Study of the Source Contribution to the Positron Lifetime Spectrum.

We are investigating the source contribution of a $^{\mathrm{22}}$Na positron source to the positron annihilation lifetime spectrum. We use a standard a fast-slow delayed coincidence apparatus to record positron lifetimes in simple metal samples. Our samples are commercial grade, and an annealing process is developed to minimize the defect concentration in the samples. The goal of the process is to allow separation of bulk lifetimes from the components due to source contributions. Multiple measurements will be performed to quantify the contribution of the positron source to the lifetime spectrum. 0