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Edition 2, No. 3 September 30, 1994 Price: FREE******************************************************************************* Contents:
The HRIBF Users Group Meeting at the fall DNP meeting is scheduled for Thursday, October 27, at 8:30 p.m., in General Lee's Redoubt. It will last an hour and will provide a progress report on the facility. Refreshments will be provided.
One of the key operating requirements of the facility is the production of RIBs at energies relevant for astrophysics studies. Production of these beams will require the tandem accelerator to operate at very low terminal potentials. This requirement was one of the motivations for replacing the old corona points with more than 3000 resistors last summer. The first measurements using this new configuration have been performed.
The overall transmission efficiency for an 16-O beam was measured in the beam energy range of 2.3 to 50.3 MeV. These measurements indicate that the accelerator can be operated at a terminal potential of 1 MV (2.3 MeV 16-O beams). While it is clear that ultra-low terminal potential operation will require further development work on the terminal potential regulation system, it is encouraging that the overall beam transmission efficiency at 2.3 MeV was observed to be only a factor of two less than that at 50.3 MeV (12.5 MV terminal voltage).
With regard to high voltages, after the installation of the resistors the tandem was quickly conditioned up to 20.7 MV (no beam) with no problems. Conditioning to the highest potentials is scheduled for early 1995.
HRIBF has been classified by the Director of the Office of Energy Research, Dr. Martha A. Krebs, as a low-hazard facility. This is an important step as all subsequent safety documents depend upon this classification. All aspects concerning the safe and routine operation of HRIBF are being actively pursued and final approval for the first production of RIBs is expected in November, 1994.
After a review of the physics experiments planned for the RMS, it has been determined that nearly all experiments will be satisfied by operating the RMS at less than half the rated power capabilities of the power supplies. In order to avoid added expense, it is proposed that the RMS be connected to the main power system as currently configured. This means that recoils requiring a K greater than 50 cannot be used. (see the review below). You are STRONGLY encouraged to review your experimental plans to ensure that no planned experiment will be compromised by this decision. This power configuration can be changed in the future should higher energy beams become available.
Please contact Carl Gross about your specific requirements for the RMS.
The original design of the RMS envisioned the use of highly inverse reactions based on high energy, heavy ion beams from the coupled operation of the tandem accelerator and the ORIC booster. Since ORIC is now used to produce RIBs, only tandem beams will be available for the RMS.
The K of a moving ion is given by, K=(Mass*Energy)/(Charge**2). For a "back of the envelope" calculation, assuming the Mass to be 2*Z and the charge is Z/2, K is approximately (8*Energy/Charge).
J. D. Cole, et al., Nuclear Instruments and Methods Phys. Res. B70, 343 (1992). K. Shima, et al., Atomic Data and Nuclear Data Tables, 51, 173 (1992).
Robinson Hall has been officially turned over to HRIBF, and the initial surveying of the hall for the location of the various components of the RMS is complete. The assembly of the RMS has started under the supervision of Paul Mantica.
Robinson Hall was officially dedicated on July 11 in honor of the long contributions of Russell L. Robinson to the Holifield Facility. Russell has been with ORNL since 1958 and a driving force that helped make the Holifield Facility into one of the world's premier user facilities for nuclear physics research. Joining HRIBF in this celebration were Russell, his family, friends, former classmates and collaborators.
At the present time the Daresbury Recoil Separator (DRS) is aboard the "Atlantic Conveyor" enroute from Liverpool to Portsmouth, Va., where it is scheduled to dock October 7. The expected arrival of the DRS in Oak Ridge is about a week later. This instrument will form the core of an Astrophysics End Station being prepared for HRIBF by the RIBENS (Radioactive Ion Beams for Explosive Nucleosynthesis Studies) Collaboration under the local direction of Michael Smith.
The newly appointed HRIBF Program Advisory Committee will hold its first meeting on October 7 in Oak Ridge. During this "get acquainted" session, the PAC members will have the opportunity to provide early guidance for the scientific program of HRIBF. The HRIBF PAC membership is:
Member Affiliation Service until
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S. M. Austin Michigan State University 1 Oct 1997
J. R. Beene Oak Ridge National Laboratory 1 Oct 1996
R. F. Casten Brookhaven National Laboratory 1 Oct 1996
R. M. Diamond Lawrence Berkeley Laboratory 1 Oct 1996
W. Gelletly University of Surrey 1 Oct 1997
W. C. Haxton University of Washington 1 Oct 1996
W. Nazarewicz Joint Institute/University of Tennessee 1 Oct 1997
P. D. Parker Yale University 1 Oct 1997
HRIBF has installed a WWW node which we hope will be accessible by October 15. This node provides information about the facility including such items as the layout of the laboratory and conceptual design of planned experimental equipment. There is a staff directory and a list of the contact personnel, directions to the laboratory, and information needed to arrange a visit. We hope to include schedules for experiments and the next PAC meeting once we are up and running. You will also be able to obtain copies of past newsletters.
To access the node, simply use your favorite WWW browser (e.g. Mosaic from ftp.NCSA.uiuc.edu), open the URL (Universal Resource Locator) to node http://www.phy.ornl.gov/. Not everything is ready but we hope to add things in a timely manner. This is a "living document" so some things will change or be added or deleted. You will find a proposed list of things you will some day be able to find on the node. If you would like to see anything else, please contact Carl Gross.
CHECK US OUT!!!!!!
****************************************************************************** ****************************************************************************** Jerry D. Garrett, Scientific Director |Email: garrett@orph01.phy.ornl.gov Mail Stop 6368 |Tel: (615) 576 5489 Carl J. Gross, Scientific Liason |Email: cgross@orph01.phy.ornl.gov Mail Stop 6371 |Tel: (615) 576 7698 Holifield Radioactive Ion Beam Facility |Tel: (615) 574 4113 Oak Ridge National Laboratory |Fax: (615) 574 1268 Oak Ridge, TN 37831