Calibration of accelerator proton energy by the 14N reaction resonances

The N 14 ( p , p ′ γ ) 14 N reaction with resonances at 3903, 3996, and 5937 keV have been exploited in calibration of the absolute proton beam energy at 4–6 MeV to a precision of better than 1 keV. The essential factor in the procedure is the commercially available appropriate thin Si3N4 membrane target. The method is reliable and fast providing accelerator energy calibration at the level sufficient for practical ion beam applications.