XAX 10 ton NobleLiquid DoublePhase TPC for Rare Processes

1
XAX10 ton Noble-Liquid Double-Phase TPC for Rare
Processes
Katsushi Arisaka
University of California, Los Angeles Department
of Physics and Astronomy arisaka_at_physics.ucla.edu
2
XAX Detector (Option A)
7m
40Ar (6 ton)
129/131Xe (14 ton)
136Xe (14 ton)
1.5 m
7 m
Water Tank Veto
11 m
3
XAX Detector (Option B)
Year 1 Natural Xe (14 ton) Year 2 Argon (6
ton) Year 3 136Xe (14 ton) Year 4 129/131Xe
(14 ton)
8 m
1.5 m
Xe (14 ton)
Water Tank Veto
8 m
4
XAX Detector Design
5
Why Multiple Targets?

• Systematic Study of Dark Matter Interaction
• Target Mass dependence of Cross section
• Xenon vs. Argon
• Spin dependence of cross section
• 129/131Xe (Spin odd) vs. 136Xe (Spin even)
• Precise determination of Mass and Cross section
• Neutrino-less Double Beda Decay (DBD)
• ? gt 1028 years by136Xe (like EXO)
• Solar Neutrino
• 1 measurement of pp chain flux by 129/131Xe.

6
QUPID(Quartz Photon Intensifying Detector)
Quartz
Photo Cathode (-10 kV)
APD (0 V)
Quartz
Quartz
7
Simulation of Electron Trajectories
8
13 inch HAPD for T2K by Hamamatsu
9
PE Distribution of 13 inch HAPD
10
Comparison
11
Expected Performance of QUPID

• Large diameter 3 inch
• Existing largest PMT with low radioactivity is 2
  inch (R8778)
• Extremely low radioactivity 1mBq (now) ? 0.1mBq
  (future)
• To be compared with
• R8778 (2 inch) 50 mBq
• R8520 (1 inch) 10 mBq
• True photon counting
• 1,2 5 photo-electron peaks are clearly visible.
• Collection efficiency is 100
• Excess Noise Factor (ENF) 1.0
• Fast Timing lt 500 psec
• 500 psec Transit Time spread expected
• Simple HV supply
• HV supply can be common for all HAPD
• No Tube to tube variation of gains
• Resister chain not necessary

12
90 CL Sensitivity for WIMP
CDMSII
CDMSII
XENON10
XENON10
LUX- 100
LUX
Super-LUX
13
Energy Resolution of XENON 10
Xe-129 236 keV
Xe-131 164 keV
Xe-129 236 keV
Xe-131 164 keV

• 0.9 at 2.5 MeV
• FWHM 50 keV expected

14
Fraction of 2 neutrino Double Beta Decay
Background vs. Energy resolution
15
Energy Spectrum (Xe 136 enriched)
2? DBD (1022 yrs)
pp Solar
Be7 Solar
0? DBD (1027 yrs)
B8 Solar
16
Expected Background from Gammas (1 mBq / QUPID)
2? DBD (1022 yrs)
0 cm shield
pp Solar
10 cm shield
Be7 Solar
20 cm shield
0? DBD (1027 yrs)
30 cm shield
B8 Solar
17
Expected Background from Gammas (1 mBq / QUPID)
? BG 10-7 dru FWHMM 50 keV ? 410-4
/FWHMkgyear
2? DBD (1022 yrs)
0 cm shield
10 cm shield
20 cm shield
30 cm shield
0? DBD (1027 yrs)
B8 Solar
18
Expected No. of DBD Signals and Backgrounds(10
ton-year of Liquid Xenon, Window 2479 25 keV)
No. of Background Events
No. of 0-Neutrino DBD Signals
14 ton
6.6 ton
2.4 ton
9 ton
4.2 ton
Self Shielding Cut (cm from wall)
Life Time (Year)
19
Summary of DBD Detection

• All the gamma ray background can be effectively
  removed.
• Low-radioactive QUPID is essential.
• lt 1 mBq for ? gt 1027 years
• lt 0.1 mBq for ? gt 1028 years
• Extensive active shielding.
• 30 cm cut required (4 ton fiducial volume out of
  14 ton.)
• Multiple hit cut.
• Ba2 tagging is not necessary, unlike EXO.
• The tail from two neutrino double beta decays is
  negligible.
• based on XENON10, the energy resolution of the
  double-phase Xenon should be superior to EXO.
• ? 1.0 at 2.5 MeV (FWHM 50 keV)
• gt 3 pe/keV is required