A Liquid Argon Ionization Chamber Measurement of the Shape of the Beta-Ray Spectrum ofK40

Abstract

A liquid argon ionization chamber has been used to compare the shape of the beta-ray spectrum of ${\mathrm{K}}^{40}$ with those of ${\mathrm{Y}}^{91}$ and ${\mathrm{P}}^{32}$. The ${\mathrm{K}}^{40}$ spectrum is found to be consistent with the shape factor $D_2=p^6+7\mathrm{}{p}^4{q}^2+7\mathrm{}{p}^2{q}^4+q^6,$ in agreement with recent measurements.