A beta—gamma ionization chamber for substandards of radioactivity—I: Uses and calibration

Abstract

This paper gives information on the construction, characteristics and calibration of the type 1383A chamber for the guidance of users. This instrument is a combination of a re-entrant cylinder (well-type) gamma-ray chamber with an approximately “2π” beta-ray chamber which in conjunction with a d.c. amplifier or electrometer, is suitable for the measurement of samples of γ-emitting and β-emitting isotopes. The γ-ray and β-ray ionization currents and the background are of the order of 10 −11, 10 −10 and 10 −14 A/mc, respectively. The calibration figures for standard Na 24, P 32, K 42, Fe 59, Co 60, Br 82, Y 90, Au 198 and Ra 226 sources and the correction factors applicable to measurements of solutions in 2 ml and 5 ml ampoules, and 10 ml bottles are given.