低气压多丝正比室及其在放射性束流实验中的应用

Low Pressure Multiwire Proportional Chamber and Its Application to Radioactive Ion Beam Experiment

介绍了为在放射性束流线上开展精确的散射和反应实验中 ,对入射束流的角度和有效数目等进行在线监测而设计制造的低气压多丝正比室 .它透射性好 ,不干扰束流 ,并方便在真空环境中工作 .测量表明 ,它的位置分辨率约0 5mm .对 2 0— 3 0MeV/u的低Z的放射性束流有着大于 90 %的位置探测效率 ,适用于中能次级束实验靶前的束流定位及在线监测 。

Radioactive ion beam is generally characterized by small beam intensity and big beam size. In order to carry on precise scattering and reaction experiments it is necessary to monitoring the incident angle and absolute number of the beam hitting the target. We therefore have designed and made up low pressure multiwire proportional chambers (LPMWPC) which have good beam transparency and are also adequate to be used in vacuum. Experiment test indicates that the position resolution of the chambers is about 0.5mm and the position determination efficiency is larger than 90% for the low Z particles at intermediate energies. This kind of chamber can then be used to detect the direction of the incident particle and to record the absolute number of the particles which really hit the target, or to detect the emitting angle of the outgoing particles.