GASPROPORTIONAL-SZINTILLATIONSZAEHLER FUER IONISIERENDE STRAHLUNG MIT STRAHLUNGSFENSTER UND NACHWEISVOLUMEN IN MITTELGROSSER UND GROSSER AUSFUEHRUNG UND VERFAHREN ZUR HERSTELLUNG

PCT No. PCT/PT93/00007 Sec. 371 Date Jun. 14, 1994 Sec. 102(e) Date Jun. 14, 1994 PCT Filed Oct. 15, 1993 PCT Pub. No. WO94/09509 PCT Pub. Date Apr. 28, 1994.Detectors for ionizing radiation (X-rays, gamma rays, electrons, protons, alpha particles, etc. as well as neutrons) of the gas proportional scintillation counter type using techniques to compensate for a loss of scintillation light reaching the photosensor due to solid angle and reflection effects. Two such techniques are disclosed. One technique involves the use of two non-parallel electrically charged grids which produce a radially increasing electric field, thus radially increasing the intensity of the scintillation light. Another technique involves the use of a mask of small opaque dots having a radially decreasing density covering the photosensor, thus radially increasing the intensity of the scintillation light transmitted to the photosensor. The preferred embodiment for X-ray detection consists in a detector, filled with very pure xenon at atmospheric pressure, with a 2.5 cm diameter radiation window (1), a grid with a spherical (2 cm radius) curvature (2) with its edges placed 0.8 cm away from a plane grid which is placed in contact with or close to a photomultiplier tube (4). This photomultiplier has uniform sensitivity in the 170 nm wavelength region. This detector presents an energy resolution of 8.0% for 5.9 keV X-rays.