Towards Direct Detection of WIMPs with the Cryogenic Dark Matter - - PowerPoint PPT Presentation

▶
towards direct detection of wimps with the cryogenic dark
SMART_READER_LITE
LIVE PREVIEW

Towards Direct Detection of WIMPs with the Cryogenic Dark Matter - - PowerPoint PPT Presentation

Nov 04, 2023 264 likes •890 views

Towards Direct Detection of WIMPs with the Cryogenic Dark Matter Search Enectali Figueroa-Feliciano Massachusetts Institute of Technology For the CDMS Collaboration Towards Direct Detection of WIMPs with the Cryogenic Dark Matter Search

slide-1
SLIDE 1

Enectali Figueroa-Feliciano Massachusetts Institute of Technology

Towards Direct Detection

  • f WIMPs with the

Cryogenic Dark Matter Search

For the CDMS Collaboration

slide-2
SLIDE 2

Enectali Figueroa-Feliciano Massachusetts Institute of Technology

Towards Direct Detection

  • f WIMPs with the

Cryogenic Dark Matter Search

For the CDMS Collaboration

slide-3
SLIDE 3

Enectali Figueroa-Feliciano - SUSY09

The CDMS Collaboration

  • Caltech
  • Case Western Reserve
  • FNAL
  • MIT
  • NIST
  • Queen’s University
  • Santa Clara University
  • Stanford University
  • Syracuse University
  • UC Berkeley
  • UC Santa Barbara
  • University of Colorado at

Denver

  • University of Florida
  • University of Minnesota
  • University of Texas A&M
  • University of Zurich
slide-4
SLIDE 4

Enectali Figueroa-Feliciano - SUSY09

The Concordance Model of Cosmology

Dark Energy Dark Matter Free H & He Stars and Gas Neutrinos Heavy Elements (Us)

Dark Energy 73% Dark Matter 23% Free H & He 3% 0.03%

All rocky planets and their inhabitants are found here

slide-5
SLIDE 5

Enectali Figueroa-Feliciano - SUSY09

The Concordance Model of Cosmology

We don’t know what 96% of the Universe is made of!!!

Dark Energy Dark Matter Free H & He Stars and Gas Neutrinos Heavy Elements (Us)

Dark Energy 73% Dark Matter 23% Free H & He 3% 0.03%

All rocky planets and their inhabitants are found here

slide-6
SLIDE 6

Enectali Figueroa-Feliciano - SUSY09

The Concordance Model of Cosmology

We don’t know what 96% of the Universe is made of!!!

Dark Energy Dark Matter Free H & He Stars and Gas Neutrinos Heavy Elements (Us)

Dark Energy 73% Dark Matter 23% Free H & He 3% 0.03%

All rocky planets and their inhabitants are found here

slide-7
SLIDE 7

Enectali Figueroa-Feliciano - SUSY09

  • The Missing Mass Problem:
  • Dynamics of stars, galaxies, and clusters
  • Rotation curves, gas density, gravitational lensing
  • Large Scale Structure formation
  • Wealth of evidence for a particle solution
  • No good MOND, Bullet Cluster,
  • Microlensing (MACHOs) limit < 1 AU
  • Non-baryonic
  • Height of acoustic peaks in the CMB (Ωb)
  • Power spectrum of density fluctuations (Ωm)
  • Primordial Nucleosynthesis
  • And STILL HERE!
  • Stable, neutral, non-relativistic
  • Interacts via gravity and/or weak force

The Nature of Dark Matter

slide-8
SLIDE 8

Enectali Figueroa-Feliciano - SUSY09

Zeroing on WIMPs

  • We “know” that Dark Matter
  • Has mass
  • Is non-baryonic
  • Was non-relativistic early on in

cosmological time

  • Has a certain annihilation cross

section

  • One theoretical candidate for such a

particle is called the Weakly Interacting Massive Particle: WIMP

  • This talk will focus on one particular

WIMP candidate, the lightest supersymmetric particle commonly referred to as the neutralino

(Roszkowski 2004)

slide-9
SLIDE 9

Enectali Figueroa-Feliciano - SUSY09

Zeroing on WIMPs

  • We “know” that Dark Matter
  • Has mass
  • Is non-baryonic
  • Was non-relativistic early on in

cosmological time

  • Has a certain annihilation cross

section

  • One theoretical candidate for such a

particle is called the Weakly Interacting Massive Particle: WIMP

  • This talk will focus on one particular

WIMP candidate, the lightest supersymmetric particle commonly referred to as the neutralino

(Roszkowski 2004) χ

slide-10
SLIDE 10

Enectali Figueroa-Feliciano - SUSY09

  • Energy spectrum & rate depend on

WIMP distribution in Dark Matter Halo

  • “Spherical-cow” assumptions: isothermal and

spherical, Maxwell-Boltzmann velocity distribution

  • vo = 220 km/s, <v> = 270 km/s, vesc= 650 km/s
  • ρ = 0.3 GeV / cm3
  • Assume mass = 60 GeV/c2
  • Density = 5000 part/m3

moo

Direct Detection Astrophysics of WIMPs

10 WIMPs

  • n average, inside a 2 liter bottle

(if mass=60 x proton)

slide-11
SLIDE 11

Enectali Figueroa-Feliciano - SUSY09

The Dark Matter Wind

apparently “blows” from Cygnus Our speed relative to the halo is ~220 km/s

slide-12
SLIDE 12

Flux

  • Density: 0.3 GeV/cm3
  • Mass: assume 60 GeV/c2
  • ~220 km/s
  • ~100,000 particles/cm2/sec
  • About 20 million/hand/sec

Enectali Figueroa-Feliciano - SUSY09

slide-13
SLIDE 13

Enectali Figueroa-Feliciano - SUSY09

F 2(Q) = 3j1 (qR1) qR1 2 exp

  • − (qs)2

Knowledge of Nuclear Structure Input from Astrophysics

T(Q) = exp

  • −v2

min/v2

  • vmin =
  • ER mN

2m2

r

v0 ≈ 220 km/s

σ0 = mr mr−p 2 A2σχ−p mr = mχ mN mχ + mN

Input from Particle Physics Our choice of Target Nucleus

dR dER = σ0ρ0 √πv0mχm2

r

F 2(Q)T(Q)

Principles of Direct Detection

mr−p = mχ mp mχ + mp

slide-14
SLIDE 14

Enectali Figueroa-Feliciano - SUSY09

WIMP Hunting

50 100 10

1

10

2

10

3

10

4

Recoil [keV] Counts [#10−6/kg/keV/day]

WIMP Elastic Scattering Differential Rate

WIMP Differential Event Rate

Ge Si Xe

Mχ = 100 GeV/c2 σχ-N = 10-45 cm2

slide-15
SLIDE 15

Enectali Figueroa-Feliciano - SUSY09

WIMP Hunting

  • Elastic scattering of a WIMP from a

nucleus deposits a small, but detectable amount of energy ~ few x 10 keV

50 100 10

1

10

2

10

3

10

4

Recoil [keV] Counts [#10−6/kg/keV/day]

WIMP Elastic Scattering Differential Rate

WIMP Differential Event Rate

Ge Si Xe

Mχ = 100 GeV/c2 σχ-N = 10-45 cm2

slide-16
SLIDE 16

Enectali Figueroa-Feliciano - SUSY09

WIMP Hunting

  • Elastic scattering of a WIMP from a

nucleus deposits a small, but detectable amount of energy ~ few x 10 keV

  • Featureless exponential energy

spectrum with 〈E〉 ~ 50 keV

50 100 10

1

10

2

10

3

10

4

Recoil [keV] Counts [#10−6/kg/keV/day]

WIMP Elastic Scattering Differential Rate

WIMP Differential Event Rate

Ge Si Xe

Mχ = 100 GeV/c2 σχ-N = 10-45 cm2

slide-17
SLIDE 17

Enectali Figueroa-Feliciano - SUSY09

WIMP Hunting

  • Elastic scattering of a WIMP from a

nucleus deposits a small, but detectable amount of energy ~ few x 10 keV

  • Featureless exponential energy

spectrum with 〈E〉 ~ 50 keV

  • no obvious peak, knee, break,

... that determines Mχ or v0

50 100 10

1

10

2

10

3

10

4

Recoil [keV] Counts [#10−6/kg/keV/day]

WIMP Elastic Scattering Differential Rate

WIMP Differential Event Rate

Ge Si Xe

Mχ = 100 GeV/c2 σχ-N = 10-45 cm2

slide-18
SLIDE 18

Enectali Figueroa-Feliciano - SUSY09

WIMP Hunting

  • Elastic scattering of a WIMP from a

nucleus deposits a small, but detectable amount of energy ~ few x 10 keV

  • Featureless exponential energy

spectrum with 〈E〉 ~ 50 keV

  • no obvious peak, knee, break,

... that determines Mχ or v0

  • Expected rate < 0.01/kg-day (based on

σnχ and ρ)

50 100 10

1

10

2

10

3

10

4

Recoil [keV] Counts [#10−6/kg/keV/day]

WIMP Elastic Scattering Differential Rate

WIMP Differential Event Rate

Ge Si Xe

Mχ = 100 GeV/c2 σχ-N = 10-45 cm2

slide-19
SLIDE 19

Enectali Figueroa-Feliciano - SUSY09

WIMP Hunting

  • Elastic scattering of a WIMP from a

nucleus deposits a small, but detectable amount of energy ~ few x 10 keV

  • Featureless exponential energy

spectrum with 〈E〉 ~ 50 keV

  • no obvious peak, knee, break,

... that determines Mχ or v0

  • Expected rate < 0.01/kg-day (based on

σnχ and ρ)

  • Radioactive background million times

higher

50 100 10

1

10

2

10

3

10

4

Recoil [keV] Counts [#10−6/kg/keV/day]

WIMP Elastic Scattering Differential Rate

WIMP Differential Event Rate

Ge Si Xe

Mχ = 100 GeV/c2 σχ-N = 10-45 cm2

slide-20
SLIDE 20

Enectali Figueroa-Feliciano - SUSY09

WIMP Hunting

  • Elastic scattering of a WIMP from a

nucleus deposits a small, but detectable amount of energy ~ few x 10 keV

  • Featureless exponential energy

spectrum with 〈E〉 ~ 50 keV

  • no obvious peak, knee, break,

... that determines Mχ or v0

  • Expected rate < 0.01/kg-day (based on

σnχ and ρ)

  • Radioactive background million times

higher

  • Background Reduction/Rejection is key

50 100 10

1

10

2

10

3

10

4

Recoil [keV] Counts [#10−6/kg/keV/day]

WIMP Elastic Scattering Differential Rate

WIMP Differential Event Rate

Ge Si Xe

Mχ = 100 GeV/c2 σχ-N = 10-45 cm2

slide-21
SLIDE 21

Enectali Figueroa-Feliciano - SUSY09

WIMP Hunting

  • Elastic scattering of a WIMP from a

nucleus deposits a small, but detectable amount of energy ~ few x 10 keV

  • Featureless exponential energy

spectrum with 〈E〉 ~ 50 keV

  • no obvious peak, knee, break,

... that determines Mχ or v0

  • Expected rate < 0.01/kg-day (based on

σnχ and ρ)

  • Radioactive background million times

higher

  • Background Reduction/Rejection is key

50 100 10

1

10

2

10

3

10

4

Recoil [keV] Counts [#10−6/kg/keV/day]

WIMP Elastic Scattering Differential Rate

WIMP Differential Event Rate

Ge Si Xe

Mχ = 100 GeV/c2 σχ-N = 10-45 cm2

Low Background (< 1) Almost a Prerequisite for Discovery

slide-22
SLIDE 22

Enectali Figueroa-Feliciano - SUSY09

The Signal and Backgrounds

χ0

v/c ≈ 7×10-4 = 210 km/s Nucleus Recoils

Er ≈ 10’s KeV

phonons Signal (WIMPs)

Er

γ

v/c ≈ 0.3 Electron Recoils Background (gammas)

Er

ionization

slide-23
SLIDE 23

Enectali Figueroa-Feliciano - SUSY09

The Signal and Backgrounds

χ0

v/c ≈ 7×10-4 = 210 km/s Nucleus Recoils

Er ≈ 10’s KeV

phonons Signal (WIMPs)

Er

γ

v/c ≈ 0.3 Electron Recoils Background (gammas)

Er

ionization

Neutrons also interact with

nuclei, but mean free path a few cm

slide-24
SLIDE 24

Enectali Figueroa-Feliciano - SUSY09

The Signal and Backgrounds

χ0

v/c ≈ 7×10-4 = 210 km/s Nucleus Recoils

Er ≈ 10’s KeV

phonons Signal (WIMPs)

Er

γ

v/c ≈ 0.3 Electron Recoils Background (gammas)

Er

ionization

Surface electrons

from beta decay can mimic nuclear recoils

Neutrons also interact with

nuclei, but mean free path a few cm

slide-25
SLIDE 25

Enectali Figueroa-Feliciano - SUSY09

Looking for the needle in the haystack

γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ

χ0

β β β β β β β β β

slide-26
SLIDE 26

Enectali Figueroa-Feliciano - SUSY09

Discrimination Strategies

Phonons

10 meV/ph 100% energy

Ionization

~ 10 eV/e 20% energy

Scintillation

~ 1 keV/γ few % energy

CRESST ROSEBUD CDMS EDELWEISS ZEPLIN II, III XENON LUX WArP ArDM SIGN NAIAD DAMA ZEPLIN I DEAP CLEAN XMASS CUORE CRESST I Ge, Si Xe, Ar, Ne TeO2, Al2O3, LiF CaWO4, BGO ZnWO4, Al2O3 ... DRIFT DM-TPC IGEX COUPP COSME ANAIS Ge, CS2, C3F8

slide-27
SLIDE 27

Enectali Figueroa-Feliciano - SUSY09

Thinking outside the Triangle...

  • Directional Detectors (Dama, DRIFT, DM-

TPC, etc...)

  • Nuclear-recoil-only trigger mechanism

(a la COUPP...)

  • Self-Shielding (XMASS)
  • Others...
slide-28
SLIDE 28

Enectali Figueroa-Feliciano - SUSY09

CDMS: The Big Picture

  • Shielding
  • Passive (Mine Depth, Pb, Poly)
  • Active (muon veto shield)
  • Energy Measurement
  • Phonon (True recoil energy)
  • Charge (Reduced for Nuclear)
  • Position measurement (x,y,z)
  • From phonon pulse timing

Use discrimination and shielding to maintain a Nearly Background Free experiment with cryogenic semiconductor detectors

slide-29
SLIDE 29

Enectali Figueroa-Feliciano - SUSY09

3” (7.6 cm) 1 cm Ge: 250 g Si: 100 g

Phonon side: 4 quadrants of athermal phonon sensors Energy & Position (Timing) Charge side: 2 concentric electrodes (Inner & Outer) Energy (& Veto)

Transition Edge Sensors (TES) Operated at ~40 mK for good phonon signal-to-noise

Z-sensitive Ionization Phonon Detectors

slide-30
SLIDE 30

Measuring the phonon signal

Transition-Edge Sensors

10 8 6 4 2 Resistance [mOhm] 0.104 0.102 0.100 0.098 0.096 Temperature [K]

Tb

C

G(T) Time Temperature

slide-31
SLIDE 31

Athermal phonon Cooper pairs Quasiparticles transport energy to the TES Trapping region Hot TES electrons Interaction site

TES Ge Absorber Al Collection Fin

Getting the Energy to the Sensors

10 8 6 4 2 Resistance [mOhm] 0.104 0.102 0.100 0.098 0.096 Temperature [K]

slide-32
SLIDE 32

Enectali Figueroa-Feliciano - SUSY09

Excellent Energy and Position Resolution

A D C B

Am241 :

γ 14, 18, 20, 26, 60 kev

Cd109 + Al foil :

γ 22 kev

Cd109 :

γ 22 kev i.c. electr 63, 84 KeV

Detector Calibration at Berkeley

slide-33
SLIDE 33

Enectali Figueroa-Feliciano - SUSY09

Excellent Energy and Position Resolution

A D C B

Am241 :

γ 14, 18, 20, 26, 60 kev

Cd109 + Al foil :

γ 22 kev

Cd109 :

γ 22 kev i.c. electr 63, 84 KeV

Detector Calibration at Berkeley

slide-34
SLIDE 34

Enectali Figueroa-Feliciano - SUSY09

Excellent Primary (γ) Background Rejection

γ source: Electron Recoil

N source: Nuclear Recoil

Radioactive source data defines the signal (NR) and background (ER)

slide-35
SLIDE 35

Enectali Figueroa-Feliciano - SUSY09

Excellent Primary (γ) Background Rejection

γ source: Electron Recoil

N source: Nuclear Recoil

>104 Rejection of γ

Radioactive source data defines the signal (NR) and background (ER)

slide-36
SLIDE 36

Enectali Figueroa-Feliciano - SUSY09

Excellent Primary (γ) Background Rejection

Phonon Recoil Energy in keV Yield = Ionization/Phonon Electron Recoils Nuclear Recoils Phonon Recoil Energy in keV Yield = Ionization/Phonon Electron Recoils Nuclear Recoils

γ source: Electron Recoil

N source: Nuclear Recoil

>104 Rejection of γ

Radioactive source data defines the signal (NR) and background (ER)

slide-37
SLIDE 37

Enectali Figueroa-Feliciano - SUSY09

Excellent Primary (γ) Background Rejection

Phonon Recoil Energy in keV Yield = Ionization/Phonon Electron Recoils Nuclear Recoils Phonon Recoil Energy in keV Yield = Ionization/Phonon Electron Recoils Nuclear Recoils

γ source: Electron Recoil

N source: Nuclear Recoil

>104 Rejection of γ

Radioactive source data defines the signal (NR) and background (ER)

Yield = Ionization/Phonon Very effective Particle ID

slide-38
SLIDE 38

Enectali Figueroa-Feliciano - SUSY09

Excellent Primary (γ) Background Rejection

Phonon Recoil Energy in keV Yield = Ionization/Phonon Electron Recoils Nuclear Recoils Phonon Recoil Energy in keV Yield = Ionization/Phonon Electron Recoils Nuclear Recoils

γ source: Electron Recoil

N source: Nuclear Recoil

>104 Rejection of γ

Radioactive source data defines the signal (NR) and background (ER)

Drooping events from β

Ionization collection incomplete on surface. Yield can be sufficiently low to pollute the signal region

Yield = Ionization/Phonon Very effective Particle ID

slide-39
SLIDE 39

Enectali Figueroa-Feliciano - SUSY09

Excellent Primary (γ) Background Rejection

Phonon Recoil Energy in keV Yield = Ionization/Phonon Electron Recoils Nuclear Recoils Phonon Recoil Energy in keV Yield = Ionization/Phonon Electron Recoils Nuclear Recoils

γ source: Electron Recoil

N source: Nuclear Recoil

>104 Rejection of γ

Need extra handle to reject βs in signal region!

Radioactive source data defines the signal (NR) and background (ER)

Drooping events from β

Ionization collection incomplete on surface. Yield can be sufficiently low to pollute the signal region

Yield = Ionization/Phonon Very effective Particle ID

slide-40
SLIDE 40

Enectali Figueroa-Feliciano - SUSY09

Surface β Rejection

10-40%

Bulk Events Surface Events

Phonon Timing: wrt Charge Pulse

Faster down conversion

  • f athermal phonons at

surface provides faster phonon signal for βs

Delay + RiseTime in µs Counts

slide-41
SLIDE 41

Enectali Figueroa-Feliciano - SUSY09

Surface β Rejection

10-40%

Bulk Events Surface Events

Phonon Timing: wrt Charge Pulse

Faster down conversion

  • f athermal phonons at

surface provides faster phonon signal for βs Cut chosen at a level to contribute ~ 0.5 event total leakage to WIMP candidate

Delay + RiseTime in µs Counts

slide-42
SLIDE 42

Enectali Figueroa-Feliciano - SUSY09

Summary of CDMS Rejection Techniques

~15σ Away from Signal Band

Yield + Timing Provide Fantastic (>million:1) rejection of Radiation Background

slide-43
SLIDE 43

Enectali Figueroa-Feliciano - SUSY09

Five Tower Runs (2006-8)

30 ZIPs (5 Towers) installed in Soudan icebox: 4.75 kg Ge, 1.1 kg Si

Combination of Ge and Si Detectors

  • Neutron background measurement
  • WIMP Mass Measurement
  • Ge more sensitive to higher mass

WIMPs, Si to lower mass WIMPs

slide-44
SLIDE 44

Enectali Figueroa-Feliciano - SUSY09

WIMP Search Region

All cuts set blind, without looking at signal

slide-45
SLIDE 45

Enectali Figueroa-Feliciano - SUSY09

WIMP Search Region

Good Inner Fiducial Vol

  • In good Fiducial Volume

All cuts set blind, without looking at signal

slide-46
SLIDE 46

Enectali Figueroa-Feliciano - SUSY09

WIMP Search Region

Good Inner Fiducial Vol

  • In the Nuclear Recoil Band
  • In good Fiducial Volume

All cuts set blind, without looking at signal

slide-47
SLIDE 47

Enectali Figueroa-Feliciano - SUSY09

WIMP Search Region

Good Inner Fiducial Vol

  • In the Nuclear Recoil Band
  • Not surface event: phonon

timing cut

  • In good Fiducial Volume

All cuts set blind, without looking at signal

slide-48
SLIDE 48

Enectali Figueroa-Feliciano - SUSY09

WIMP Search Region

Good Inner Fiducial Vol

  • In the Nuclear Recoil Band
  • Not surface event: phonon

timing cut

  • Not a Multiple Scatter
  • In good Fiducial Volume

All cuts set blind, without looking at signal

slide-49
SLIDE 49

Enectali Figueroa-Feliciano - SUSY09

The WIMP Search Data: Ge

All cuts set and frozen! Predict 77 ± 15 single scatters in NR

slide-50
SLIDE 50

Enectali Figueroa-Feliciano - SUSY09

The WIMP Search Data

97 Singles in Signal region before applying surface cut

slide-51
SLIDE 51

Enectali Figueroa-Feliciano - SUSY09

Open The Box: Surface Event Cut

Expected Background: 0.6 ± 0.5 surface events and < 0.2 neutrons

0 Observed Events!

slide-52
SLIDE 52

Enectali Figueroa-Feliciano - SUSY09

Open The Box: Surface Event Cut

Expected Background: 0.6 ± 0.5 surface events and < 0.2 neutrons

0 Observed Events!

slide-53
SLIDE 53

Enectali Figueroa-Feliciano - SUSY09

Spin-Independent Exclusion Limit

Projected CDMS II

4.75 kg Ge, 1.1 kg Si

First 5-Tower results - published PRL 102 p. 011301 (Jan 2009)

slide-54
SLIDE 54

Enectali Figueroa-Feliciano - SUSY09

4 kg 15 kg 150 kg

See e.g. ‘Background Penalty Factor’, Scott Dodelson arXiv 0812.0787v2

SuperCDMS phases - Moore’s Law if zero bkgd

slide-55
SLIDE 55

Enectali Figueroa-Feliciano - SUSY09

SQUET card Tower

CDMS II tower vs SuperTower at Soudan

slide-56
SLIDE 56

Enectali Figueroa-Feliciano - SUSY09

Charge collection in dislocation-free Ge (Berkeley, February 2008)

  • 3cm x 1cm sample of H-grown

dislocation-free Ge (E.E. Haller)

  • Unusable @77K, but can be

neutralized at <100mK

  • Excellent charge collection @ low

voltages

  • Available in >6” diameters (standard

detector grade Ge limited to 3-4”)

3”x1cm: 250g (CDMS II)

6”x2”: 5kg?

Path to Large Ge Crystals - purity

slide-57
SLIDE 57

Enectali Figueroa-Feliciano - SUSY09

iZIP/double-sided detectors with outer phonon channel (A) to reject perimeter events. In iZIP charge electrodes interleaved with narrow strips occupied by phonon sensors. Less phonon timing information for surface events But now charge channels can veto surface events

Future detector ideas – iZIP

slide-58
SLIDE 58

Enectali Figueroa-Feliciano - SUSY09

Icebox for 1 tonne of Ge ~ inner can 1 m on a side

  • ~160 kg of Ge shown deployed, corresponding to SuperCDMS

Phase B (SNOLAB) cross-section of 0.3 zeptobarns. either 3 inch or 6 inch diameter detectors.

Ice-box for 1 tonne of Ge (sub zeptobarn, < 10-45 cm2)

slide-59
SLIDE 59

Enectali Figueroa-Feliciano - SUSY09

Cryogenic Dark Matter Search at Soudan

  • Final (5-tower) run of CDMS II completed
  • Analysis of last 1000 kg-days underway,
  • Expect analysis completion and announcement during summer 2009.
  • First SuperTower (3kg) installed at Soudan
  • Detector fabrication rate x5 faster (per unit mass) than CDMS II.
  • Establish new detector design rejection capability at deep site.
  • Measure reduced surface contamination levels.
  • Construct more SuperTowers for SuperCDMS Soudan
  • Detectors for second SuperTower already fabricated and undergoing cryogenic testing.
  • Review this summer to allow further SuperTower deployment at Soudan.
  • Sensitivity goal is WIMP-nucleon cross-section 5 x 10-45 cm2 (5 zepto-barns)

Beyond Soudan

  • Background-free 100 kg Ge at >4000 mwe depth, looks straightforward
  • Sensitivity goal is WIMP-nucleon cross-section 3 x 10-46 cm2 (0.3 zepto-barns)
  • Exploring new technologies and approaches to reach 1 tonne Ge under for

DUSEL

Conclusions

slide-60
SLIDE 60
slide-61
SLIDE 61

Enectali Figueroa-Feliciano - SUSY09

  • CDMS II (Soudan) 4.5 kg Ge
  • Total cost (5-tower) 30M$ (Project 18.3M$ + Base 11.7M$ )
  • Detector production 1 M$/kg (Raw Ge 24 k$/kg + Fabrication&Testing 1M$/kg)
  • SuperCDMS Detector R&D 6 kg Ge
  • Total cost (2-Supertower) 13M$ (Project 6.6M$ + Base 6.4M$)
  • Detector production 368 k$/kg (Raw Ge 18 k$/kg + Fabrication&Testing 350k$/kg)
  • SuperCDMS Soudan 9 kg Ge (awaiting approval)
  • Total cost (3-Supertower) 11M$ (Project 5.9M$ + Base 5.1M$)
  • Detector production 368 k$/kg (Raw Ge 18 k$/kg + Fabrication&Testing 350k$/kg)
  • SuperCDMS (SNOLAB) 40-190 kg Ge (proposal this summer)
  • Total cost (6-19 Supertower) 36M$ (Project 13M$ + Base 23M$)
  • Detector production 190-24 k$/kg (Raw Ge 20-5 k$/kg + Fabrication&Testing

170-19 k$/kg)

  • GEODM (DUSEL) 1400 kg Ge (S4 Engineering study proposal submitted)
  • Total cost (-Supertower) 50M$ (Project 25M$ + Base 25M$)
  • Detector production 24k$/kg (Raw Ge 5 k$/kg + Fabrication&Testing 19 k$/kg)

Costs – Ge raw material cost insignificant.