A parallel-plate analyser with time focusing

The design and performance of a new tandem parallel-plate analyser (PPA) are presented. The main advantage of this instrument is its time-focusing; i.e., within its angular acceptance (±10°), particles entering at different angles reach the detector nearly at the same time. In coincidence measurements, this is particularly useful at low energies for increasing signal-to-background levels. In its present realization, its relative energy resolution is 7.5%.