M. Schumann (Freiburg) – XENON 1
XENON1T
Marc Schumann (Freiburg U)on behalf of the Collaboration
LNGS Open Session, 03.04.2017
M. Schumann (Freiburg) – XENON 2
The XENON Collaboration
22 institutions 10 countries 3 continents135 scientists
M. Schumann (Freiburg) – XENON 3
New science results published:
Several studies are currently being prepared for submission...
XENON100XENON100
M. Schumann (Freiburg) – XENON 4
Detector
Pressure [bar]
Temperature [K]
Analysis
Cut Acceptance
Rate
Multiples(=background)
Singles(=signal)
Data acquired over 4 years: Jan 2010 – Jan 2014→ longest LXe TPC operation ever
Highlight: Annual Modulation 2.0PRL 118, 101101 (2017)
M. Schumann (Freiburg) – XENON 5
Detector
Pressure [bar]
Temperature [K]
Analysis
Cut Acceptance
Rate
Multiples(=background)
Singles(=signal)
Highlight: Annual Modulation 2.0PRL 118, 101101 (2017)
M. Schumann (Freiburg) – XENON 6
single scatter, low E→ signal region (2-6 keV)
multiple scatter, low E
single scatter, high E
● additional data improves upon previous analysis PRL 115, 091302 (2015)
● no significant modulation observed
● Dark matter explanation of DAMA/LIBRA signal excluded @ 5.7σ
Highlight: Annual Modulation 2.0PRL 118, 101101 (2017)
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M. Schumann (Freiburg) – XENON 7
XENON100: R&D for XENON1T
● Integration of XENON1T distillation column into XENON100 system
● 222Rn activity inside XENON100 monitored by α-tagging
● 222Rn concentration artificially increased
● measured reduction factor of >27 (@ 95% CL)
1. Demonstration of online 222Rn-removal by cryogenic distillation
arXiv:1702.06942
M. Schumann (Freiburg) – XENON 8
228Th source emanates 220Rn
use β-decay of 212Bi to calibrate low energy region
time distribution of later chaindetermined by 212Pb→ back to background level after ~6.5 days
2. Demonstration of low-E bulk calibration with 220Rn source
XENON100: R&D for XENON1T
uniform distribution in TPC
arXiv:1611.03585
M. Schumann (Freiburg) – XENON 9
Successfully used in XENON1T
P R E L I M I N A R Y
M. Schumann (Freiburg) – XENON 10
XENON1T
largest LXe TPC ever built cylinder: 96 × 97 cm active LXe target: 2.0t (3.2t total)
248 PMTs (Hamamatsu R11410-21)
M. Schumann (Freiburg) – XENON 11
XENON1T: all systems running
Purification
Kr RemovalStorage/Recovery
DAQ + Computing
Calibration
Slow Control
Water Shield
Muon Veto
TPC + PMTs
Cryogenics
M. Schumann (Freiburg) – XENON 12
XENON1T: Data Taking
commissioningcompleted!
XENON1T operates stably
P R E L I M I N A R Y
M. Schumann (Freiburg) – XENON 13
Data Taking: Neutrons
calibrationof signal region
Light: ~8 PE Charge: ~240 PE
→ a WIMP would look similar
earthquakes!!!
M. Schumann (Freiburg) – XENON 14
Data Taking: 83mKr
calibration ofdetector response:energy, positions
S2 corrections
top
bottom
P R
E L I M
I N A
R Y
E
neg HV
pos HV
liquidtarget
gas
PMT
M. Schumann (Freiburg) – XENON 15
Data Taking: 83mKr
calibration ofdetector response:energy, positions
Light and Charge Yields
P R E L I M I N
A R Y
8.0 PE/keV @ 122 V/cmfor 41.5 keV
→ ~8.9 PE/keV @ zero-field
→ 2× higher than XENON100
M. Schumann (Freiburg) – XENON 16
Data Taking: Dark Matter
start takingblinded
dark matter data
early 220Rn data
P R E L I M I N A R Y
blinded in DM data
M. Schumann (Freiburg) – XENON 17
Data Taking: 220Rn
calibrate ERbackground in
bulk LXe
P R E L I M I N A R Y
M. Schumann (Freiburg) – XENON 18
Data Taking: LED
regular PMTcalibrations
PMT Gain Stability
gains were chosen to optimizeindividual single photoelectronresponse while avoiding exceedingly high bias voltages
P R E L I M I N A R Y
M. Schumann (Freiburg) – XENON 19
Data Taking: Dark Matter
dark matter data
M. Schumann (Freiburg) – XENON 20
Jan 18: Earthquake again...
up to 5.5 mag, epicenter ~20 km away
we clearly see earthquakes in our LXe level sensors and detector tiltmeters
→ January 18 earthquake caused high voltage trips
M. Schumann (Freiburg) – XENON 21
Data Taking: Dark Matter
check integrityof detector
Use „natural break“ todefine science run 0 (SR0)
adds up to ~35 live days
M. Schumann (Freiburg) – XENON 22
Continue Data Taking
data taking ongoing;data quality good,NR region blinded
regular calibrations
M. Schumann (Freiburg) – XENON 23
SR0: Detector Stability
P R E L I M I N A R Yall detector parameterscontinuously monitoredby slow control system
→ excellent stability
M. Schumann (Freiburg) – XENON 24
SR0: BackgroundsWIMP ROI: 1–12 keV interval
Electronic Recoils Nuclear Recoils(gamma, beta) (neutron)
JCAP 04, 027 (2016)
negligible forSR0 exposure
natKr: 0.2 ppt
222Rn: 10 µBq/kg
final goals intrinsic:
M. Schumann (Freiburg) – XENON 25
SR0: BackgroundsWIMP ROI: 1–12 keV interval
Electronic Recoils Nuclear Recoils(gamma, beta) (neutron)
JCAP 04, 027 (2016)
negligible forSR0 exposure
natKr: 0.2 ppt
222Rn: 10 µBq/kg
final goals intrinsic:
Measured 222Rn emanation
Cryosystem,Connections
TPC+Cryostat
Expected background:
(11±2) µBq/kg prelim.
agrees with preliminaryvalue from α-counting
P R E L I M I N A R Y
PurificationSystem
✓
M. Schumann (Freiburg) – XENON 26
SR0: BackgroundsWIMP ROI: 1–12 keV interval
Electronic Recoils Nuclear Recoils(gamma, beta) (neutron)
JCAP 04, 027 (2016)
negligible forSR0 exposure
natKr: 0.2 ppt
222Rn: 10 µBq/kg
final goals intrinsic:
✓
new: online Kr-Removal
● 3.5 slpm from Xe-gas phase are passed through distillation column● return to TPC via PUR system
→ online removal of natKr while detector acquired science data
natKr/Xe = (0.6±0.1) ppt achieved
→ lowest value in LXe experiments ever→ sufficient for SR0
P R E L I M I N A R Y
✓
M. Schumann (Freiburg) – XENON 27
SR0: Status● intense „analysis bootcamp“ completed
● analysis is being finalized
● expect result soon
M. Schumann (Freiburg) – XENON 28
XENON1T: Full SensitivityJCAP 04, 027 (2016)
assumptions: energy interval: 4 – 50 keV, ER rejection as XENON100: 99.5% @ 50% NR acc.
all backgrounds included, 2 t×y exposure:
M. Schumann (Freiburg) – XENON 29
XENON1T - 2t active LXe target- operating in DM mode- first results soon
Already existing/operational: ● Muon Veto● Cryostat Support ● Outer Cryostat● in-LXe Cabling● LXe storage system● Cryogenic system● Purification system● Kr removal● DAQ● 95% of Electronics● Calibration System● 260 PMTs● >8t of LXe (was 4.5t one year ago!)● Screening facilities● dedicated nT funding
Already started:● 230 new PMTs ordered● TPC/Cryostat design● first material orders● Screening campaign● Neutron veto studies● 2nd storage vessel ordered● Rn reduction system design● purification improvements● etc.
~140cm
JCAP 04, 027 (2016)XENON1T → XENONnT
XENONnT- 6t active target- projected to start science in 2019
M. Schumann (Freiburg) – XENON 30
The XENON Future
some projects are missing...
www.xenon1t.org