Beam position monitor upgrade for the Los Alamos Proton Storage Ring

The beam diagnostics for the Los Alamos Proton Storage Ring (PSR) are being upgraded in several areas, including the closed-orbit beam-position system, the high-frequency longitudinal and transverse beam diagnostics, and the extraction-line beam-position monitoring system. The closed-orbit beam-position measuring system is based on detecting the 201 MHz modulation on the injected beam, which disappears in about 10 mu s, due primarily to the beam's momentum spread (about +or-0.1%), and the consequent spread in the revolution frequencies. Thus, although the first few turns of the injected beam are monitored with the system, the main body of the stored beam, which has lost its 201 MHz component, is not. In order to monitor the position of the stored beam, the ring beam-position system is being redesigned to operate at the revolution frequency, 2.8 MHz.<>