A microscope for the Glasgow photon tagging spectrometer in Mainz

A 96-element plastic-scintillator detector array has been constructed to improve the energy resolution and tagged-photon flux over a moveable energy range of up to 60MeV in the Glasgow photon tagging spectrometer at Mainz. Test results are presented which demonstrate that this device improves the resolution by a factor of about 6 compared to the main detector array. It is also shown that it is possible to achieve accurate energy calibration by using electron beams of several different accurately known energies from the Mainz accelerator.