Minutes from June 3 Meeting
Goal for this Group for the summer:
On May 21, Maury, Steve, and Debbie met with Mike Witherell to talk about
what the future of this group is--long ago we were asked to do a study
about detector r&d for future neutrino experiments, and we really should
get down the business of writing up this document. Witherell suggested
that the document focus really on what detector r&d needs to get done
in order to propose a numi off-axis experiment to search for nu_mu to nu_e
oscillations. Over the past few months there have been several interesting
studies presented, now it's time to synthesize all that information. To
that end we had two presentations on detector r&d today, which would
presumably make up part of this report. This document is to be presented
to the Fermilab PAC this fall, and people should start thinking about what
they want to contribute now!
Slides from Alan Bross's Presentation (post-script) or here's the
(power point file)
Alan gave a talk about the new scintillator facility that he
has been working on out at the village at Fermilab. They have
been able to substantially reduce the cost of scintillator since
the days when MINOS was buying it, and if they can get industry
to adopt their techniques, very large quantities of high-quality
scintillator could be made for a lower cost.
For a detector with 10 times the fiducial mass of MINOS (10x5kton)
and 1/4 radiation length sampling, you end up wanting something like
12ktons of solid scintillator. They have been able to reduce the cost of
the scintillator itself, but you can't get past the $4/kg cost of the
raw material. They're now at $5/kg (or $5M/kton) after working hard to
cut production costs. The fiber costs could be significantly smaller
by goingto smaller fiber diameters, (which would be possible in the new
geometry configuration Alan describes). Finally, VLPC's have come a long
way since MINOS was proposed, they might also provide a big cost savings over
what it would cost to just re-build MINOS but with much more segmentation.
Alan estimates that one could possibly do a factor of 10 cheaper with readout
by going to VLPC's, although VLPC's need to be at liquid helium temperatures.
Slides from Peter Shanahan's Presentation (pdf)
Peter Shanahan gave a talk on cosmic ray measurements that are planned
with plastic and the RPC's that they have received from Virginia Tech.
Everyone agrees that the issue of cosmic rays has to be extremely well
understood (and measured!) before one would pick a far detector site
(or design the overburden scheme). However, there was some worry
about the fact that with "only" 20 RPC's from VT, and assuming readout
every 1/4 or 1/3 of a radiation length, you would only be able to look
at a detector which was 5-7 radiation lengths long, and typically
electromagnetic showers are much longer than that--the shower maximum might
be somewhere around a few radiation lengths.
Of course with cosmic rays there are two issues: can you survive the
data-taking rate to begin with, and
how often would one of these cosmic ray events look like a nue cc event?
What kind of veto shield would be necessary?
Last modified: Tue Jun 18 13:10:35 CDT 2002