Non-Accelerator Physics with the Homestake “Megaton Array”

Non-Accelerator Physics with the Homestake “Megaton Array” • 1) Nucleon Decay Po + e+, & P  K+ +e (improved PMTs may permit spatial & time recognition of K+ +e) • 2) Prompt SN neutrinos – our Galaxy and nearby galaxies • 3) Relic SN neutrinos (greater depth provides critical C.R. muon background reduction) • 4) Low background shield • (Used Hank Sobel talk-Korea 2005 & Ed Kearns talk -NNN07)

Various Detection Techniques

Detector Location Constraints • 1) Depth • 2) Distance from Power Reactors – • Lead, SD is ~ 500 km from “nearby” U.S. power reactors – factor 30 (1/r2) better than Kamioka location

Vertex Reconstruction of Events • PMT times used to reconstruct event position • Resolution ~15 cm UNTAGGED TAGGED

Large Format PMTs 20 inch For Better Detection Efficiency Applications: Neutrino Experiment 13 inch PMT is very low profile despite its diameter. R3600 13 inch 10 inch 8 inch R8055 R7081 R5912 Trial for High QE

Hamamatsu PMT Characteristics

Bialkali QE Comparison UBA:43% Example Data for UBA : R7600-200 SBA : R7600-100 STD : R7600 x1.6 x1.3 SBA:35% STD:26%

Example data R7081 (10 inch) High QE Type Champion Data 35% at 380 nm Samples:22 pcs Average:31.6% Standard 26% at 380 nm

Non-Accelerator Physics with the Homestake “Megaton Array”