Teruyuki Okada

Soda-glass capillary plate gas detector

A new capillary plate (CP) has been developed for a hole-type micropattern gas detector. The plate consists of a bundle of fine soda-glass capillaries with a diameter of 100 /spl mu/m and a length of 1 mm. The electrodes on the surfaces of both ends of CP were coated with Inconel metal. The plate is similar to a conventional CP, except that the material used is not lead glass, but soda glass. The main advantages of the soda-glass CP compared to the lead-glass CP are a low surface resistivity and low background properties. The soda-glass CP gas detector was operated with a gas mixture of Ar(90%) + CH/sub 4/(8%) + TMA(2%) using 5.9 keV X-rays. Using the scintillation light emitted from the soda-glass CP, we successfully obtained the energy spectrum and accumulated image for the 5.9 keV X-rays. In this paper, we report on the characteristics of the new soda-glass CP and the background properties of both the soda-glass and lead-glass CPs. We also describe the outlook on the future development of an optical gas photomultiplier with the soda-glass CP.

Gain of a gas photomultiplier with CsI photocathode

A Gas PMT with the CsI photocathode was fabricated as a phototube of a glass vessel identical to a conventional vacuum PMT. A GEM and a Micromegas were installed in the phototube of the Gas PMT. The Gas PMT was operated with two different gas mixtures, Ar (90%) + CH4 (10%) and Ne (90%) + CF4 (10%), at the gas pressure of 1 atm. The gain of 105 was obtained for both the gas mixtures. It was found that the gain of the Gas PMT can be described using the Townsend ionization coefficient for the Micromegas. The imaging capability of the Ne gas mixture was checked by an optical imaging capillary (CP) gas detector, using X-ray beams. The image of an X-ray resolution chart indicates that the imaging resolution is determined by the diameter of the capillary, here 100 μm. The Ne gas mixture appropriate to the Gas PMT is well suited for a fine imaging detector.

Soda glass capillary plate gas detector

A new capillary plate (CP) has been developed for a hole-type micropattern gas detector. The plate consists of a bundle of fine soda-glass capillaries with a diameter of 100 /spl mu/m and a length of 1 mm. The electrodes on the surfaces of both ends of CP were coated with Inconel metal. The plate is similar to a conventional CP, except that the material used is not lead glass, but soda glass. The main advantages of the soda-glass CP compared to the lead-glass CP are a low surface resistivity and low background properties. The soda-glass CP gas detector was operated with a gas mixture of Ar(90%) + CH/sub 4/(8%) + TMA(2%) using 5.9 keV X-rays. Using the scintillation light emitted from the soda-glass CP, we successfully obtained the energy spectrum and accumulated image for the 5.9 keV X-rays. In this paper, we report on the characteristics of the new soda-glass CP and the background properties of both the soda-glass and lead-glass CPs. We also describe the outlook on the future development of an optical gas photomultiplier with the soda-glass CP.

Optical Imaging Capillary Plate Gas Detector

A capillary plate (CP) gas detector with a CF4 gas mixture of argon and pure xenon has been successfully operated as a visible and near-infrared (NIR) scintillation proportional counter. Gas gains of up to 104 can be achieved using these gas mixtures. The scintillation light emitted during the generation of electron avalanches can be observed using a photomultiplier tube (PMT) and a compact optical imaging system which consists of a CP gas detector and a cooled charge-coupled device (CCD) camera coupled to lens optics. Using this optical imaging system, clearer images of X-rays have been obtained with the above gas mixtures. The successful operation using these gas mixtures has allowed us to realize a novel imaging device with a CP for medical imaging and gaseous PMTs sensitive to visible light.