matter project dark matter searches and other physics ... · dark matter qcd light bosons axions...
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Dark Matter Searches and Other Physics Signals in
XENON1T, XENONnT and DARWIN
Patrick [email protected]
XeX E N O NDark Matter Project
Patrick Decowski - Nikhef
Rotational Curves
Large Scale Structure
Weak Lensing
Anisotropy in CMB
Much astrophysical evidence for Dark Matter
Galaxy Clusters
On all distance scales in the Universe!
Patrick Decowski - Nikhef/UvA
Cosmological Evidence for DM
ΩΛ
0.2 0.4 0.6 0.8
20
40
60
80
100
∆T(µK)
Ωtot
0.2 0.4 0.6 0.8 1.0
Ωbh2
10
0.02 0.04 0.06
100 1000
20
40
60
80
100
l
∆T(µK)
10 100 1000
l
Ωmh2
0.1 0.2 0.3 0.4 0.5
(a) Curvature (b) Dark Energy
(c) Baryons (d) Matter
Ωm = Ωdm + Ωb
Curvature Dark Energy
Baryons Matter
Dark Matter Candidates
Dark matter
Light bosonsQCDaxions
Axion-likeparticles
Fuzzydark
matter
Standard-model Sterile
neutrinos
Super-symmetry
Weak scale
Extradimensions
LittleHiggs
Effective
theorymodels
Neutrinos
neutrinos
MOG
TeVeS gravity
MOND Emergentgravity
Otherparticles WIMPzilla
Self-interacting
Macroscopic
MaCHOs
Macros
Primordialblack holes
Modified
Simplified
Superfluid
field
Bertone, Tait, Nature 562, 51
Patrick Decowski - Nikhef/UvA
WIMPfrom galactic halo
Target Nucleusin laboratory
v~220 km/s v~0 km/s
ER~20 keVr
θR
WIMP
Elastic collision
ER =µ2v2
mT(1 cos ) vmin =
smTEth
2µ2
M. W. Goodman and E. Witten, Phys. Rev. D 31, 3059 (1985).
w [km/s]0 100 200 300 400 500 600
f(w) [
s/km
]
0
0.001
0.002
0.003
0.004
0.005
0v esc
v
SHM
Detection of DM Particle Recoils
WIMP velocity distrib
Assume WIMP is not only gravitationally interacting
What can be measured?
d
dER=
mT
2µ2v2SIF
2SI(ER) + SDF 2
SD(ER)
dR(t)
dER= NT
m
Z vesc
vmin
d3vd
dERvf(v, ve(t))
with scalar (SI) and axial-vector (SD) couplings:
We measure:
Need input fromAstrophysics
Effective interaction Lagrangian (low E limit, vWIMP~10-3c):
Scalar Axial
Le = fqqq + dqµ5qµ5q + ...
WIMP-Nucleus Cross Section
SI =4µ2
[Zfp + (A Z)fn]
2 / A2
SD =32µ2
G2
FJ + 1
J[aphSpi+ anhSni]2
Spin-independent cross section:
Better sensitivitywith high A
Need nucleus with spin:19F, 23Na, 73Ge, 127I, 129Xe, 131Xe, 133Cs (but no Ar!)
Spin-dependent cross section:
Only axial vector describing state
of nucleus as q → 0WIMP couplings to protons & neutrons
Nuclear model:Sp,n = N |Sp,n|N
Analysis is done attributing all the (lack of) rate to SI or SD
Recoil energy (keV)0 20 40 60 80 100 120 140 160 180 200
dR/d
E (D
RU
)
12−10
11−10
10−10
9−10
8−10
7−10
6−10
5−10
4−10
3−10
2−10
1−101 = 1000 GeVχm
Energy Recoil Spectra
Inelastic Scattering: χN → χ* Nδ is χ - χ* mass splitting
Recoil energy (keV)0 20 40 60 80 100 120 140 160 180 200
dR/d
E (D
RU
)
12−10
11−10
10−10
9−10
8−10
7−10
6−10
5−10
4−10
3−10
2−10
1−101
= 0 keVδ
= 100 keVδ
= 200 keVδ
= 300 keVδ
= 1000 GeVχm
(keV
x k
g x
day)
-1min =
r1
2MNEnr
MNEnr
µ+
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Typically consider Elastic Scattering“Vanilla WIMP Model”
Searching for Sub-GeV WIMPs
LUX
“Migdal”-effect
10− 1 100 101 102 103
Dark matter particle mass (GeV/c2)
10− 50
10− 45
10− 40
10− 35
10− 30
Interactionstrength(σ
SI,cm2 )
XENON1T*S2only BS
XENON1T*S2only NR
LUX 2017
PandaX-II2017
CDMSLite 2015
CRESST-III2017
CRESST-prototype2017
DarkSide-50S2only 2018
XENON1T2017
CNNS
Dark matter modelshere are excluded
Thesis Jelle Aalbers
Other ways to get sub-GeV
Drive to be sensitive to sub-GeV mass DM
Patrick Decowski - Nikhef/UvA
Use annual modulation: DM claim
2-6 keV
Time (day)
Res
idua
ls (c
pd/k
g/ke
V) DAMA/LIBRA-phase1 (1.04 ton× not 31.1( 2esahp-ARBIL/AMAD)ry ×yr)
Modulation present in 2-6 keV, absent above 6 keV
Apr 2018: 12.9σ significance of modulation signal
Patrick Decowski - Nikhef/UvA
Particle-dependent Response
χ, n
β,ɣ
Image E.Pantic
CDMS, CRESST, DarkSide, LUX, XENON etc.
10cm
XAMS (0.5kg Xe)
Thesis Erik Hogenbirk
arXiv:1807.07121
arXiv:1803.07935
arXiv:1602.01974
Live Time (d)1 10 210 310
(yr)
1/2
T
2110
2210
2310
2410
excluded
predicted
yr×t2
Double Electron Capture
• Second order process like double β-decay, but longer lived - so far only measured in 130Ba and 78Kr
• 124Xe is a candidate isotope
• 0.095% Nat. abundance
• Peak at 64.3 keV from K-shell captures
XENON100, arXiv:1609.03354
Nuclear Matrix Element
T 22EC1/2 / G2 |M2 |2
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Phase Space Factor
Physics Channels• WIMP searches
• Spin-independent • Spin-dependent and inelastic interactions
• Solar axions and galactic axion-like particles (ALPs)• Alternative dark matter candidates• Coupling to electrons via axio-electric effect
• Supernova neutrinos• Sensitivity to all neutrino flavors (via CNNS)• Complementarity to large-scale neutrino detectors
• Coherent neutrino-nucleus scattering (CNNS)• Predicted by SM, only very recently observed!
• Low-energy solar neutrinos: pp, 7Be• Test/improve solar model, test neutrino models
• Neutrinoless double beta decay• Lepton number violating process, effective Majorana mass • No enrichment in 136Xe required
ER
NR
NR
NR
ER
ER
As
dete
ctor
siz
e in
crea
ses
phys
ics
chan
nels
ope
n up
Coherent Neutrino-Nucleus Scattering
• ν + NXe → ν + NXe
• Predicted by SM, recently observed• CNNS is background for WIMPs,• Steeply falling spectrum
Energy [keV]-110×4 1 2 3 4 5 6 7 8 910 20
]-1
keV
× -1
y× -1 t×
Rate
[evt
s
-310
-210
-110
1
10
210
2WIMP 100 GeV/c
2WIMP 40 GeV/c
2WIMP 6 GeV/c: SumνB8: ν
: atmν
: DSNBν
: hepν 2 cm-4710×2
2 cm-4810×2
2 cm-4510×4
JCAP 01, 044 (2014)
Supernova NeutrinosR. Lang et al., arXiv:1606.09243
• Low threshold (due to S2-only)• Negligible background due to short burst (~sec)• >5σ sensitivity to a supernova burst in Milky Way• Detection of all 6 neutrino species via neutral current reactions
• Hundreds of events for a 27M⊙ SN progenitor at 10 kpc • Flavor-insensitive neutrino energy measurement
→ constrain total explosion energy and reconstruct the SN light curve
Solar Neutrinos• Neutrino-electron elastic scattering
• Real-time measurement of neutrino flux → 7.2 events/day from pp → 0.9 events/day from 7Be
• 2% (1%) statistical precision after 1 year (5 years) → constrain solar models
• Neutrino survival probability measurement → deviation from prediction indicates new physics• Atomic binding effects have to be taken into account!
Neutrino Energy [keV]210×2 310 310×2 410 410×2
eeP
0.2
0.3
0.4
0.5
0.6
0.7
0.8pp Be7 pep B8
DARWIN
Energy [keV]0 100 200 300 400 500 600 700
]-1
keV
× -1
y× -1 t×
Rat
e [e
vts
-210
-110
1pp
Be7
+eeν+exν
Sum
Be (862 keV)7
Be (384 keV)7
Chen et al, arXiv:1610.04177
JCAP 01, 044 (2014)
(40 ton LXe detector)
Neutrinoless Double Beta Decay
• 136Xe abundance in natural xenon 8.9%• 40t of Xe has 3.6t of 136Xe
• Q-value (2458.7±0.6) keV• Energy resolution (σ/μ) at Qββ 1%
214Bi → 214Po + e– + γ (2448 keV)
Intrinsic BG only
4.6 events/year within ±3σ
JCAP 01, 044 (2014)
T1/2 > 8.5×1027 yr (140t x yr)
T1/2 > 5.6×1026 yr (30t x yr)
current limit (KamLAND-Zen)
Is the neutrino a Majorana particle?
Completed / Operating / Planning: XENON10, XENON100, XENON1T, XENONnT
XeX E N O NDark Matter Project
25 institutions, 150 people
Patrick Decowski - UvA/NikhefCredit: Google
Gran Sasso National Parknear L’Aquila, Italy
Patrick Decowski - UvA/Nikhef
XENON1T Dark Matter Experiment
Dual-Phase Xe TPC
E
Anode
Cathode
Liquid Xe
Gas Xe5mm
~100cm
~10 kV/cm
~0.2 kV/cm
Top PMT Array
Bottom PMT Array
XENON1T: 3.2 tons of liquid xenon
Dual-Phase Xe TPC
E
Top PMT Array
Bottom PMT Array
direct (S1)
proportional (S2)
e-
WIMP
ɣ,β
Signal:Nuclear recoilDrift Time
S1 S2
Background:Electron recoil
Drift Time
S1 S2
ɣ, β
WIMP
S2
S1,>
S2
S1WIMP
Cryogenics & Purification
Electronics & DAQ
Xe storage & DistillationWater-Cherenkov
muon veto
Xe TPC3.2 tons Xe with
2 tons ‘active’
Calibration System
TPC assembly during Fall 2015
Patrick Decowski - Nikhef/UvA
Main Backgrounds
NR
ER
Electronic recoils (ER): • Materials: Low energy
Compton scatters from radioactive contamination in detector components: U and Th chains, 40K, 60Co, 137Cs
• Solar neutrino scattering off electrons
• Intrinsic contaminants: β decays of 222Rn daughters, 85Kr, 136Xe
Nuclear Recoils (NR): • Radiogenic neutrons: spontaneous fission and (α, n) reaction from the U and Th
chains in detector components• Muon-induced neutrons• Coherent scattering of neutrinos (mostly solar) off Xe nuclei
Radon decay chains
“Bad” Radon “Good” Radon
Background Calibration Thesis
Sander Breur
Patrick Decowski - Nikhef/UvA
3.8 d
3.1 m
26.8 m
19.9 m
164 μs
1600 y
238 92U
234 90Th
234 91Pa
234 92U
222 86Rn
22688Ra
230 90Th
218 84Po
214 82Pb
21483Bi 210
83Bi
214 84Po
210 82Pb 206
82Pb
21084Po
(stable)
α decayβ decay
214 82Pb
214 83Bi
Qβ=1023 keV
553 keV
53 keV
839 keV
352 keV
295 keV
6 %
49 %
1 %
2 %
42 %352 keV
242 keV295 keV
22 y
Electronic Recoil Energy [keV]0 500 1000 1500 2000 2500
] -1
keV
)⋅
day
⋅
ER R
ate
[ ( k
g
8−10
7−10
6−10
5−10
4−10
3−10
2−10
1−10
Total Rn222
materials Kr85
Xe136 νsolar
222Rn background dominating
Electronic Recoil Energy [keV]0 50 100 150 200 250
] -1
keV
)⋅
day
⋅
ER R
ate
[ ( k
g
7−10
6−10
5−10
4−10
3−10
2−10Total Rn222 materials
Kr85 Xe136 νsolar
DM Search Region
XE
NO
N C
oll., arXiv:1512.07501
ER Background
Reached design goal of 10 μBq/kg 222Rn concentration
“Bad” Radon
XE
NO
N C
oll., arXiv:1512.07501
10-6
10-1
ER R
ate
[ (kg
x d
ay x
keV
)-1]
]2 [mm2R0 20 40 60 80 100 120 140 160 180 200 220
Z [m
m]
-400
-300
-200
-100
0
100
200
300
400 ] -1
keV
)⋅
day
⋅
Rate
[ ( k
g
-610
-110-1
]2 [mm2R0 20 40 60 80 100 120 140 160 180 200 220
310×
Z [m
m]
-400
-300
-200
-100
0
100
200
300
400 ]-1 k
eV)
⋅ d
ay
⋅NR
Rate
[ ( k
g
-910
-510 Fiducial Mass [kg]200 400 600 800 1000 1200 1400 1600 1800
] -1
keV
)⋅
day
⋅
ER R
ate
[ (kg
7−10
6−10
5−10
4−10
3−10Total
Xe (2ν2β)136
Rn (10 µBq/kg)222
Kr (0.2 ppt natKr/Xe)85
MaterialsνSolar
[1-12 keVee]
LXe self-shielding
• ER backgrounds from materials are on the surface: fiducial mass cuts effective
• Intensive campaign to select clean materials• 222Rn is dominant ER BG• Radiogenic neutrons dominant NR BG
ER BackgroundER Background
Neutron Background
Calibration Systems• Variety of calibration sources:
• “Internal” sources: 83mKr, 220Rn
• External sources: 241AmBe, neutron generator
• Materials: 60Co, 129mXe, 131mXeThesis
Erik Hogenbirk
Cryogenic System
Xenon is continuously circulated through purification system
Electron Lifetime
E
Top PMT Array
Bottom PMT Array
direct (S1)
proportional (s2)
e-
Xenon is continuously purifiedFull drift length is 673 μs
Exposure
• Detector ran smoothly - DAQ efficiency ~99%
• Two Science Runs: 32 days and 247 days
• About 1 ton-year of exposure accumulated in 1.3 ton fid. volume
SR0 SR1
Examples of Corrections
S2 Top ArrayS1 Light Yield
Correction of E-field distortion
Position
83mKr calibrations
Wide range energy reconstruction
0ν2β in 136Xe 2 E.C. in 124Xe
Energy Reconstruction
• Parametrized in g1 and g2
• Detector dependent
• Excellent ER energy reconstruction
• From 40 keV to 2.2 MeV
E = W · (nph + ne) = W ·S1
g1+
S2
g2
13.7 ± 0.2 eV
Improved calibration statisticsSR0 SR1
ER ER
NR NR
Median±2σ
“Good” Radon “Good” Radon
Detailed Response Model of detector
0 10 20 30 40 50Energy [keVnr]
0
5
10
15
20
25
Phot
onyi
eld
[ph
keV
1 ]
> 10% efficiency
0 10 20 30 40 50Energy [keVnr]
0
2
4
6
8
10
12
14
Cha
rge
yiel
d[e
keV
1 ]
> 10% efficiency XENON1T, this result (82 V cm1)Aprile 2005 (0 V cm1)Aprile 2006 (2 kV cm1)Aprile 2009 (0 V cm1)Aprile 2013 (530 V cm1)Plante 2011 (0 V cm1)Sorenson 2009 (730 V cm1)Manzur 2010 (0 V cm1)Manzur 2010 (1 kV cm1)LUX 2017 (180 V cm1)NEST v1.0 (82 V cm1)
0 5 10 15 20Energy [keVee]
0
10
20
30
40
50
60
Phot
onyi
eld
[ph
keV
1 ]
> 10% efficiency
XENON1T, this result (220Rn, 82 V cm1)XENON1T, this result (220Rn, 200 V cm1, extrapolation)XENON100 (CH3T, 92 V cm1, cred. region)
LUX (127Xe, 180 V cm1)LUX (CH3T, 105 V cm1)
PIXeY (37Ar, 200 V cm1)NEST v2.0 beta (82 V cm1)Error bars are stat. + sys.
0 5 10 15 20Energy [keVee]
20
30
40
50
60
70
80
Cha
rge
yiel
d[e
ke
V
1 ]
> 10% efficiency
ER
NR
Efficiency
0 10 20 30 40 50 60 70Nuclear recoil energy [keVnr]
0.0
0.2
0.4
0.6
0.8
1.0
Effic
ienc
y
Energy Region
SelectionDetection
WIMPWIMP
Rat
e[a
.u.]
10 GeV
50 GeV
200 GeV
WIMP Search Region
ROI: 3PE < S1 < 70PEequiv: ER: 1.4 - 10.6 keVee
NR: 4.9 - 40.9 keVnr
Analysis was: Blinded“Salted"
Fiducial mass Selection
• Signal and background are modeled in (cS1, cS2, R, “z”) space
• Fiducial mass increased from 1 ton → 1.3 tons
• Total exposure of SR0+SR1: 1 ton x year
Ultra Low ER Background
• ER rate initially dominated by 85Kr
• Distilled out - remainder is due to 222Rn decay
• Measured BG: (82 ± 5) events/(keVee x yr x t)
• Lowest ever achieved in a dark matter detector!
ER rateComponent [ev/(keVee · t · yr))]214Pb 56± 685Kr 7.7± 1.3Materials 8± 1Solar 2.5± 0.1136Xe 22 0.8± 0.1Total pred. MC 75± 6Measured 82+5
3(syst)±3(stat)<latexit sha1_base64="bUc6TuaMWvwYI9EYyS+PPgih6Is=">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</latexit><latexit sha1_base64="bUc6TuaMWvwYI9EYyS+PPgih6Is=">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</latexit><latexit sha1_base64="bUc6TuaMWvwYI9EYyS+PPgih6Is=">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</latexit><latexit sha1_base64="bUc6TuaMWvwYI9EYyS+PPgih6Is=">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</latexit>
• 85Kr: 85Kr/natKr ~10-11
“Bad” Radon
Thesis Sander Breur
Lowest Background of any DM experiment
Thesis Sander Breur
Accidental + Surface BackgroundsAccidental Background Surface Background
Thesis S.Breur
Plate out of 210Po andincomplete
charge (S2) collection
NR Background
0 3 10 20 30 40 50 60 70 80 90 100cS1 [PE]
200
400
1000
2000
4000
8000
cS2 b
[PE]
3s2s
1s
Multiple Scatter NeutronER Background
0 500 1000 1500 2000 2500R2 [cm2]
100
80
60
40
20
0
Z[c
m]
Neutrons will multiple scatter in LXe - WIMPs will not
Validation of NR model
NR rateComponent [ev/(t · yr))]Radiogenic n 0.6 ± 0.1CNNS 0.012Cosmogenic <0.01
<latexit sha1_base64="0YNk6y7yUc2j0bDaEDTGinWuzdk=">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</latexit><latexit sha1_base64="0YNk6y7yUc2j0bDaEDTGinWuzdk=">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</latexit><latexit sha1_base64="0YNk6y7yUc2j0bDaEDTGinWuzdk=">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</latexit><latexit sha1_base64="0YNk6y7yUc2j0bDaEDTGinWuzdk=">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</latexit> 1 ton FV
Results after unblinding + unsalting
Pie charts: events passing all cuts, rel. prob. of BG and signal, assuming 200GeV WIMP
Ref NR region
200 GeV WIMP(for illustration)
Had to make post-unblinding changes to BG model and Fiducial
Mass segmentation: 2% (4%) increase in final
limit (med. sens.)
Final limits from XENON1T
PRL 121, 111302, arXiv:1805.12562
101 102 103 104
WIMP mass [GeV/c 2]
10−49
10−48
10−47
10−46
10−45
10−44
10−43
WIM
P-nu
cleo
nσ S
I[cm
2 ] XENON100
(2016)
LUX (2017)
PandaX (2017
)
XENON1T
(2017)
Billard 2013
, neutrino
discovery
limit
101 102 103 104
WIMP mass [GeV/c 2]
10−49
10−48
10−47
10−46
10−45
10−44
10−43
WIM
P-nu
cleo
nσ S
I[cm
2 ] XENON100
(2016)
LUX (2017)
PandaX (2017
)
XENON1T
(2017)
Billard 2013
, neutrino
discovery
limit
101 102 103 104
WIMP mass [GeV/c 2]
10−49
10−48
10−47
10−46
10−45
10−44
10−43
WIM
P-nu
cleo
nσ S
I[cm
2 ] XENON100
(2016)
LUX (2017)
PandaX (2017
)
XENON1T
(2017)
XENON1T
(1 t year, t
his work)
Billard 2013
, neutrino
discovery
limit
101 102 103 104
WIMP mass [GeV/c2]
1049
1048
1047
1046
1045
1044
1043
WIM
P-nu
cleo
ns S
I[c
m2 ] XENON100 (2016)
LUX (2017)
PandaX (2017)
XENON1T (2017)
XENON1T (1 t year, this work)
XENONnT (20 t year Projection)
Billard 2013, neutrino discovery limit
10 1 10 2 10 3
WIMP mass [GeV/c 2 ]
10−1
10 0
10 1
Normalized
• Reuse most of XENON1T
• Larger inner cryostat vessel
• New TPC
• Additional ~250 PMTs (~500 total)
• Total of ~8 tons of LXe
• Funding complete
• Detector being built / designed
• Start in 2019
From XENON1T to XENONnT
Our XENONnT Goal
• Increase Xe mass by 3x
• Reduce 222Rn background by 10x
• Veto the ultimate neutron background
• Complement continuous gas purification by liquid purification
XENON1T
XENON1T First Result
XENONnT
LZ
2016 2018 2020 2022 202410
-48
10-47
10-46
10-45
10-44
Crosssection @ 50GeV [cm2]
Apr
2020
Aug
2019
Aug
2018
New Magnetic Pump
• XENONnT R&D on XENON1T
• New Magnetic Pump
• Increase LXe purity - longer drift
• Reduce 222Rn contamination (from emanation of pump materials)
Jan 2018
Feb 2018
Mar 2018
Apr 2018
May 2018Jun 2018
Jul 2018
Date
400
500
600
700
800
900
1000
1100
Elec
tron
Life
time
[µs]
Pow
erO
utag
e
Pur.
upgr
ade:
1”O
Dpi
pes
Pur.
upgr
ade:
mag
.pum
pin
stal
latio
n
PRELIMINARY
End
Scie
nce
Run
1
48 SLPM 70 SLPM 80 SLPM
83mKr
222Rn Background
• Ten-fold radon reduction:
• New pumps:
• Novel magnetic piston pump R&D
• Continuous radon distillation
• Already shown to work
222Rn contributions in XENON1T
~2xreduction ~20x
reduction
XENON100 as a test bed
Even further downstream
53
XENONnT DARWIN8t of LXe totalReuse a lot of XENON1T infrastructureFunding fully securedStart in 2019
50t of LXe totalGlobal effortFunded through 2 ERC grantsStart in 2025
1.4m2.6m
Summary XeX E N O NDark Matter Project
• The XENON1T experiment is world’s most sensitive direct detection dark matter experiment
• Achieved ~1 ton x year of exposure, unprecedented radiopurity
• Larger experiments will allow for more physics channels:
• alternative DM particles, neutrino physics
• Planning XENONnT with 3x more Xe and 2x more PMTs
• Dreaming of 50t of Xe with DARWIN project…
Patrick Decowski - Nikhef/UvA
LXe: Larger detectors, lower backgrounds
5 34 118 306 1042
0.20.82.65.31000
Low-energy ER background[events / (ton keV day)]
Fiducial mass [kg]
XENON10XENON100
LUX
PandaX
XENON1T
Cut & Count
bution.
Mass 1.3 t 1.3 t 0.9 t 0.65 t
(cS1, cS2 b) Full Reference Reference Reference
ER 62 7±18 1.62 ±0.30 1.12 ±0.2 1 0.60±0.13
neutron 1.43±0.66 0.77±0.35 0.41±0.19 0.14±0.07
CEνNS 0.05 ±0.01 0.03±0.01 0.02 0.01
AC 0.47+0.27−0.00 0.10+0.06
−0.00 0.06+0.03−0.00 0.04+0.02
−0.00
Surface 106±8 4.84±0.40 0.02 0.01
Total BG 735 ±2 0 7.36±0.61 1.62 ±0.2 8 0.80±0.14
WIMPbest-fit 3.5 6 1.70 1.16 0.83
Data 739 14 2 2
Using full S+BG model(S1, S2, R, “Z”) space
“Safe” reference regions
Plate out in PTFE
30000 40000 50000 60000 70000cS1 [PE]
0
100000
200000
cS2[PE]
100
101
102
Coun
t
0 500 1000 1500 2000
r2 [cm2]
0
1
2
3
4
cS2/cS1
100
101
102
Coun
t
Thesis S.Breur
222Rn218Po
210Po
222Rn 218Po
210Po
LXe purification
Uwe Oberlack IDM 2018 24-07-18 23
New System: TPC
1.48 m
1.34 m
TPC size maximized to fit XENON1T outer cryostat
same holding structure and leveling mechanism as 1T TPC
technical design and FEM largely completed→ mockup components being tested (electrodes, TPC structure, PMT support, …)
optimized for low material budget and reduction of wall charge-up.
Design drift field strength reduced to more moderate values, requiring only 30kV on cathode
all TPC electrodes made from single wires
Purity
Monitor
LXe
Pump
O2 Filter
LXe
purifcation
vessel
Testing Cryogenic Liquid Purificationwith XeCLiPSe R&D System (Xenon Cryogenic Liquid Purification Setup)
To LXe purification
Demonstrator at Columbia