Production of selected cosmogenic radionuclides by muons: 2. Capture of negative muons

摘要

We have determined the production yields for radionuclides in Al_2O_3, SiO_2, S, Ar, K_2SO_4, CaCO_3, Fe, Ni and Cu targets, which were irradiated with slow negative muons at the Paul Scherrer Institute in Villigen (Switzerland). The fluences of the stopped negative muons were determined by measuring the muonic X-rays. The concentrations of the long-lived and short-lived radionuclides were measured with accelerator mass spectrometry (AMS) and γ-spectroscopy, respectively. Special emphasis was put on the radionuclides ~(10)Be, ~(14)C and ~(26)Al produced in quartz targets, ~(26)Al in Al_2O_3 and S targets, ~(36)Cl in K_2SO_4 and CaCO_3 targets, and ~(53)Mn in Fe_2O_3 targets. These targets were selected because they are also the naturally occurring target minerals for cosmic ray interactions in typical rocks. We also present results of calculations for depth-dependent production rates of radionuclides produced after cosmic ray μ~- capture, as well as cosmic ray-induced production rates of geologically relevant radionuclides produced by the nucleonic component, by μ~- capture, by fast muons and by neutron capture.