Development of a multiwire position sensitive proportional counter

Abstract

Preliminary measurements in a proportional counter with two independently counting wires have shown that counting rates up to 106 counts/s per wire can be reached without critical loss in the “true versus measured” linearity relation. In this paper, a gas-flow multiwire proportional counter designed and constructed in Iran, is presented. Results obtained with a fabricated detector, containing 32 Ni-chromic anode wires, are shown. Each wire is associated with a fast pre-amplifier and a discriminator channel. Counting rates of over 107 events per second are measured. The diameter, length, and resistance per unit length of anode wires are 35 µm, 3 cm and 10 Ω/m, respectively. The cathode is constructed of two fiber glass printed sheets of 4 x 12cm2 dimensions. In this detector, P10 gas (10% of methane and 90% of argon) is used. The volume of the detector sensitive area is 24 cm3. Detector signals are analyzed carefully through data acquisition systems (MCA, amplifier and preamplifier). Our study indicates that the present detector is a position sensitive detector and that the obtained position sensitivity resolution of this instrument is 3.5 mm.

Keywords

• proportional counter
• position sensitivity
• ionization
• gas multiplication
• charge division