Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2018, Vol. 29 ›› Issue (4): 60 doi: 10.1007/s41365-018-0390-4

• NUCLEAR ELECTRONICS AND INSTRUMENTATION • Previous Articles    

Geant4 analysis and optimization of a double crystal phoswich detector for beta–gamma coincidence detection

Di Yang 1,2 • Zhe Cao 1,2 • Xin-Jun Hao 3,4 • Yi-Ren Li 3,4 • Shu-Bin Liu 1,2 • Chang-Qing Feng 1,2 • Qi An 1,2   

  1. 1 State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei 230026, China
    2 Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
    3 Division of Space Physics, University of Science and Technology of China, Hefei 230026, China
    4 CAS Key Laboratory of Geospace Environment, Hefei 230026, China
  • Received:2017-02-13 Revised:2017-04-13 Accepted:2017-04-19
  • Contact: Zhe Cao E-mail:caozhe@ustc.edu.cn
  • Supported by:

    This work was supported by the National Key Scientific Instrument and Equipment Development Projects of the National Natural Science Foundation of China (No. 41327802) and China Mars Project.

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Di Yang, Zhe Cao, Xin-Jun Hao, Yi-Ren Li, Shu-Bin Liu, Chang-Qing Feng, Qi An . Geant4 analysis and optimization of a double crystal phoswich detector for beta–gamma coincidence detection.Nuclear Science and Techniques, 2018, 29(4): 60     doi: 10.1007/s41365-018-0390-4

Abstract:

Readout electronics is developed for a prototype time-of-flight (TOF) ion composition spectrometer for in situ measurement of the mass/charge distributions of major ion species from 200 to 100 keV/e in space plasma. By utilizing a constant fraction discriminator (CFD) and time-to-digital converter (TDC), challenging dynamic range measurements were performed with high time resolution and event rates. CFD was employed to discriminate the TOF signals from the micro-channel plate and channel electron multipliers. TDC based on the combination of counter and OR-gate delay chain was designed in a highreliability flash field programmable gate array. Owing to the non-uniformity of the delay chain, a correction algorithm based on integral nonlinearity compensation was implemented to reduce the time uncertainty. The test results showed that the electronics achieved a low timing error of < 200 ps in the input range from 35 to 500 mV for the CFD, and a time resolution of ∽ 550 ps with time uncertainty <180 ps after correction and a time range of 6.4 μs for the TDC. The TOF spectrum from an electron beam experiment of the impacting N2 gas further indicated the good performance of this readout electronic.

Key words: Space plasma, Ion composition analyzer, Readout electronics, Constant fraction discriminator, Time-to-digital converter