Energy and active volume calibration of Xe-filled proportional counters in the 1 to 10 KeV range

Proportional counters (PC), containing xenon as a component of the counting gas, can be calibrated in the energy range of 1 to 10 keV by means of an external cerium-X-ray source. Three composite peaks emerge at 1.1, 5.1 and 9.8 keV. Additionally the gas gain along the anode wire can be scanned by collimating the cerium-X-ray source, thus the actual active volume of the PC can be determined. This calibration method is used in the GALLEX solar neutrino experiment.