Single electron detection in quadruple-GEM detector with pad readout

Using a system of four gas electron multipliers (GEMs) operating in tandem and coupled to pad readout, we have demonstrated the detection of single electrons in ethane at 1 bar. The paper presents measurements of single electron pulse height distributions, total gas gain measurement and calculation, pad-to-pad cross-talk, quenching capability, high rate capability, charging effects, etc. We describe the overall operational experience, including addition of a gaseous photocathode, TMAE, and compare it to the SLD CRID single-electron detector (Nucl. Instr. and Meth. A 343 (1994) 74; Va’vra, Nucl. Instr. and Meth. A 433 (1999) 59), which has been operational during the past decade.