Cryogenic Argon Ionization Chamber Detector for Analysis of Radioactive Noble Gases

摘要

Two ionization chamber detectors, using liquid or solid argon as their medium were designed, constructed and tested as an improved means of analyzing quantitatively xenon 131m and xenon 133. Problems with the first detector, including vibrational noise and inadequate temperature control, limited its use to studies using solid argon. In the second design, many operating problems of the first detector were corrected. Properties of the detectors were studied using external gamma sources and xenon 131m dispersed inside the detector medium. The xenon sample and argon were purified and cryogenically pumped into the detector for spectral analysis. Both the purity of the argon and bias voltages affected resolution by changing the trapping distance of the electrons in the medium. Lower temperatures increased detection efficiency by condensing more of the sample into the cell. No clearly recognizable energy peak could be found in spectra from external or internal sources.