Gyromagnetic Ratios of Hydrogen, Tritium, Free Electrons, andRb85

Abstract

The spin-exchange optical pumping technique has been used to measure the gyromagnetic ratios of hydrogen, tritium, and free electrons in terms of the electronic gyromagnetic ratio of ${\mathrm{Rb}}^{85}$. A direct measurement was also made of the ratio of the electronic $g$ factors of tritium and hydrogen. The 60-G magnetic field in which these measurements were made was produced by a precision-wound solenoid which was surrounded by three concentric magnetic shields. The magnetic field varied by 5 parts in ${10}^6$ over the region occupied by a typical absorption flask. The free electrons were produced by ionization resulting from the beta decay of the radioactive tritium atoms. Measurements were made in various sizes of absorption flasks and in flasks containing different pressures of helium, argon, and neon buffer gases. The measured $g$-factor ratio did not depend upon the nature or pressure of the buffer gas. The results of these measurements were as follows: $\frac{g_J\left(\mathrm{Rb}\right)}{g\left(e\right)\mathrm{}}=1+(6.3\mathrm{}\pm 1.0)\times {10}^{-6\mathrm{}}; \frac{g_J\left(\mathrm{Rb}\right)}{g_J\left(\mathrm{H}\right)}=1+(23.74\mathrm{}\pm 0.1)\times {10}^{-6\mathrm{}};$ $\frac{g_J\left(\mathrm{T}\right)}{g_J\left(\mathrm{H}\right)}=1-(0.11\mathrm{}\pm 0.3)\times {10}^{-6\mathrm{}}; \frac{g_J\left(\mathrm{H}\right)}{g\left(e\right)\mathrm{}}=1-(17.4\mathrm{}\pm 1.0)\times {10}^{-6\mathrm{}}.$