Increased ion intensity and reliability of the Stockholm electron beam ion sourcea)

Abstract:  Abstract The electron beam ion source, CRYSIS, produces highly charged ions for injection into the heavy ion storage ring-CRYRING at MSL, as well as low energy atomic physics experiments and the Stockholm-Mainz Penning trap recently installed at MSL. CRYSIS has produced ions up to Ar18+ and 136Xe52+. Pulsed beams of Ar13+ ions 60 ?s in duration have been injected into CRYRING via an RFQ and ions of charge up to 136Xe44+ have been used in atomic physics experiments with pulse duration 10-250 ms. A vacuum separation of the cryostat and ionization volumes has been made. Temperature control and measurement of internal electrodes have increased the gas injection efficiency and reduced the memory effect associated with a cryogenic EBIS. External ion injection has been added as an alternative to neutral gas injection for introducing the species to be ionized to high charge states. Monitoring of the radio frequency noise signal with a spectrum analyzer has aided in the propagation of quiet, high current (450 mA) dc electron beams. These quiet electron beams have been used to produce extracted ion pulses of higher intensities than in previous operation.