Time bunching of slow positrons for annihilation lifetime and pulsed laser photon absorption experiments

Methods are described for gathering positrons from an extended region and causing them to impact upon a target surface within a small time interval. The most optimistic of these proposed schemes suggests that one should be able to produce ∼10⁻⁹s positron pulses with peak intensities of ∼10¹¹s⁻¹ starting with a ∼200 m Ci⁵⁸Co β⁺ source. These pulses should be useful for studying time-dependent interactions of positrons at surfaces.