Effects of the Leakage Magnetic Field from an Analog Meter on the Response of Scintillation Survey Meters

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Vol.2 No.1, 2003

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Vol.1 No.1, 2002

Paper	Radiation Safety Management Vol.2, No.1 (24-28)

Effects of the Leakage Magnetic Field from an Analog Meter on the Response of Scintillation Survey Meters
Toshiaki Abe¹⁾, Hisao Yamamoto¹⁾, Toshiyuki Norimura²⁾ and Akira Katase³⁾
1) Radioisotope Research Center, 2) Department of Radiation Biology and Health,School of Medicine, University of Occupational and Environmental Health, Japan. 3) Yohshindo Laboratory
Received February 21, 2003; accepted September 3, 2003

Effects of the weak leakage magnetic field are studied on the response of two kinds of scintillation survey meters: an ordinary type for γ-rays and that optimized for the detection of low-energy photons from ¹²⁵I. In the presence of the magnetic field, the response of the optimized survey meter decreases to the photons from ¹²⁵I, and increases considerably to the background radiations. On the other hand, the response of the ordinary survey meter decreases slightly to both the γ-rays from ¹³¹I and the background radiations. From analysis of the pulse-height spectra for the radiations, such variations of the response are ascribed to the reduction of the amplification factor of photomultiplier tubes by the magnetic field.

Key words:

magnetic field, scintillation survey meter, background radiation, photomultiplier tube