The EDELWEISS-III Experiment Silvia Scorza on behalf of the - - PowerPoint PPT Presentation

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The EDELWEISS-III Experiment Silvia Scorza on behalf of the - - PowerPoint PPT Presentation

Jun 29, 2023 139 likes •386 views

The EDELWEISS-III Experiment Silvia Scorza on behalf of the EDELWEISS collaboration Institut fr Experimentelle Kernphysik, Karlsruhe Institute of Technology KIT University of the State of Baden-Wuerttemberg and www.kit.edu National

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KIT – University of the State of Baden-Wuerttemberg and 
 National Research Center of the Helmholtz Association

www.kit.edu Institut für Experimentelle Kernphysik, Karlsruhe Institute of Technology

The EDELWEISS-III Experiment

Silvia Scorza on behalf of the EDELWEISS collaboration

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Silvia Scorza Astroparticle Physics 2014 2

Direct Detection Principle

WIMP

from galactic halo

Target Nucleus

in laboratory

v~220 km/s v~0 km/s ER~30 keVr θR WIMP Elastic collision

Detection of the energy deposited due to elastic scattering off target nuclei

  • Elastic scattering of a WIMP deposits small

amount of energy into recoiling nucleus 
 (~ few 10s of keV)

  • Expected rate: 


< 0.1 interaction per ton per day
 (7.6 x 10-46 cm2 for mχ = 33 GeV)

  • Radioactive background of most materials

gives higher rate

  • Event ID from measurements of ionization and

phonon energies

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SLIDE 3

Silvia Scorza Astroparticle Physics 2014

The EDELWEISS Experiment

3

n, polyethylene shield e+,e-, γ, Pb shield µ, Muon Veto µ-n, Neutron counter

5 µ/m2/day 4800 mwe

(deepest in Europe)

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Silvia Scorza Astroparticle Physics 2014

  • Total fiducial exposure : 113 kg.d
  • 3 evts observed in the WIMP box 


(one event for Mχ = 10 GeV)

  • Estimated background (5-20 keV):

Neutron < 1.7 evt, most probable 1.0 evt
 (based on Monte-Carlo + activity meas.) Gamma < 1.2 evt

  • Limits on σSI derived from Poisson


statistics

  • Significantly extends EDW limits 


for Mχ = 7-30 GeV

Low WIMP Mass Analysis 
 EDELWEISS-II

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PRD, 86, 051701(R), (2012)

neutron calibration 95% rejecton (ID3)

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SLIDE 5

Silvia Scorza Astroparticle Physics 2014

EDELWEISS-III Improvement

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lead

PE PE

Goal: 10-45 cm2 with FID800 (24 kg fiducial)

  • Improved material selection
  • Extra internal PE shield:


ca.10 cm below bolometers


  • ca. 5 cm around and on top
  • Upgrades of muon veto, cryogenics, 


cabling, thermal screens

  • Modify electronics and DAQ (scalability): 


360 channels + auxiliary detectors

  • New event-based readout
  • More analysis tools:

Kdata: ROOT-based, multi-tier, db, …

NIM A 684 (2012) 63

Background (20 – 200 keV) EDW-2 (evt / kg.d) EDW-3 (evt / kg.d) Improvement

Gamma rate 82 14 – 44 up to 6 Ambient neutrons < 8.1·10-3 (0.8 – 1.9)·10-4 up to 100 Muon-induced neutrons < 2·10-3 < 2·10-4 up to 10

  • Astropart. phys. 47 (2013) 1 - Astropart. Phys. 44 (2013) 28
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Silvia Scorza Astroparticle Physics 2014 6

  • Additional PE shield, new Cu thermal screens
  • Kapton cables and connectors between 1 K-10 mK (Steel) and 10 mK-10 mK (Cu)
  • ALL cold electronics at 100 K: relays instead of resistors for feedback and detector biases

J Low Temp Phys 167 (2012) 645

EDELWEISS-III Improvement

Thermal
 screen New PE
 (1 K) Digitization 
 300 K FETs
 100 K Roman Pb Detector 
 plate Kapton cables New PE
 (1 K)

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SLIDE 7

Silvia Scorza Astroparticle Physics 2014

FID detector scheme

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+4V

Full Inter-Digitized 800 g HP-Ge Detector

Width: 7 cm Height: 4 cm

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Silvia Scorza Astroparticle Physics 2014

Background Rejection

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e-

NTD NTD

h+

10

e- h+

Bulk Event


  • Charge collected
  • n fiducial

electrodes B & D Surface Events
 Charge collection shared between one veto and its neighbor fiducial electrodes, e.g. C & D Most backgrounds (e, γ) produce electron recoils Yield (Ionization/recoil) ~1 WIMPs and neutrons produce nuclear recoils Yield (Ionization/recoil) ~0.3 ID400 Fiducial Events

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Silvia Scorza Astroparticle Physics 2014

Recoil Energy (keV)

FID Gamma Rejection

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EDELWEISS-II 
 ID 400 g with 10x 160 g fiducial mass

ID (350000 γ)

EDELWEISS-III FID 800 g with 36x ~600 g fiducial mass

FID Rejection 
 factor < 6 x 10-6

NTD NTD

Fiducial Volume 75 %

ID Rejection 
 factor: 3+-1 x 10 -5 Ionization Yield Ionization Yield

FID (411000 γ) 133Ba Calibration

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Silvia Scorza Astroparticle Physics 2014

Ionisation Yield Recoil Energy (keV)

FID Surface Rejection

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FID 800 β! β!

α

210Pb 210Bi 210Po 206Pb

105 Kg.d equivalent

4·10-5 misidentified events/(kg.d) (90% CL, Er >15 keV)

  • 50 nm

350 nm 20 µm 700 µm 2 mm

Ge

γ

Surface zone rejected

β!

210Bi 210Pb

β!

5,3MeV 206Pb

α

100keV

210Po

10keV 100keV 1MeV

Fiducial Volume

Al amGe Cu

Ionisation Yield

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SLIDE 11

Silvia Scorza Astroparticle Physics 2014 11

  • Additional spatial information on z-axis of

bolometer

  • Improved understanding of charge migration
  • Identifying double scatter events
  • Surface event rejection
  • Event based readout needed for 40 MHz channel
  • → Trigger on ionization channel

Time Resolved Ionization Channel

C1 +4 V V1 -1.5 V

NTD NTD

V2 +1.5 V C2 -4 V

10 20 30 40 50 60 70 80 90 Amplitude in ADU 2.5 5 7.5 10 12.5 15 17.5 20 22.5 25 Time in µs (40 MS/s) Time in µs

  • 1

Amplitude normalized 1 1

C1 V2 C2

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Silvia Scorza Astroparticle Physics 2014

Upgrades - Resolution/Threshold

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Cryogenics
 
 Pulse Tubes close to the cryostat removed and replaced by GM thermal machines outside of the shields (cryoline upgraded)


  • > Microphonic noise reduced


Electronics Resistors removed, no active feedback, replaced by a relay system

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SLIDE 13

Silvia Scorza Astroparticle Physics 2014

Upgrades - Resolution/Threshold

12

Cryogenics
 
 Pulse Tubes close to the cryostat removed and replaced by GM thermal machines outside of the shields (cryoline upgraded)


  • > Microphonic noise reduced


Electronics Resistors removed, no active feedback, replaced by a relay system

  • FWHM (keV)

EDELWEISS II EDELWEISS III Ionization 900 600 Heat 1.2 1.0

Baseline Resolution

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SLIDE 14

Silvia Scorza Astroparticle Physics 2014

Upgrades - Resolution/Threshold

12

Cryogenics
 
 Pulse Tubes close to the cryostat removed and replaced by GM thermal machines outside of the shields (cryoline upgraded)


  • > Microphonic noise reduced


Electronics Resistors removed, no active feedback, replaced by a relay system

  • R&D (JFET -> HEMT)


FWHM (keV) EDELWEISS II EDELWEISS III Ionization 900 600 Heat 1.2 1.0

300

X

Baseline Resolution

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Silvia Scorza Astroparticle Physics 2014

2014 Status

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November 2013 - January 2014: 15 x 800 g, commissioning phase
 February 2014: 36 x 800 g detectors installed in cryostat 
 (+ 3 Lumineu double beta decay detectors)
 24 kg of fiducial mass in germanium Facility able to acquire 3000 kg.d per 6 months

  • Expected background

from internal neutrons limits total exposure with <1 bkg event from 
 4500 kg.d (2.5x10-9 pb) to 12 000 kg.d (10-9 pb)

  • Baseline resolution: <650 eV>


Ba 356-keV resolution: <10 keV>

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SLIDE 16

Silvia Scorza Astroparticle Physics 2014

2014 Status

13

November 2013 - January 2014: 15 x 800 g, commissioning phase
 February 2014: 36 x 800 g detectors installed in cryostat 
 (+ 3 Lumineu double beta decay detectors)
 24 kg of fiducial mass in germanium Facility able to acquire 3000 kg.d per 6 months

  • Expected background

from internal neutrons limits total exposure with <1 bkg event from 
 4500 kg.d (2.5x10-9 pb) to 12 000 kg.d (10-9 pb)

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Silvia Scorza Astroparticle Physics 2014

The LUMINEU project: tests of ZnMoO4 crystals within EDWIII cryostat for ββ measurement. 0νββ of 100Mo -> information on neutrino nature, mass and hierarchy

  • 





Within the Cryostat …

14

313g ZnMo04 bolometer operated at LSM in the EDELWEISS setup and its light detector.

2014: 2 enriched Zn100MoO4 crystals (~60g each) have been produced at NIIC and successfully tested aboveground. They are now installed at LSM, ready to take data.

  • A.S. Barabash et al., arXiv:1405.6937

Light vs. heat @ LSM background measurement

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Silvia Scorza Astroparticle Physics 2014 15

Installation of 36 FIDs

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Silvia Scorza Astroparticle Physics 2014 16

Current Status

  • Commissioning of FID detectors
  • 36 detectors installed, 24 being

read out

  • Cool down ongoing

End of 2014/ Early 2015

Reach 3000 kg.d 
 (6 months of data taking)

2016

Reach 12000 kg.d (10-9 pb) Low Mass WIMP 1200 kg.d (4 FID)
 Er > 3 keV, 300 eV FWHM with HEMT 
 
 Standard WIMP 12000 kg.d no event
 Er > 15 keV (10%efficiency at 6 keV)
 


Timeline

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Silvia Scorza Astroparticle Physics 2014 17

]

2

WIMP Mass [GeV/c 3 4 5 6 7 10 20 30 40 100 200 1000 2000 10000 ]

2

WIMP-Nucleon Cross Section (SI) [cm

  • 47

10

  • 46

10

  • 45

10

  • 44

10

  • 43

10

  • 42

10

  • 41

10

  • 40

10

  • 39

10

COUPP (2012) EDELWEISS (2010/2011) CRESST-II (2012) DAMA (Savage, 2009) CoGeNT (2012) ZEPLIN-III (2011) XENON10 (2011) SIMPLE (2012) CDMS (2010/2011) CDMS-Si (2013) XENON100 (2012) XENON1T (2017) L U X ( 2 1 3 ) B u c h m u e l l e r ( 2 1 1 ) Roszkowski (2013) EURECA Edelweiss 3 SCDMS at Soudan SCDMS at SNOLAB Neutrino background

Next Step: EURECA

200kg phase
 under investigation with new performances (EDW-III & CRESST update) standard high mass search (ton-scale)

  • Ge/CaWO4 detectors
  • Cooperation with

SuperCDMS

  • 200kg low mass phase

followed by ton-scale upgrade 


  • Conceptual Design

Report


Physics of the Dark Universe, Volume 3, p. 41-74.

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Silvia Scorza Astroparticle Physics 2014

10 times less 


misidentified gammas/(kg.d)

30% better resolutions

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Summary

  • FID 800 g, 75% VFID




New electronics & cryogenics 
 
 Gamma rejection improvement
 Surface rejection improvement
 
 
 New shielding & cabling ×15 fiducial mass ×100 neutron suppression

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SLIDE 22

Silvia Scorza Astroparticle Physics 2014

10 times less 


misidentified gammas/(kg.d)

30% better resolutions

18

Summary

  • FID 800 g, 75% VFID




New electronics & cryogenics 
 
 Gamma rejection improvement
 Surface rejection improvement
 
 
 New shielding & cabling ×15 fiducial mass ×100 neutron suppression

GOAL: Reach 12000 kg.d (10-9 pb) 
 in 2 years (EDW-II sensitivity ×15)

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Silvia Scorza Astroparticle Physics 2014 19

Thanks!

CEA Saclay (IRFU & IRAMIS) CSNSM Orsay (CNRS/IN2P3 & Paris Sud) IPNL Lyon (CNRS/IN2P3 & Univ. Lyon 1) Néel Grenoble (CNRS/INP) LPN Marcoussis (CNRS) KIT Karlsruhe (IKP, EKP, IPE)

  • JINR Dubna
  • Oxford University

University of Sheffield