non-accelerator physics with the homestake “megaton array”
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
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
%Free Protons
% Nuclei Features
Water 11% 89% Cerenkov radiation
Liquid ScintillatorCould insert into center of 100 kton water detector
~10% ~90% Signal from slow particles
Liquid Argon 0% 100% Tracking
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 Vertex Reconstruction of EventsEventsN16
PMT times used to reconstruct event position
Resolution ~15 cm
UNTAGGEDUNTAGGED
TAGGEDTAGGED
8 inch 10 inch13 inch
20 inch
13 inch PMT is very low profiledespite its diameter.
Large Format PMTsLarge Format PMTs
Applications:Neutrino Experiment
For Better Detection EfficiencyFor Better Detection Efficiency
Trial for High QE
R7081R7081R5912R5912
R8055R8055
R3600R3600
Hamamatsu PMT Characteristics
PMT Dia. Quantum Efficiency
Rise Time
Transit time jitter
3600 20” 20% 10 ns 5.5 ns
7081 10.5” >35% 4.3 ns 2.9 ns
Bialkali QE ComparisonBialkali QE Comparison
0
10
20
30
40
50
200 300 400 500 600 700Wavelength [nm]
Qu
an
tum
Effi
cien
cy [
%] Example Data for
UBA : R7600-200SBA : R7600-100STD : R7600
UBA:43%
SBA:35%
STD:26%
x1.3
x1.6
0
5
10
15
20
25
30
35
40
200 300 400 500 600 700 800
Wavelength [nm]
Qu
an
tum
Effi
cie
ncy [
%]
Example data R7081 (10 Example data R7081 (10 inch)inch)
StandardStandard26% at 380 nm26% at 380 nm
High QE TypeHigh QE TypeChampion DataChampion Data35% at 380 nm35% at 380 nm
0
2
4
6
8
10
12
~28 ~30 ~32 ~34 ~36QE at 380 nm (%)
Samples:22 pcsAverage:31.6%