BNL, Upton, Long Island, New York, USA
ITEP, Moscow, Russia
RHIC polarized proton operation requires fast and reliable proton polarimeter for polarization monitoring during stores. Polarimeters based on p-Carbon elastic scattering in the Coulomb Nuclear Interference(CNI) region has been used. Two polarimeters are installed in each of the two collider rings and they are capable to provide important polarization profile information. The polarimeter also provides valuable information for polarization loss on the energy ramp. As the intensity increases over years, the carbon target lifetime is getting shorter and target replacement during operation is necessary. Simulations and experiment tests have been done to address the target lifetime issue. This paper summarizes the recent operation and the target test results.
BNL, Upton, Long Island, New York, USA
A proposal for a future ultra relativistic polarized electron-proton collider (eRHIC) is based in part on the transport of multiple electron beams of different energies through two FFAG beam transports around the 3834 m long RHIC tunnel circumference in order to recirculate them through an Energy Recovery Linac for their stepwise acceleration and deceleration. For each of these transports, the beams will travel in a common vacuum chamber, horizontally separated from each other by a few mm. Determining the position of the individual bunches is challenging due to their very short length (~12 ps rms) and their temporal proximity (less than 4 ns in some cases). Providing pulses adequate for accurate sampling is further complicated by the less-than-ideal response of long coaxial cables. Here we propose two approaches to produce enhanced, i.e. stretched pulse shapes of limited duration; one based on specially shaped BPM electrodes and the other one on analog integration of more conventional stripline BPM signals. In both cases, signals can be generated which contain relatively flat portions which should be easier to sample with good precision without requiring picoseconds timing accuracy.