Secondary electron time detector for mass measurements at CSRe

The Isochronous Mass Spectrometry is a high accurate mass spectrometer.A secondary electrons time detector has been developed and used for mass measurements.Secondary electrons from a thin carbon foil are accelerated by an electric field and deflected 180° by a magnetic field onto a micro-channel plate.The time detector has been tested with alpha particles and a time resolution of 197 ps (FWHM) was obtained in the laboratory.A mass resolution around 8×10~(-6) for △m/m was achieved by using this time detector in a pilot mass measurement experiment.