RA2. Accelerator System Status
ORIC Operations and Development (B. A. Tatum)
During the reporting period, ORIC provided 85-MeV alpha and 50-MeV deuteron beams to IRIS1 for the production of Fluorine beams. However, this was a very difficult period of operation for ORIC that included a considerable amount of unscheduled maintenance related to failure of the coaxial magnetic extraction channel. This is a very high current device (up to 6000A dc) that developed water leaks which resulted in high tank pressure. We also experienced air and water leaks on the rf system shorting plane. All of these leaks were challenging to locate, and difficult and time-consuming to repair. We also experienced problems with the main field motor-generator set regulator and a few older power supplies. In addition, there was a scheduled shutdown period following Thanksgiving during which the new HRIBF cooling tower was brought on line and new substation circuit breakers installed.
We are anticipating a resumption of routine operation in early 2010 with an extended neutron-rich campaign and final commissioning of IRIS2 with RIB.
RIB Injector Operations and Development (P.E. Mueller)
During the period from 1 July 2009 to 31 December 2009, the 25 MV Tandem Electrostatic Accelerator delivered beams of
1 Mpps [10.76 MV 4+ terminal gas stripped] 54 MeV 50% 17F / 50% 17O to Beam Line 41, and 1.1 Mpps [8.87 MV 4+ / 9+ terminal gas / post foil stripped] 44 MeV 17F to Beam Line 14.
The 17F beams were produced via the 16O(d, n)17F reaction by bombarding a fibrous HfO2 target coupled to a Kinetic Ejection Negative Ion Source (KENIS) with 5 uA of 44 MeV 2H+ from the Oak Ridge Isochronous Cyclotron (ORIC).
Also during this period, significant maintenance was performed on the high voltage platform in C111S. Five of the six turbopumps (excluding the one associated with the charge exchange cell) were replaced, as were all six of the turbopump controllers on the high voltage platform in C111N. The ORIC beam line (BL-9) acceleration tube was reconfigured to accommodate both a new diagnostics chamber with water-cooled, self-suppressed Faraday Cup and water-cooled insertable aperture and a rotating-wire beam position monitor, all identical to those used in C112 (IRIS2).
Tandem Operations and Development (M. Meigs)
The Tandem Accelerator was operated for more than 1800 hours since the last report. The machine ran at terminal potentials of 1.34 to 23.38 MV. The KENIS ion source was used on IRIS1 to provide 289 hours of the radioactive beam, 17F. In addition, the SNICS was used to provide the stable beams 1H, 16,17O, 19F, 58Ni, and 124Sn. About 385 hours were spent conditioning, which was necessary to recover from a large SF6 leak in the low energy acceleration tube. Three tank openings were completed during this period; the first to allow the Discovery Channel to film inside the tank for a documentary, the second to remove the Faraday cup at the D4 position which had developed a large leak in its bellows, and the last to check for suspected leaks and to repair the gas stripper. Quite a few hours during this period were spent on SNICS development, leading to a greater understanding of the best methods to produce some difficult ion beams.