A two-dimensional position sensitive microstrip gas chamber for single VUV photons

Nuclear Instruments and Methods in Physics Research Section A:

Covita

et al. 2006

The performance of a high-pressure xenon gas proportional scintillation counter/microstrip gas chamber (GPSC/MSGC) hybrid detector has been investigated for filling pressures from 1 up to 10 bar, for 22-, 30-and 60-keV photons. GPSC/MSGC hybrid detectors are based on a xenon-GPSC instrumented with a CsI-coated microstrip plate photosensor placed directly within the xenon envelope, as a substitute for the photomultiplier tube. This design avoids the constraints due to the use of a quartz scintillation window for GPSC-photosensor coupling, which absorbs a significant amount of scintillation and is a drawback for applications where large detection areas and high filling pressures are needed. The lowest energy resolutions are achieved for 2 bar (5.5% and 3.4%, FWHM, for 22-and 60-keV photons, respectively). Increasing the pressure to the 5-6 bar range, competitive energy resolutions of 7% and 4.5% are still achieved for 22-and 60-keV photons, respectively. This detector could be a compelling alternative in applications where compactness, large detection area, insensitivity to strong magnetic fields, room temperature operation, large signal-to-noise ratio and good energy resolution are important requirements. r

Section: Introductionmentioning

confidence: 99%

High-pressure operation of a xenon-GPSC/MSGC hybrid detector for hard X-ray spectrometry

Coelho

Nuclear Instruments and Methods in Physics Research Section A:

Covita

et al. 2006

“…An important application of the micropattern technology has been the development of novel photosensitive gas detectors-based on CsI photocathodes. These include MSPs and GEMs, either combined with semi-transparent CsI photocathodes placed few mm apart, or else with a reflective CsI-layer covering the upper part of the microstructure [2][3][4][5][6][7][8]. These photon-detectors present an inexpensive alternative to photomultiplier tubes (PMT) with the additional advantages of compactness, low power consumption, the capability of having large sensitive areas, being position-sensitive and operating under strong magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

The gas proportional scintillation counter/microstrip gas chamber hybrid detector

Freitas

Nuclear Instruments and Methods in Physics Research Section A:

Monteiro

et al. 2003

The gas proportional scintillation counter/microstrip gas chamber (GPSC/MSGC) hybrid detector for X-ray spectrometry is described. The detector uses a CsI-coated microstrip plate placed in direct contact with the gas-filling as the photosensor readout for the GPSC scintillation substituting for the photomultiplier tube (PMT). Usable photosensor maximum gain is limited by optical positive feedback due to the additional scintillation produced in the electron avalanche process at the MSP anodes, in the absence of quenching. A low-photoelectron collection efficiency is achieved in the gas atmosphere, resulting in a scintillation conversion efficiency that is about a factor of 5 lower than that achieved with PMT-based GPSCs. However, energy resolutions of 11% for 5.9 keV X-rays are achieved with this detector. r

“…To circumvent the problem of variable photoelectron gain another variant of the detector is proposed that locates a semitransparent CsI-photocathode on the quartz window that isolates the MSP from the xenon envelope of the GPSC [5], [6]. In this configuration ( Fig.1 (b)), the photoelectrons emitted by the semi-transparent CsI-photocathode drift towards the MSP anodes where charge multiplication occurs.…”

Section: Rationalementioning

confidence: 98%

“…From (5) and (6) L is calculated by 10 (7) For the experimental conditions (E/p= 6 V cm -1 Torr -1 , V a = 420 V and p P10 = 800 Torr) G d / G c , was calculated by numerical simulation, as explained above (Section III), and was found to be 0.37. W Xe = 22-eV [9] and W P10 = 26-eV [16].…”

Section: A Determination Of L-valuementioning

confidence: 99%

“…For the reflective operation mode the amplitude of the 22-keV interactions in the xenon chamber can be given by A xe = C* N Xe *L* G c (5) where N Xe is the number of primary electrons produced in xenon (= 22-keV/W xe ), G c is the average photosensor gain for photoelectrons emitted from the cathode strips and C is a factor related to the electronic signal amplification.…”

Section: A Determination Of L-valuementioning

confidence: 99%

See 1 more Smart Citation

Reflective and semi-transparent CsI-photocathodes in microstrip plate gas chamber photosensors for gas proportional scintillation counters: a comparative study

2001 IEEE Nuclear Science Symposium Conference Record (Cat. No.01CH37310)

Freitas

Santos

et al.

We report the results of a comparative study of a xenon gas proportional scintillation counter instrumented with photosensors based on a microstrip plate. The photosensor is isolated from the gas proportional scintillation counter by a quartz window and is operated in P-10 gas at atmospheric pressure. The CsI-photocathode is operated either in the reflective or semi-transparent mode. In the reflective mode, the CsI-photocathode is deposited directly on the microstrip plate. Gain fluctuations due to a geometric factor, which degrade the energy resolution, are observed. In the semi-transparent mode the CsI-photocathode is deposited onto the surface of the quartz window resulting in two potential improvements: an increase in the number of photoelectrons produced in the photocathode and a reduction of geometry-related effects. Both modes of operation will be evaluated and their performance characteristics determined.