慢正电子寿命谱仪电子学系统原型机研制

A prototype of electronic system for low-energy positron lifetime spectroscopy

我们采用低能脉冲调制正电子束技术设计了一套慢正电子寿命谱仪装置。此装置要求其脉冲调制系统能够给出一路边沿<2ns、宽度≈7ns、幅度>5V的50MHz脉冲信号和两路频率分别为50MHz、200MHz的正弦信号,同时要求其时间测量系统能达20ns的量程和74ps的测量精度。本文介绍了脉冲调制和时间测量系统原型机设计及各项主要指标的测试。结果表明,电子学系统原型机已达到谱仪系统设计指标要求。

An apparatus of low-energy positron lifetime spectroscopy using beam pulsing method has been established at the Nuclear Solid State Physics Laboratory, University of Science and Technology of China. It requires of a beam-pulsing subsystem capable of generating three signals： a 50 MHz signal in amplitude of 〉5 V, edge time of 〈2 ns and pulse width of about 7 ns, and another two sine signals at 50 MHz and 200 MHz. A time measuring subsystem capable of measuring the life time within 20 ns at 74 ps resolution is required, too. A prototype design of the two subsystems is presented in this article. Test results of the prototype show that all requirements by the low-energy positron lifetime spectroscopy have been met.