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一种高性能多极双维位置灵敏平行板雪崩计数器(multi-plate parallel plate avalanchecounter,MPPAC)在兰州中能重离子加速器放射性次级束流线(radioactive ion beam line in lanzhou,RIBLL)上被应用,由二次雪崩带来的高增益使它很适合探测较高能量的较轻粒子,它主要由1个中心阳极,x,y位置栅极和2个阴极组成,位置信号由x,y位置栅极采用电荷分除法读出,使用异丁烷工作气体,气压650Pa,阳极+400V,阴极-350V时,对于α粒子位置分辨为0.55mm(半高全宽度,fwhm),位置线性色散远好于±0.2mm,探测效率大于99.2％,同时,也研究了位置分辨与阳极、阴极电压的关系,与放大器成形时间常数的依赖,随工作气压变化等。
A high performance multi-plate parallel plate avalanche counter (MPPAC) was applied to a radioactive ion beam line in lanzhou (Lanzhou, RIBLL) of Lanzhou heavy ion accelerator The high gain due to secondary avalanche makes it well suited for detecting lighter particles of higher energy. It consists of a central anode, a grid of x and y grids and two cathodes. The position signal consists of the x and y positions The gate was read by charge-division method, using isobutane working gas at atmospheric pressure of 650 Pa, anode + 400 V, and cathode of -350 V, the positional resolution for the alpha particle was 0.55 mm (FWHM, fwhm) At ± 0.2mm, the detection efficiency is more than 99.2%. Meanwhile, the relationship between the position resolution and the anode and cathode voltages, the dependence on the time constant of the amplifier shaping, and the variation of the operating pressure are also studied.