The transfer reaction of negative muons from $(\mu {p)}_{1s}$ atoms to ${}^3$He and ${}^4$He was studied at 30 K, and the transfer rate to ${}^3$He was determined. Germanium detectors were employed to measure the time distribution of muonic neon x rays in triple-gas mixtures H${}_2$+${}^{3,4}$He+Ne. The rates for the two helium isotopes, normalized to the atomic density of liquid hydrogen, are determined as ${\lambda }_{p^3\mathrm{He}}=(0.29\mathrm{}\pm 0.12)\times {10}^8$ s${}^{-1}$ and ${\lambda }_{p^4\mathrm{He}}$=(0.55$\pm$0.07)$\times$10${}^8$ s${}^{-1}$. The transfer rate to neon was obtained from binary H${}_2$+Ne gas mixtures, measured at the same experimental conditions as for the triple-gas mixtures, with the result ${\lambda }_{p\mathrm{Ne}}$=(0.0677$\pm$0.0032)$\times$10${}^{11}$ s${}^{-1}$.

• Received 17 October 1997

DOI:https://doi.org/10.1103/PhysRevA.57.2496