1. CDMS IIDAQ `Final’ Detector Design Meeting April 3, 2008 University of California, Santa Barbara Harry Nelson

2. nUCSB April 3, 2008 n Detector Meeting - Harry Nelson 2 Signal from γ’s from Neutron Capture in 0.2% GdCl 3 From Super-K (courtesy of Mark Vagins UCI) About 22 pe (5 pe/MeV) Acceptance… 40% U/Th Chain

3. nUCSB April 3, 2008 n Detector Meeting - Harry Nelson 3

4. nUCSB April 3, 2008 n Detector Meeting - Harry Nelson 4 200 cm (79”) A `Box of Rain’ – Calculate 5 pe/MeV White Diffusive Reflector Water + GdCl 3 Two Super-K Tubes – need low level coincidence 60 cm (24”)

5. nUCSB April 3, 2008 n Detector Meeting - Harry Nelson 5 Formulas for Collection Efficiency

6. nUCSB April 3, 2008 n Detector Meeting - Harry Nelson 6 Required Diffuse Reflectivity 200 x 100 x 60 cm 3 → 2 Super-K PMTs → φ=3.8% for ε >40%, need R>94% (8.4 bounces) Next Prototype: Cube 40 x 40 x 40 cm 3 → 2 8” SK Veto PMTs → φ=5.9% for ε >40%, need R>90%, (5 bounces) Take this to Soudan…

7. nUCSB April 3, 2008 n Detector Meeting - Harry Nelson 7 Schedule…. Proceed with 40 x 40 x 40 detector – 2 months (?)  Susanne has scoped out halon manufacture Give up on scintillator (95% confident) Major acquisitions split between FY2008/2009