1. HRIBF Update and Near-Term
(J. R. Beene)
The August 2005 issue of the HRIBF Newsletter discussed the challenges presented to the HRIBF operations staff by the effort to continue normal running of the HRIBF science program while successfully completing the HPTL project. This trying combination of tasks has, indeed, been completed. The HRIBF staff deserves our thanks and admiration for this achievement, and for the sustained, intense, focused and effective effort they provided to get it done. The commissioning of the HPTL is now complete and it is fully ready for the experimental program to begin. The only missing detail is the delivery and installation of a bridge crane for handling activated target ion source assemblies. The crane, which is not needed for the initial round of experiments, will be delivered and installed by the end of February.
The DOE Office of Nuclear Physics (DOE-NP) held a closeout review of HPTL project at ORNL on October 23 and 24, 2005. This review also served as a baseline cost, schedule and technical review of the IRIS2 project. The closeout review was very favorable as was the IRIS2 baseline review. Initial funds for the three-year IRIS2 project are allocated in the FY2006 DOE budget, and it has now begun.
The HRIBF Program Advisory Committee (PAC) met on December 8 and 9, 2005, to consider a set of high-quality proposals. A total of 149 eight-hour shifts of beam-time were approved out of 370 shifts requested (see section 8). The Scientific Policy Committee (SPC) met with Physics Division management and HRIBF management and staff on December 10 and 11. The present membership of the SPC includes seven distinguished scientists from the U.S. and Europe: Juha Aysto (chair, Jyvaskyla), Brad Fillppone (Cal Tech), John Hardy (Texas A&M), Thomas Glasmacher (NSCL), K. E. Rehm (Argonne), A. Shotter (TRIUMF), and F-K. Thielemann (Basel). The SPC provides us with advice and counsel on a wide range of topics and issues. Substantial time was devoted at this meeting to a discussion of the draft HRIBF Strategic Plan which was developed at the behest of DOE-NP to serve as a framework for the effort to optimize the development of HRIBF and ensure that it is well aligned with the priorities of DOE-NP and the Office of Science. This Plan is discussed more in detail in a separate article in this newsletter.
In spite of this sustained effort on HPTL as well as other maintenance tasks, just over 1200 hours of RIB were delivered to experiments in FY2005 as a part of 3363 total research hours. Fiscal 2006 has so far been devoted to HPTL commissioning, stable beam experiments and scheduled maintenance. A major tandem tank opening began on December 5 and lasted six weeks through the holiday period. This was the first extended tank opening since May 10 (there was a one-day unscheduled opening in September). A variety of routine but pressing maintenance issues were addressed. The first quarter resulted in 932 research hours of beam, including a nuclear astrophysics experiment during which the 25 MV tandem was operated are a record low voltage of 1.245 MV. The range of voltage over which this machine can deliver beam stably is remarkable.
The schedule for the remainder of FY2006 will be devoted largely to neutron-rich RIBs. We expect to wage two nearly back-to-back n-rich campaigns of roughly three month duration each, with only brief interruptions for stable-beam runs. Several of the n-rich experiments call for relatively high tandem voltages. Our current inventory of SF6 is less than optimal for running at the highest voltages. Consequently we intended to purchase additional SF6 this fall. Unfortunately, hurricane Katrina resulted in a worldwide shortage of this material. It will not be possible to purchase enough to impact performance until May at the earliest. Following the n-rich campaigns, we will have another 4-week period of scheduled maintenance in late summer, and end the fiscal year with a proton-rich beam campaign (Al or F). A new feature of our schedule in FY2006 will be the inclusion of beam-development and target testing experiments utilizing ORIC beams at the HPTL