Observation of X-ray and Auger electron spectra in a 4π proportional counter for 4π(e, X)–γ coincidence measurements

Abstract

For the standardization of electron capture nuclides followed by γ-transitions, the 4π(e, X)–γ coincidence counting method is mainly adopted. To examine how the spectra of the (e, X) channel change with gas nature and pressure, pulse-height spectrum measurements of signals from a 4π pressurized proportional counter were carried out under various conditions for 54Mn and 88Y sources together with 4π(e, X)–γ coincidence counting. The spectra were measured for each half of the counter and for the combined 4π signal. The nature of counting gas (P-10 or methane) and its pressure was reflected in the X-ray peak intensity, and the Auger electron spectra were influenced significantly by the absorption in a thin VYNS film and the source conditions.In the measurements, we employed a pill-box type 4π counter in which the anodes were very thin gold-coated tungsten wires (30μm ∅). In this system, spectra down to 0.2keV were clearly seen. The gas pressure can be raised up to 0.6MPa. Counting electronics used for 4π(e, X)–γ coincidence measurements were conventional modules and a list mode two-parameter data acquisition system.