Dear Colleagues, Ed and I have tried to put together the points that people brought up at the last phone meeting. Below you will find an initial strawman experiment baseline and the associated questions that people thought might be important for defining the baseline. Over this next week, we should have an email discusion of these points and issues. It would be great if we could have the questions defined for discussion at next Friday's meeting. It would also be good for people to start thinking about where they would like to contribute and what tasks they can take on. As was brought up several times last week, we need to develop some common tools soon so that we can work in a coherent way. One crucial need is a detector monte carlo and packages that allow simulations of the signal and the various backgrounds. This is probably a straight-forward although time consuming task. It probably should be our first "task force" item. We hope some of you can put some time into this. We can talk about organizing this during next Fridays phone meeting. So, give things some thought and let the group know your comments, suggestions, and ideas. Ed and Mike ================================================== Strawman Baseline: Site: Flat Terrain and Geology like Byron, IL Two high efficiency power reactors Detector positions: 200m and 1800m Detector Size: Near 1 25 ton fiducial Far 2 25 ton fiducial Detector Depth: 300ft Detector fiductial volume doped with Gd Detector with 2 zones (oil, scint+Gd) Near to Far Location connected by a tunnel which allows the Far detector to move to near site Full coverage veto system with passive shielding before detector. Low activity PMTs with ??% photocathode coverage Electronics with pulse shape discrimination capability Questions: - How well can absolute detection efficiency be established for each detector in situ (without moving)? - How well can energy calibration for each detector be unerstood in situ (without moving)? Answering the above questions requires developing a real strategy for detection efficiency measurement and energy calibration. - Which systmetaic errors related to detection efficiency and energy calibration would be improved by moving the detectors? How much improvement can be expected? What new systematic errors could result from moving the detectors? --Background strategy and estimated background systematic error for o 1 reactor vs 2 reactors o different depths and veto system o Gd-loaded vs conventional scintillator Need to create matrix of background sources vs. above options. Background sources: o backgrounds associated with detected muon (depends on veto eff.) o random backgrounds from radioactivity, etc. o correlated spallation background (e.g., 2 spallation n from 1 muon) o 9Li, 8He made by spallation muon followed by beta decay with 100-200 ms lifetime (e.g., 9Li -> beta- + n + 2alpha) 2 zone vs. 3 zone: How does scintillating buffer region effect systematic error for -- movable detectors -- non-movable detectors -- What is the impact on the size? *** One goal of the above questions is to document the realistic size of various systematics for input into an oscillation sensititivity program that will give the prospects for the measurement precision. ******* Stability of Gd-loaded scintillator? Additional issues associated with conventional liquid scintillator detector? -------------------------------------------------------------- Low background phototubes. Benefit of having both near and far detectors at same depth? Engineering questions. Understand real volume of detector that could be moved in 6 meter tunnel. (with 2 zones, with 3 zones) What is the required photocathode coverage?