HRIBF Initiatives

Special announcement

The HRIBF has developed several possible upgrade paths to ensure the future health of the facility. These paths cover a wide range of complexity and cost, and their relevance depends on the future plans of the nuclear science community for a next-generation exotic beam facility. Our upgrade paths are consistent with the HRIBF Integrated Strategic Plan which is available to our users and we welcome their comments. Please send comments to either Jim Beene (beenejr@ornl.gov) or Witek Nazarewicz (witek@utk.edu).

Our Scientific Policy Committee advises the facility as to which initiatives to pursue. HRIBF and ORNL Physics Division staff and management are committed to enhancing the ability of HRIBF to reliably deliver radioactive ion beams (RIBs) of high quality and intensity, but limited by extremely tight operating budgets.

A project is now underway to improve the reliability, flexibility and capability of RIB delivery by providing HRIBF with a second RIB production station. This project, known as the Injector for Radiaoctive Ion Species 2 (IRIS-2), will incorporate the newly completed High Power Target Laboratory (HPTL) , and will provide badly needed redundancy for front-end RIB production, as well as substantial increase in beam production and manipulation functionality. We expect the IRIS-2 project to be completed at the end of this fiscal year.

The reliability of ORIC, which is approaching 50 years of service, has been an issue throughout the life of HRIBF. An aggressive accelerator improvement program replaced or upgraded many aging and obsolete components over the last decade, and had a very large impact on reliability. Recently some of these improvement funds have been diverted to fund the HPTL and IRIS2 projects. This has slowed the pace and scope of ORIC improvements. It is important that the improvement program be re-invigorated and made even more aggressive. A somewhat larger scale effort, which would replace the ORIC internal ion source with external ion sources and an axial injection system should have a dramatic effect on ORIC operating efficiency, as well as providing greater flexibility in the variety of driver beams ORIC can deliver. The age of ORIC has led to the consideration of purchase of a "turn-key" cyclotron or electron accelerator to provide redundancy as well as to enhance the facility's performance. A white paper on a new cyclotron to replace ORIC is now available. Perhaps the most cost effective path to a significant improvement in performance appears to be an electron accelerator capable of providing high-power (up to 100 kW), near CW beams at energies of 25 to 50 MeV. Such a device (e.g. a small commercial LINAC or Rhodotron) would enhance our production of very neutron rich species by factors of more than 1000. Improvements on the proton-rich RIBs would depend on the enhanced capability of ORIC, plus target, ion-source and beam-manipulation improvements provided at IRIS2.

There is a strong physics motivation to increase maximum energy of post-accelerated RIBs at HRIBF. Installation of a new type of accelerator tubes in the tandem might make it possible to reach terminal potentials of 27 MV with beam, compared to our current capability of 24 MV (note that we expect to restore operation at 25 MV as soon as a temporary interruption in the supply of SF₆ is alleviated). At present the risk of this tube replacement is considered too large for the modest gains in beam energy that would result. Ultimately, a new post-accelerator could be imagined that could directly accelerate positive ions or possibly serve as a booster to tandem beams. The cost of such a machine makes it an unlikely option in the near term, however the dramatic results of reliability and beam intensity upgrades now underway or being planned should provide greater justification of such a project.