Measurements of Negative-Muon Lifetimes in Light Isotopes

Abstract

Negative muons from the Carnegie Tech synchrocyclotron were stopped in the following targets: separated isotopes of lithium (${\mathrm{Li}}^6$ and ${\mathrm{Li}}^7$) and boron (${\mathrm{B}}^{10}$ and ${\mathrm{B}}^{11}$), and natural beryllium, carbon, nitrogen, and oxygen. From an analysis of the resulting time spectrum of the decay electrons, the negative-muon lifetime in each of these substances was obtained. From a separate measurement of the ${\mu }^{+}$ lifetime, (2.202±0.003) μsec, the capture rates in the above elements were determined. They are (in units of ${10}^5$/sec); ${\lambda }_{\mathrm{cap}}\left({\mathrm{Li}}^6\right)=0.061\mathrm{}\pm 0.014$, ${\lambda }_{\mathrm{cap}}\left({\mathrm{Li}}^7\right)=0.018\mathrm{}\pm 0.014$, ${\lambda }_{\mathrm{cap}}\left({\mathrm{B}}^{10}\right)=0.265\mathrm{}\pm 0.015$, ${\lambda }_{\mathrm{cap}}\left({\mathrm{B}}^{11}\right)=0.218\mathrm{}\pm 0.016$, ${\lambda }_{\mathrm{cap}}\left(\mathrm{Be}\right)=0.10\mathrm{}\pm 0.02$, ${\lambda }_{\mathrm{cap}}\left(\mathrm{C}\right)=0.397\mathrm{}\pm 0.013$, ${\lambda }_{\mathrm{cap}}\left(\mathrm{N}\right)=0.65\mathrm{}\pm 0.04$, and ${\lambda }_{\mathrm{cap}}\left(\mathrm{O}\right)=0.98\mathrm{}\pm 0.03$.