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?
Deborah Harris
Last modified: Tue Jun 18 13:10:35 CDT 2002