Novel Source Ionizer Options for Polarized Ions

Abstract

Presently, the RHIC Spin project includes a polarized proton program. And, there is a future need for sources of polarized 3 He ions for RHIC and elsewhere. Ideas for intense sources of H + and 3 He ++ ions, as well as ionizer options for polarized 3 He ion sources are discussed. Polarized 3 He ions had been accelerated over thirty years ago. However, only a few 3 He ion sources have been in operation, even though polarized 3 He ion beams can be very useful in nuclear and high energy physics research. A major problem is the low output current yields and/or low polarization of these sources. A major culprit for the low outputs has been poor ionizer performance. Two types of ionizers are considered: magnetized Z-pinches and fiber cathode electron beam ionizers. Recently copious amounts of fully striped helium have been extracted from LIZ-MeV (A magnetized Zpinch ion source). Several kA of current were extracted. Discharge pulse length was 2.2 ìsec. To realize the magnitude of this output, 1 kA of He ++ in this pulse length yields about 1.4x10 16 He ++ per pulse. A minute fraction of this output would satisfy any RHIC polarized neutron program requirements. A magnetized Z-pinch ion source can generate even larger quantities of H + to enhance OPPIS. Polarized 3 He ion source ionizers are evaluated: one utilizes a fiber tip electron beam to ionize helium of an existing polarized 3 He internal target. The other method relies on fast stripping of 3 He atoms to form 3 He ++ inside LIZ-MeV. Quick ionization (before any depolarization or other losses can occur) and simplicity are the main advantages of these approaches.