Design of a Low-Q S-Band Cavity Beam Position Monitor

Design of a Low-Q S-Band Cavity Beam Position Monitor

The accelerator test Facility (ATF) 2 at high energy accelerator research organization (KEK) has been considered as a test facility to investigate two major challenges of the International Linear Collider (ILC)[1] Beam Delivery System (BDS): focusing the beams to nanometer size and providing sub-nanometer stability. Beam position monitors (BPMs)[2,3] with a resolution in a few hundred nanometers range are required to align the final focus magnets to within 1 μm in the final focus system at the ATF2. Due to the large beam size at the final focus magnets, an S-band cavity BPM has to be considered to realize this requirement. By using the electromagnetic field simulation programs MAFIA and HFSS, we have designed an S-band cavity BPM with a low Q-value in order to achieve easier separation of individual bunches in a multi-bunch signal. The results of the design studies showed a signal decay time of 35 ns and a resolution of a few nanometers. We present the results of design studies in which investigations for the effects of other signals besides the position signal are included.

The accelerator test Facility (ATF) 2 at high energy accelerator research organization (KEK) has been considered as a test facility to investigate two major challenges of the International Linear Collider (ILC)[1] Beam Delivery System (BDS): focusing the beams to nanometer size and providing sub-nanometer stability. Beam position monitors (BPMs)[2,3] with a resolution in a few hundred nanometers range are required to align the final focus magnets to within 1 μm in the final focus system at the ATF2. Due to the large beam size at the final focus magnets, an S-band cavity BPM has to be considered to realize this requirement. By using the electromagnetic field simulation programs MAFIA and HFSS, we have designed an S-band cavity BPM with a low Q-value in order to achieve easier separation of individual bunches in a multi-bunch signal. The results of the design studies showed a signal decay time of 35 ns and a resolution of a few nanometers. We present the results of design studies in which investigations for the effects of other signals besides the position signal are included.