A Mass-Spectrograph Study of Ba, Sr, In, Ga, Li, and Na

Abstract

A mass spectrograph of the 180° type of 22 cm radius has been constructed. The magnetic field of 1400 gauss is supplied by permanent magnets and the accelerating potential by a stabilized rectifier. A mass analysis has been made for a number of elements of the ions obtainable from coated filaments. A peak of Sr at mass 84 comprising 0.5 percent of the total Sr current, and one of Ba at mass 134 comprising 1.8 percent of the total Ba current are concluded to be new isotopes of Sr and Ba, respectively. A search for a third isotope of indium was made but none found. The relative abundances of ${\mathrm{Ga}}^{69}$ and ${\mathrm{Ga}}^{71}$ were determined to be 38.8 percent and 61.2 percent respectively. The existence of ${\mathrm{Li}}^5$ and ${\mathrm{Na}}^{22}$ recently reported by Brewer was not confirmed. Lower limits were placed on other possible isotopes of these elements.