Applied Diamond, Inc., Wilmington, Delaware, USA
BNL, Upton, New York, USA
Recently new high energy electron cooling beam projects, CeC and LEReC, were proposed at Brookhaven National Laboratory as part of a future electron-ion collider. Efficient electron cooling requires a high quality, high power electron beam with tight parameters (energy and space trajectory). In order to achieve and maintain the required parameters and stability of the electron beam, its parameters have to be continuously monitored and feedback control has to be developed. However, existing detectors are not suitable for invasive profile measurements of powerful continuous wave (CW) electron beams. As a result, the beam profile of powerful CW electron beams is currently monitored in low repetition pulsed mode and assumed to remain the same in CW mode. The first prototype of a fast scanning diamond beam profile detector (DBPD) suitable for invasive high power CW electron beam core profile measurements in transmittance mode was developed. It consists of a multi-strip solid state diamond detector to scan with high speed (up to 1 m/s) and precision (about 5 um) through the core of an electron beam. The diamond sensor was made from a thin pc-CVD diamond plate with highly B-doped CVD diamond conductive strips. Transient currents from the multi-strip detector were measured with fast digitizing electrometers. Successful operation of the DBPD was demonstrated for pulsed (5 Hz) and CW (78 kHz) CeC beams, including the detector’s ability to withstand a 20 sec insertion into the CW CeC beam core. The X-Y beam spatial profile was measured in one scan. Thermal modeling demonstrated a manageable thermal impact even from a relatively long (up to 2 min) insertion of the diamond sensor into the CW CeC core. Electrical impedance modeling of the detector and vacuum chamber assembly demonstrated minimal impact on beam line impedance with diamond sensor insertion.
