1. Past , Present and Future
CDMS
Past , Present and Future
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Durdana N Balakishiyeva UFL

2. Durdana N Balakishiyeva UFL
For very long time all physicists spoke of Matter and Anti- Matter : Barion asymmetry. We knew that our solar system is made entirely of matter because we have visited the moon and sent probes to several planets. As Steigman pointed out, for detecting antimatter in such a fashion, 杯he most rudimentary detector� will be sufficient: simply place it down and wait. If the detector disappears, antimatter has been discovered.� So, the fact that objects on earth don’t spontaneously disappear in a burst of gamma rays should be very convincing proof that at least on the scale of our solar system, everything is made of matter. Somewhat more rigorously (but no more convincingly) we also know that the sun is made of matter by studying the solar wind. Particles ejected from the sun collide with the planets in our solar system continuously and if either the sun or the planets were made of antimatter then the gamma ray signature from the particle- antiparticle collisions would make them the brightest gamma ray sources in the sky.
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Durdana N Balakishiyeva UFL

3. Durdana N Balakishiyeva UFL
V=1000 km/s
M/L ∼ 300 hM /L
All made sense until Fritz Zwicky (1933) studied 8 galaxies in Coma cluster and found that V ∼ 1000 km/s which gives a mass to light ratio M/L ∼ 300 hM /L. This is about 400 times larger than the estimate based on the number of galaxies and the total brightness of the cluster. He concluded that there must be some non visible form of matter which
would provide enough of gravity to hold the cluster together.
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Durdana N Balakishiyeva UFL

4. Durdana N Balakishiyeva UFL
The Dark Side of The Universe
Jonghee Yoo 4
Rotation Curves of Galaxies
CMB
Large Scale Structure
Galaxy Cluster
Dark Matter Ring
Bullet Cluster
Observational data strongly suggests existing of non-baryonic DARK Matter. Direct detection of it is a challenging task:event rate is less than 1/kg/day,energies of recoiling nucleus is typically keV,background rate from residual contamination and cosmogenic activation is very high.CDMS conducting experiments to search for WIMPs in the galactic halo using terrestrial detectors. WIMPs favored candidates for stable relic particles produced in early universe that could have decoupled from hot baryonic plasma and make up the dark matter in galaxies and clusters of galaxies.
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Durdana N Balakishiyeva UFL

5. Durdana N Balakishiyeva UFL
Cygnus - a constellation in the northern hemisphere between Pegasus and Draco in the Milky Way; contains a black hole
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Durdana N Balakishiyeva UFL

6. Durdana N Balakishiyeva UFL
CDMS Detector
Jonghee Yoo 6
1 m tungsten
380m x 60m aluminum fins
Electro Thermal Feedback R T
Tc~80mK
~10mK Al
Transition Edge
Sensor
Ge or Si
Quasiparticle
diffusion
phonons
Because of unusual combination of requirements in CDMS-low noise,low background,high channel count and low temperature collaboration came up with state of the art multi-temperature-stage modular coaxial wiring package called “Tower”.Tower stages heatsunk to appropriate temperature stages of the dilution refrigerator and are ~ 10mK,50 mK, 600 mK and 4K.6 detectors are being mounted to the tower. Simultaneously measure in a cooled semiconducting crystal of germanium or silicon the full recoil energy using thermal calorimetric measurement and ionization signal. TES operated at Electro Thermal Feedback mode.Phonons are collected over the large fraction of the surface by coupling TES with Al quaziparticle traps.These sensors are voltage biased that results in a current signal that is read out with SQUIDs. TES operated at transition temperatures,so a mK temperature change will result in transition from SC to normal.
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Durdana N Balakishiyeva UFL

7. Durdana N Balakishiyeva UFL
So,we are looking for a single scatter nuclear recoil event with ionization ~3 times lower than electron recoil that is a result of dominant radioactive backgrounds(gammas and betas).
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Durdana N Balakishiyeva UFL

8. Durdana N Balakishiyeva UFL
Detector Readout A C B D
Phonon signal
from a quadrant
Phonon sensor
Recoil Energy
19 Ge zips (250 g each)
11 Si zips (100 g each)
1 cm thick crystals
Here is a crude simplification of the elaborate readout circuit. Charge channel read by charge amplifier. A recoil event in the detector will create a number of electron hole pairs given by E_recoil/Energy band gap. Biasing voltage typically 3V.
Ionization energy Charge Sensor
Charge signal
from inner electrode
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Durdana N Balakishiyeva UFL

9. Durdana N Balakishiyeva UFLEr 
  0.3
More ionization
Electron Recoils
Reduced Ionization for Nuclear Recoils
Yield = E(ionization) / E(recoil)
Photons
  710-4 0
Less ionization Er
Nuclear Recoils
Neutrons
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Durdana N Balakishiyeva UFL

10. carrier back diffusion
Delay and Rise Time
Clear distinction in pulse shape and rise
time
Surface Events due to reduced ionization
by a dead layer
Yield and Timing Parameter reject surface
events
Phonon
Charge
~10 μm
“dead layer”
-3V
carrier back diffusion
surface event
nuclear recoil
rising edge slope
For a subset of e-recoils that occur within 10 mikrometers from surface charge carriers can diffuse against the el. Field and be collected on a wrong electrode.So fewer charge part. Reach charge amplifier that results in reduced ionization that mimics nuclear recoil.
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Durdana N Balakishiyeva UFL

11. Discrimination power of Timing Parameter
Improvement of Surface Event Discrimination since 2008
(shown for 1 zip)
Timing Parameter (s)
Ba surface
Cf neutron
Ba surface
Cf neutron
Surface Event Discrimation
approximate signal region
133Ba e-recoil
133Ba surface
252Cf n-recoil
Timing Parameter (s)
Ionization Yield
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Durdana N Balakishiyeva UFL

12. Durdana N Balakishiyeva UFL
Detector Calibration
Gammas and Betas as electron recoils
Ionization Yield Analysis alone gives 1:104 rejection of gammas
Detectors need to be properly neutralized
133Ba
252Cf
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Durdana N Balakishiyeva UFL

13. Durdana N Balakishiyeva UFL
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Durdana N Balakishiyeva UFL

14. Durdana N Balakishiyeva UFL
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Durdana N Balakishiyeva UFL

15. Durdana N Balakishiyeva UFL
Backgrounds
“Cosmogenic”Neutrons from Muon spallation give low ionization like WIMP’s :use muon veto and go deep underground
Poly shielding stops low energy neutrons
Copper and Lead for gammas
Underground Mine + Shielding + Computer Simulation=Neutron Bkgd Rejection
ancient lead shielding
ultra-clean materials and careful handling
An isolated neutron with several MeV of kinetic energy can cause a Ge recoil that is indistinguishable from a recoil caused by a WIMP. The motivation for deploying the CDMS-II detector at the deep underground site in Soudan, MN is to reduce the ambient cosmic-ray neutron flux. Other sources of neutron backgrounds at Soudan include environmental radioactivity, primarily from the uranium/thorium decay chain and from particle cascades induced by muons that penetrate to Soudan's depth of 2096 mwe.
Passive shielding:
Pb shielding
Passive shielding:
Polyethylene
Active shielding:
Muon veto
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Durdana N Balakishiyeva UFL

16. Analysis Routine Blind the potential WIMP signal region
Establish all the “cuts” to be applied before unblinding
Low yield singles masked
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Durdana N Balakishiyeva UFL

17. Durdana N Balakishiyeva UFL
Analysis Routine
KS test
Fiducial Volume
Muon Scintillator Veto:no event within 200 s window around the trigger
Single Detector Event with Energy deposition with >4 above mean noise
2 nuclear recoil band
Phonon Timing/Surface Events cut
Expected Electron Bkgd 0.6±0.5 events
Expected neutron <0.2 events
Gammas rejected>106
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Durdana N Balakishiyeva UFL

18. Durdana N Balakishiyeva UFL
Analysis Routine
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Durdana N Balakishiyeva UFL

19. With and Without Timing Cut
PRL 102, (2009)
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Durdana N Balakishiyeva UFL

20. Spin Independent Limit
No events observed
“Zero” background
CDMSII @60GeV:
=6.6x10-44cm2 (90%CL)
CDMSII Combined
(add data collected during Oct July 2007)
@60GeV:
=4.6x10-44cm2 (90%CL)
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Durdana N Balakishiyeva UFL

21. Durdana N Balakishiyeva UFL
Push the Current Limit
CDMS II kg/day raw data;121 kg/day after “cuts”
CDMS II 2009 close to 750 kg/day before “cuts”
Ongoing Analysis
of Remaining Data
End Run March 18
2009
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Durdana N Balakishiyeva UFL

22. Durdana N Balakishiyeva UFL
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Durdana N Balakishiyeva UFL

23. Durdana N Balakishiyeva UFL
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Durdana N Balakishiyeva UFL

24. Durdana N Balakishiyeva UFL
SuperCDMS at Soudan 2009
Super Tower installed. Collecting Data.
Detector 1”thick and 7 cm in diameter--> 600 grams
� Why larger detectors? � Reduce surface/volume ratio - decreases background � Ease of manufacture for large scale detectors � How? � Dislocation-free crystals can be grown up to 30 cm in diameter � Impurities not a problem for CDMS. We create metastable states where impurities are neutralized and do not trap drifting charge.
Phonon collection improved
Better background rejection
5/29/2019
Durdana N Balakishiyeva UFL

25. Durdana N Balakishiyeva UFL
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Durdana N Balakishiyeva UFL

26. First Super Tower Installed
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Durdana N Balakishiyeva UFL

27. Durdana N Balakishiyeva UFL
Plans
Super Towers
Operation w/15 kg
Ge for 2
Soudan 2090 mwe;
0.05 n/y/kg
Going deeper:
SNOLAB 100 kg
Ge; 6060 mwe;
0.2 n/y/ton
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Durdana N Balakishiyeva UFL

28. Future Detectors……………..
iZIP/double-sided detectors with outer
phonon channel (A) to reject perimeter
events.
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
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Durdana N Balakishiyeva UFL

29. Durdana N Balakishiyeva UFL
Plans
� Data taken between Oct and July 2007 has been analyzed and a cross section limit of < 4.6 x 10-44cm2 (90% CL) was placed for a WIMP of mass 60 GeV/c2. � CDMS II finished taking data on March 18, We are currently analyzing the last data sets. � SuperCDMS is an experiment under development by the CDMS collaboration which is planned for operation in Soudan. For this purpose we have enhanced the design of the CDMS detector. � The first SuperTower has been installed at Soudan and is under commission. Initial tests on the surface are promising.
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Durdana N Balakishiyeva UFL

30. Thank You, CDMS Collaboration!!!
Brown University
M.J. Attisha, R.J. Gaitskell
Case Western Reserve Univers
ity
D.S. Akerib, C. Bailey, P. Brusov, M.R. Dragowsky, D.D.Driscoll, D. Grant, R. Hennings-Yeomans, S.Kamat, T.A. Perera, R.W.Schnee, G.Wang
California Institute of Technology
S.Golwala, Z.Ahmed, J. Filippini
Fermi National Accelerator Laboratory
D.A. Bauer, M.B. Crisler, R. Dixon, F. DeJongh, D. Holmgren, L. Hsu, J.Hall, E.Ramberg, J. Yoo
Lawrence Berkeley National Laboratory
R. McDonald, R.R. Ross, A. Smith
Massachusetts Institute of Technology
E.Figueroa-Feliciano, S.Hertel, K.McCarthy
National Institute for Standards and Technology
K. Irwin
Santa Clara University
B.A. Young
Stanford University
P.L. Brink, B. Cabrera, C.L. Chang, J. Cooley, R.W. Ogburn, M. Pyle, S.Yellin
TAMU
R.Mahapatra
University of California, Berkeley
M. Daal, A. Lu, V. Mandic, P.Meunier, N. Mirabolfathi, B. Sadoulet, D.N. Seitz, B. Serfass, K.M. Sundqvist
University of California, Santa Barbara
R. Bunker, D.O. Caldwell, R. Ferril, H. Nelson, J. Sander,
University of Colorado at Denver and Health Sciences Center
M. E. Huber
University of Florida
T. Saab, D.N.Balakishiyeva
University of Minnesota
P. Cushman, L. Duong, A. Reisetter, M.Fritts, X.Qiu
University of Zurich
S.Arrenberg, L.Baudis, T.Bruch, M.Tarka
Queen’s University
W.Rau
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Durdana N Balakishiyeva UFL