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  • Design of a 0.1pA-Level Microcurrent Transimpedance Amplifier Circuit Based on Domestic Components

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-07-09

    Abstract: [Background]: In nuclear radiation detection, detectors that output microcurrents commonly use the ADA4530 chip, designed and manufactured by Analog Devices, Inc. (ADI), to construct transimpedance amplifier circuits for measuring microcurrent signals. [Purpose]:To address the issue of dependency on foreign technology in the field of weak current measurement and to achieve the goal of designing weak current amplification circuits using entirely domestic components. [Methods]:The circuit design uses entirely domestic components and is based on the I-V conversion method for transimpedance amplification. [Results]: After careful design considerations and the selection of domestic components, a microcurrent transimpedance amplifier circuit with an output voltage range of 0 to 10V was successfully constructed. [Conclusions]:Testing showed that with a feedback resistor of 100GΩ, the linear fit for an input current of 0.1 to 100pA had an R2value of 0.99998, a relative deviation of less than 0.235%, and a noise peak-to-peak value of 0.057pA. When the feedback resistor is 10GΩand the input current is 1pA, the temperature drift over a range of -10℃to 80℃ is less than 0.042pA/℃. When the feedback resistor is 10GΩand the input is left floating, the output drift is less than 0.2662pA during a 6-hour stability test at room temperatu

  • Design of mixed-mode readout electronics for large-area SiPM arrays

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-07-04

    Abstract: [Background]: Accurate localization of radioactive material is essential for finding "orphan sources", decontaminating and decommissioning nuclear facilities, and optimizing radiation protection. Silicon Photomultiplier (SiPM) has been widely used in scintillator detection systems. [Purpose]: To realize a low-cost large-field-of-view high-resolution detection system, a mixed-mode readout circuit combining a resistive network, a preamplifier circuit and an ASIC module is designed and verified. [Methods]: Firstly, by changing the rising edge, falling edge, pulse width and amplitude of the input pulse, the requirements of the A5202 module on the input pulse are experimentally measured to achieve the best data acquisition performance. When the rise time of the input pulse is less than 150ns and the amplitude is greater than 20mV, the data measured by the A5202 module has less noise and higher energy resolution. Then simulation is carried out by Multisim software. This simulation analyzes in detail the relationship between the resistor resistance and the rise time of the output signal. It determines the optimum resistor resistance value for the symmetric charged division circuit. The rise time of the output signal is relatively minimized when the resistance value of the first stage shunt resistor is 1 kOhm and the resistance value of the second stage shunt resistor is 100 ohms. Finally, in order to simultaneously take into account the characteristics of the output signal of the symmetric charged division circuit and the requirements of the A5202 module for the input signal, an inverse proportional operational amplifier circuit with the AD8066ARZ chip as the core is designed. It is used to connect the A5202 module and the symmetric charged division circuit. After the scintillator detection system was assembled, the stability of the system was examined, then the RMS noise of the system was measured, and finally the positioning accuracy of the system was examined. In order to improve the robustness of localization, the localization threshold was first calibrated with a single LYSO. The LYSO was further replaced with an array of Cerium-doped Gadolinium Aluminum Gallium Garnet (GAGG(Ce)) crystals and the calibration results were examined with a 241Am source. [Results]: The test results show that the readout circuit has an RMS noise of about 3 mV, retains the energy and position information of the signal well, and has an average energy resolution of about 12.13%. [Conclusions]: The readout circuit designed in this paper simplifies the 64-channel SiPM signal into 4 channels, and reduces the number of detector output signal channels by 16 times. A single ASIC module can read out 1024 SiPMs at the same time, which can greatly reduce the cost of readout for large-area SiPM arrays.

  • Simulation and experimental comparison of the performance of four-corner-readout plastic scintillator muon-detector system

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-07-04

    Abstract: Cosmic-ray muons are highly penetrating background-radiation particles found in natural environments. In this study, we develop and test a plastic scintillator muon detector based on machine-learning algorithms. The detector underwent muon position-resolution tests at the Institute of Modern Physics in Lanzhou using a mul tiwire drift chamber (MWDC) experimental platform. In the simulation, the same structural and performance parameters were maintained to ensure the reliability of the simulation results. The Gaussian process regression (GPR) algorithm was used as the position-reconstruction algorithm owing to its optimal performance. The re sults of the Time Difference of Arrival algorithm were incorporated as one of the features of the GPR model to reconstruct the muon hit positions. The accuracy of the position reconstruction was evaluated by comparing the experimental results with Geant4 simulation results. In the simulation, large-area plastic scintillator detectors achieved a position resolution better than 20 mm. In the experimental-platform tests, the position resolutions of the test detectors were 27.9 mm. We also analyzed factors affecting the position resolution, including the crit ical angle of the total internal reflection of the photomultiplier tubes and distribution of muons in the MWDC. Simulations were performed to image both large objects and objects with different atomic numbers. The results showed that the system could image high- and low-Z materials in the constructed model and distinguish objects with significant density differences. This study demonstrates the feasibility of the proposed system, thereby providing a new detector system for muon-imaging applications.

  • Research on Calculation Methods of Important Parameters in Radioactivity Measurement

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-06-28

    Abstract: Abstract Background : Radioactivity measurement is widely used in various fields of nuclear technology application. The measurement uncertainty, confidence interval and detection limit are important parameters of radioactivity measurement. Different calculation methods may get different results, and the calculation results directly affect some important and relevant decisions. Purpose : It is important to analyze whether the calculation method is used properly.  Methods : The important parameters of α particle activity concentration measurement were studied by partial derivative method and Monte Carlo method. In this study, based on the measurement of α activity concentration, the sources of uncertainty for the measurement results were analyzed. The measurement uncertainty, confidence limits, decision threshold and detection limit of α particle activity concentration under different input modes were derived and calculated by partial derivative and MC methods. Results : The results show that when the input uncertainty is higher than 10%, the relative deviation between confidence interval and uncertainty results obtained by the two calculation methods is greater than 15%. When the relative uncertainty of the input is small, the detection limit is about 2 times of the decision threshold. Conclusions : The partial derivative method is widely used, but it does not consider the probability distribution of the input, and it is not suitable for complex and special input models. Under the circumstances, Monte Carlo method can be used to obtain more reliable calculation results. The two approaches can be applied in complementary ways.
     

  • Research on simulation calculation method of CdZnTe detection efficiency based on ideal mode

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-06-28

    Abstract: [Background] There is an efficiency loss in calculating the detection efficiency of CdZnTe detector using the traditional Monte Carlo method. [Purpose] Calculate the efficiency of CdZnTe detectors using sourceless efficiency calibration technique. [Methods] A method for calculating the detection efficiency of CdZnTe based on the ideal model (only considering the interaction between photons and the detector crystal and structural materials) was proposed. [Results] A 152Eu standard source sample was used to verify the reliability of the calculation method, the results show that the deviation between the calculated results and the reference values is less than 5%. [Conclusions] This method does not need to consider the complex process of incomplete carrier collection in CdZnTe crystal, and can obtain reliable efficiency calculation results by simple operation process.

  • CMOS direct conversion X-ray detector coupled with fluorinated liquid

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-06-25

    Abstract: X-ray detectors show potential applications in medical imaging, materials science, and nuclear energy. To achieve high detection efficiency and spatial resolution, many conventional semiconductor materials, such as amorphous selenium, cadmium telluride zinc, and perovskites have been utilized in direct conversion X-ray detectors. However, these semiconductor materials are susceptible to temperature-induced performance degra-dation, crystallization, delamination, uneven lattice growth, radiation damage, and high dark current. This study explores a new approach by coupling an FC40 electronic fluorinated liquid with a specialized high-resolution and high-readout-speed complementary metal-oxide-semiconductor (CMOS) pixel array, specifically the Top-metal II− chip, to fabricate a direct conversion X-ray detector. The fluorinated liquid FC40 (molecular formula: C21F48N2) is an electronic medium that is minimally affected by temperature and displays no issues with uniform conductivity. It exhibits a low dark current and minimal radiation damage and enables customizable thickness in X-ray absorption. This addresses the limitations inherent in conventional semiconductor-based de-tectors. In this study, simple X-ray detector imaging tests were conducted, demonstrating the excellent coupling capability between FC40 electronic fluorinated liquid and CMOS chips by the X-ray detector. A spatial reso-lution of 4.0 lp/mm was measured using a striped line par card, and a relatively clear image of a cockroach was displayed in the digital radiography imaging results. Preliminary test results indicated the feasibility of fabricating an X-ray detector by combining FC40 electronic fluorinated liquid and CMOS chips. Owing to the absence of issues related to chip-material coupling, a high spatial resolution could be achieved by reducing the chip pixel size. This method presents a new avenue for studies on novel liquid-based direct conversion X-ray detectors.

  • Geant4 simulation study of β-γ coincidence detector for 41Ar measurement

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-06-03

    Abstract: [Background] As one of the main radionuclides released into the environment by the operation of reactors and accelerators, the measurement of 41Ar activity concentration is of great significance for ensuring public health. In the field of radioactive gas measurement, the β-γ coincidence method is widely used because it can significantly reduce the background and improve the sensitivity of the detector. However, at present, there is little study on β-γ coincidence detectors for 41Ar measurement. [Purpose] In order to realize high sensitivity measurement of 41Ar, a detector composed of plastic scintillator and CsI(Tl) scintillator is designed, and an optimization method of detector structure based on minimum detectable activity concentration (MDC) is proposed. [Methods] The optimization process of the detector is realized based on Geant4 simulation. Firstly, the energy deposition of β-rays in CsI(Tl) with different thicknesses of BC404 was simulated. Secondly, the peak efficiency of 1293.6 keV γ-ray in CsI(Tl) scintillator with different thicknesses was simulated. Thirdly, assuming that the sampling time of argon is proportional to the volume of the detector’s gas chamber, by simulating with different gas chamber volume, the comprehensive effects of β detection efficiency, γ peak efficiency, gas chamber volume and sampling time on MDC were analyzed. Finally, the influence of measurement time on MDC under different background counting rates was analyzed. [Results] It is concluded that the particle number percentage of the energy deposited by 41Ar decay β-rays in CsI(Tl) is about 0.74% when the thickness of BC404 is 3 mm. The γ peak efficiency increases with the increase of CsI(Tl) scintillator thickness. With the argon sampling rate of 600 mL/h, the optimal detector size parameters that minimize MDC are completely determined. When the background count rate is 1×10-3 ~1 cps, the recommended measurement time for 41Ar is about 200 minutes. [Conclusions] When the measurement time is 200 minutes, the sample cooling time is 30 minutes and the background count rate is 5×10-3 cps, the MDC of the optimized β-γ coincidence detector for 41Ar measurement is about 1.7 Bq/m3.

  • Boron shielding design for neutron and gamma detectors of a pulsed neutron tool

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-05-27

    Abstract: Shielding material is critical for downhole pulsed neutron tool design as it directly influences the accuracy of formation measurements. A well-designed shield configuration ensures that the response of the tool is maximally representative of formation without being impacted by tool and borehole environment. This manuscript investigates the effects of boron-containing materials on neutron and gamma detectors based on a newly designed logging-while-drilling tool, which is currently undergoing manufacturing process. As boron content increases, its ability to absorb thermal neutrons significantly enhances. Through simulation, it is proven that boron carbide (B4C) can be used as an effective boron shielding material for thermal neutrons and therefore employed in this work. To shield against thermal neutrons migrating from mud pipes, the optimal shielding thicknesses for near and far neutron detectors are determined to be 5mm and 4mm. For an example, at a porosity of 25 p.u., the near neutron sensitivity shows a 5.6% increase in response. Furthermore, in order to shield capture gamma generated by thermal neutrons once they enter tool from the mud pipe and formation, the internal and external shields for the gamma detector is evaluated.  Results show internal shield needs 75% boron content while the external shield is of 14.2mm thickness and 25% boron content to minimize tool effect.

  • Development of a MWDC prototype of the CSR external-target experiment

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-05-21

    Abstract: The cooling storage ring (CSR) external-target experiment (CEE) is a spectrometer used in construction to study the properties of nuclear matter in high-baryon density regions at the Heavy-Ion Research Facility in Lanzhou (HIRFL). This study presents the design, simulation, manufacturing, and testing of a half-size prototype of a multi-wire drift chamber (MWDC) for the CEE. First, the performance of the MWDC connected to home-made electronics was simulated. The results demonstrated that an energy resolution of 18.5% for 5.9-keV X-rays and a position resolution of 194 um for protons can be achieved by the current design. Because the size of the largest MWDC reached 176 × 314 cm, a set of 98 × 98 cm prototypes was built using the new techniques. The positioning accuracy of the anode wires in this prototype exceeded 20 um. After optimization using commercially available electronic devices, the prototype achieved an energy resolution of 19.7% for a 55Fe X-ray source. The CEE-MWDC detector and electronics were simultaneously tested. An energy resolution of 22% was achieved for the 55Fe source; the track residuals were approximately 330 um for the cosmic rays. The results demonstrate that the current design and techniques meet the requirements of the CEE-MWDC array.

  • Preamplifier design and analysis for dual output silicon photomultiplier

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-05-21

    Abstract: [Background]: In order to apply in different scenarios of silicon-photomultiplier-coupled scintillator detector, Preamplifiers need to fulfill different requirements. [Purpose]: This study aims to design high-bandwidth, low-noise preamplifiers to cater for different output modes of silicon-photomultiplier-coupled scintillator detector. [Methods]: Based on OPA855 and consideration of bandwidth and noise, a transimpedance amplifier (TIA) and a voltage feedback amplifier (VFB) were designed. The amplifier circuits were simulated and analysed using PSpice for TI software to obtain circuit parameters. Finally, the signal response and noise baseline level were measured, and signals of 241Am source were analysed using a silicon-photomultiplier-coupled Cerium-doped Gadolinium Aluminum Gallium Garnet (GAGG(Ce)) detector. [Results and Conclusions]: These preamplifiers have good gain stability. TIA's bandwidth is 101MHz lower than VFB's 381MHz, but its baseline noise level σnoise≅ 448.32μV is better than the VFB's σnoise≅ 680.96μV . In addition, TIA is suitable for energy measurements and small-area SiPM applications, while VFB is more suitable for time measurements and large-area SiPM arrays.

  • Analysis of Gamma Influencing Factors in Neutron Gamma Integration with Drilling

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-05-18

    Abstract: [Background] Due to the independence of traditional neutron and density measurement instruments, in order to improve the safety and efficiency of geological information.[Purpose]Integrate the design of existing neutron and density instruments to merge the neutron density components And analyze in detail the gamma influencing factors in integrated design.[Methods] In order to investigate the influence of the distance between neutron and gamma sources on detector measurements, Monte Carlo simulation was used to analyze detector counts and energy spectra at different distances between neutron and gamma sources, and the results were validated under different rock and density conditions.[Results] Keeping the true instrument source distance, neutron source intensity and other parameters unchanged, the neutron radiation field has no significant impact on the density measurement results when the neutron and gamma sources are 410mm apart, and the absolute error of the inversion density is less than 0.015g/cm3. By changing the neutron source intensity to explore the impact of source intensity on integrated research, and simulating multiple neutron sources with different intensities, it can be found that as the neutron source intensity gradually increases, the optimal distance between the neutron source and gamma source gradually increases and presents a quadratic function relationship.[Conclusions] Based on such findings, the distance between the two sources can be flexibly determined based on the strength of the neutron source, enabling rapid performance evaluation of on-site instrument testing and providing theoretical guidance for integrated design.

  • Simulation study of a wide energy range neutron beam monitor for TMSR-PNS

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-05-11

    Abstract: [Background]:In response to the issue of neutron beam instability or misfire during the operation of the Thorium Molten Salt Reactor with a Particle and Neutron Source (TMSR-PNS), it is necessary to design and develop a neutron beam monitor with high counting rate, low neutron beam perturbation, and high neutron/gamma discrimination capability. [Purpose]: This study aims to investigate the influence of structural parameters of neutron beam monitors on their performance. [Methods]: Firstly, considering that the energy spectrum of TMSR-PNS mainly focuses on the energy range from thermal neutrons to 1 MeV, LiF was chosen as the neutron conversion material. The SRIM program was used to calculate the range of secondary charged particles in the neutron conversion layer and the scintillator, providing a preliminary reference for determining the thickness. Subsequently, a relevant physical model was established using Geant4, irradiating with neutrons and gamma rays of different energies. Finally, the simulation results were used to determine the effects of parameters such as neutron conversion layer thickness, scintillator thickness, metal shell, and the placement angle of the PMT on the detector performance. [Results]: The neutron conversion layer thickness of the scintillator is relatively suitable at about 2 µm for intrinsic detection efficiency. With a scintillator thickness of 2 mm and a discrimination threshold of 0.1 MeV, the detector demonstrates insensitivity to gamma rays. Additionally, by comparing the impact of different shell materials on electron generation by gamma rays, iron, which produces fewer electrons, was selected as the shell material. [Conclusions]: The influence of detector structural parameters on detector performance obtained in this study is of guiding significance, providing theoretical reference for the subsequent preparation of detectors.

  • Optimized design and measurement verification of ultra-slim X-ray density logging tool

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-05-07

    Abstract: [Background]: With the deepening of oil and gas exploration, the research on the design and measurement methods of X-ray density logging tools, as a new generation of controllable sources, has attracted widespread attention. [Purpose]: Based on the prototype of ultra-slim gamma logging tool, the gamma source is replaced with an X-ray source. [Methods]: The specific content includes: 1) simulating and matching the energy spectrum of the X-ray source; 2) comprehensively guiding the forward design of the key parameters of the tool through indicators such as detection efficiency, formation sensitivity, and detection depth; 3) conducting X-ray density measurements based on the multivariate forward and inverse modeling method, and comparing them with gamma density logging results. [Results]: The results show that when the short and long-spaced detectors’ source distances of the X-ray tool are set to 110mm and 290mm, it can achieve comparable or even higher detection indicators compared to gamma tool. Compared with gamma logging, X-ray logging has better formation sensitivity, vertical resolution, and formation measurement accuracy. The formation density and Pe are within 0.015g/cm3 and 0.2b/e, respectively. Especially in the barite mudcake scenario, the accuracy of Pe measurement has been improved by 47%. [Conclusions]: These studies provide reference for tool forward design and X-ray density measurement.

  • Optimized design and measurement verification of ultra-slim X-ray density logging tool

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-05-06

    Abstract: [Background]: With the deepening of oil and gas exploration, the research on the design and measurement methods of X-ray density logging tools, as a new generation of controllable sources, has attracted widespread attention. [Purpose]: Based on the prototype of ultra-slim gamma logging tool, the gamma source is replaced with an X-ray source. [Methods]: The specific content includes: 1) simulating and matching the energy spectrum of the X-ray source; 2) comprehensively guiding the forward design of the key parameters of the tool through indicators such as detection efficiency, formation sensitivity, and detection depth; 3) conducting X-ray density measurements based on the multivariate forward and inverse modeling method, and comparing them with gamma density logging results. [Results]: The results show that when the short and long-spaced detectors’ source distances of the X-ray tool are set to 110mm and 290mm, it can achieve comparable or even higher detection indicators compared to gamma tool. Compared with gamma logging, X-ray logging has better formation sensitivity, vertical resolution, and formation measurement accuracy. The formation density and Pe are within 0.015g/cm3 and 0.2b/e, respectively. Especially in the barite mudcake scenario, the accuracy of Pe measurement has been improved by 47%. [Conclusions]: These studies provide reference for tool forward design and X-ray density measurement.

  • Construction and performance test of charged particle detector array for MATE

    Subjects: Physics >> Nuclear Physics Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-04-28

    Abstract: A charged particle array, named MATE-PA, which serves as an auxiliary detec#2;tor system to the Multi-purpose Active-target Time projection chamber for nuclear astrophysical and exotic beam Experiments (MATE) has been con#2;structed. The array is composed of twenty single-sided strip-silicon detectors, covering around 10% of the solid angle. It is dedicated for the detection of reaction-induced charged particles which penetrate the MATE active volume. The performance of MATE-PA has been experimentally studied using an alpha source, and a 36-MeV 14N beam injected into the chamber of MATE, filled with a mixture gas of 95% 4He and 5% CO2 under the pressure of 500 mbar, at the Radioactive Ion Beam Line in Lanzhou (RIBLL). The results demonstrate good separation of light charged particles with the forward double-layer silicon detectors of MATE-PA. The energy resolution of the Si detectors was deduced to be about 1% (σ) for an energy loss of about 10 MeV by the α particles. The inclusion of MATE-PA helps improve particle identification, and increases the dynamic range for the kinetic energy of charged particles, in particular that of α particles up to about 15 MeV.

  • Development of ground test system for silicon charge detector beam prototype

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-04-26

    Abstract: [Background]: The High Energy Cosmic Radiation Detection Facility (HERD) is a flagship scientific instrument planned to be deployed on the Chinese Space Station, aiming to indirectly detect dark matter, accurately measure cosmic ray compositions, and conduct surveys of high-energy gamma-ray emissions. Among them, the silicon charge detector is one of the key components of HERD, used to measure the charges of cosmic rays ranging from hydrogen to nickel.[Purpose]: To validate and analyze the charge measurement capability of silicon charge detectors, a ground test system was designed for a prototype silicon charge detector beamline.[Methods]: The ground test system utilizes Xilinx's ZYNQ UltraScale+ MPSoC chip as the control chip, achieving functions including LVDS data reception, encoding and decoding, RS-422 control, and gigabit Ethernet data reception and storage. [Results]: The silicon charge detector beamline prototype participated in heavy ion beam experiments at the European Nuclear Research Center, with the ground test system collecting 100G of experimental data during the beamline experiments. [Conclusions]: The Ground Test system demonstrated good stability and reliability during the beam experiment, providing important technical support and data foundation for subsequent experiments of the HERD project's silicon charge detector.

  • Design of IMPix-N1, a silicon pixel detector readout chip for multi-dimensional measurements

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-04-19

    Abstract:  In order to meet the demand for elementary particle detection and analysis in high-energy physics experiments, modern pixel detector increasingly tends to pursue the performance requirements of low power consumption, high resolution, and high readout efficiency.This paper describes a silicon pixel detector digital-analogue hybrid readout chip named IMPix-N1. The pixel array consists of 16 rows × 16 columns of pixel units, each with an area of 100 μm × 100 μm, and the pixel array part is controlled by a 1-row × 8-column pixel unit as a superpixel, which has a common logic circuit. The chip has a pixel configuration mode and three pixel address readout modes of operation, which realises the measurement, storage and readout of the time, energy and position information of the hitting particles. The time-to-digital conversion circuit (TDC) can simultaneously measure and record the arrival time TOA and the over-threshold time TOT of the particles, with a time measurement accuracy of 5 ns. The IMPix-N1 is suitable for particle detection experiments requiring high temporal and spatial resolution as well as fast data acquisition capabilities.The chip as a whole is designed using the digital-on-top methodology in TSMC 180nm process. The design is simulated to verify the digital circuit of the pixel unit, the super pixel control circuit and the peripheral digital circuits, and the before and after simulation results are consistent and meet the design requirements.

  • Development of a capacitance-integrating radioactivity meter

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-04-07

    Abstract: Background Rapid and accurate measurements of radionuclide activities in the field play an important role in radiological medical diagnosis. Purpose This study aims to develop a capacitance-integrated activity meter. Methods A circuit structure of the capacitive-integral type was adopted, and a low-noise preamplifier circuit was designed. The designed structure was matched with high-precision signal acquisition and processing circuit to successfully develop a weak current measurement circuit, achieving weak current measurements ranging from 20 fA to 10 μA. Results The test results show that the repeatability of the proposed radioactivity meter is consistent with the performance of the commercial RM-905A, with a background lower than 0.065 MBq, a repeatability not exceeding 0.84%, and an instability of 1.94%. Conclusions We designed a capacitive integral weak-current preamplifier and built a prototype radioactivity meter device.

     

  • Research on distributed data acquisition software for high frame rate area detectors

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-03-28

    Abstract: Background : High frame rate area detectors play a crucial role in experiments such as coherent diffraction imaging and serial crystallography conducted at the Shanghai HIgh repetitioN rate xfel and Extreme light facility (SHINE). Their high data transmission rates and extensive processing needs pose grand challenges for the data acquisition system. Purpose : To support the continuous operation of a megapixel detector working at 10kHz frame rate, the DAQ software must deliver a data throughput of no less than 20 GB·s-1. Methods : In order to meet the requirement of high throughput data readout and processing of many detector modules, this research developed a distributed DAQ software based on C++ language, which is designed to run on multiple servers in parallel. This research adopts a memory based MapReduce-like method to realize the online event reconstruction. And also tested the Bitshuffle+LZ4/ZSTD data compression algorithm. Results : The software successfully achieved a throughput of 20GB·s-1 for data transmission and event reconstruction by using 4 DAQ servers. It also includes the implementation and testing of various functions, such as data calibration, lossless compression, and the distributed operation capability of the whole system. Conclusions : This research will provide essential support for some related experiments using area detectors which require high throughput data acquisition.

  • Experimental Study on the Laser and Radiation Source Detection of Working Gas Properties in Detectors

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-03-20

    Abstract: The properties of working gases in gas detectors,such as the average ionization energy,Fano factor,and drift velocity,have a significant impact on the preliminary simulation,parameter design,and trajectory reconstruction of the detectors.SeF6,as the target working gas in domestic neutrinoless double beta decay experiments,has unknown parameters that need to be investigated.To study the relevant parameters of this gas,a measurement scheme was designed and the accuracy and reliability of the experimental plan were tested using Ar/CH4=90/10(P10) as the working gas.In the experiment,the average ionization energy of P10 was measured using a grid ionization chamber with an 𝛼 source,yielding a value of 27.10±0.04 eV,and the Fano factor was determined to be 0.175±0.001 when the energy resolution reached 0.91% after subtracting noise through calibration electronics.Additionally,the drift velocity was measured using a 266 nm laser and a time projection chamber,and the results were consistent with the Garfield++ simulation results.The experimental results indicate the feasibility of the measurement scheme and demonstrate high reliability of
    the measurement results.This provides a solid foundation for further research on the properties of SeF6.