Past , Present and Future CDMS Past , Present and Future 5/29/2019 Durdana N Balakishiyeva UFL

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. 5/29/2019 Durdana N Balakishiyeva UFL

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. 5/29/2019 Durdana N Balakishiyeva UFL

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 10-100 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. 5/29/2019 Durdana N Balakishiyeva UFL

Durdana N Balakishiyeva UFL Cygnus - a constellation in the northern hemisphere between Pegasus and Draco in the Milky Way; contains a black hole 5/29/2019 Durdana N Balakishiyeva UFL

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. 5/29/2019 Durdana N Balakishiyeva UFL

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). 5/29/2019 Durdana N Balakishiyeva UFL

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 5/29/2019 Durdana N Balakishiyeva UFL

Durdana N Balakishiyeva UFL Er    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 5/29/2019 Durdana N Balakishiyeva UFL

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. 5/29/2019 Durdana N Balakishiyeva UFL

Discrimination power of Timing Parameter Improvement of Surface Event Discrimination since 2008 (shown for 1 zip) Timing Parameter (s) - 2008 133Ba surface 2008 252Cf neutron 2009 133Ba surface 2009 252Cf neutron Surface Event Discrimation approximate signal region 133Ba e-recoil 133Ba surface 252Cf n-recoil Timing Parameter (s) Ionization Yield 5/29/2019 Durdana N Balakishiyeva UFL

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 5/29/2019 Durdana N Balakishiyeva UFL

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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 5/29/2019 Durdana N Balakishiyeva UFL

Analysis Routine Blind the potential WIMP signal region Establish all the “cuts” to be applied before unblinding Low yield singles masked 5/29/2019 Durdana N Balakishiyeva UFL

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 5/29/2019 Durdana N Balakishiyeva UFL

Durdana N Balakishiyeva UFL Analysis Routine 5/29/2019 Durdana N Balakishiyeva UFL

With and Without Timing Cut PRL 102, 011301 (2009) 5/29/2019 Durdana N Balakishiyeva UFL

Spin Independent Limit No events observed “Zero” background CDMSII 2008 @60GeV: =6.6x10-44cm2 (90%CL) CDMSII Combined (add data collected during Oct. 2006 - July 2007) @60GeV: =4.6x10-44cm2 (90%CL) 5/29/2019 Durdana N Balakishiyeva UFL

Durdana N Balakishiyeva UFL Push the Current Limit CDMS II 2008 398 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 5/29/2019 Durdana N Balakishiyeva UFL

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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

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First Super Tower Installed 5/29/2019 Durdana N Balakishiyeva UFL

Durdana N Balakishiyeva UFL Plans Super Towers Operation w/15 kg Ge for 2 years @ Soudan 2090 mwe; 0.05 n/y/kg Going deeper: SNOLAB 100 kg Ge; 6060 mwe; 0.2 n/y/ton 5/29/2019 Durdana N Balakishiyeva UFL

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 5/29/2019 Durdana N Balakishiyeva UFL

Durdana N Balakishiyeva UFL Plans � Data taken between Oct. 2006 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, 2009. 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. 5/29/2019 Durdana N Balakishiyeva UFL

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 5/29/2019 Durdana N Balakishiyeva UFL