BEAM FORMATION AT THE MUNICH ATOMIC-BEAM SOURCE

A Stern-Gerlach atomic-beam ion source (ABS) with an electron cyclotro n resonance (ECR) ionizer and a Cs gas target as charge exchange units will replace the Munich Lamb-Shift polarized hydrogen source. The goa l is to achieve intense negative beams of polarized H- and D- of high brightness for injection into the 14 MV MP tandem accelerator and beam intensity of about 2 mu A on the target. At the entrance of the ECR i onizer the observed intensity of the neutral beam of polarized atoms i s 6.4 +/- 0.4 x 10(16) H/s, equivalent to 10 particle/mA before ioniza tion, Comparing beam transport calculations with beam intensity measur ements under various conditions allows a consistent description of the beam formation in the ABS with respect to the degree of dissociation (similar or equal to 83%), peaking (similar or equal to 1.6), beam abs orption (similar or equal to 40%), and pumping speeds to be made. (C) 1998 American Institute of Physics.