Oak Ridge 25URC Tandem Accelerator 1999 SNEAP Lab Report

Conference · Fri Oct 01 04:00:00 EDT 1999

OSTI ID:14978

Haynes, D L ^[1]; Juras, R C; Meigs, M J

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1. ORNL

A major milestone was reached in the end of October 1998, when an experimentally-useful {sup 17}F beam (t{sub 1/2}=64.5 s) of 3 x 10{sup 4} ions per second (ips) was delivered to experimenters at the astrophysics endstation. A beam of {approx}8 {micro}A of 44 MeV deuterons incident on a target of thin fibers of HfO{sub 2}, together with an aluminum vapor feed, produced a beam of Al{sup 17}F{sup +} ions which, after first-stage mass analysis and breakup/charge exchange in Cs vapor, yielded 4 x 10{sup 7} ips F{sup {minus}} off the RIB platform. The {sup 17}F produced for this first useful experiment had only slight contamination of {sup 17}O (<1%), but the breakup of the molecular AlF introduced a large energy spread and the large emittance of the beam probably resulted in some transmission loss through the tandem. A new negative surface ionization source was installed and was used for most of the 1119 hours of {sup 17}F production in FY 1999. This source has been used to deliver 2 x 10{sup 5} ips of {sup 17}F (with {approx}3 {micro}A incident deuterons) but it can be highly contaminated with more than ten {sup 17}O for every {sup 17}F. A pure {sup 17}F beam of this magnitude has been obtained by using post-stripping to produce fully stripped fluorine ions with greater efficiency being obtained for the higher accelerated beam energies. Ion source development continues both at the UNISOR facility and at two ion source test stands. The next priority for RIB development is the production of a {sup 56}Ni beam. Because of the long lifetime and the highly refractory nature of Ni, the beam will not be produced by conventional ISOL techniques, but rather in a multi-sample sputter source, in which a target can be bombarded with Oak Ridge Isochronous Cyclotron (ORIC) beam for a period comparable with its half-life, and then rotated to a position where the activity can be exposed to a sputter beam for production of a {sup 56}Ni negative-ion beam. This batch mode source is designed so that one production target can be exposed to ORIC beams while another is simultaneously being sputtered. The batch mode source has produced stable beam on the RIB injector platform. Other development activities are primarily focused on a uranium carbide/reticulated vitreous carbon fiber target for production of neutron-rich beams by fission and a liquid germanium target system for production of proton-rich isotopes of As, Ga, and Se.

• Research Organization: Oak Ridge National Lab., TN (US)
• Sponsoring Organization: USDOE Office of Science (US)
• DOE Contract Number: AC05-96OR22464
• OSTI ID: 14978
• Report Number(s): ORNL/CP-105233
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
43 PARTICLE ACCELERATORS
ACCELERATORS
ALUMINIUM FLUORIDES
FLUORINE 17
FLUORINE IONS
HAFNIUM OXIDES
ION SOURCES
ISOCHRONOUS CYCLOTRONS
ISOTOPE PRODUCTION
NICKEL 56
NICKEL IONS
RADIOACTIVE ION BEAMS
SURFACE IONIZATION
TANDEM ACCELERATORS