Braidwood letter

From: Ed Blucher (
Date: Tue May 09 2006 - 06:12:19 CDT

Here's the last draft of the letter to Staffin (with the original last
paragraph) for discussion at today's meeting.


Dear Dr. Staffin and Dr. Orbach:

    We are writing to express our frustration with the recent
decision of the DOE to deny R&D support to the Braidwood
experiment. This decision was made without benefit of
the expected technical comparison among competing
experiments. We believe eliminating this technical
competition will harm the quality of the
experiment, wherever it is ultimately done.

    A precision measurement of sin2(2th13) below the 0.01
level is recognized as the key next step for
understanding neutrino masses and mixing, and as an
important component of the long term neutrino program.
The importance of this measurement has been affirmed by
the APS Neutrino Study, as well as the Neutrino
Scientific Assessment Group.

    A measurement of this precision is extremely challenging,
representing more than an order of magnitude improvement
over the best previous experiment.
It amounts to measuring the difference in counting rates at different
locations to the level of 0.1%.
Our collaboration's
studies showed that reaching this precision in a
convincing way requires an experiment that follows
certain basic principles:

- multiple large, spherical detectors that minimize
boundary effects
- all detectors protected by an equal and well-understood overburden
so cosmic ray backgrounds are similar
- detectors on the reactor symmetry axis to eliminate reactor flux effects.
- a robust shielding system to reduce and measure backgrounds in situ.

The unique features of the Braidwood site allowed our
group to design an experiment incorporating these
critical points. We are concerned that the Daya Bay
design does not include these features, and that US
groups may have limited ability to effect changes.

    We believe that thorough peer review of experiments is
critical to the health of the U.S. high energy physics
program. Supported competition between Braidwood and
Daya Bay will produce the best and most cost effective
version of this extremely challenging experiment. We
therefore request that R&D funding be awarded to both
Daya Bay and Braidwood, and that a full technical review
of both experiments be carried out.

The Braidwood Collaboration

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