The scintillation of GEMS coated with wavelength shifters

The optical readout of GEMs, presented a few years ago, is currently being considered for several detector projects. Although using suitable gaseous mixtures the GEM avalanches emit a large number of photons in the visible and/or NIR regions, many gaseous mixtures of great interest for detectors scintillate mainly in the UV, and the readout of these detectors is usually inefficient or very expensive. In this work we report on the operation of GEMs coated with a wavelength converter. We show that using a GEM with an optimal geometry the wavelength conversion process can be quite efficient and does not degrade the intrinsic position resolution of the detector, an usual drawback of the utilisation of wavelength shifters.http://www.sciencedirect.com/science/article/B6TJM-4C7B66V-1/1/ea672f73675fd42cd4f864c479c5bfb

Time analysis of the light pulses on gaseous active scintillators using GEMs with He/CF4

The time structure of light pulses from GEM detectors operated in scintillation mode with He/CF4 mixtures, previously used with integrating readout devices for neutron detection, has been investigated. A system using photomultipliers (PMs) and charge preamplifiers coupled to a fast digitizer has been used to measure simultaneously both the charge and light signals of the avalanches and the dependence of these signals on the operating conditions of the GEM, such as gain, transfer yield and collection field. The present results show that detectors relying on photon counting techniques, using of position sensitive PMs or arrays of avalanche photodiodes, are most promising as fast position sensitive neutron detectors.http://www.sciencedirect.com/science/article/B6TJM-48408MT-T/1/d28fe3c77462b34770621afe4d9da89

Luminescence and imaging with gas electron multipliers

Although the GEM has been mainly used as a gaseous preamplifier device, it has been shown that using suitable gaseous mixtures the avalanches emit a large number of photons, in the UV, visible and/or NIR bands. This scintillation, readout by CCDs, has been used recently for the development of imaging detectors to be used with X-rays, alpha particles and neutrons. The luminescence process in the GEM and a summary of its applications will be presented. The latest developments, including the operation of the GEMs in photon counting mode, will also be referred.http://www.sciencedirect.com/science/article/B6TJM-49FGX8X-B/1/95c4ce32cbe642552741e1461297c1d