Comparison of Four Calibration Techniques of a Silver-Activated Geiger Counter for the Determination of the Neutron Yield on the Frascati Plasma Focus Experiment

摘要

The theoretical background of four independent calibration methods and their application to the silver activated Geiger counter used to determine the neutron yield of the Frascati 1 MJ plasma focus machine are described. The first method is based on the exposure of an indium foil to a number of plasma focus shots sufficient to induce a measurable activity in the foil. This method requires knowledge of the plasma focus neutron spectrum and of the indium energy-dependent activation cross section. The following two methods resort to a reference radioactive neutron source, used respectively in the saturation and in the removal mode. The fourth method is based on the exposure of a nuclear emulsion plate to a single shot of the plasma focus machine. The experimental results are reported and discussed. Possible improvements, including use of a rhodium activated counter, are pointed out. (ERA citation 07:045353)