The Committee unanimously recommends
the establishment of a deep premier national underground scientific laboratory
to enable US leadership and synergism in a broad array of scientific fields in
the coming decades.
The committee endorses a single
primary site as the most effective method of realizing the anticipated
scientific program.
The Committee believes that there
are two excellent sites for a premier deep underground science laboratory:
Homestake and San Jacinto. The committee admires the commitment of the
proponents of the proposals to outreach and communication of basic science to
the American public. Based on the information we have received, and on the
independent assessment by the committee, we judged that Homestake and San
Jacinto are very similar in their technical suitability for underground
experiments. Although the committee is not charged with making a formal site
selection, time is of the essence, and the agencies need to be aware of the
time-sensitive nature of the site selection.
We strongly encourage interagency cooperation to help realize this
exciting opportunity for science.
At the time of this meeting the
committee favors the Homestake site for the following reasons:
- faster time scale to produce
important scientific results,
- less initial capital outlay to
produce world-class science,
- greater positive impact on the
local population,
- lower inherent uncertainties.
The San Jacinto site is also judged
to have great potential for several reasons:
- horizontal access allows simple and cost effective access and
operation,
- lower operating costs,
- the close proximity of strong
scientific research universities.
The Homestake pre-proposal at
present is not complete. First the indemnification problem must be solved.
Second, a representative, national group of underground scientists must be
involved in the preparation of a formal proposal that describes a detailed
science program and a complete cost estimate for the laboratory. Given the imminent closure of the Homestake
mine, these two issues must be solved in a timely fashion, or the advantages
which lead us to favor the Homestake site will be significantly reduced.
Like Homestake, San Jacinto could
become the premier site in the world, but further work is needed. Concerns
include cost, construction permitting, and site optimization. A more broadly
representative group of proposers would be desirable, as well as a comparison
of the San Jacinto site to nearby alternatives. We encourage the San Jacinto
site advocates to continue working on the preparation of a proposal. If the
issues with the Homestake mine are not resolved adequately in a timely fashion,
the San Jacinto site is an excellent opportunity.
The Committee has received and
considered a pre-proposal from advocates for the Carlsbad Underground National
Laboratory. The Technical Assessment Sub-Committee visited the Carlsbad site
and the existing Soudan Underground Laboratory. The Committee believes that
both these sites have played important roles in the development of underground
physics.
The considerable resources of the
Carlsbad site and the relative ease of excavation in salt have and will likely
continue to facilitate a number of prototype experiments. The support in New
Mexico for fundamental physics at Carlsbad is impressive and provides an
excellent example of how a future national laboratory should inform and educate
the American people.
The Soudan Laboratory has well
hosted the Soudan 2 detector for more than a decade and has recently expanded
to house the far detector for the important MINOS Fermilab-to-Soudan neutrino
oscillation experiment and the CDMS-II dark matter detector. The physics
program at Soudan is an excellent model for how to work collaboratively to
inform and educate both the general public and K-12 school children about
science.
Despite
these considerable assets, the Committee strongly believes that limited depth,
and thus excessive cosmogenic background, preclude these facilities from being
general purpose underground science facilities for the United States. The
Committee further believes that while these sites have a future role in a
comprehensive program, the advantages of collaboration and synergy favor
focusing the majority of future detectors at a single deep site.