A Sealed Xenon Gas Scintillation Proportional Counter for X-Ray Astronomy

A gas scintillation proportional counter operating without the conventional gas purification system, for use in instruments for X-ray astronomy, is under development. A parallel grid detector has been built employing ultra high vacuum technology, equipped with a caesium getter to maintain purity, filled with xenon at one atmosphere and sealed. The detector does not employ a wavelength shifter (the scintillation being in the UV region) and no attention was paid to optimising the light collection efficiency. The experimental results demonstrate that the output signal is in the form of a pulse-train, which offers unforeseen possibilities for direct digital energy measurements, involving high frequency pulse counting and pulse-train length discrimination for the vetoing of particles producing extended ionisation trails.