The collimation system design for the Booster Ring in the HIAF project

The dynamic vacuum effect induced by the charge exchange beam loss will seriously limit the ion intensity and beam lifetime in the Booster Ring (BRing) of the High-Intensity Heavy Ion Accelerator Facility (HIAF). A dedicated collimation system has been designed to decrease the ion-induced gas desorption to suppress the dynamic vacuum effect. In order to reach 100% collimation efficiency, the optics lattice of BRing has been changed from original FODO to DBA structure. The distance between dipole and quadrupole in each lattice cell of BRing was optimized to maintain the high collimation efficiency. The hardware structure of the collimator was designed based on the simulation result and mechanical instrument control principle in the UHV vacuum system. The vacuum chamber and pump installment with collimators has been designed. A prototype collimator with vacuum chamber has been installed on the beamline to measure the gas desorption with beam and verify the availability and reliability of mechanical design. This prototype collimator has passed factory field tests and used to measure the gas desorption rate with the beam 112Sn26+ at the energy 150 MeV/u successfully.