Dark Matter Searches and Other Physics Signals in

XENON1T, XENONnT and DARWIN

Patrick Decowskidecowski@nikhef.nl

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=">AAADXHicbVLbbtNAEN0kBVqXQtpKvPCyIgtKhGpsh1weKyIkJBQpQJNGitNovd4kVnzT7rpS5Pr/+AVeeOFHGDtWS1tGsjw758zsmZl1Yt+TyjB+Vaq1vSdPn+0faIfPj168rB+fTGSUCMbHLPIjMXWo5L4X8rHylM+nseA0cHx+6WwGOX55zYX0ovBCbWM+D+gq9JYeowpCi+PKje3wlRemikJKpt2dEp+KLPVvWKbhd/jzdyyo4ti2tUEUxFHIQwXhGbEDqtYiSPn1h+aGTxYp5xm2mRsprMr/VrQy0prbNrbXuU6NXKWW+TEjIwdKkE4X23GAuwRqA9LvZOSryIGe3isQU2/n2BDuFx71ZY71d0ge/xGBUkzsMCE5YumdAjN0s6xotrsZmXKAgGNBh4oWTEPv/8ssxV1EivoYhujqeDgodHTuBJakIacyAUohxbpK33eyRXrWzkhTbqVqEeCTdlMqqlp5Eg/d25HenmDci3rD0I3C8GPHLJ0GKm20qP+03YglAUyf+VTKmWnEap5SoTxWrC+RPKZsQ1c8LR5Hht9CyMXLSMAHOyui93g0kHIbOMDMVykfYnnwf9gsUcv+PPXCOFE8ZLuLlomPVYTzl4ZdT3Cm/C04lAkPFGK2poIyWKPUoHXzYaOPnYmlm+B/sxrnn8oh7KPX6A1qIhP10Dn6gkZojFjlT/WgelI9rf6u7dUOa0c7arVS5pyie1Z79Rf7KPuA</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=">AAACo3icbVHLbtNAFB2bVzGvAEs2I+JWLYtiZwEsWFR0g4QUhdC0hYwVjceTZNR5WDPXlSLjv2PBL/A3jB2rqC1XGuncc8+d+8pLKRwkyZ8gvHP33v0HOw+jR4+fPH02eP7i1JnKMj5jRhp7nlPHpdB8BgIkPy8tpyqX/Cy/OG7jZ5fcOmH0CWxKnim60mIpGAVPLQa/SM5XQtdAfUYT/fMqSW1Ty5+sifAeHk+xpcAxIdGxUaXRXIOn5zFRFNZW1fzy7T5gwgoDeGMPmvggIwSTddtXNKWFMCuuBcPaZyWH73BMShV7lLY/jsffOjpJR9sKTvXyPRx/jNtAyxOui6vWrjzf9mIw9JrO8G2Q9mCIepssBr9JYVil/BRMUufmaVJCVlMLgnVrqBwvKbugK153O27wrqcKvDTWPz97x17TUeXcRuVe2a7E3Yy15P9i8wqWH7Ja6LICrtm20LKSGAxuD4YLYTkDufGAMit8h5itqaUM/FkjP3p6c9Db4HR0mHr8dTQ8+tQvYQe9Qq/RPkrRe3SEPqMJmiEWvAkmwffgR7gbfgmn4clWGgZ9zkt0zcLsL21QxsE=</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