Readout electronics of a prototype spectrometer for measuring low-energy ions in solar wind plasma

Readout electronics is developed for a prototype spectrometer for in situ measurement of low-energy ions of30 e V/e–20 ke V/e in the solar wind plasma.A low-noise preamplifier/discriminator(A111F) is employed for each channel to process the signal from micro-channel plate(MCP) detectors.A high-voltage(HV) supply solution based on a HV module and a HV optocoupler is adopted to generate a fast sweeping HV and a fixed HV.Due to limitation of telemetry bandwidth in space communication,an algorithm is implemented in an FPGA(field programmable gate array) to compress the raw data.Test results show that the electronics achieves a 1 MHz event rate and a large input dynamic range of 95 p C.A slew rate of 0.8 V/ls and an integral nonlinearity of 0.7-LSB for the sweeping HV,and a precision of less than 0.8 % for the fixed HV are obtained.A vacuum beam test shows an energy resolution of 12 ± 0.7 % full width at half maximum(FWHM) is achieved,and noise counts are less than10/sec,indicating that the performance meets the physical requirement.

Upgrade to the front-end electronics of the BESⅢ muon identification system

Resistive Plate Chambers(RPCs) built from a new type of Bakelite developed at Institute of High Energy Physics(IHEP),Chinese Academy of Sciences have been used in the BESⅢ Muon identification system for several years without linseed oil coating,but characteristic aging performances were observed.To adapt to the RPCs in the aging state,the front-end electronics have been upgraded by enhancing the front-end protection,improving the threshold setting circuit,and separating power supplies of the comparator and the field programmable gate array(FPGA).Improvements in system stability,front-end protection and threshold consistency have been achieved.In this paper,the system upgrade and the test results are described in detail.

Radiation tolerance studies on the VA32 ASIC for DAMPE BGO calorimeter

The Dark Matter Particle Explorer(DAMPE) is being constructed as a scientific satellite to observe high energy cosmic rays in space.As a crucial detector of DAMPE,the BGO calorimeter consists of 1848 PMT dynode signals which bring difficulties in front-end electronics on the space-limited and power-limited satellite platform.To overcome the challenge,a low-noise,low-power and high-integration ASIC chip,named VA32HDR14.2,is taken into account.In order to evaluate the radiation tolerance of the chip in space radiation environment,both single event effect(SEE) and total ionizing dose(TID) tests were performed.The SEE test result shows that the effective linear energy transfer(LET) threshold of single event latch-up(SEL) of the chip is around 23.0 MeVcm^2/mg,which is relatively sensitive,thus protection methods must be taken in the electronics design.The TID test result shows that the TID performance of the chip is higher than 25 Krad(Si),which satisfies the design specification.

General transmission method based on PXI platform for physical experiments

In this paper,a general method of data transmission system design on PXI platform is proposed.It can be used in readout system design for physical experiments.It aims at providing reusable and general interfaces for customized design of PXI while maintaining the transmission performance.It has three main features:(1)universal logic hardware interface,(2)ethernet based socket software interface,and(3)specific and simple data transmission protocol.Data transmission on PXI bus can be realized with the said two universal interfaces coordinated by this specific protocol.Test shows that this method is feasible and stable.This method can be easily reused in readout system designs for different experiments.

Clock and data alignment scheme for readout electronics prototype of PandaX-nT

Purpose This work proposes a clock and data alignment scheme for the readout electronics system of the future PandaX-nT dark matter detection experiments.Since the waveform information of the photomultiplier signal is obtained by accumulating all acquisition channels of the front-end digitization module(FDM),it is required that each FDM acquisition channel should be synchronized.Methods The readout electronics system is composed of a clock distribution module,64 FDMs,and 4 data acquisition(DAQ)modules.The multi-board synchronous acquisition circuit can provide the same REF CLOCK and SYSREF signal for multiple FDMs boards to ensure the alignment of the sampled data collected by the analog-to-digital converter.The data aggregation circuit can ensure that the sampled data of multiple FDM boards are aligned with each other when they are aggregated to the DAQ board.Results and conclusions The functional verification test results show that the synchronization between the prototype electronics channels is less than 80 ps,thus enabling to meet the requirements of the readout electronics prototype of PandaX-nT.

A prototype scalable readout system for micro-pattern gas detectors

A scalable readout system （SRS） is designed to provide a general solution for different micro-pattern gas detectors in various applications. The system mainly consists of three kinds of modules： the ASIC card, the adapter card and the front-end card （FEC）. The ASIC cards, mounted with particular ASIC chips, are designed for receiving detector signals. The adapter card is in charge of digitizing the output signals from several ASIC cards. The FEC, edged-mounted with the adapter, has field-programmable gate array （FPGA）-based reconfigurable logic and I/O interfaces, allowing users to choose different ASIC cards and adapters for different experiments, which expands the system to various applications. The FEC transfers data through Gigabit Ethernet protocol realized by a TCP processor （SiTCP） IP core in FPGA. By assembling a flexible number of FECs in parallel through Gigabit Ethernet, the readout system can be tailored to specific sizes to adapt to the experiment scales and readout requirements. In this paper, two kinds of multi-channel ASIC chip, VA140 and AGET, are applied to verify the scalability of this SRS architecture. Based on this VA140 or AGET SRS, one FEC covers 8 ASIC （VA140） cards handling 512 detector channels, or 4 ASIC （AGET） cards handling 256 detector channels, respectively. More FECs can be assembled in crates to handle thousands of detector channels.

First results of the low energy ion spectrometer onboard a Chinese geosynchronous satellite

A Chinese geosynchronous satellite was launched on June 23,2020.It carried a plasma detection package to monitor the space environment around the orbit.Here we report the inflight performance of a low energy ion spectrometer(LEIS),one of the primary instruments in the plasma detection package,and its initial observations in flight.Benefiting from the state-of-the-art design of a top-hat electrostatic analyzer cooperated with angular scanning deflectors,three-dimensional measurement of ions in space with a large field of view of 360°×90°and a wide energy range from 50 eV to 25 keV per charge has been achieved.The differential energy flux spectra of ions around the orbit have shown clear signatures of surface charging and storm/substorm ion injections.The occurrence of surface charging could be caused by the lack of photoemission at the Earth's eclipse(near the midnight)or the storm energetic electron injection at the dawn sector.The present results demonstrated a good performance of the LEIS payload in flight for monitoring the space ion environment around the orbit.In situ measurements of the LEIS payload provide us an opportunity to understand the magnetospheric ion dynamics and forecast the associate space weather impacts.

A low-energy ion spectrometer with half-space entrance for three-axis stabilized spacecraft

A low-energy ion spectrometer(LEIS) for use aboard three-axis stabilized spacecraft has been developed to measure ion energy per charge distribution in three-dimensional space with good energy-, angular-and temporal-resolutions. For the standard top-hat electrostatic analyzer used widely in space plasma detection, three-axis stabilized spacecraft makes it difficult to obtain complete coverage of all possible ion arrival directions. We have designed angular scanning deflectors supplementing to a cylindrically symmetric top-hat electrostatic analyzer to provide a half-space field of view as 360°×90°(–45°–+45°), and fabricated the LEIS flight model for detecting magnetospheric ions in geosynchronous orbit. The performance of this payload has been evaluated in detail by a series of simulation and environmental tests, and the payload has also been calibrated through laboratory experiments using a low-energy ion source. The results show that capabilities of the LEIS payload are in accordance with the requirements of a magnetospheric mission.

Study of CdMoO4 crystal for a neutrinoless double beta decay experiment with ^116Cd and ^100Mo nuclides

The scintillation properties of a CdMoO4 crystal have been investigated experimentally.The fluorescence yields and decay times measured from 22 K to 300 K demonstrate that CdMoO4 crystal is a good candidate for an absorber for a bolometer readout,for both heat and scintillation signals.The results from Monte Carlo studies,taking the backgrounds from 2ν2β of^100 42Mo ^116 48Cd） and internal trace nuclides ^214Bi and ^208Tl into account,show that the expected sensitivity of a CdMoO4 bolometer for neutrinoless double beta decay experiments with an exposure of 100kg·years is one order of magnitude higher than those of the current sets of the limT1/2^0νββ of ^100 42Mo and ^116 48Cd.