JINST Instrumentation Theses Archive

M.Sc. degree thesis
accepted by Weizmann Institute, Israel, in 2005

Chen Shalem

Supervisor: Amos Breskin and Rachel Chechik

R&D of a novel gas electron multiplier * the THGEM

 Keywords:

• Charge transport and multiplication in gas Electron multipliers (gas)
• Gaseous detectors
• Detector modelling and simulations II (electric fields, charge transport, multiplication and induction, pulse formation, electron emission, etc)

 Abstract:
The operation mechanism and properties of Thick GEM-like (THGEM) gaseous electron multipliers, operated at atmospheric and low pressure, are presented. They are made of standard printed-circuit board, perforated with sub-millimeter diameter holes, etched at their rims. Gas multiplication factors of 105 and 107 at low (1 Torr) and atmospheric pressure respectively were obtained. Fast pulses in the few nanosecond rise-time scale were reached in single and cascaded double-THGEM elements, in standard gas mixtures with single photoelectrons. Energy resolution of 20% FWHM was recorded with 5.9 keV X-rays at a gain of 105. High single-electron detection efficiency is obtained in photon detectors combining THGEMs and semitransparent UV-sensitive CsI photocathodes or reflective ones deposited on the top THGEM face; the latter benefits of a reduced sensitivity to ionizing background radiation. Stable operation was recorded with photoelectron fluxes up to the MHz/mm2 scale. Some potential applications of these simple and robust multipliers are discussed.