BEAM PROFILE MEASUREMENTS BASED ON BEAM INTERACTION WITH RESIDUAL GAS

摘要

Traditional methods of beam profile measurementsrnlike wire scanners, harps, and screens have therndisadvantage of intercepting the beam. Diagnostics ofrnintense particle beams requires development of new non-interceptingrnbeam monitoring methods. There are severalrnkinds of diagnostic devices based on registration ofrnproducts of accelerated beam particles interaction withrnatoms and molecules of residual gas in an acceleratorrnvacuum chamber. Usually these devices are used as beamrnprofile monitors, which register electrons or/and ionsrnproduced in collisions of beam particles with residual gasrn(residual gas ionization profile monitor). Some attemptsrnwere made in application of light radiation of excitedrnatoms (gas scintillation profile monitor). The non-interceptingrnmethod of beam diagnostic based on lightrnradiation of atoms excited by the beam particles has thernadvantage to be insensitive to external magnetic andrnelectric fields and, as a consequence, to the beam spacerncharge field. It allows to get higher spatial and timernresolution. Measurements under different conditions atrnCOSY-Juelich and in a cyclotron beamline at I'ThembarnLABS are presented and the pros and cons of the methodsrnare discussed.