XAX Can DM and DBD detectors combined? Katsushi Arisaka University of California, Los Angeles Department of Physics and Astronomy arisaka@physics.ucla.edu 9/12/2018 Katsushi Arisaka

XAX paper by UCLA Group 9/12/2018 Katsushi Arisaka, UCLA

XAX (Xenon-Argon-Xenon) Water Tank Veto WIMP (Spin even) Double Beta Decay WIMP (Spin odd) Solar Neutrino WIMP (Spin even) 12 m 40Ar 70 ton (50 ton) 136Xe 7 ton (4 ton) 129/131Xe 12 ton (6 ton) 1.2 m 2 m 4 m 12 m 14 m 9/12/2018 Katsushi Arisaka, UCLA

Separation of Odd and Even SpinXenon 9/12/2018 Katsushi Arisaka

Why Multiple Targets? Systematic Study of Dark Matter Interaction Target mass dependence of Cross section and Energy spectrum Xenon vs. Argon Spin dependence of Cross section 129/131Xe (Spin odd) vs. 132/134/136Xe (Spin even) Precise determination of Mass and Cross section Neutrino-less Double Beta Decay  > 1028 years by 136Xe Solar Neutrino 1% measurement of the pp chain flux by 129/131Xe. Supernova Neutrino Measurement of the total energy and temperature by coherent elastic scattering. 9/12/2018 Katsushi Arisaka, UCLA

Energy Spectrums (Natural Xe) 100 GeV WIMP (10-44 cm2) 2 DBD (1022 yrs) pp Solar Be7 Solar 0 DBD (1027 yrs) B8 Solar 9/12/2018 Katsushi Arisaka, UCLA

Concept of one of XAX Detectors Liquid Xe (19 ton) TPB + Resistive Coating (ATO) + Acrylic Vessel Radiation- free Photon Detector (3” QUPID, Total 3950) 2 m OFHC (Oxygen-Free High Conductivity Copper) Vacuum Vessel 9/12/2018 Katsushi Arisaka, UCLA

Concept of Double Layer XAX 2 m -17.5 kV -200 kV -10 kV 0 V Gas Xe 136Xe 7 ton Radiation-free Photon Detectors (QUPID) TPB +ATO + Acrylic Vessel + ITO Coating TPB + ITO Acrylic Sheet + ITO + TPB Coating TPB + Acrylic Sheet + ATO Coating 129/131Xe 12 ton 9/12/2018 Katsushi Arisaka, UCLA

Equipotential lines and Electron Trajectories 0 V ITO (Indium Tin Oxide) Transparent Conductive Coating (~1 k⁄☐) -6 kV -13.5 kV ATO (Antimony Tin Oxide) Transparent Resistive Coating (~ 1 G⁄☐) Electron Trajectories ITO (Indium Tin Oxide) Transparent Conductive Coating (~1 k⁄☐) -200 kV -6kV 0 V 9/12/2018 Katsushi Arisaka, UCLA

Expected No. of Photoelectrons per keV (Abs. Length = 10 m, Scat Expected No. of Photoelectrons per keV (Abs. Length = 10 m, Scat. Length = 50 cm) PTFE on Side Wall (Reflectivity = 98%) Photon Detectors on Side Wall ~ 1.5 pe/keV ~ 3 pe/keV 9/12/2018 Katsushi Arisaka, UCLA

Expected No. of Photoelectrons per keV (Center of 2m Xenon Detector) Absorption Length Scattering Length 50 cm 1 m 2 m PTFE on side (Reflectivity = 95%) 5 m 1.0 1.2 1.4 10 m 1.7 2.0 2.2 20 m 2.4 2.8 3.1 PTFE on side (Reflectivity = 98%) 1.3 1.5 2.1 2.3 2.6 3.0 3.2 PTFE on side (Reflectivity = 99%) 1.8 2.7 3.3 QUPID on side 1.6 2.5 3.5 3.8 4.3 9/12/2018 Katsushi Arisaka, UCLA

(1) Dark Matter 9/12/2018 Katsushi Arisaka, UCLA

Gamma Backgrounds after S2/S1 cut (1 mBq / QUPID, 2m Xenon Detector)  BG (0 cm shield) 100 GeV WIMP (10-44 cm2)  BG (5 cm shield) 2 DBD (1022 yrs) 1 TeV  BG (10 cm shield) pp Solar Neutrino 10 TeV Be7 Solar Neutrino 9/12/2018 Katsushi Arisaka, UCLA

Xenon (2m) Expected Background from Gammas (1 mBq / QUPID, 1 year, Multi Hit Cut, No S2/S1 cut) Xenon (2m) 0.01  /10ton-year after S2/S1 cut < 10–8 DRU 10 ton 9/12/2018 Katsushi Arisaka, UCLA

Neutron Backgrounds after Multi-hit Cut (1 n/year/QUPID, 2m Xenon Detector) 100 GeV WIMP (10-44 cm2) 1 TeV 10 TeV 0 cm 10 cm 20 cm 30 cm 9/12/2018 Katsushi Arisaka, UCLA

Xenon (2m) Expected Background from Neutrons (1 n/year/QUPID, 10 year, Multi Hit Cut) Xenon (2m) 0.4 n /10ton-year < 10–8 DRU 10 ton 9/12/2018 Katsushi Arisaka, UCLA

Expected No. of WIMP Signals and Backgrounds (10 ton-year of Liquid Xenon, Window = 3 – 15 keVee) No. of Background Events No. of WIMP Signals 10-44 cm2 1 mBq /QUPID Gamma (no cut) 10-45 cm2 G1 Gamma (S2/S1 cut) 10-46 cm2 G2 Neutron (no cut) 10-47 cm2 pp-chain Solar (S2/S1 cut) G3 Neutron (multi-hit cut) 10-48 cm2 2-Neutrino DBD (S2/S1 cut) 19.2 ton 14.0 ton 9.8 ton Self Shielding Cut (cm from wall) WIMP Mass (GeV) 9/12/2018 Katsushi Arisaka, UCLA

Summary of WIMP Detection Sensitivity: < 10-47 cm2 at 100 GeV WIMP mass. (< 10-46 cm2 at 1 TeV) Background: Completely free from external gamma ray backgrounds. < 10 mBq / PMT QUPID is < 1 mBq (Goal is < 0.1 mBq) 10 cm active shielding S2/S1 cut Neutrons background is negligible too. < 1 neutron / year / PMT required. QUPID goal is < 0.1 n/year (Current R8778 is < 5 n/year) Irreducible background comes from pp-chain solar neutrino. ~10-7 /kg/keV/day  ~0.5 event /ton/year (in 3-15 keVee window) Assuming 99% rejection by S2/S1 cut. Still investigating other backgrounds Internal Krypton and Radon in Xenon Photon Detection: Complete surface coverage by QUPID ensures > 3 pe/keV. 9/12/2018 Katsushi Arisaka, UCLA

(2) Neutrino-less Double Beta Decay 9/12/2018 Katsushi Arisaka, UCLA

Sensitivity of Neutrinoless Double Beta Decay to Neutrino Mass Normal Scheme Inverted Scheme DBD Life Time Cosmology (Figure from C. Giunti) 1026 yr 1027 yr 1028 yr Laurent SIMARD, LAL - Orsay 9/12/2018 Katsushi Arisaka, UCLA

Energy Resolution of XENON 10 236 keV Xe-131 164 keV Xe-129 236 keV Xe-131 164 keV = 0.9% at 2.5 MeV FWHM = 50 keV expected 9/12/2018 Katsushi Arisaka

136Xe Double Beta Decay and Gamma Background (1 mBq / QUPID, 2m Xenon Detector) 0 cm 2 DBD (1022 yrs) 10 cm  BG ~ 10-7 dru FWHM = 50 keV  5*10-4 /FWHM*kg*year 20 cm 30 cm 40 cm 50 cm 0 DBD (1027 yrs) B8 Solar 9/12/2018 Katsushi Arisaka, UCLA

Expected Background from Gammas (1 mBq / QUPID, 1 year, Multi Hit Cut) < 10–8 DRU 4.1 ton 9/12/2018 Katsushi Arisaka, UCLA

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 1 mBq/Qupid 0.1 mBq/Qupid 19.2 ton 14.0 ton 9.8 ton 6.6 ton 4.1 ton Self Shielding Cut (cm from wall) Life Time (Year) 9/12/2018 Katsushi Arisaka, UCLA

Expected No. of DBD Signals and Backgrounds (1 ton-year of Liquid Xenon, Window = 2479 ± 25 keV) No. of Background Events No. of 0-Neutrino DBD Signals 1 mBq/Qupid 0.1 mBq/Qupid 2.4 ton 1.2 ton 0.5 ton 0.2 ton Self Shielding Cut (cm from wall) Life Time (Year) 9/12/2018 Katsushi Arisaka, UCLA

Double Beta Decay Sensitivities XAX (1 mBq) 136Xe 4000 50 0.0005 ~1027 15 – 95 XAX (0.1mBq) 136Xe 4000 50 0.00005 ~1028 10 – 60 9/12/2018 Katsushi Arisaka, UCLA

Double Beta Decay Experiments EXO200 EXO 1Ton CANDLES III No. of Backgrounds (/year) 1025 yrs 1026 yrs 1027 yrs 1028 yrs CUORE I NEMO3 (Mo) XAX (Enriched) XAX (Natural) XENON1T CUORE III Cuoricino Super-NEMO (Se) GERDA III GERDA I CUORE II COBRA EXO 1Ton (Ba tag) NEMO3 (Se) GERDA II Mass (kg) 9/12/2018 Katsushi Arisaka, UCLA

Summary of DBD Detection All the gamma ray background can be effectively removed. Low-radioactive QUPID is essential. < 1 mBq for  > 1027 years < 0.1 mBq for  > 1028 years Extensive active shielding. 40 cm cut required (4 ton fiducial volume out of 19 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) > 3 pe/keV is required 9/12/2018 Katsushi Arisaka

From MAX to XAX 9/12/2018 Katsushi Arisaka, UCLA

MAX Detector 40Ar Xe 5 ton (2.5 ton) 2.4 ton (1.2 ton) DUSEL S4 Study funded by NSF ($3.5M) 9/12/2018 Katsushi Arisaka, UCLA

G2 MAX 40Ar Xe 1 m 2 m WIMP WIMP Double Beta Decay 10 ton (5 ton) 9/12/2018 Katsushi Arisaka, UCLA

G3 XAX Phase I 40Ar Xe 70 ton (50 ton) 129/131Xe 2 m 4 m WIMP WIMP Double Beta Decay Solar Neutrino 40Ar 70 ton (50 ton) Xe 20 ton (10 ton) 129/131Xe 2.4 ton (1.2 ton) 2 m 4 m 9/12/2018 Katsushi Arisaka, UCLA

G4 XAX Phase II 40Ar 136Xe 129/131Xe 70 ton (50 ton) 1.2 m 2 m 4 m WIMP WIMP (Spin even) Double Beta Decay WIMP (Spin odd) Solar Neutrino 40Ar 70 ton (50 ton) 136Xe 7 ton (4 ton) 129/131Xe 12 ton (6 ton) 1.2 m 2 m 4 m 9/12/2018 Katsushi Arisaka, UCLA

MAX and XAX G2 G3 G4 Detector Size Target Mass 1m x 1m 2m x 2m 4m x 4m   Detector Size Target Mass 1m x 1m 2m x 2m 4m x 4m Total Mass Fiducial Mass QUPID 3" at Top 190 750 3000 6" at Side/Bottom 210 850 3400 (ton) MAX Xe 2.4 1.2 40Ar 10 5 XAX (Phase I) 129/131Xe 20 70 50 XAX (Phase II) 13 6 136Xe 7 4 G2 G3 G4 9/12/2018 Katsushi Arisaka, UCLA

MAX and XAX G2 G3 G4 Detector Size Target Mass No. Events 1m x 1m   Detector Size Target Mass No. Events 1m x 1m 2m x 2m 4m x 4m Total Mass Fiducial Mass WIMP Double Beta Decay pp Solar Neutrino Super Nova Neutrino QUPID 10-46 cm2 1027 years 10 kpc 3" at Top 190 750 3000 100 GeV 3x1053 erg 6" at Side/Bottom 210 850 3400 / 1yr / 1 yr (ton) MAX Xe 2.4 1.2 12 0.4 11 40Ar 10 5 14 XAX (Phase I) 129/131Xe 500 11  20 100 3.3 95 70 50 141 XAX (Phase II) 13 6 60 2500 56 136Xe 7 4 40 30 39 G2 G3 G4 9/12/2018 Katsushi Arisaka, UCLA

MAX and XAX G2 G3 G4 Detector Size Target Mass No. Events 1m x 1m   Detector Size Target Mass No. Events 1m x 1m 2m x 2m 4m x 4m Total Mass Fiducial Mass Cost for Target WIMP Double Beta Decay pp Solar Neutrino Super Nova Neutrino QUPID 10-46 cm2 1027 years 10 kpc 3" at Top 190 750 3000 100 GeV 3x1053 erg 6" at Side/Bottom 210 850 3400 / 1yr / 1 yr Cost for QUPID $2M $9M $36M (ton) MAX Xe 2.4 1.2 $7M 12 0.4 11 40Ar 10 5 $3M 14 XAX (Phase I) 129/131Xe ?  500 11  20 $40M 100 3.3 95 70 50 $20M 141 XAX (Phase II) 13 6 ? 60 2500 56 136Xe 7 4 40 30 39 G2 G3 G4 9/12/2018 Katsushi Arisaka, UCLA

Summary 9/12/2018 Katsushi Arisaka, UCLA

Summary on XAX XAX incorporates several innovative concepts: The largest detector (> 10 ton) compatible with Argon and Xenon Background free Radiation-free photon detector: QUPID Thick (20 cm) self shielding Multi-hit cut and S2/S1 cut by double phase TPC Pulse shape discrimination (for Ar) with “reconstructed” S1 signal Best photon collection 4π coverage of photon detectors (like single phase detectors) XAX can achieve four important scientific goals: Systematic study of WIMP properties Sensitivity below 10-47 cm2 at 100 GeV (< 10-46 cm2 at 1 TeV) Determination of Mass and Cross section Target mass (A) dependence of Cross section (Argon vs. Xenon) Spin dependence (129/131Xe vs. 132/134/136Xe) Neutrino-less Double Beta Decay (by 136Xe) Sensitivity up to 1028 years pp-chain Solar Neutrino (by 129/131Xe) Flux with 1% statistical error Supernova Neutrino by elastic scattering Total Energy with 8% statistical error Temperature with 5% statistical error 9/12/2018 Katsushi Arisaka, UCLA