Theβ-Radiations of UraniumX1

Abstract

An investigation of the distribution with momentum of the $\beta$-rays of uranium $X_1$ has been made by analyzing them with the magnetic electron lens spectrometer. The results are recorded by an electrical counter detection and mechanical recorder in the range between $H_{\rho }<650\mathrm{}$ and $H_{\rho }>1875\mathrm{}$. The lower limit of the range is limited by the window of the detecting device. The results of the experimental records $\frac{N}{H_{\rho }}$ are plotted against $H_{\rho }$ and the plot represents the normalized energy spectrum. In the continuity of the spectrum there is a clear evidence of three distinct peaks. The energy values of these peaks which represent three groups of $\beta$-rays due to internal conversion agree with those obtained by Meitner. The spectrogram shows that the end point of the continuous $\mathrm{U}{X}_1$ $\beta$-ray spectrum is at $H_{\rho }$ 1617 (189.9 kev), a value which agrees with those that are obtained by absorption method but differs considerably from Marshall's value obtained by the method of the expansion chamber. The present value, unlike that of Marshall, gives a point on the Sargent diagram nearly on the curve of allowed transitions.