Edition 5, No. 3 December 17, 1997 Price: FREE


We would like to take this opportunity to extend our best wishes for the coming holidays!

Editor: Carl J. Gross

Contributors: C. Baktash, H. K. Carter, F. Ervin, J. D. Garrett, C. J. Gross, M. J. Meigs, A. Mezzacappa, M. R. Strayer

1. Results from the Meeting of HRIBF PAC-3

The HRIBF Program Advisory Committee (PAC) met at the Holifield Radioactive Ion Beam Facility (HRIBF) in Oak Ridge on October 21, 1997, to consider the next round of proposals for experimental studies at the HRIBF. Five hundred ninety-eight shifts of radioactive beams and 181 shifts of stable beams were requested in 24 proposals. In general the scientific content of the proposed experimental studies was judged to be excellent, and the proposals were well written. Obviously, it was not possible to grant all of requested experimental time at the HRIBF, which is expected to run a radioactive beam research program of about 1200 hours this fiscal year. The PAC was instructed to recommend a "start-up" program for radioactive 17F and 18F beams and a similar program for radioactive 56Ni. One hundred seventy-seven shifts of radioactive ion beams were assigned to the eight radioactive ion proposals approved (93 shifts of radioactive fluorine and 84 shifts of 56Ni). In addition, 90 shifts of stable beams were assigned to those radioactive ion beam proposals which also requested stable ions and to the four proposals which were accepted that requested only stable beams.

A list of the approved experiments can be obtained from the HRIBF web site at

2. HRIBF Users Group Meeting at Whistler Well Attended

The annual HRIBF Users Meeting took place at the Autumn Meeting of the Division of Nuclear Physics in Whistler, British Columbia. Over 50 people attended the presentations given by Jim Beene, Jerry Garrett, Carl Gross, and Michael Smith. Highlights included the successful completion of the first RIB experiment using 69As, progress on the development of 17F beams of 107 particles per second, successful experiments completed on the RMS, commissioning of the DRS, plans to bring the Enge spectrometer on-line, and initial information on the request for proposals submitted to PAC-3.

3. Users Executive Committee Election Results

More than 130 HRIBF Users have voted to elect Michael Wiescher of Notre Dame and Brad Sherrill of Michigan State to the Users Executive Committee. They will replace Carrol Bingham and Joe Hamilton in January 1998 and will serve through December 2000. We wish to thank Carrol and Joe for their service these past three years.

The membership of the HRIBF Users Executive Committee for 1998 is:

Noemie Benczer Koller
John D'Auria
Mark Riley
Brad Sherrill
Michael Smith, Chair
Michael Wiescher.

4. UNISOR Mass Separator Modified for Negatively Charged Ions

Modifications to the UNISOR isotope separator have recently been completed and tested, allowing this facility to operate with both negative and positive ion sources. Prior to this, only operation with positive ion sources was possible. Instrumental in our development of RIBs, the UNISOR separator serves as the on-line test stand for the various ion sources and targets being developed for the RIB platform by utilizing beams from the 25 MV tandem accelerator. The present modifications will allow negative ion sources, such as those used to produce Fluorine beams, to be developed and tested.

5. Tandem Changes and Status

During Fiscal Year 1997 the 25 MV tandem has provided approximately 1850 hours of beam for the commissioning of experimental equipment, development of beams of radioactive ions, and the experimental program. Low-energy beams have been provided for the commissioning of the DRS with terminal voltages of only 3 MV. Attempts will be made in the new year to improve the efficiency and beam transport of low energy beams. One nasty problem which has plagued high-voltage operations this year has been the installation of defective charging chains at the beginning of this calendar year. The hardened chromium coating that is used on the surface of the chains to minimize wear proved inadequate and has resulted in over four pounds of metal powder deposited throughout the tandem column. A settlement has been reached with NEC, and new, properly plated chains will be installed during the Christmas maintenance period.

Four new operators have been certified, bringing the total number of qualified operators up to 8. The tandem control has now been transferred to the VISTA system, which now controls via computer almost all the HRIBF beam lines and accelerators.

6. Second Oak Ridge Symposium on Atomic and Nuclear Astrophysics

On December 2-6, 1997, the Oak Ridge National Laboratory, in conjunction with the Joint Institute for Heavy Ion Research and the University of Tennessee, hosted the Second Oak Ridge Symposium on Atomic and Nuclear Astrophysics. A total of 127 scientists were in attendance, presenting 91 invited talks and invited and contributed posters on stellar atmospheres, stellar evolution, stellar explosions (novae, supernovae, and x-ray bursters), pregalactic and galactic chemical evolution, the interstellar medium, and atomic and nuclear data for astrophysics. The presentations covered observations, modeling, and the atomic and nuclear physics foundations (data, experiments, and theories) essential to understanding these astrophysical objects and events.

The proceedings of the Symposium will be published by the Institute of Physics Publishing and will be available in June of 1998.

7. Announcement of Nuclear Structure 1998 International Conference

The Physics Division of the Oak Ridge National Laboratory will host an international conference covering current topics in nuclear structure physics from August 10-15, 1998, in Gatlinburg, Tennessee. This is the next conference in a series of North American biennial meetings that have been hosted alternatively by the Argonne National Laboratory, Chalk River Laboratory, Lawrence Berkeley Laboratory, and Oak Ridge National Laboratory. The first circular will be distributed in the coming weeks. The deadline for abstracts will be in early May 1998.

8. Presidential Early Career Award for Science to Theorist David Dean

David Dean of ORNL's Nuclear Theory Group has received the Department of Energy's Young Scientist Award and the Presidential Early Career Award for Science and Engineers. These awards are given each year to a few outstanding scientists and engineers at the beginning of their research careers. For example, the Presidential Early Career Award was given to about 60 young researchers from all disciplines. These awards are intended to recognize individuals who show exceptional potential for leadership at the frontiers of scientific knowledge during the 21st century. The Presidential Award is the highest honor bestowed by the U.S. government on outstanding scientists at the onset of their careers. David received the awards in recognition of his research in nuclear structure physics recognizing his critical contributions to the development of the Shell Model Monte Carlo methods. These developments make possible the extension of shell model calculations to heavier nuclei. David's research emphasizes the interplay between theoretical and experimental physics and spans the spectrum of nuclear physics.

9. HRIBF Guest Hostel

The HRIBF guest hostel has 10 dormitory rooms, a fully equipped kitchen, and a lounge area. These accommodations are provided at no charge for visiting scientists conducting experiments at the HRIBF. As soon as you know the dates you will arrive to work on an experiment, you may make reservations through your local ORNL contact or by directly contacting the HRIBF Liaison Secretary, Franda Ervin, at 423-574-4113 (e-mail: The room key may be picked up from the Liaison Office just inside the main entrance to Building 6000 (the building with the tandem tower) when you arrive. Should you arrive after office hours (8:00 am - 5:00 pm), prior arrangements should be made and keys for your reserved room may be obtained from the guard at the ORNL main gate

Please remember that alcoholic beverages are strictly forbidden at the HRIBF hostel, as on all ORNL property.

Additional copies of the newsletter and more information about HRIBF can be found on the World Wide Web at You may contact us at the addresses below.

Jerry D. Garrett Carl J. Gross
Scientific Director Scientific Liaison
Mail Stop 6368 Mail Stop 6371
+1-423-576-5489 +1-423-576-7698

Holifield Radioactive Ion Beam Facility
Oak Ridge National Laboratory
Oak Ridge, Tennessee 37831 USA
Telephone: +1-423-574-4113
Facsimile: +1-423-574-1268