Measurement of DT neutron-induced activity in glass-microshell laser fusion targets

Laser fusion targets consisting of DT gas contained in Teflon-coated glass microshells produce 14.1-MeV neutrons that can interact with the 28Si nuclei in the glass to produce radioactive 28Al. Using a very efficient collection-detection scheme that could detect the decay of 10% of the 28Al created, we identified these nuclei by their 1.78-MeV γ ray, which decayed with a 2.2-min half-life. From the number of 28Al nuclei created and the neutron yield the compressed glass areal density was found to be 0.0059 g/cm2.