Features of high-precision 14 V beta-spectrum detection by means of a proportional counter

The methodology of high-precision registration of β-spectrum 14 C within the energy range of 10-160 keV is described. The measurements were carried out through wall-less proportional counter, consisting of the central counter and protection near-wall annular counter. Switching on the detectors into anticoincidence mode makes it possible to avoid β-spectrum distortions, relative to the boundary effect. The detector is placed in a lead protection shell with the purpose of reducing natural activity background. Selection of xenon as a working gas properties for high efficiency of decay electron absorption. Results on measuring the counter amplitude and time characteristics make it possible to account for possible factors of β-spectrum distortion. 7 refs., 12 figs., 1 tab