Patent ID: 6271516
Filing Date: 2001-08-07
Classification: G01T

Abstract:
A G.M. tube environment radiameter including a sensitivity degradation monitoring device, comprising:a) a power operated movable support for a weak radioactive source, adapted to alternatively move said weak radioactive source between two stable positions, including a first position in which said weak radioactive source is located close to the G.M. tube thereby causing the G.M. tube to provide pulses of magnitude equal to pulses generated by the G.M. tube in response to background radioactivity, and a second position spaced apart from the G.M. tube in which pulse intensity of said weak radioactive source is negligible with respect to pulse intensity caused by background radioactivity;b) a cyclic counter circuit for contemporaneously counting pulses generated by the G.M. tube in response to both the weak radioactive source and the background radioactivity when the weak radioactive source is in the first position; andc) a circuit for measuring and storing pulse intensities both in a test stage when the weak radioactive source is in the first position and in subsequent times when the weak radioactive source is in the second position, as well as for providing a ratio of said pulse intensities.