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Characterization of an energy dispersive X-ray fluorescence imaging system base...
Silva, A. L. M.; Azevedo, C. D. R.; Oliveira, C. A. B.; Santos, J. M. F. dos; Carvalho, M. L.; Veloso, J. F. C. A.An Energy Dispersive X-ray Fluorescence (EDXRF) imaging system based on a Micropattern Gas Detector has already shown good results for di erent applications. An X-ray tube, a pinhole camera and a Micro-Hole and Strip Plate (MHSP) based detector are the main components of the experimental system. The detector uses an MHSP in a Xe atmosphere at 1 bar, acting as a photon counting device, i.e., it is capable to rec...
PACEM: a new concept for high avalanche-ion blocking
Veloso, J. F. C. A.; Amaro, F. D.; Azevedo, C. D. R.; Santos, J. M. F. dos; Breskin, A.; Lyashenko, A.; Chechik, R.We present the Photon-Assisted Cascaded Electron Multiplier (PACEM) as a potential alternative for ion back-flow suppression in gaseous cascade electron multipliers. Using a Micro Hole and Strip Plate-Gas Electron Multiplier (MHSP-GEM) configuration, the number of ions flowing back to the scintillation region is about 1.5 ions per primary electron at an optical gain of 6.5 and a drift field of 0.1 kV/cm, and ab...
Further studies on the gain properties of a Gas Electron Multiplier with a Micr...
Mir, J. A.; Stephenson, R.; Rhodes, N. J.; Schooneveld, E. M.; Luz, H. Natal da; Veloso, J. F. C. A.; Santos, J. M. F. dos; Azevedo, C. D. R.A Gas Electron Multiplier with Micro-Induction Gap Amplifying Structure (GEM-MIGAS) is formed when the induction gap of the GEM is set between 50 and 100 [mu]m using kapton pillars spaced at regular intervals. This configuration combines the properties of a GEM and Micromegas, allowing operation in tandem to generate high charge gains. We measured the essential operational parameters of this system using argon-...
High-rate operation of the Micro-Hole and Strip Plate gas detector
Veloso, J. F. C. A.; Caldas, C. C.; Oliveira, C. A. B.; Azevedo, C. D. R.; Santos, J. M. F. dos; Breskin, A.; Chechik, R.We report the performance of the Micro-Hole-and-Strip-Plate (MHSP) operated in xenon, under high-flux irradiation of a 30-kV X-ray Cu-tube. Stable operation in pulse-counting mode for gas gains above 104 was measured up to counting rates of 5×105 Hz/mm2. A gain variation of less than 5% was observed for gains of 104, while the energy resolution for 8-keV X-rays degrades from ~16% to ~18%. No visible degradation...
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