Electronic gain study of single resistive electrode thick electron multiplier (RETGEM) radiation detectors with various resistive layers and substrates in P-10 gas

Abstract

The study of resistive electrode thick gas electron multipliers (RETGEMs) of various designs is described. Four types of RETGEMs were tested. One was made of a substrate of a flame-retardant glass epoxy FR4 board coated with graphite as a resistive layer. The second was made of an FR4 board laminated with Kapton as a resistive layer. The third was made of a polyvinyl chloride (PVC) board coated with graphite as a resistive layer. Finally, a RETGEM with a diamond-like carbon coating produced by CERN was also tested. Multiple characteristics of the single RETGEM detector, such as absolute gas gains and maximum applicable voltages, were measured for all four types of RETGEMs at various voltages applied to the RETGEMs and various sizes of induction gaps, using Cm-244 alpha and F-55 X-ray sources. The results have shown that the highest absolute gas gain is achieved with the FR4 board laminated with Kapton. On the other hand, the PVC board coated with graphite gives the minimum voltage at which the signal can still be observed.