SLIDE 1
Current status
4/20/17 Presenter | Presentation Title or Meeting Title 2
Liquid Noble DM Detectors Hugh Lippincott Cosmic Science Working - - PowerPoint PPT Presentation
Liquid Noble DM Detectors Hugh Lippincott Cosmic Science Working - - PowerPoint PPT Presentation
Liquid Noble DM Detectors Hugh Lippincott Cosmic Science Working Group 20 April 2017 Current status DS-50 2.6 tonne-day exposure LAr, background free (50 kg fiducial, 50 days) Xenon100 17.6 tonne- day exposure LXe, ~5 events (30-40
SLIDE 2
SLIDE 3
Very near future
4/20/17 Presenter | Presentation Title or Meeting Title 3
DS-50 – Still running, expect ~40-50 tonne-day exposure (half that in hand), after another 2 years (x20 improvement) DEAP-3600 – full since November, 500 tonne-days raw exposure so far (my guess would be ~100 tonne-days with fiducial cuts, maybe matches LUX)
SLIDE 4
Very near future
4/20/17 Presenter | Presentation Title or Meeting Title 4
PandaX-II – still running, up to factor x3 improvement at this point? XENON1T – Running interrupted by earthquake in January, >=40 days in hand, supposedly 1 ton fiducial (would match LUX exposure)
SLIDE 5
]
2
WIMP mass [GeV/c 10
2
10
3
10 ) [pb]
SI p
σ (
10
log
- 12
- 10
- 8
]
2
[cm
SI p
σ
- 49
10
- 48
10
- 47
10
- 46
10
- 45
10
- 44
10
- 43
10
scattering
- N coherent
ν 1 e v e n t 1000 tonne-years significance σ 3 LZ projected Median Significance σ 5 Median Significance σ 3 90% CL Median (Baseline) XENON1T 90% CL
Near future
4/20/17 Presenter | Presentation Title or Meeting Title 5
LZ – 5.6 ton fiducial – begins 2020 (trying to advance) XENONnT – 86% LZ by mass – upgrade to begin in 2018 in parallel with XENON1T operation Nothing revolutionary in design
}
SLIDE 6
Mid to long term future - Argon
4/20/17 Presenter | Presentation Title or Meeting Title 6
- DarkSide-20K – “start operation
2021…”
– Merger of DS50, DEAP, MiniCLEAN, ArDM – 20 tonne argon, two phase TPC – Approved at INFN as of this month – SiPMs for light readout
- SNR decreases with increasing surface
area
- 5x5 cm tile demonstrated in March
– Low radioactivity (Ar39 depleted) argon
- Aria – isotopic purification using
distillation column the size of Eiffel tower – under construction
- Urania – underground argon at large
scale
- Argo/DEAP-nT - mid 2020s
– Kton –year exposures – R&D starting now (e.g. digital SiPM array)
SLIDE 7
]
2
WIMP mass [GeV/c ]
2
Cross Section [cm
- 49
10
- 48
10
- 47
10
- 46
10
- 45
10
- 44
10
- 43
10
- 42
10
- 41
10 5 6 8 10 20 30 40 60 100 200 400 600 1000
PandaX y) × DARWIN (200 t XENON100 XENON1T XENONnT / LZ DarkSide-50 DEAP-3600 L U X
- line (Billard)
ν DarkSide-20k
Mid to long term future - Xenon
4/20/17 Presenter | Presentation Title or Meeting Title 7
- LZ – not currently working on G3
– Can break 1e-48 barrier if hit targets – Expecting 0.5 neutrino events in 1000 days (2020-2023)
- DARWIN – successor to XENON
– 40ton active (~$100M in xenon, worlds annual production) – Not that much bigger than LZ/XENONnT – Proposed project start in 2019-2020
SLIDE 8
Xenon-Argon ~100 GeV WIMP considerations
4/20/17 Presenter | Presentation Title or Meeting Title 8
- Xenon is a better target for the most part
– At high mass, 3.2x better sensitivity per unit mass – At low mass, >>3.2x better sensitivity (lower threshold) – More flexible physics
- Spin dependent couplings, double beta decay, axion searches, electron interaction searches,
etc
– Denser (better self-shielding, smaller detectors/unit mass) – Not as cryogenic – 165K vs 85K (may have been a factor in PMT operation)
- Two major exceptions
– Cost – raw material is much more expensive
- Although the effort needed to find low radioactivity argon is significant. Unclear how this
scales, probably argon still comes out way ahead for ~100 tonne scales, assuming it works
– Electron recoil rejection
- Rn/pp solar neutrinos are the biggest backgrounds in LZ/XENONnT. Because ER rejection is
- nly ~1e-3-1e-4, you need to do really well at radon mitigation. Argon does not have this
problem (~1e-8 or better)
- How important is the last decade to the neutrino floor?
– LZ expects 0.5 neutrinos, so diminishing returns starts then – ~x50 increase in exposure gives ~x10 sensitivity
SLIDE 9
Reach thermal DM production parameter space in <1 year!
plots from Essig et al, cf. arXiv:1703:00910 Xe 3 events 1 kg-year The only existing limits on dark sector DM are from liquid xenon targets Xe 3 events 1 kg-year
8
Other ideas
4/20/17 Presenter | Presentation Title or Meeting Title 9
- Xenon
– Doping with He/Ne for low mass sensitivity – use existing detector, extend reach down to 1 GeV or below in optimistic scenario (my EC proposal from 2015)
- Not competitive with dedicated detector like SuperCDMS, but not too bad either
– Single electron counting – P. Sorensen at CV workshop
- Optimize on S2, forget about S1
- R&D on eliminating electron backgrounds observed in LUX/XENON100
- Proposal for 10 kg scale, could then scale up and observe freeze-in/freeze-out regions
- [/]
- []
- []
- ν
ν
LZ Neon LZ Helium LZ Helium S2-only
LZ Xe
SLIDE 10
Superfluid helium detector (Hertel, McKinsey, etc)
4/20/17 Presenter | Presentation Title or Meeting Title 10
- Aiming for 1 MeV to 1 GeV dark matter
– Detection of either He recoils (100 MeV dm masses) or electron recoils (<100 MeV)
- Excitations in superfluid He
– Excimers (He2* molecules, created with eV-scale excitations) – Photons, rotons, at meV scale
- Demonstration of excimer detection
using TES sensors in He (1605.00694)
- Rotons are “high-momentum phonons”
– Difficult to detect, but many ideas (HERON, quantum evaporation)
101 102 103 104 105
Recoil Energy [eV]
0.2 0.4 0.6 0.8 1
Energy Fraction Nuclear Recoil
101 102 103 104 105
Recoil Energy [eV]
0.2 0.4 0.6 0.8 1
Energy Fraction Electron Recoil
Singlet Excimers Triplet Excimers IR photons Phonons/R-/R+
- und up.
: partitioning
George Seidel, unpub.
23
SLIDE 11
Superfluid helium detector (Hertel, McKinsey, etc)
4/20/17 Presenter | Presentation Title or Meeting Title 11
- Backgrounds
– Standard radioactivity, neutrinos, gammas (LHe is radiopure) – Alan’s gamma-NR background – Arguments for low dark rate
- Can do ER discrimination