Low Pressure Two Dimensional Position Sensitive Multiwire Proportional Chamber for the Radioactive Ion Beam Experiment

Low pressure two dimensional position sensitive multiwire proportional chamber(MWPC) was developed to be used to study the nuclear reaction induced by radioactive ion beam. Each detector has a 50 mm×50 mm sensitive area and consists of three grids(x-position, cathode, y-position). The position was determined through delay line readout mode. The detectors have good beam transparency and are also adequate to be used in vacuum. The MWPC was tested at a pressure of 800 Pa of n-heptane and a bias voltage of 720 V. The test results indicate that two track position resolution of the chamber is Δx=Δy=1 mm and position determination efficiency is larger than 80% for the low Z particle at intermediate energies. This kind of chamber can be used to determine the (direction) of the incident particle and to detect the emitting angle of the reaction products.