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A new technique is presented for high-pressure gaseous radiation detectors leading to pulse amplitudes at least one order of magnitude larger than in ionization-chamber-based gamma-ray detectors. The technique uses room-temperature pure Xe or Xe-based gaseous mixtures at pressures of about 5–20 bar (or higher) to detect ionizing radiation in a multigrid high-pressure gas proportional scintillation counter (MGHP-GPSC) with a CsI deposit as the photocathode in direct contact with the gas, with no optical windows. The detector relies on secondary scintillation as the amplification stage followed by photoelectron production in a CsI photocathode layer. Experimental results are presented for a small prototype filled with pure Xe up to 5 bar, showing that the principle of operation of the detector works. The maximum detector gain obtained so far is about 10. [ABSTRACT FROM PUBLISHER]

An experimental study of the ω-values and Fano factors for Ar-Xe gaseous mixtures at atmospheric pressures for 5.895 keV X-rays was carried out with two experimental set-ups based on gas proportional scintillation counter techniques. For the 100% Xe, Ar-40% Xe, Ar-20% Xe and Ar-10% Xe mixtures at 800 Torr the measured ω-values were 21.61 eV, 21.63 eV, 21.64 eV and 21.42 eV, respectively, within an accuracy of ±0.21 eV. For the same mixtures the Fano factors were 0.254, 0.258, 0.250 and 0.256, respectively, within an accuracy of about ±0.004. For lower Xe concentrations of 5%, 3% and 1% the Fano factors were ≈0.24, ≈0.23 and ≈0.22, respectively. These experimental results are compared with those available in the literature. [ABSTRACT FROM AUTHOR]