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NEWAGE d irection-sensitive dark matter search experiment. TAUP 2011@Munich 2011/09/05. Kiseki Nakamura (Kyoto university). T.Tanimori , H .Kubo , K.Miuchi , T.Mizumoto , J.Parker , A.Takada , H.Nishimura , S.Iwaki , T.Sawano , Y.Matsuoka , S.Komura , Y.Sato.
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NEWAGE • direction-sensitive dark matter search experiment TAUP2011@Munich2011/09/05 Kiseki Nakamura (Kyoto university) T.Tanimori, H.Kubo, K.Miuchi, T.Mizumoto, J.Parker, A.Takada, H.Nishimura, S.Iwaki, T.Sawano, Y.Matsuoka, S.Komura, Y.Sato • Direction-sensitive method • NEWAGE experiment • Low pressure gas study • Summary
Direction-sensitive DM detection σSD=1pb M=100GeV target:F • Incoming direction of DM (new) • Nuclear track -> Gas detector • Require for 3s : ~20events • Annual modulation (conventional) • Large mass->Solid or liquid detector • Require for 3s : ~10000events Expected cosθ distribution Large difference in forward to back DM θ Nucleus cosq
NEWAGE Detector "m-TPC" 30 or 50 cm New general WIMP search with an Advanced Gaseous tracker Experiment • GEM • size : 28x23cm • thickness : 50mm • hole : 70mm • pitch : 140mm • m-TPCmicro-Time-Projection-Chamber • 3-dimensionaltracker • gas : CF4 (0.1-0.2atm) 0.5cm • m-PIC • micro-Pixel-Chamber • size : 30x30cm • pitch : 400mm • x-y strip readout 65cm ASD 30cm m-TPC 45cm 45cm Flash ADC Position Encoder
Kamioka underground laboratory • Kamioka status • Depth : 2700m.w.e • Low background • Particles at Kamioka • Muon : 6.0x10-8 [/cm2/s/sr] • neutron : ~10-6 [/cm2/s] • gamma-ray : ~3x10-2 [/cm2/s] • radon : 200-3000 [Bq/m3] • We get outside-air(40Bq/m3) into our experiment place Cosmic muonvs depth Kamioka Kamioka
PLB 686 (2010) 11 DM searchup to 2010 • Condition • Place : Kamioka • Exposure : 0.524 [kg days] • Pressure : 0.2atm • Obtained • Energy spectrum : 50 dru @100keV • |cosq| distribution : Flat • Limit : 5600pb for 150GeV Energy spectrum at Kamioka obtained cosq distribution
Next • We aim to search DAMA-region (sensitivity x~1000) • Background: 1/10 ( x10) • ->Radon elimination (sub talk) • Material selection • Energy threshold: 1/2 ( x10) • ->low pressure gas (main talk) • Large size ( x10) • ->Several 1m3size detectors • ( current : (30cm)3 ) • Head-tail identification ( x3) • -> New DAQ (time-over-threshold) Expected limit curve of the WIMP-proton SD elastic scattering cross section (90%C.L.) PLB686 (2010) 11
Gas circulation system Detector wall • Circulation with cooled charcoal • Radon rate : 1/4(prototype pump) • Further reduction is expected with full spec (600ml/min) pump Detection region (76torr CF4) U Rn Rn a-decay (about 6MeV) Time dependence of Rn cooler 210K pump 20ml/min without circulation charcoal 160g ・ spiral:60g ・ cylinder:100g with circulation
How to make threshold lower Expected energy spectrum Energy threshold : 100keV -> 50keV -> Sensitivity to DM : x10 σ=1pb, M=100GeV, target:F new threshold (plan) • Low pressure gas(152torr ->76torr) • ->Track length: x2 • Advantage • Sensitive to low energy (short) tracks • Improve angular resolution • Difficulty • Electrons density : half • ->Necessary gas gain : x2 (=1500) current threshold gas gain Gain curve GEM:-500/-280V 2 times gain from 0.2atm anode voltage[V]
Angular resolution • Compare the cosq distribution between measured to simulation (simulate each angular resolution) • We checked 50-100keV range : 40[deg] • (Can't be seen at 0.2atm) F nucleus tracks 252Cf Simulated cosqdistribution (400-800keV) cosq distribution (400-800keV) angular resolution 252Cf Blue:measured Green:simulation(s=49deg) neutron Blue : This work (0.1atm) Red : Previous (0.2atm) q nuclear
Detection efficiency Expected energy spectrum • Detection efficiency : 0.6@50keV • (ratio of measured to simulation) • Energy threshold : 100 -> 50keV angular resolution σ=1pb, M=100GeV, target:F new threshold (plan) current threshold detection efficiency
Summary • NEWAGE • Direction-sensitive DM search with MPDG "m-TPC" • We obtained direction-sensitive exclusion limit for DM • Gas circulation • Radon rate : 1/4 with prototype pump • Low pressure (152torr⇒76torr) • Operation test • u-PIC work at 76torr with sufficient gain • Angular resolution • 40°+3.1-2.9@50-100keV • Detection efficiency • 0.6@50keV • Energy threshold : 100 -> 50keV • Next to search DAMA • Update gas circulation system for radon elimination • Use new DAQ for head-tail identification • Simulation for constructing the large size detector
Summary • NEWAGE • Direction-sensitive DM search with MPDG "m-TPC" • We obtained direction-sensitive exclusion limit for DM • Gas circulation • Radon rate : 1/4 with prototype pump • Low pressure (152torr⇒76torr) • Operation test • u-PIC work at 76torr with sufficient gain • Angular resolution • 40°+3.1-2.9@50-100keV • Detection efficiency • 0.6@50keV • Energy threshold : 100 -> 50keV • Next to search DAMA • Update gas circulation system for radon elimination • Use new DAQ for head-tail identification • Simulation for constructing the large size detector Thank you for your attention! Mascot of NEWAGE "Daakumatan"