser, a light collection system, a spectroscope, and a digitizing system. The Korea Superconducting Tokamak Advanced Research (KSTAR) Thomson scattering system has all of these, but because of the superconducting tokamak, a cassette system (called a port plug in ITER) is required to diagnose the plasma. This cassette system is of length 1.8 m and is mounted on the cryostat. For this reason, when plasma disruption occurs, vibration impact is transferred to the collection lens in the cassette as presently designed, causing the problem of Thomson scattering signal measurement. To solve this problem, an anti-vibration lens support system was installed, and the collection lenses (core and edge lenses) were redesigned to upgrade their performance while also reducing their weight. Simulation of this new lens design has confirmed that it reduces vignetting and improves the modulation transfer function compared with previous lenses [1]. In the new core lens design, the f-number more than doubled from 2.26 (old) to 5.9 (new) and the mass was reduced from 26 to 18 kg. In the new edge lens design, the f-number increased to 2.27 times that of the old lens, and the mass was reduced from 23 to 12 kg. The improved light collection optic systems were used in the KSTAR campaign in 2018 and were able to measure Thomson signals without any vibration effect. Herein we explain the newly designed lenses and briefly describe the collection lens support system.

The RFX-mod experiment is currently undergoing a challenging upgrade of the machine assembly. One of the main purposes of RFX-mod2, the upgraded device, is the achievement of better performances by decreasing the tearing modes amplitude in Reversed-Field Pinch (RFP) configuration thanks to a higher plasma-shell proximity. Moreover, most of the innovations characterizing the device and its diagnostics are conceived with the aim of operating as both RFP and tokamak. These different configurations are taken into account in the electrostatic sensors design and layout. RFX-mod2 will be equipped with poloidal and toroidal arrays of electrostatic probes, measuring plasma density and temperature, plasma potential, particle and energy fluxes and floating potential fluctuations. Two toroidal arrays of 72 probes each (one on the high field side and one on the low field side), along with four poloidal arrays of 28 elements, are foreseen. Such a large amount of sensors is due to the requirement of a better characterization of the numerous instabilities observed in the RFP plasma edge, with the possibility to study the plasma shape in different tokamak configurations (circular, single null, double null). Three different kinds of Langmuir probe configurations will be installed: single probes, 5-pin balanced triple probes and ball-pen probes. The conceptual design of the sensors takes inspiration from the model successfully installed on RFX-mod, that allows the removal of tiles in case of damage, by means of a remote handling manipulator.

JETPEAK is a comprehensive stationary-state database and a work environment for JET diagnostics data, processed data and simulations suitable for a wide variety of analytical tasks. It enables systematic modelling and efficient interpretation of synthetic neutron diagnostics and validation of fast particle and fusion product calculations. We present a processing chain connecting the ASCOT orbit following code and AFSI fusion source simulator Monte-Carlo codes, providing synthetic diagnostics data for systematic comparison with measured data and model validation. The ASCOT code defines the reactant distribution functions and the additional AFSI module creates fusion products as 4D (R, z, E, pitch) distributions, which serve as input for synthetic diagnostics calculations. In this contribution we present synthetic neutron emission rates for the JET neutron camera lines of sight. First results show a fair agreement of the synthetic camera results with the horizontal JET neutron cameras and systematic differences, which are not understood, between the ratios of neutron emission measurements and modelled for the vertical and horizontal cameras.

The CMS experiment, located at the Large Hadron Collider (LHC) in CERN, has a redundant muon system composed by three different gaseous detector technologies: Cathode Strip Chambers (in the forward regions), Drift Tubes (in the central region), and Resistive Plate Chambers (both its central and forward regions). All three are used for muon reconstruction and triggering. The CMS RPC system confers robustness and redundancy to the muon trigger. The RPC system operation in the challenging background and pileup conditions of the LHC environment is presented. The RPC system provides information to all muon track finders and thus contributing to both muon trigger and reconstruction. The summary of the detector performance results obtained with proton-proton collision at √s = 13 TeV during 2016 and 2017 data taking have been presented. The stability of the system is presented in terms of efficiency and cluster size vs time and increasing instantaneous luminosity. Data-driven predictions about the expected performance during High Luminosity LHC (HL-LHC) stage have been reported.

Several theoretical models inspired by the idea of supersymmetry (SUSY) accommodate the possibility of Heavy Stable Charged Particles (HSCPs). The Phase II upgrade of the CMS-RPC system will allow the trigger and identification of this kind of particles exploiting the Time-of-Flight Technique with the improved time resolution that a new Data Acquisition System (DAQ) system will provide (∼2 ns). Moreover, new Resistive Plate Chambers (RPC) detector chambers will be installed to extend the acceptance coverage up to |η|<2.4 with similar time resolution and better spatial resolution. We present a trigger strategy to detect HSCPs with the RPC detectors. Its performance is studied with Monte Carlo simulations and the expected results with the High Luminosity Large Hadron Collider (HL-LHC) data are shown.

A high quality hot spot is crucial in the laser driven inertial confinement fusion. The hot spot self-emitted X-ray images in a high spatial resolution may be used to analyze the hot spot asymmetry and some fine structures induced by mix. The high spatial resolved X-ray imaging diagnostics can also serve in the hydrodynamic instability growth radiography and some other physical research in the inertial confinement fusion. The Kirkpatrick-Baez microscope can provide a higher resolution and throughput efficiency diagnostic. A new four-channels KB microscope was designed and built for the <10 keV X-ray imaging. The Pt coated reflective mirror pairs were used to obtain a wide grazing angle bandwidth. The variation of the X-ray reflectivity was small in a large field of view. The microscope had a magnification of about 20. The spatial resolution in the central field of view was about 7 μm. The similarities between the different channel images were about 97%. The KB microscope is in operation in the directly or indirectly driven implosions by 10–100 kJ lasers on Shenguang laser facility in China. The time-integral hot spot asymmetry has been diagnosed, and the time-resolved imaging will be implemented in the following work.

In this paper we present the results of the R&D work that has been performed on avoiding electron cyclotron (EC) gas breakdown inside the launcher transmission line (TL) of the ITER collective Thomson scattering (CTS) diagnostic, due to encountering the fundamental EC resonance, which is located inside the port plug vacuum for the baseline ITER magnetic field scenario. If an EC breakdown occurs, this can lead to strong local absorption of the CTS gyrotron beam, as well as arcing inside the ITER vacuum vessel, which must be avoided. Due to the hostile, restrictive, and nuclear environment in ITER, it is not possible to implement the standard method for avoiding EC breakdown - a controlled atmosphere at the EC resonance. Instead, the CTS diagnostic will include a longitudinally-split electrically-biased corrugated waveguide (SBWG) in the launcher transmission line. The SBWG works by applying a transverse DC bias voltage across the two electrically-isolated waveguide halves, causing free electrons to diffuse out of the EC resonant region before they can cause an electron-impact ionisation-avalanche, and thus an EC breakdown. Due to insufficient experimental facilities, the functionality of the SBWG is validated through Monte Carlo electron modelling.

The CIS115 is a Teledyne-e2v CMOS image sensor with 1504 × 2000 pixels of 7 μm pitch. It has a high optical quantum efficiency owing to a multi-layer anti-reflective coating and its backside illuminated construction, and low dark current due to its pinned photodiode 4T pixel architecture. The sensor operates in rolling shutter mode with a frame rate of up to 7.5 fps (if using the whole array), and has a low readout noise of ∼5 electrons rms. The CIS115 has been selected for use within the JANUS instrument, which is a high resolution camera due to launch on board ESA's JUpiter ICy moons Explorer (JUICE) spacecraft in 2022. After an interplanetary transit time of over 7 years, JUICE will spend 3.5 years touring the Jovian system, studying three of the Galilean moons in particular: Ganymede, Callisto and Europa. During this latter part of the mission, the spacecraft and hence the CIS115 sensor will be subjected to the significant levels of trapped radiation surrounding Jupiter. Gamma and proton irradiation campaigns have therefore been undertaken in order to evaluate both ionising and non-ionising dose effects on the CIS115's dark current performance. Characterisations were carried out at expected mission operating temperatures (−35 ± 10^oC) both prior to and post-irradiation. Models of the resulting degradation in dark current behaviour will be combined with expected doses during the JUICE mission in order to predict the performance of the CIS115 at the mission end-of-life.

Neutron Imaging System (NIS) has been used to image the burn volume and cold fuel volume of imploding fusion capsules. In this work, we present a design of neutron imaging aperture for inertial confinement fusion in Laser Fusion Research Center. Since the total neutron yield should be less than 10¹⁴, the penumbral aperture has been chosen. A geometric model has been developed to assess the performance of the neutron imaging system, including the spatial resolution, the field of view and the signal-to-noise ratio. This model reproduces the performances of neutron image systems on OMEGA. The spatial resolution of designed NIS is about 22 μm for a field of view of 250 μm. The signal-to-noise ratio can be better than 10, if the neutron yield is higher than 10¹³.

The upgrade of the high field side (HFS) edge charge exchange recombination spectroscopy (CXRS) system of ASDEX Upgrade is presented. This diagnostic provides temperature, rotation and radiance measurements of impurity species by taking advantage of the gas puff based CXRS technique (GP-CXRS). The system is formed by a fast piezoelectric valve, that injects thermal neutrals into the plasma, and two optical heads. The localized gas injection together with properly aligned lines of sights (LOS) lead to a high spatial resolution of 5–19 mm. Fast gas puff modulation allows a precise subtraction of the passive part of the signal. The existing poloidal optical head has been replaced with a new one to increase the radial resolution. The number of lines of sight (LOS) of the poloidal optical head has been increased from 8 to 16 covering around 7 cm of the plasma edge at the HFS. The same radial range is also viewed by a toroidal optical head. The neutral deposition, needed to calculate the impurity density profile, has been modelled using the FIDASIM code. A realistic gas puff geometry has been implemented in the code. The first measurements of impurity temperature, rotation and radiance utilizing the upgraded diagnostic are presented.

A new scintillator-based fast-ion loss detector (FILD) has been deployed ∼45^o below the midplane of the ASDEX Upgrade tokamak. Port unavailability at this remote location requires an in-situ magnetically driven manipulator to move the diagnostic head horizontally through the scrape-off layer (SOL). The linear displacement is produced by an externally energized coil, whose magnetic dipole tries to align with the toroidal component of the tokamak magnetic field. The insertion is given by force balance between a retaining spring and the energized solenoid, whose current is regulated in real-time, opening the possibility of self-adaptive real-time control of the probe head location based on its temperature. The diagnostic head contains a scintillator screen, Faraday cup, thermocouple and collimator systems. The scintillator image is transferred to a vacuum window using a 3.5 meters quartz image guide. The light acquisition system is composed by a charge coupled device (CCD) camera, for high velocity-space resolution, and by an 8×4 channels avalanche photo diode (APD) camera, for high temporal resolution (up to 2 MHz). First measurements of magnetohydrodynamic (MHD) induced fast-ion losses and radially resolved fast-ion losses are presented.

Single event effects like Single Event Upset (SEU) and Single Event Transient (SET) are big concerns in detector operation in high radiation environment. The single event effects are being more visible in the operation of the ATLAS Insertable B-Layer (IBL) located on the 3.3 cm radius from the beam pipe, as the instantaneous luminosity at the LHC increases. In this paper, studies of single event effects on the front-end ASICs used for the IBL detector will be described.

Planar silicon pixel sensors with modified n⁺-implantation shapes based on the IBL pixel sensor were designed in Dortmund. The sensors with a pixel size of 250 μm × 50 μm are produced in n⁺-in-n sensor technology. The charge collection efficiency should improve with electrical field strength maxima created by the different n⁺-implantation shapes. Therefore, higher particle detection efficiencies at lower bias voltages could be achieved. The modified pixel designs and the IBL standard design are placed on one sensor to test and compare the designs. The sensor can be read out with the FE-I4 readout chip. At the iWoRiD 2018, measurements of sensors irradiated with protons and neutrons respectively at different facilities were presented and showed incongruent results. Unintended annealing during irradiation was considered as an explanation for the observed differences in the hit detection efficiency for two neutron irradiated sensors. This hypothesis will be examined and confirmed in this work, presenting first annealing studies of sensors irradiated with neutrons in Ljubljana.

Long pulse operation of present and future magnetic fusion devices requires sophisticated methods for protection of plasma facing components from overheating. Typically, thermographic systems are being used to fulfill this task. Steady state operation requires, however, autonomous operation of the system and fully automatic detection of abnormal events. At Wendelstein 7-X (W7-X), a large advanced stellarator, which aims at demonstrating the capabilities of the stellarator line as a future fusion power plant, significant efforts are being undertaken to develop a fully automatic system based on thermographic diagnostics. In October 2018, the first divertor-based experimental campaign has been finished. One of the goals of this operation phase (named OP1.2) was to study the capabilities of the island divertor concept using an uncooled test divertor made of fine-grain graphite tiles. Throughout this campaign, it was possible to test the infrared imaging diagnostic system, which will be used to protect the actively water-cooled plasma facing components (PFCs) during the steady-state operation in the next experimental campaign. An overview of the most relevant thermal events on the PFCs that were detected in OP1.2 using this system are presented. This includes events that limited operation during the campaign, like baffle hot spots and divertor overloads, events that are potentially critical in steady state operation like leading edges, events caused by the ECRH and NBI heating systems (shine-through hot spots and fast particle losses) and other events which are a common source of false alarms like surface layers. The detected thermal events are now part of an important and extensive image database which will be used to further automate the system by means of computer vision and machine learning techniques in preparation for steady-state operation, when the system must be able to detect dangerous events and protect the machine in real-time.

The JET tokamak is equipped with extensive diagnostic systems for tomography, including bolometers and soft X-ray (SXR) detectors. The tomographic reconstructions presented in this contribution were obtained using an algorithm based on Tikhonov regularisation and Minimum Fisher information. A new method for subsequent interpretative analysis of the tomographic reconstructions will be introduced. It is based on a comparison of radiated power from different regions of reconstruction, that can be defined by a rectangle or by a flux surface. The method was also used for comparative analysis of data obtained by reconstructing signals from different detectors. Both combined and separate reconstructions will be analysed. Example applications are presented, showing electron temperature drop, sawteeth instability and transport after laser blow-off.

The response of a sealed MicroPatterned Gaseous Detector (MPGD), with an enclosed gas purification system based on getters, was monitored for several weeks. An average of 2 discharges per day was registered during the monitoring period and the charge gain varied a maximum of 15% during the more stable period. The temperature of the getters was varied from 180^oC to 250^oC and no significant influence was registered in the detector response. A reactivation of the getters also did not affect the charge gain, which means that their gettering rate was at full efficiency before the reactivation. However, careful attention is paid to charge gain reduction for long times of operation which can denote a loss of getters efficiency along time and the need of getter reactivation. On the other hand, turning off the getters lead to a rapid decrease in the charge gain. This allows concluding that a purification system based on getters is really effective in removing gas impurities, being a crucial component of the detection system for a sealed gaseous detector.

The article presents an experimental investigation on Langmuir probe measurements in a magnetized plasma column which exhibits two-temperature electron populations. It is a known fact that probe I(U) traces follow the usual exponential law if the measurements are performed with a reference electrode in good contact with plasma; which is usually a grounded discharge electrode. However in the present case, as the grounded probe reference is not a part of the discharge circuit the resulting I(U) analysis is not straightforward. It is found that owing to the high impedance between bulk plasma and probe reference, the probe measurement results in lower values of electron saturation current as compared to the ideal scenario. An appropriate correction is thus required to account actual electron saturation current and thereby to extract subsequent plasma parameters. Therefore, a simple analysis technique has been proposed to interpret probe I(U) traces resulting from such magneto-plasma devices, where reference to the probe is in partial/ poor contact with the bulk plasma.

IEAP of CTU operates a Van de Graaff accelerator (VDG) that provides protons and light positively charged particles with energy in the range 0.3 MeV/u–2.3 MeV/u. The purpose of this article is to describe the electrostatic separator that enables to obtain protons with the energy lower than 0.3 MeV. We let the beam of protons with the energy 1.0 MeV impact to tungsten target. The Rutherford scattering take place on the target, scattered protons then enter the electrostatic separator. Applying different high voltage between quarter-circular electrodes of the separator, we selected the energy of protons that pass the separator. We used the electrostatic separation because the control over the high voltage is simple and efficient. For the measurement of proton energy, we used the Silicon Surface Barrier Detector Ortec. We proved that the electrostatic separator can provide protons with adjustable energy from 32 keV to 400 keV, FWHM is in the range 13 keV–19 keV. The separator extends possibilities of the VDG usage. In our further research, we intend to focus on investigation of the profile of the beam getting out of the separator using a pixel detector to obtain information on 3D distribution of the beam energy.

Here we report on the characterization of one of the large-volume LaBr₃:Ce detectors for the ELIGANT project at ELI-NP. The main focus of this work is the response function for high-energy γ rays of such detectors. In particular, we compare a selection of unfolding methods to resolve small structures in γ-ray spectra with high-energies. Three methods have been compared using γ-ray spectra with energies up to 12 MeV obtained in an experiment at the 3 MV Tandetron^TM facility at IFIN-HH. The results show that the iterative unfolding approach gives the best qualitative reproduction of the emitted γ-ray spectrum. Furthermore, the correlation fluctuations in high-energy regime from the iterative method are two orders of magnitude smaller than when using the matrix inversion approach with second derivative regularization. In addition, the iterative method is computationally faster as it does not contain large matrix inversions. The matrix inversion method does, however, give more consistent results over the full energy range and in the low-statistics limit. Our conclusion is that the performance of the iterative approach makes it well suitable for semi-online analysis of experimental data. These results will be important, both for experiments with the ELIGANT setup, and for on-line diagnostics of the energy spread of the γ-ray beam which is under implementation at ELI-NP.

At high frequencies, the impedance matching along the transmission line such as between an integrated circuit and the Printed Circuit Board (PCB) is critical to maintain the signal quality and integrity. This paper focuses on studying the impedance of transmission lines in MRPC detectors. We present the 3D electromagnetic (EM) simulation for the real MRPC configurations to obtain the impedance results by using CST Microwave studio. The simulated results show a nice agreement with the results obtained by actual measurements. The strip impedance associated to different MRPC structure configurations has been has been analyzed and discussed in detail.

Digital pulse shape analysis (dpsa) has been used with a Frisch-gridded ionization chamber to study the charged particle emission reactions induced by fast neutrons. The structure of Frisch-gridded ionization chamber and his performance were presented in more detail in ref. [1]. Here we describe experimental use of the ionization chamber combined with PXI system in detection of charged particles. The PXI system consisting of a chassis NI PXI-1031, an embedded controller NI PXI-8820 and a high-speed digitizer pixie-4 from XIA [2]. The pixie-4 is a PCI/PXI 4-channel all-digital waveform data-acquisition card featuring on-line pulse-shape analysis. Incoming signals are digitized with 14-bit 75 msps ADCs. Rise-time dpsa has been employed using data as an examples measurements of charged particles originating from reactions on ⁶Li and ¹⁰B nuclei induced by thermalized neutrons from an ²⁴¹Am-Be source.

Affordable electronics for instrumentation play a vital role in academia since research budgets are tight nowadays. In this paper a low-cost open-source high-frequency portable Raspberry Pi-based pulse counter is presented. Although it is designed as a 2 channel counter, it can be easily modified to a 4 channel counter. It provides a relay control interface for experimental-setup integration and counts pulses up to 10 MHz frequency. Presented system is proved to be accurate by an Xray transmission rate measurement experiment.

A digitizer capable of processing 32-channel signals is designed for a thermal neutron detector array. The field-programmable gate array in the digitizer performs the case selection of extensive air showers that is usually performed on a personal computer. Because the amount of data transmitted to the personal computer is reduced considerably, the problem of data blocking and dead time for a large detector array is solved.

We studied the effectiveness of the purification of molybdenum trioxide (MoO₃) powder with the sublimation method. To utilize the method, we have designed sublimation apparatus to purify the powder and annealing apparatus to collect the fine powder, followed by the wet chemistry method. As part of purification R&D, MoO₃ powder was purified using a low vacuum sublimation method to remove radioactive elements such as Ra, Th, U, etc. The purification was performed at different temperatures to determine the optimum conditions for high decontamination factors and high recovery efficiencies. After applying the sublimation method, the powder was dissolved in aqueous ammonia; recrystallized to obtain polyammonium molybdate (PAM); and annealed to acquire MoO₃ fine powder. The phase of MoO₃ powder was studied by using X-ray diffraction (XRD) techniques. The effectiveness of the purification techniques was checked with inductively coupled plasma mass spectrometry (ICP-MS) measurements and the radioactivity from Ra, Th, and U were measured with high purity germanium (HPGe) detectors at Yangyang underground laboratory in Korea. The purified MoO₃ powder was used by the AMoRE (Advanced Mo-based Rare process Experiment) collaboration to grow scintillating crystals.

A digital pulse shape discrimination (PSD) system has been built using a high speed digital oscilloscope NI-5772 and tested with an EJ-301 liquid scintillation detector. The sampling frequency of this system is 1.6 Gs/s. In this work, the charge comparison method, the rise time method and the zero-crossing time method are used to perform neutron-gamma discrimination. Experimental results show that the studied digital PSD algorithms can discriminate neutron and gamma rays in mixed radiation fields. The digital rise time method shows the optimal neutron-gamma discrimination with integration parameter RC of 10000 ns. Moreover, the zero-crossing time method is investigated through CR-R₁C₁ and CR-R₁C₁-R₂C₂ shaping networks. It is found that for the same pair of values for the two kinds of network, the CR-R₁C₁-R₂C₂ shaping network presents better neutron-gamma discrimination with R₂C₂ of 5 ns. In addition, through the investigation of the distribution of neutron and gamma peaks for different energy regions, the relationship between the ionization density of liquid scintillation detector and the contribution of slow component in the light outputs is demonstrated.

Please see the PDF file for details.

Please see the PDF file for details.