Fabrication and testing of two-dimensional Micro-Edge Gas Chamber (2D-MEGC)

Abstract

This work proposes using silver flat ribbon cable to fabricate a new type of position-sensitive gaseous detector. This structure consists of a thin conductive silver of flat ribbon cable (anodes) and thicker copper sheets (cathodes) separated by a plastic insulator. To fix the position of the anodes and the cathodes, a holder compressed the layers. The layers are cut from the edges and polished at several steps to have a smooth surface. These arrays of anodes and cathodes, created by the proposed method, act as a two-dimensional position-sensitive proportional detector. Applying a suitable voltage between the anodes and cathodes produces a strong electric field near the vicinity of the anodes. This electric field multiplies primary electrons generated by ionizing radiation. The experimental results show that for the proposed two Dimensional Micro Edge Gas Chamber (2D-MEGC), at HV1 = 350 with the gas mixture of (Ar 85 % - CO2 15 %), the maximum multiplication factor without electric discharge is around 250. All pixels were separately connected to the preamplifier-amplifier setup to test the position sensitivity of 2D-MEGC. As expected for a non-collimated alpha source, the maximum recorded interactions are related to the closest pixel to the radioactive source. The Raether limit is a good benchmark concerning the quality of fabricated gaseous detectors. In the best design conditions, this value for Micro Strip Gas Chamber (MSGCs) is 4 × 10⁷. For the fabricated 2D-MEGC, this number is 2.5 × 10⁷. This result shows that the proposed 2D-MEGC performs well despite its simple structure and fabrication.