Listening for the Dark Harry Nelson UCSB
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Listening for the Dark Harry Nelson UCSB HNN CDMS Plan Massive Dark Matter Direct Detection Xenon CDMS Future 9/15/05 Penn State Colloquium 2 HNN CDMS 0.01% Metals (us) 0.5% Visible Baryons `We Declare a New Order’ (Joel Primack) Dark Baryons 5% Cold Dark Matter (WIMPs?) 25% Cosmological Constant 70% 9/15/05 Penn State Colloquium 3 HNN CDMS r 9/15/05 v; = v/c Penn State Colloquium 4 HNN 9/15/05 CDMS Penn State Colloquium 5 HNN CDMS b = 0.488 ± 0.009 a M = (1.85 ± 0.06) 1030 kg 9/15/05 Penn State Colloquium 6 HNN CDMS Stars w/r Galaxy Center: v/c = constant 0.7 10-3 Planets about sun Msun = (1.85 ± 0.06) 1030 kg Moons about Saturn MSaturn = (5.5 ± 0.2) 1026 kg 9/15/05 Penn State Colloquium 7 HNN CDMS Galactic Dark Matter R is the distance from center v v is the speed (tangential) R 9/15/05 Penn State Colloquium 8 HNN CDMS What about our home galaxy (Milky Way)? Honma and Sofue, 1996 v 220 km/s Without the Dark Halo (Binney & Tremaine) :v0=180 km/s 9/15/05 Penn State Colloquium R 9 HNN CDMS Milky Way: mainly a dark cloud Bulge Disk Sun: moves in plane of disk v/c = 0.7 10-3 Particles in `halo’: 3-d = mc2 n 1/3 GeV/cm3 (1/2 of total mass density) Maxwellian/Gaussian (simple) v/c = 0.7 10-3 9/15/05 Penn State Colloquium 10 HNN CDMS Design a Particle and an Experiment 0 v/c = 0.7 10-3 Neutral: cool particles neutral – , n, , K0, Z0, H0… v/c = 0.7 10-3 We use Germanium, A=73, mc2=67.6 GeV; others: Si, S, I, Xe, W Massive: Mc2100 GeV hinted ER½ mGec2 2 ½ 68 GeV ½ 10-6 at by accelerator data 20 keV x-ray energy ! Easy! `Weak Scale’ 9/15/05 Penn State Colloquium 11 HNN Arguments for characteristic of weak interaction CDMS 1. Particle physics… chose Mc2 100 GeV, `Weak Scale’ 2. Big Bang… independently implies weak cross section as well… Coincidence(s)… or Clues ??? 9/15/05 Penn State Colloquium 12 HNN CDMS What is the weak interaction cross section? Donald H. Perkins, 1987 9/15/05 Penn State Colloquium 13 HNN Rate governed by scattering cross section, 9/15/05 Penn State Colloquium CDMS 14 HNN Coherence, density of states enormous bonus! CDMS Scattering off a proton…. …. Hopeless! 0 A = # neutrons + # protons 0 Indistinguishable Density of States: 9/15/05 Penn State Colloquium 15 HNN Rate of Main Background CDMS Rate about 103 / (kg-day) !!! Shield… but that radioactive too Strategies: DAMA… huge target mass (100 kg), look for astrophysical modulation CDMS… small target mass (few kg) distinguish electron from nucl. recoil 9/15/05 Penn State Colloquium 16 HNN CDMS Signal Shape A2 MWIMP=100 GeV 10-42 cm2/nucleon Silicon, Sulphur Germanium Iodine, Xenon Nucleus Recoils Er Slope: Maxwell-Boltzmann Diffraction WIMPs in Galaxy 0 9/15/05 Penn State Colloquium 17 HNN Catalog of Direct Detection Experiments CDMS Indirect Detection: Super-Kamiokande, Amanda, Ice-Cube, HEAT, GLAST, Egret… Look for astrophysical neutrinos, gammas From WIMP annihilation 9/15/05 Penn State Colloquium 18 HNN Direct Detection: Signal and Main Background Signal Background Nucleus Recoils Electron Recoils Er v/c 710-4 dense energy deposition efficiency low distinct energy scale 0 (calibrate: neutron) 9/15/05 CDMS Er v/c 0.3 Sparse Energy Deposition Differences the Basis of Particle ID Penn State Colloquium 19 HNN ZEPLIN II, III, MAX, XMAS, XENON CDMS IGEX, DRIFTI, II ionization CDMS, EDELWEISS Q NAIAD, ZEPLIN I, DAMA CRESST II, ROSEBUD CRESST I, PICASSO, COUPP Tim Sumner 9/15/05 Penn State Colloquium 20 HNN CDMS Xenon – nuclear recoils give 1/7 scintillation/energy, compared to electron recoils (``quenching’’)…. Sets recoil energy scale – Bernabei et al. – Arneodo et al. – Akimov et al. – Aprile et al. – LIP work Lindhard Hitachi Tim Sumner 9/15/05 E. Aprile et al., arXiv:astro-ph/0503621 Penn State Colloquium 21 HNN Zeplin 1 – Scintillation Alone CDMS Nucl. Recoil Electron Recoil 125 keV 30 keV 3.2 kg Xe Nuclear Recoils – Faster Risetime… 30 keV Risetime (ns) 9/15/05 Penn State Colloquium 22 HNN CDMS Zeplin-I Limit- Background Weakens 300 kg-days 10-42 cm2 CDMS: 100 kg-days 9/15/05 Penn State Colloquium 23 HNN CDMS 2-Phase (Liquid/Gas) Noble … Ar or Xe Nuclear Recoil S1 S2 S2 Electron Recoil S2 S1 S1 9/15/05 Penn State Colloquium 24 HNN Gamma + neutron source Gamma source Zeplin-II 9/15/05 Penn State Colloquium CDMS Zeplin-II 25 HNN Analysis…. Appears scalable CDMS However, unforeseen backgrounds are the rule as sensitivity increases Promising… ZEPLIN-II and Xenon-10 soon deployed in deep sites 9/15/05 Penn State Colloquium 26 HNN CDMS CDMS: Adapt Traditional Ionization Detector ER10’s keV Holes e- Electrode Implants E 1 cm Germanium (or Silicon) 7.6 cm ¼ kg (1/10 kg) 0 9/15/05 What rate? (in, say, 1kg) Backgrounds? ….…. Gamma rays, neutrons, surface beta-decay Penn State Colloquium 27 HNN CDMS Our Hunting Ground Weakly Interacting Massive Particle Experiment CDMS (shallow) DAMA (old!) 1/10 9/10 Theory SUSY, various constraints including Big Bang Gaitskell/Mandic 9/15/05 Penn State Colloquium 28 HNN DAMA – Exploit Annual Modulation CDMS Signal: higher rate in June, lower in December Background: constant in time 9/15/05 Penn State Colloquium 29 HNN CDMS CDMS Collaboration (Mar. 2002) 9/15/05 Penn State Colloquium 30 HNN CDMS CDMS Collaboration Brown University Stanford University M.J. Attisha, R.J. Gaitskell, J-P. F. Thompson Case Western Reserve University D.S. Akerib, P. Brusov, C. Bailey, M.R. Dragowsky, D.D.Driscoll, S.Kamat, A.G. Manalaysay, T.A. Perera, R.W.Schnee, G.Wang University of Colorado at Denver M. E. Huber Fermi National Accelerator Laboratory P.L. Brink, B. Cabrera, J.P. Castle, C.L. Chang, J. Cooley, M. Kurylowicz, L. Novak, R. W. Ogburn, M. Pyle, T. Saab, A. Tomada University of California, Berkeley Cryogenic Fillipini, A. Lu, V. Mandic, P.Meunier, N. Mirabolfathi, M.C.Perillo Isaac, W. Rau, B. Dark Sadoulet, D.N.Seitz, B. Serfass, G. Smith, A. Spadafora, K. Sundqvist Matter Search University of California, Santa Barbara D.A. Bauer, R. Choate, M.B. Crisler, R. Dixon, M. Haldeman, D. Holmgren, B. Johnson, W.Johnson, M. Kozlovsky, D. Kubik, L. Kula, B. Lambin, B. Merkel, S. Morrison, S. Orr, E.Ramberg, R.L. Schmitt, J. Williams, J. Yoo Lawrence Berkeley National Laboratory J. Alvaro-Dean, M.S. Armel, M. Daal, J. R. Bunker, S. Burke, D.O. Caldwell, D. Callahan, R.Ferril, D. Hale, S. Kyre, R. Mahapatra, J.May, H. Nelson, R. Nelson, J. Sander, C.Savage, S.Yellin University of Florida L. Baudis, S. Leclerq J.H Emes, R. McDonald, R.R. Ross, A. Smith Santa Clara University B.A. Young 9/15/05 University of Minnesota J. Beaty, P. Cushman, L. Duong, A. Reisetter Penn State Colloquium 31 HNN CDMS Nuclear Recoil bad at making Ionization Holes eGermanium more ionization! Both deposit, say, 0 20 keV 9/15/05 Need a second, `fair’ measure of deposited energy… sound! Penn State Colloquium 32 HNN CDMS Our Detectors Phonon D SQUID array R bias `Phonon sensor (4)’ (TES) R feedback I bias Array of Transition Edge Sensors Ionization Electrodes (2) D A C B x-y-z imaging: Q outer Q inner from timing, sharing Vqbias Z-coordinate, Ionization, Phonons ZIP Operate at 0.050 Kelvin 9/15/05 Penn State Colloquium 33 HNN CDMS The Phonon Sensor quasiparticle trap W quasiparticle Transition-Edge diffusion Sensor (TES) Al Collector Cooper Pair Al Ge or Si phonons ~ 10mK normal RTES () 4 3 2 1 superconducting Tc ~ 80mK T (mK) R. Schnee 9/15/05 Penn State Colloquium 34 HNN CDMS Pulses 20 KeV Phonon (4) Charge (2) 0 30 Time (s) 300 0 Time (s) 300 -30 -30 9/15/05 30 -30 Penn State Colloquium 30 35 HNN CDMS Separation of the types of recoils (electron recoils) Neutrons cause (nuclear recoils) recoils nuclear too! Another background… Sound 9/15/05 Penn State Colloquium 36 HNN CDMS SUF Run 21 Germanium – Low Threshold 1.3 keV xray, L-shell Capture Shallow Site Neutron Background 71Ge K-shell Capture 10.4 keV Ga x-rays from R. Bunker 9/15/05 Penn State Colloquium 37 HNN CDMS Background Neutrons from Cosmic Ray Muons Limited our earlier results…moved to a deep mine 9/15/05 Penn State Colloquium 38 HNN Go Deep Underground to Evade Muons 9/15/05 Penn State Colloquium CDMS 39 HNN CDMS Deep Facility Soudan Mine Hosts: State of Minn., U Minn., Fermilab 690 meters underground 2090 meters water equivalent 9/15/05 Penn State Colloquium 40 HNN CDMS Down deep in the Soudan mine DAQ/Electronics HVAC RF-shielded Clean room Soudan II Mezzanine MINOS connecting tunnel 9/15/05 Mezzanine Shield Mechanical Pumps, Cryogenics Fridge Front-end Electronics Icebox Penn State Colloquium Detector Prep Clean Benches 41 HNN CDMS Outside In lead plastic scintillators outer polyethylene ancient lead 9/15/05 inner polyethylene Penn State Colloquium 42 HNN CDMS A Cold Heart Results from first… FET cards SQUID cards 4K 0.6 K 0.06 K 0.04 K ZIP 1 (Ge) ZIP 2 (Ge) ZIP 3 (Ge) ZIP 4 (Si) ZIP 5 (Ge) ZIP 6 (Si) Two `towers’ poorer resolution 14C 14C 14C 6 detectors… 10 cm 4 Germanium (0.25 kg each), 2 Silicon (0.1 kg each) 9/15/05 Penn State Colloquium 43 HNN Calibration (133Barium) (e recoils) Ionization L. Baudis 9/15/05 CDMS Phonons Energy, KeV Penn State Colloquium 44 HNN CDMS Better Source, Calibration Ionization 9/15/05 Penn State Colloquium Phonons 45 HNN CDMS n Calib. (252Californium) (nuclear recoils) S. Kamat 9/15/05 Reconstructed recoil energy, KeV Penn State Colloquium 46 HNN CDMS Soudan Data First Run 92 calendar days 53 live days, 1 kg Germanium Tower 1 Second Run 140 calendar days 74 live days, 1.5 kg Germanium 0.6 kg Silicon Double `Exposure’ 9/15/05 Penn State Colloquium 47 HNN CDMS Reject Multiple Interactions FET cards SQUID cards WIMPs Backgrounds don’t scatter oftentwice do 4K 0.6 K 0.06 K 0.04 K ZIP 1 (Ge) ZIP 2 (Ge) ZIP 3 (Ge) ZIP 4 (Si) ZIP 5 (Ge) ZIP 6 (Si) 9/15/05 14C 14C 14C Penn State Colloquium 0 n, 48 HNN CDMS First Run Prior to timing cuts After timing cuts, which reject external electrons 10.4 keV Gallium line External e (address with timing cuts) B. Cabrera 9/15/05 Nuclear Recoils induced by a neutron source Penn State Colloquium 49 HNN CDMS External e : surface events, ionization missed External e decay contamination, escaping compton recoils Ionization not collected z Electrode Germanium Implants E `ZIP’ : `reconstruct’ z with start time, risetime 9/15/05 Penn State Colloquium 50 HNN CDMS External e decay contamination, Edge Induces escaping compton recoils Phonon Energy Downshift Phonon Sensors Distinct Sensor Sharing 0 9/15/05 Primary Phonons Lower Energy Eventually energy low, `High Energy,’ Phonons Have pathlength long, `Rayleigh Scatter’ Longer Pathlength, `phonons ballistic’ so theygodiffuse Diffuse More Promptly + energy downshift Penn State Colloquium 51 HNN Timing rejects surface/external e CDMS Nuclear Recoils e External e 9/15/05 Penn State Colloquium 52 HNN CDMS WIMP search data with Ge detectors Z2, Z3, Z5 Prior to timing cuts After timing cuts, which reject external electrons 10.4 keV Gallium line B. Cabrera 9/15/05 (yellow points are from neutron calibration) State Colloquium Nuclear RecoilsPenn induced by a neutron source 53 HNN CDMS All the features on one plot Z2, Z3, Z5 10.4 keV Gallium line Surface Rejection: Omitted Applied 10 keV threshold (1 20 keV) 9/15/05 0.7 0.35 external e, 0.07 recoils from neutrons expected 2/3 event expected from Barium calib Penn State Colloquium Energy Estimate Corrected (non-blind) 54 HNN CDMS Second Run – twice the exposure After timing cuts, which reject most electron recoils Prior to timing cuts 1.5 1.5 Z2/Z3/Z5/Z9/Z11 Ionization Yield Ionization Yield 10.4 keV Gallium line 1.0 1.0 0.5 0.5 1 candidate (barely) 0.0 0 Z2/Z3/Z5/Z9/Z11 10 20 30 40 50 60 70 80 Recoil Energy (keV) 9/15/05 90 100 0.0 0 10 20 30 40 1 near-miss 50 60 70 80 90 100 Recoil Energy (keV) ESTIMATE: 0.37 0.20 (sys.) 0.15 (stat.) surface electron recoils, 0.05 recoils from neutrons expected Penn State Colloquium 55 HNN CDMS Limits DAMA 9/15/05 Penn State Colloquium 56 HNN CDMS The Near Future Installed 3 additional towers November 2004 Improvements 30 detectors in 5 towers of 6 9/15/05 Cryogenics, backgrounds, DAQ Currently commissioning 4.75 kg of Ge, 1.1 kg of Si to run through 2006 Improve sensitivity x10 Penn State Colloquium 57 HNN CDMS Sensitivity Expectations: Distant Future 9/15/05 Penn State Colloquium 58 HNN CDMS Projected Sensitivies 9/15/05 Penn State Colloquium 59 HNN CDMS CDMS Collaboration(March 2002) 9/15/05 Penn State Colloquium 60 HNN DAMA – 100 kg of NaI CDMS Sodium, A=23 Eobs(KeVee)0.25 Erecoil (KeV) Erecoil Light Iodine, A=127 Eobs(KeVee)0.09 Erecoil (KeV) Copper 9/15/05 NaI Lead PMT PMT vk = 15 km/s Poly Penn State Colloquium 61 HNN CDMS DAMA Background and Signal 0.01950.031 -0.00010.019 cpd/kg/keV Energy Spectrum Bkgd 1 cpd/kg/keV 2-6 KeV 8-24 KeV Na(23) 20-70 KeV I(127) through through2000 2003… …4 6.3 Bernabei et al., astro-ph/0307403 9/15/05 Penn State Colloquium 62 HNN Similar Exposure… Stanford Site Surface electrons Z1 () or Z5 (+) Nuclear Recoils 9/15/05 Penn State Colloquium CDMS Neutrons!! Soudan rock filters the muons that make them (but not WIMPS) 63 HNN CDMS Limits DAMA 1-4 58,000 kg-days CDMS Stanford Edelweiss Non-blind blind (10’s of kg-days) Various Models 9/15/05 Penn State Colloquium 64
