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This paper reports on the development of a resource-efficient FPGA-based neural network regression model for potential applications in the future hardware muon trigger system of the ATLAS experiment at the Large Hadron Collider (LHC). Effective real-time selection of muon candidates is the cornerstone of the ATLAS physics programme. With the planned ATLAS upgrades for the High Luminosity LHC, an entirely new FPGA-based hardware muon trigger system will be installed that will process full muon detector data within a 10 μ s latency window. The large FPGA devices planned for this upgrade should have sufficient spare resources to allow deployment of machine learning methods for improving identification of muon candidates and searching for new exotic particles. Our neural network regression model promises to improve rejection of the dominant source of background trigger events in the central detector region, which are due to muon candidates with low transverse momenta. This model was implemented in FPGA using 157 digital signal processors and about 5000 lookup tables. The simulated network latency and deadtime are 122 and 25 ns, respectively, when implemented in the FPGA device using a 320 MHz clock frequency. Two other FPGA implementations were also developed to study the impact of design choices on resource utilisation and latency. The performance parameters of our FPGA implementation are well within the requirements of the future muon trigger system, therefore opening a possibility for deploying machine learning methods for future data taking by the ATLAS experiment. [ABSTRACT FROM AUTHOR]

A 256-channel time-of-flight electronics system has been developed for a facility called “Back-n white neutron source (WNS)” in China Spallation Neutron Source (CSNS). This paper presents the structure and performance of the electronics system and test results at CSNS-WNS. A piece of lithium glass scintillator, coupled with a 256-channel multi-anode photomultiplier tube, is placed at the center of the neutron beam line as the detector. A 256-channel readout electronics system, including one front-end board (FEB), four time-to-digital converter (TDC) cards and one clock distribution module (CDM), measures the arrival time of each signal from the detector. Signals are sent to FEB from the detector through 15-cm cables and discriminated on FEB. FEB drives differential signals over 2-m cables to the TDC cards. Each TDC card has 64 channels, using a field-programmable gate array (FPGA) to measure the arrival time of each signal. The CDM supplies clock signals to the TDC cards to make them work synchronously. The TDC cards and CDM are housed in one peripheral component interconnect (PCI) eXtensions for Instrumentation chassis. The TDC cards achieve a timing precision of 3.5 ns. The electronics system meets the requirement of the experiment and is currently being used in CSNS. [ABSTRACT FROM AUTHOR]

The Alice pixel detector (ALPIDE) chip is a CMOS monolithic active pixel sensor developed by the A Large Ion Collider Experiment collaboration. It measures 15 mm $\times30$ mm and contains a matrix of $512 \times 1024$ pixels, each one measuring $26.88\,\,\mu \text{m}\,\,\times 29.24\,\,\mu \text{m}$. The sensor can achieve a spatial resolution of $5~\mu \text{m}$ , and an event time resolution of 2– $4~\mu \text{s}$. The ALPIDE chip is suitable to be used as a sensor plane for the construction of a high-precision beam telescope, considering its excellent tracking performance. As a prototype of a single plane of the future ALPIDE-based beam telescope, we present a readout system for the ALPIDE chip in this paper. Chip threshold calibration was carried out with this system. The capability to read out the hit rate of 6 MHz/cm2 was achieved in an X-ray radiation experiment. The spatial resolution of $\sim 5~\mu \text{m}$ was measured in a laser beam test. [ABSTRACT FROM AUTHOR]

A real-time $n/\gamma $ discrimination prototype system based on high-speed waveform sampling and high-performance field-programmable gate array (FPGA) is presented in this paper. In order to accurately record detector signals, a high-speed sampling board with a 14-bit analog-to-digital converter (AD9680) is designed. The BC501A liquid scintillator is employed as the neutron detector, and a discrimination algorithm is implemented in the FPGA of the sampling board. The system is calibrated by 22Na, 137Cs, and 60Co $\gamma $ -sources. A PuC neutron source is used to evaluate the discrimination ability. The figure-of-merit of PuC neutron source is determined to be about 1.005 over an energy range of 0–4000 keVee, which is consistent with the test results of the commercial digitizer, and the false alarm rate of 60Co is 0.19%. This system has been successfully applied for the environmental neutron monitoring experiment during the first commissioning of white neutron source tunnel of China spallation neutron source. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the hardware implementation of two feedforward neural networks (NNs) using a field-programmable gate array (FPGA), then used the networks for alpha–gamma discrimination in barium fluoride (BaF2). The BaF2 detector output was sampled using a 1-GSPS ADC, and then we extracted six information of the pulses in FPGA as the input features to the NNs. The performance of this method turned out very good, the false alarm rate of the networks was less than 0.3%. Besides, dead time of the networks was less than 820 ns. Low logic occupancy is also discussed. [ABSTRACT FROM AUTHOR]

In this paper, a portable gamma-ray spectrometer for real-time and in-situ gamma-ray detection applications is presented. By combining a quasi-hemispherical CdZnTe (CZT) semiconductor detector and a Geiger-Muller (GM) counter together, a wide dose rate range is achieved, ranging from 0.1 μSv/h to 100 mSv/h with a relative error of less than 10%. The GM counter is used to measure dose rate from 1 mSv/h to 100 mSv/h. With CZT, the spectrometer can provide a high energy resolution spectrum for nuclide identification and a high precision dose rate at low dose rates. The full width half maximum (FWHM) resolution is 2.2% at 662 keV below 70 μSv/h and is better than 3.3% at 3.8 mSv/h. The weight of the spectrometer is 3.2 kg for handheld and the runtime is up to 12 h without charging. For preliminary applications, the spectrometer was used to measure the gamma radiation around the Back-n white neutron beam line at China Spallation Neutron Source and around the steam generator in the nuclear power plant at Daya Bay Nuclear Power Station. • The design of a portable gamma-ray spectrometer based on CZT and GM counter was proposed. • High energy resolution of 2.2% at 662 keV and wide dose rate range from 0.1 μSv/h to 100 mSv/h. • Radioactive sources were used to calibrate the spectrometer and examine its performance. • Preliminary application for gamma radiation detection around a neutron beam and in nuclear power plant. [ABSTRACT FROM AUTHOR]

An (e, 2e+ion) Electron momentum spectrometer (EMS) upgraded from the third-generation (e, 2e) spectrometer is constructed in the University of Science and Technology of China (USTC). In the EMS, the energy-momentum density of electrons is derived through the charge measurement using the signals of the position sensitive detector (PSD). The information of ion fragments is derived through the time measurement and that information will be used for more research on collision dynamics. A PXI-based data acquisition (DAQ) system was designed. The system mainly consists of a 6-channel charge digital module (CDM) and a 9-channel time digital module (TDM). Shaping amplifiers (SAs) are also designed for charge measurement with CDM. According to the design specification, the CDM with SAs needs to measure charge from 100 to 900 fC with an accuracy of better than 1%. The TDM needs to measure the flight time from 0 to 15 us with a resolution of better than 100 ps. The TDM and CDM can be combined to run synchronously using a coincidence unit which also rejects the background events based on the tracking information of the electrons and the ions. Test results indicate that, within the dynamic range, the accuracy of the CDM is better than 0.4%. The RMS time resolution of better than 30 ps is achieved by using the method of time-to-digital converter (TDC) implemented in a field-programmable gate arrays (FPGA). The DAQ system has been assembled and works well with the EMS detectors. [ABSTRACT FROM AUTHOR]

The DAMPE (DArk Matter Particle Explorer) is a scientific satellite being developed in China, aimed at cosmic ray study, gamma ray astronomy, and searching for the clue of dark matter particles in the near future. The BGO (Bismuth Germanate Oxide) Calorimeter, which consists of 616 PMTs (photomultiplier tubes) and 1848 dynode signals, is a crucial part of the DAMPE payload for measuring the energy of cosmic ray particles, distinguishing interesting particles from background, and providing trigger information. An electronics system, which consists of 16 FEE (Front End Electronics) modules with a total power consumption of about 26 W, has been developed. Its main functions are based on the low power, 32-channel VA160 and VATA160 ASICs (Application Specific Integrated Circuits) for precisely measuring the charge of PMT signals and providing“hit”signals as well. To assure the long-term reliability in harsh space environment, a series of critical issues such as the radiation hardness, thermal design, components and board level quality control, etc., are taken into consideration. Test result showed that the system level ENC (equivalent noise charge) for each channel is about 10 fC in RMS (root mean square), and the timing uncertainty of the hit signals is about 300 ns, both of which satisfy the physics requirements of the detector. Experiments with ^60\ Co radioactive source proved that 20 krad(Si) TID (Total Ionizing Dose) level is achieved, while the heavy ion beam and laser beam tests indicated that its SEL (Single Event Latch-up) and SEU (Single Event Upset) performance in orbit will be acceptable by taking some hardness measures. All the readout modules successfully passed the board-level screening, the sub-system level and finally the satellite system level environmental tests, and behave well in the beam test at CERN (European Organisation for Nuclear Research). [ABSTRACT FROM AUTHOR]

The BGO calorimeter, which provides a wide measurement range of the primary cosmic ray spectrum, is a key sub-detector of the Dark Matter Particle Explorer (DAMPE). The readout electronics of calorimeter consists of 16 pieces of Actel ProASIC Plus FLASH-based field-programmable gate array (FPGA), of which the design-level flip-flops and embedded block random access memories (RAM) are single event upset (SEU) sensitive in the harsh space environment. To comply with radiation hardness assurance (RHA), SEU mitigation methods, including partial triple modular redundancy (TMR), CRC checksum, and multi-domain reset are analyzed and tested by the heavy-ion beam test. Composed of multi-level redundancy, a FPGA design with the characteristics of SEU tolerance and low resource consumption is implemented for the readout electronics. [ABSTRACT FROM PUBLISHER]

A high precision, low dead time, large dynamic range time-to-digital (TDC) architecture, suited to be implemented in Actel flash-based and anti-fuse FPGAs, is presented in this paper. A prototype board has been designed with such a TDC implemented in three different industrial grade FPGAs: an anti-fuse FPGA AX500, flash-based FPGAs APA600 and A3PE1500. Test results showed that a time resolution of 225 ps RMS with a 758 ps averaged bin size was obtained for APA600, while 127 ps RMS with 427 ps bin size for A3PE1500. For a TDC in AX500, a RMS of 37 ps with 75 ps bin size was obtained. Thermal tests suggested that the prototype TDCs operate well in a temperature range from -21^\circC to +71^\circC with a constant performance after applying a compensation mechanism utilizing the linear relation between TDC bin sizes and ambient temperature. The TDC structure can be directly migrated into space-qualified FPGAs and applied in space experiments. [ABSTRACT FROM AUTHOR]

This paper describes a high-precision time measurement module for the end-cap time-of-flight (ETOF) upgrade of the Beijing Spectrometer (BES III). ETOF is scheduled to be upgraded with the multi-gap resistive plate chambers (MRPCs) instead of a scintillator. The new ETOF of BES III will have 1728 readout channels, which is a big challenge for the readout electronics. The time resolution of the readout electronics system is required to be better than 25 ps. [ABSTRACT FROM AUTHOR]

In this paper, a time projection chamber (TPC) system for α radiation detection with ultra-low background is presented, which is based on Micromegas, a type of micro-pattern gaseous detector. Based on multi-dimensional information acquired by the TPC, such as the features of particle energy deposition and 3D track, the system can achieve the purpose of α identification with ultra-low background. A prototype TPC with the volume of 15 × 15 × 6.5 cm3 was developed. It was filled with a gas mixture of 95% neon and 5% isobutene at about 1 bar, and no additional shielding or control of alpha-emitting materials was employed. A low-noise high-integration electronic system based on multi-channel waveform sampling techniques was adopted to read out the anode strip signals. A test with a 241Am α source (5.5 MeV), a 49-h background test, and several other tests with weak radioactive samples in the laboratory environment were conducted. A feature selection method was designed to maximize the suppression of background events while retaining the events of interest. Test results showed that within an assumed 5 × 5 cm2 effective area in the center region of the TPC window, the background count rate of this system was lower than 1.6 × 10−3 counts per minute at 95% confidence level, while retaining the acceptance rate of about 96% for 241Am α particles. [ABSTRACT FROM AUTHOR]

The application and fate of antibiotics are closely related to human health and the ecological balance, which has gradually aroused the widespread global concerns. Long-term antibiotic residues can easily induce antibiotic resistance and antibiotic resistance genes (ARGs) in the environment. Although many studies have investigated the metabolic pathways of biosynthesis or degradation of oxytetracycline (OTC) and its influencing factors under laboratory or controlled conditions, the understanding of OTC degradation pathways and influencing factors in the environment is still poor. In the present study, the role of Pseudomonas (T4) in OTC biodegradation were investigated with different carbon sources, metal ions, substrate concentrations, temperatures, and pH values, as well as the temporal changes in the relative abundance of OTC ARGs. It was found that OTC could be degraded by T4 as a sole carbon source. Comparison with Cu2+, the addition of Fe3+ could significantly promote the growth of T4, and then increased the OTC degradation percentage to 65.3%. The initial concentration of OTC, temperature, and pH had significant impacts on OTC degradation. At the initial OTC concentration of 50 mg L−1, the percentage degradation of OTC by T4 could reach 81.0% at the presence of Fe3+, and at 40 °C and pH = 7. Common tetracycline ARGs were not found during the OTC degradation by T4 in the present study. The eight main putative OTC degradation byproducts were identified by ultra-high definition accurate-mass quadrupole time-of-flight tandem mass spectrometry (QTOF/MS). Six different reaction types and seven possible degradation pathways were proposed, including enol-ketone conversion, hydroxylation, dehydration, deamination, demethylation and decarbonylation. Under optimal conditions, the OTC degradation percentages by T4 could reach to 88.2%, 91.6% and 92.0% in pond water, fish wastewater and industrial wastewater, respectively. These results demonstrate the high effectiveness of T4 at the presence of Fe3+ for the enhanced biodegradation of OTC in water environment, without resulting in the occurrence of ARGs. This has important implications for the removal of OTC from aquatic environments by the technology proposed from this study. Image 1 • A bacterium (pseudomonas) that can rapidly degrade the oxytetracycline (OTC) was screened. • Fe3+ plays a key role in the degradation of OTC by pseudomonas. • The possible degradation pathways and products of OTC were proposed. • There were no common tetracycline resistance genes to be induced during OTC degradation. [ABSTRACT FROM AUTHOR]

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

The particle and astrophysical xenon experiment III (PandaX-III) is aimed to search for the Neutrinoless Double Beta Decay (NLDBD) using 200-kg radio-pure high-pressure gaseous xenon time projection chamber (TPC) with Micromegas detectors at both ends. A small-scale prototype TPC equipped with seven Microbulk Micromegas modules has been developed. Each Micromegas module has 128 anode strip signals to be processed. Highly integrated front-end electronics composed of four front-end cards (FECs) with 1024 channels are designed to read out the charge of Micromegas anode signals digitize the waveform after shaping and send compressed data to the data collection module (DCM). The cornerstone of the front-end electronics is a 64-channel application-specific integrated circuit (ASIC) named AGET, which is based on switched capacitor arrays (SCAs). According to the test results, the integral nonlinearity (INL) of the front-end electronics is less than 1%, and the noise of each readout channel with the input floating is less than 0.9 fC on the condition of 1- $\mu \text{s}$ peaking time and 1-pC dynamic range. Joint tests of front-end electronics with the prototype TPC were carried out using the radioactive sources 137Cs and 241Am. The hit map of the Micromegas modules and the energy spectrum have been reconstructed successfully, and the results are satisfying. [ABSTRACT FROM AUTHOR]

Transcription factors (TFs) play critical roles in mediating the plant response to various abiotic stresses, particularly heat stress. Plants respond to elevated temperatures by modulating the expression of genes involved in diverse metabolic pathways, a regulatory process primarily governed by multiple TFs in a networked configuration. Many TFs, such as WRKY, MYB, NAC, bZIP, zinc finger protein, AP2/ERF, DREB, ERF, bHLH, and brassinosteroids, are associated with heat shock factor (Hsf) families, and are involved in heat stress tolerance. These TFs hold the potential to control multiple genes, which makes them ideal targets for enhancing the heat stress tolerance of crop plants. Despite their immense importance, only a small number of heat-stress-responsive TFs have been identified in rice. The molecular mechanisms underpinning the role of TFs in rice adaptation to heat stress still need to be researched. This study identified three TF genes, including OsbZIP14, OsMYB2, and OsHSF7, by integrating transcriptomic and epigenetic sequencing data analysis of rice in response to heat stress. Through comprehensive bioinformatics analysis, we demonstrated that OsbZIP14, one of the key heat-responsive TF genes, contained a basic-leucine zipper domain and primarily functioned as a nuclear TF with transcriptional activation capability. By knocking out the OsbZIP14 gene in the rice cultivar Zhonghua 11, we observed that the knockout mutant OsbZIP14 exhibited dwarfism with reduced tiller during the grain-filling stage. Under high-temperature treatment, it was also demonstrated that in the OsbZIP14 mutant, the expression of the OsbZIP58 gene, a key regulator of rice seed storage protein (SSP) accumulation, was upregulated. Furthermore, bimolecular fluorescence complementation (BiFC) experiments uncovered a direct interaction between OsbZIP14 and OsbZIP58. Our results suggested that OsbZIP14 acts as a key TF gene through the concerted action of OsbZIP58 and OsbZIP14 during rice filling under heat stress. These findings provide good candidate genes for genetic improvement of rice but also offer valuable scientific insights into the mechanism of heat tolerance stress in rice. [ABSTRACT FROM AUTHOR]

To guarantee a good resolution of a Time-Of-Flight Mass Spectrometer (TOF-MS), a high-performance time measurement system was required. This paper presents a time measurement system based on waveform digitization. The critical part, the 2-GSPS analog-to-digital converter is implemented using the Time-Interleaved Analog-to-Digital Conversion (TIADC) technique. Through a digital post-processing algorithm, the mismatch errors between the interleaving TIADC channels are corrected, which significantly improves the ADC performance. A Peripheral Component Interconnect (PCI) bus interface is used to communicate with a computer, achieving a data transfer rate up to 20 MByte/s using Direct Memory Access (DMA). Initial test results indicate that the system timing precision is about 196 ps Root-Mean-Square (RMS), which is good enough for the given requirements. [ABSTRACT FROM PUBLISHER]

Environmental γ -rays constitute a crucial source of background in various nuclear, particle and quantum physics experiments. To evaluate the flux rate and the spectrum of γ background, we have developed a novel and straightforward approach to reconstruct the environmental γ flux spectrum by applying a portable CZT γ detector and iterative Bayesian unfolding, which possesses excellent transferability for broader applications. In this paper, the calibration and GEANT4 Monte-Carlo modeling of the CZT detector, the unfolding procedure as well as the uncertainty estimation are demonstrated in detail. The reconstructed spectrum reveals an environmental γ flux intensity of 3. 3 ± 0. 9 × 1 0 7 (m 2 ⋅ sr ⋅ hour)−1 ranging from 73 to 3033 keV, along with characteristic peaks primarily arising from 232Th series, 238U series and 40K. We also give an instance of background rate evaluation with the unfolded spectrum for validation of the approach. [ABSTRACT FROM AUTHOR]

The high-pressure xenon time projection chamber (TPC) utilizing micro-pattern gaseous detector readout has emerged as a highly promising technical solution for the search of neutrino-less double beta decay events. This approach offers exceptional features, including high energy resolution, fine granularity, low background radioactivity, and scalability for large-scale experiments. In line with these advantages, the PandaX-III experiment aims to implement a 10 bar X e 136 TPC, employing a readout plane comprising 52 194 × 194 mm2 Micromegas detectors, within the China Jinping Underground Laboratory. To fulfill the stringent experimental requirements of PandaX-III, a low-background Micromegas detector with high energy resolution was proposed and developed using the thermal bonding method. The performance of the thermal bonding Micromegas prototypes was investigated using X-ray characterization under various gas mixtures with argon and isobutane from 1 bar to 10 bars. Remarkable results were presented at 1 bar gas pressure, where a maximum gas gain of ∼8 × 104 and the best energy resolution (FWHM @5.9 keV) of 13.6% is obtained, and at 10 bar pressure, where maximum gas gain exceeding 104, the best energy resolution of 19%, and excellent stability over a test duration exceeding 150 h is achieved. [ABSTRACT FROM AUTHOR]

Cosmic ray muon has strong penetrating power and no ionizing radiation hazards, which makes it an ideal probe for detecting special nuclear materials (SNMs). In this article, a high spatial resolution muon tomography system based on Micromegas detectors is proposed to optimize the imaging time and quality. The proposed system includes eight Micromegas detectors based on the thermal bonding technique and a scalable readout system. In addition, a multiplexing method based on position encoding is developed to reduce the number of electronics channels by order of magnitude. The spatial resolution of the proposed system with encoding readout can reach a value of hundred micrometers. Finally, a tomography test is performed, and test results show that this proposed system can image 2-cm objects and distinguish different materials. [ABSTRACT FROM AUTHOR]

A high-speed and high-resolution Analog-to-Digital Conversion circuit is the crucial part in many physics experiments, data communication, and measurement instrumentation. We present the design and test results on a 1.6-Gsps high-resolution waveform digitizer based on a high-speed AD conversion and time-interleaved technique. Considering the mismatch (gain, offset, and skew) among different ADC channels, we employ real-time correction algorithms integrated in an FPGA to enhance the system performance. In the very high-speed situation, simplification of digital processing algorithms is an important task to guarantee a high processing speed. We proposed a novel correction method based on a fully parallel structure. To achieve good performance, we designed a special jitter-cleaning circuit for the sampling clock and front end coupling circuits for the ADCs, and carefully implemented the hardware circuits to guarantee the signal integrity. Test results indicate that this waveform digitizer achieves a sampling rate of 1.6 Gsps and an ENOB around 11 bits for an input signal from 5 MHz to 150 MHz. The ENOB is still above 10.4 bits for an input up to 300 MHz, with the correction algorithms applied. [ABSTRACT FROM PUBLISHER]

We introduce a fast pulse sampling module with the use of switched-capacitor arrays (SCAs). The module is in the size of 3U for PCI extensions for Instrumentations (PXI), and there are a total of six channels with a sampling rate of up to 5 giga samples per second (GS/s) per channel. With this module, we evaluate the issues of fast pulse timing from reconstructed waveform, as well as the scheme of interleaved sampling between adjacent channels within the module. The timing precision of this module is proved to be below 10 ps RMS at 4.7 GS/s after a series of calibration strategies. We have also achieved 9.4 GS/s with two channels interleaved on board. [ABSTRACT FROM PUBLISHER]

Double-sided silicon strip detectors (DSSDs) have been widely used in interplanetary exploration. In this study, the prototype readout electronics of a DSSD for space exploration is presented. It mainly includes a front-end readout module (FEM) and a data acquisition module (DAM). The FEM is responsible for acquiring the charge of the DSSD signals based on an application-specific integrated circuit and polarity inverter circuits. The DAM with a field programmable gate array is employed to perform online calculations of the position and energy as well as data packaging and transfer. Test results show that the electronics has dynamic ranges of 6–2500 and −6 to −2500 fC with an integral nonlinearity of no more than 0.5%, while the root-mean-square noise level is less than 1.9 fC. Joint tests with the DSSD indicate that a full width at half maximum energy resolution of 3.25% at 5.486 MeV and a position resolution of 1.19 mm were achieved. [ABSTRACT FROM AUTHOR]

Aluminum and its alloys are widely used in the nuclear industry. Therefore, it is essential to precisely measure and accurately know the neutron total cross section of aluminum in the wider energy region. The measurement is performed by using the transmission method at the Back-n White Neutron Source of CSNS. Two aluminum samples 70 mm in diameter and thicknesses of 40 and 60 mm, respectively, were positioned at 55 m from the neutron source. The transmission detector consisted of a multi-layer fast fission chamber loaded with 235 U and 238 U, and it was located at the 76-m measurement station. By applying the time-of-flight technique, it was possible to extract the n+ 27 Al total cross section in a wide energy region, from 1 eV to 20 MeV, after the correction for the double-bunch mode of the CSNS accelerator. The total cross sections obtained with the two Al samples are consistent and the results obtained with the 235 U fission cells are in good agreement with that with 238 U in the energy range of 1–20 MeV. The uncertainty of neutron total cross section measured with 235 U for 40 mm and 60 mm thick aluminum is 0.7–22.3% and 0.6–12.4% in the energy range of 10 keV–20 MeV. Results are in fair agreement with respect to previous data and evaluations. [ABSTRACT FROM AUTHOR]

The Multi-purpose Time Projection Chamber (MTPC) is a gas-filled detector designed to measure cross sections of neutron-induced light-charged particle emission and fission reactions at the Back-streaming white neutron facility (Back-n) at the China Spallation Neutron Source. A prototype MTPC has been constructed with a drift volume, a resistive Micromegas charge amplification structure, and a high-density pixelated anode readout plane with 1519 hexagonal pads. Test measurements have been performed using a four-component alpha source. Alpha-particle track reconstruction is performed to obtain the deposited energy and length information of the trajectory. The performance test and characterization of the detector have served as the basis for the optimized design of the MTPC, which is currently undergoing commissioning at Back-n. [ABSTRACT FROM AUTHOR]

In situ radioactivity measurements in a deep ocean environment are essential for marine environmental pollution monitoring and seabed geological exploration. In the past, the most widely used gamma spectrometers were based on towed instrumentation, which could only be operated underwater at a depth of less than 1500 m. In this study, a compact gamma spectrometer with small-size, light weight, and low power consumption was designed for working in a marine in situ environment. This spectrometer, with two essential parts: detector and electronics, was designed to work on different underwater platforms in the real-time control mode or autonomous operation mode. Multiple small volume avalanche photodiodes were coupled with NaI(Tl), which can significantly reduce the spectrometer volume compared with the option of the photomultiplier tube. Integrated readout electronics were employed to digitize all detector signals for miniaturization and low power consumption. The field programmable gate array (FPGA) was used to obtain the energy spectrum in real-time and an online multi-channel summation with temperature calibration algorithm was employed to improve detection efficiency. Relevant tests were also conducted in the laboratory to evaluate critical techniques and system performance. Results show that the energy resolution (full width at half maximum over the peak position) was ∼7.5% at 662 keV, verifying the online multi-channel summation with temperature calibration based on the FPGA. Moreover, the compact prototype spectrometer worked well in the power-on hydraulic test. [ABSTRACT FROM AUTHOR]

Nowadays, the data compression technique is fully developed and widely used in many fields, such as communication, multi-media, image processing, and so on. In large physics experiments, especially the ones with micropattern gas detectors (MPGDs), there are always large numbers of readout channels and many data to be transferred. However, the data compression technique is seldom applied in this field. In this paper, a real-time lossless data compression method, which can reduce the data transmission bandwidth while keeping all information of data is proposed and successfully implemented in a general-purpose MPGD readout system. The compression method discussed in this paper mainly consists of two steps: The first step is to preprocess the data according to the signal characteristics and the second step is to compress the preprocessed data using a common lossless compression algorithm. In addition, the whole compression method is implemented in the field-programmable gate array (FPGA) and can run in real time. The compression method is validated with two different signals and the compression ratios reach 43% and 30%, respectively. [ABSTRACT FROM AUTHOR]

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

Abstract The DArk Matter Particle Explorer (DAMPE), which is a Chinese space telescope for the precise measurement of high-energy electrons, gamma rays, and nuclei from deep space, was successfully launched on December 17, 2015. The DAMPE electromagnetic calorimeter made of bismuth germanium oxide (BGO) crystals can measure incident hadron energies from 50 GeV to 100 TeV. The calorimeter was tested with ion beams at CERN in 2015. The energy responses to ions from helium to argon are investigated. The result is reproduced by a Monte Carlo simulation based on Geant4 with two physics process models. It shows that the simulation results of a beam test are independent of the physics models adopted. Additionally, quenching effects of the BGO crystal on the ions are observed with this beam test. The quenching attenuations increase with the atomic number and were approximately 7% for boron and 40% for argon. [ABSTRACT FROM AUTHOR]

The Dark Matter Particle Explorer developed in China was designed to search for evidence of dark matter particles by observing primary cosmic rays and gamma rays in the energy range from 5 GeV to 10 TeV. Since its launch in December 2015, a large quantity of data has been recorded. With the data set acquired during more than a year of operation in space, a precise time-dependent calibration for the energy measured by the bismuth germanate oxide (BGO) electromagnetic calorimeter (ECAL) has been developed. In this paper, the instrumentation and development of the BGO ECAL are briefly described. The calibration on orbit, including that of the pedestal, attenuation length, minimum ionizing particle peak, and dynode ratio, is discussed, and additional details about the calibration methods and performance in space are presented. [ABSTRACT FROM AUTHOR]

Micropattern gas detectors (MPGDs) have a wide application in high-energy physics, astrophysics, nuclear physics, medical imaging, and so on. The demand for large area and good spatial resolution requires a large number of channels. The conventional 2-D tracking for MPGDs requires a large number of electronic channels, and in consequence poses a big challenge for the integration, power consumption, cooling, and cost, which has become a problem to the further applications of MPGDs. In this paper, a new tracking method for MPGDs based on 2-D encoded multiplexing readout is presented, which is easily extensible and can significantly reduce the number of electronic readout channels. [ABSTRACT FROM AUTHOR]

The DArk Matter Particle Explorer (DAMPE) is a space experiment designed to search for dark matter indirectly by measuring the spectra of photons, electrons, and positrons up to 10 TeV. The BGO electromagnetic calorimeter (ECAL) is its main sub-detector for energy measurement. In this paper, the instrumentation and development of the BGO ECAL is briefly described. The calibration on the ground, including the pedestal, minimum ionizing particle (MIP) peak, dynode ratio, and attenuation length with the cosmic rays and beam particles is discussed in detail. Also, the energy reconstruction results of the electrons from the beam test are presented. [ABSTRACT FROM AUTHOR]

A Multi-purpose Time Projection Chamber prototype based on a resistive Micromegas technique has been proposed, designed and fabricated at China Spallation Neutron Source to measure the cross sections of neutron-induced light-charged particle emission reactions and fission reactions at the Back-n white neutron source. For the requirements of working stability with high voltage and high granularity of readout, the prototype is fabricated by applying a resistive Micromegas with high-density pixelated anode plane. In order to fully understand the process of charge spreading and signal induction on the anode plane covered by a resistive layer, a simulation method is developed and the energy correction function is then obtained, which can be used in the further energy correction in the experimental data analysis. Measured with a 55Fe X-ray source, the uniformity of gain and avalanche gap are specially analyzed by combining the simulated gas avalanche parameters with fitting of experimental data in which the parallel plate avalanche model is adopted. [ABSTRACT FROM AUTHOR]

A base board for photomultiplier tube (PMT) with multi-dynode readout has been developed for the BGO electromagnetic calorimeter (ECAL) of the Dark Matter Particle Explorer (DAMPE). In order to cover a high dynamic range of energy measurements, the signals are read out from different sensitive dynodes 2, 5, and 8 (Dy2, Dy5 and Dy8). The performance of this new type of base board is studied with a light-emitting diode (LED) system and cosmic rays. A wide measuring range from 0.5 to 1.0×10 5 MIPs can be achieved using the VA32 readout Application Specific Integrated Circuit (ASIC). [ABSTRACT FROM AUTHOR]

The original article can be found online at https://doi.org/10.1140/epja/s10050-021-00513-9. J. A (2021) 57:232 https://doi.org/10.1140/epja/s10050-021-00513-9 In the original article the name of the second author was incorrectly written as Yiwei Zhang. [Extracted from the article]

The presented work is dedicated to designing a readout ASIC used in CdZnTe-based gamma-ray spectrometers for radionuclide identification. In order to achieve high linearity in a large dynamic range, an active resistor is utilized. Since the active resistor induces high noise, a CR − (RC) 2 slow shaper with two different stages is proposed to suppress the noise. The integrating resistors in the first stage are implemented by transistors operating in triode region, while the active resistor is utilized in the second stage. A prototype chip with eight channels has been designed and fabricated in a standard commercial 1P6M 0.18 μ m CMOS process. The measured nonlinear error is less than 1% with the input charge ranging from − 1. 4 fC to − 56 fC, owning to the proposed slow shaper. Measured ENC is about 180 e − at input capacitance of 0 F with a slope of 7.7 e − /pF. [ABSTRACT FROM AUTHOR]

Accurate nuclear data measurements require a good background control of the experimental environment. At the back-streaming white neutron source (the so-called Back-n White Neutron Source) at China Spallation Neutron Source that is dedicated for nuclear data measurements, comprehensive shielding measures have been employed around the neutron beam line to reduce the neutron and γ backgrounds in the experimental end-stations. The basic background generated by the neutron beam without samples was simulated by the Monte Carlo method and correspondingly measured with a Bonner sphere spectrometer. The results show that the experimental measurements and simulations are generally in good agreement, and the neutron background level meets the requirements of the nuclear data experiments. Moreover, the γ background that was measured by using liquid BC501A and NaI scintillator detectors is mainly from the natural radioactivity of environment, and the beam induced γ background is very weak, whereas the natural γ background can be removed by a coincidence in time with beam bunch or be deducted by background measurement without samples. While the present measurements prove that the neutron/ γ basic background has been well controlled, the experimentalists can devote the effort to solve the background problem caused by the samples. [ABSTRACT FROM AUTHOR]

• Measured the 238U/235U fission cross section ratio in 1–20 MeV. • The nonuniformity of the neutron beam profile was considered. • Experimental uncertainties of 2.3%–3.6% in 1.4–20 MeV while 4.1%–11% in 1–1.4 MeV. • Provide information and data support in relevant nuclear data evaluation. Based on the China Spallation Neutron Source (CSNS) – Back-streaming white neutron source (Back-n WNS), the measurement of the U-238/U-235 fission cross section ratio in 1–20 MeV neutron energy region has been carried out by a multi-cell fast fission ionization chamber using the time-of-flight method. The measured resonance peaks of the 235U(n, f) reaction are in good agreement with those of the ENDF/B-8.0 database. The measured six groups of the U-238/U-235 fission cross section ratios in 1–20 MeV neutron energy region agree with those of the ENDF/B-8.0 database in trend, and the average discrepancies between experiment and database are from 1.9% to 2.6%. The relative experimental uncertainties are 2.3%–3.6% (1.4–20 MeV), and the measured data agree with those of database within experimental uncertainties at most energy points. The measured U-238/U-235 fission cross section ratio could provide information and data support in relevant nuclear data evaluation. [ABSTRACT FROM AUTHOR]

The Back-n white neutron beam line, which uses back-streaming white neutrons from the spallation target of the China Spallation Neutron Source, is used for nuclear data measurements. A Micromegas-based neutron detector with two variants was specially developed to measure the beam spot distribution for this beam line. In this article, the design, fabrication, and characterization of the detector are described. The results of the detector performance tests are presented, which include the relative electron transparency, the gain and the gain uniformity, and the neutron beam profile reconstruction capability. The result of the first measurement of the Back-n neutron beam spot distribution is also presented. [ABSTRACT FROM AUTHOR]

A white neutron source for nuclear data measurement has been built and put into operation on China Spallation Neutron Source (CSNS). We developeda beam monitor for real-time online monitoring of neutron flux on the white neutron source. The beam monitor work simultaneously with other nuclear data measurement detectors to provide neutron flux for data analysis. To minimize beam disturbance and reduce the background generated by the monitor, a structure in which neutron conversion layer and Si detectors are separated is employed: A 6LiF film with a mass thickness of 360 μ g/cm 2 was deposited on a 10 μ m aluminum foil and placed inside the beam line. Eight Si-detectors with a size of 20 × 20 mm2 were placed around the film outside the beam to maximize the reception of secondary particles from the conversion layer and to avoid neutron beam irradiation. The simulation of the beam monitor (layout, counting rate, neutron disturbance, etc.), construction and online performance are described in the paper. Good online performance of the monitor was achieved during the CSNS white neutron source flux calibration experiment in March, 2018: The counting rate for the beam line operating at Ф30 mm and Ф60 mm beam pattern modes was normalized to 100 kW proton beam power, and the result is consistent with the simulation. The total uncertainty of the normalized counting rate is less than 1%. Moreover, the measurement of neutron flux in low energy region below 10 keV of the white neutron source by the monitor is discussed. [ABSTRACT FROM AUTHOR]

China Spallation Neutron Source (CSNS) has been built and commissioned successfully in 2018 which is implemented by impinging 1.6 GeV protons onto a tungsten target with 25 Hz repetition frequency. An associated white neutron beam line exploiting the back-streaming neutrons, named Back-n, with a flight path of 55 m in endstation 1 (#ES1) and 76 m in endstation 2 (#ES2) was built mainly for nuclear data measurements. The Back-n beam line started running since the beginning of 2018 and the neutron energy spectrum was measured at the very beginning since it is an essential information for feasibility study and analysis of any measurement. In this paper, the measurement of the neutron energy spectrum of Back-n #ES2 is reported. The first result of the neutron flux from 1 eV to 100 MeV measured by a fission chamber based on the 235U(n, f) reaction is presented. The total neutron flux normalized to the proton beam power of 100 kW is 7. 03 × 10 6 neutrons/cm2/s. The results show a good agreement with that of the Monte Carlo simulation as well. [ABSTRACT FROM AUTHOR]