Investigation of Characteristics of Low-energy X-ray Radiated from the Crookes Tube Used in Radiological Education

Abstract

Crookes tubes have been used as fundamental equipment for science education in junior-high schools in Japan. However, radiation protection and safety guidelines have not been evaluated sufficiently to date. Estimations of the X-rays radiated from the Crookes tubes under various systematic conditions are required to establish these guidelines. Energy spectrum of the X-rays was obtained by CZT detector with very fine collimator to avoid pile-up effect. The peak energy of the X-rays was about 20 keV, and the most frequent voltage of pulses applied from an induction coil was matched with this peak energy. The correlation between the distribution of the applied voltage and X-ray spectra was obtained in this study. The energy of the X-rays was also estimated by a linear attenuation coefficient of Al plates. The effective X-ray energy estimated by this conventional method showed good agreement with the result obtained by CZT detector.