Last year, the Senate Energy and Water Development Appropriations Subcommittee
included language in its FY 2006 report requesting the Department of
Energy to submit a report regarding the Rare Isotope Accelerator. House
and Senate conferees reiterated this requirement, stating, "The
conferees support the Rare Isotope Accelerator (RIA) but are concerned
that the Department does not seem to be making tangible progress toward
realization of RIA." DOE had 120 days to submit a report "to
define a specific path forward on RIA." The report, less the "Introduction
and Charge" which excerpted the Senate report language (and which
can be read under "Nuclear Physics" at http://www.aip.org/fyi/2005/098.html
) is below:
"Response to Questions in Senate Report 109-84 Regarding the
Rare Isotope Accelerator (RIA)
[One-page "Introduction and Charge" with the Senate Energy
and Water Development Appropriations Subcommittee report language was
excerpted at this point.]
"This report, prepared by the Office of Science for Nuclear Physics,
is in response to this request.
"Plans Regarding Moving Forward with RIA
"Even with the planned doubling of funding for basic research
in the physical sciences over the next ten years announced by the President
in his State of the Union address, the Department is compelled to balance
commitments to specific programs in the context of its broader research
portfolio and the Department's and the Nation's priorities.
"The RIA as originally envisioned would be a facility with unprecedented
capabilities world-wide, but with an estimated cost of $1.1 billion,
it would represent a major investment by the Federal Government. Consistent
with advisory committee guidance, the highest priority for Nuclear Physics
facilities is the effective use of its existing world-class facilities—the
Relativistic Heavy Ion Collider and the Continuous Electron Beam Accelerator
Facility—to foster the discoveries and advancements in scientific
understanding for which they were built. The FY 2007 Budget Request
and the subsequent five-year budget plan fully support this top facility-related
priority as well as the critical need to maintain a strong ongoing university
and the national lab research program. Given these priorities, the Department
has concluded that it is not prudent to proceed with RIA at this time.
The Department continues to believe that research in rare isotopes is
an important element in the Nation's portfolio of scientific capabilities.
The Department believes that the United States can maintain leadership
in this area of nuclear physics via the alternate path described below.
"The Department is exploring the possibility of starting design
and construction of an alternate exotic beam facility around the end
of this decade. Near-term funding would be provided to develop research
capabilities at both domestic and international facilities so that the
U.S. research community is fully engaged at the forefront of nuclear
structure and astrophysics studies and prepared to fully utilize the
U.S. exotic beam facility when it would come into operation. In keeping
with this strategy for an alternative future facility, the FY 2007 Budget
supports generic exotic beam research activities but not RIA-related
conceptual design work.
"The FY 2007 OSTP/OMB R&D Budget Priorities Memorandum stated
that ‘Within discovery-oriented physical science investments, priority
will be given to those projects and programs that are demonstrably well-coordinated
with related programs in other agencies and countries.' Our near-term
plans are consistent with this guidance, and we will actively pursue
partnerships with other countries and other agencies, including the
National Science Foundation (NSF), for this alternate exotic beam facility.
The NSF supports the National Superconducting Cyclotron Laboratory at
Michigan State University, which is considered to be the leading rare
isotope facility in the United States and serving over 600 scientists
from the U.S. and abroad. With expertise in exotic beam research crossing
agency boundaries, it is natural to ensure that efforts are coordinated
across agencies to support an optimal nuclear physics program for the
Nation. The Department is proposing a path forward that will address
the Nation's needs in this scientific area while ensuring the overall
scientific productivity of the Office of Science's programs.
"The Department will seek outside expert guidance from the scientific
community and advisory bodies such as the National Academies and the
DOE/NSF Nuclear Science Advisory Committee (NSAC) in defining this alternate
facility. A scientific assessment of the role and importance of rare
isotope science in a national and international context is underway
at this time by the National Academies, with a report expected this
fall. The Academy's findings as well as guidance from NSAC will be important
input to the Department's decision on how to proceed with the implementation
of national capabilities for exotic beam studies.
"Answers to Specific Questions
"Q. The status and progress of the conceptual research and
development supporting the development of RIA over the past 6 years
"A. Research and development activities directed towards
the RIA were begun in 2000 based on guidance provided in 1999 by a NSAC
study. In August 2003, a RIA research and development (R&D) workshop
was held at which experts in the field identified areas for prioritized
efforts for R&D required prior to the construction of RIA. Since
then, R&D has been based on these priorities, which address performance
enhancement and cost and schedule risk. On an annual basis, the priorities
have been revisited and found to remain appropriate. All R&D activities
since FY 2006 have been directed to generic studies related to a next
generation rare isotope beam capability; no efforts directed towards
a project-specific Conceptual Design Report for RIA have been funded.
Major Areas of R&D:
The gas cell, where unstable nuclei can be brought to rest
and then rapidly extracted to produce reaccelerated beams, is an innovative
device that greatly extends the capability to study the most unstable
nuclei. R&D efforts have demonstrated that ions can be extracted
from a gas cell in tens of milliseconds with nearly 50% efficiency.
A prototype high performance electron-cyclotron resonance ion
source for the driver accelerator has been built, and tests have demonstrated
extraction of bismuth ions; testing to meet the specifications for uranium
is ongoing.
Prototype superconducting accelerator cavities for the low
and medium velocity segments of a heavy-ion driver linear accelerator
have been developed.
Development of targets that produce radioactive elements reliably
while having the capability to dissipate high power levels is being
pursued. The so-called ‘two stage' target, where a neutron production
stage is separated from the radioactive element production stage, has
been tested.
The efficient acceleration of heavy ions requires one or two
stages of stripping to increase the ion charge state. A project is underway
to investigate a concept utilizing flowing liquid lithium films to withstand
the high power beams without failure.
Laboratory tests using high power electron beams to simulate
uranium beams show that lithium films can withstand high power beams
without degradation.
Diagnostics concepts for low intensity beams have been developed
and devices built and tested, and are already in use in several accelerator
facilities.
Fragment separators collect the shower of nuclear species produced
in a fragmentation reaction and separate the species of interest from
the rest. Several designs, each adapted for a different use in an exotic
beam facility, are being investigated. Studies are underway to investigate
the suitability of superconducting materials in the high radiation environment
of these separators.
Advanced computer software for beam dynamics calculations has
been developed, and is being used to study beam halo effects, a significant
source of unwanted equipment activation.
"Q. The priority research areas the Department will complete
prior to site selection for RIA
"A. Given the Department's position on RIA as stated above, there
are no RIA-specific priority research areas that are currently targeted.
In FY 2007 and the outyears, generic R&D continues for an exotic
beam facility aimed at topics that optimize performance and reduce cost
and schedule risks.
"Q. The process by which the Department selects recipients
for its research and development funding
"A. R&D funds are awarded on an annual basis according to
merit-based peer review. Each year proposals are solicited separately
from universities and laboratories. A panel of experts is convened to
assess the scientific and technical merit of the proposals, the validity
and feasibility of their approach, the competence of the proposer(s),
and the appropriateness of their budget and schedule.
"The criteria for assessing scientific and technical merit of
R&D proposals includes the degree to which the acquired knowledge
could enhance the performance, reduce the construction and/or operating
costs, and reduce the engineering and scheduling risks associated with
a rare isotope beam facility.
"Q. How the results of current and future research and development
may affect the design of RIA or the path forward
"A. The results of current and future research and development
will be used to optimize the scientific and performance capabilities
of a rare isotope facility and to reduce the cost, schedule and risk
of its construction.
"Q. What technical hurdles remain before RIA site selection
can resume?
"A. The Department is not aware of any ‘show-stopping' technical
hurdles relevant to site selection for a future exotic beam facility.
R&D, as discussed above, will continue to be supported to optimize
performance and reduce costs and technical risk. This R&D will address
issues that will need to be resolved before the final design and start
of construction (e.g., to verify the best method to stop and collect
rare isotopes for reacceleration and that targets can withstand high
intensity beams).
"Q. What funding will be required to clear those hurdles and
what is the expected length of time for completion of these activities.
"A. Annual funding at roughly the level proposed in the FY 2007
Budget Request ($4 million) will be required until final decisions are
made on the technical design and construction begins. Of course, several
National Laboratories may well continue to augment these efforts by
supporting relevant R&D activities via their indirectly-funded Laboratory
Directed Research and Development (LDRD) programs."
Richard M. Jones
Media and Government Relations Division
American Institute of Physics
fyi@aip.org
301-209-3095
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