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NEWAGE -- A direction-sensitive dark matter search

NEWAGE -- A direction-sensitive dark matter search. ( Ne w generation W IMP search with an a dvanced g aseous tracker e xperiment). Kentaro Miuchi （ Kyoto University) H. Nishimura T. Tanimori, H. Kubo, S. Kabuki, K. Tsuchiya, A. Takada, Y. Okada, K. Hattori, K. Ueno, S. Kurosawa

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NEWAGE -- A direction-sensitive dark matter search

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  1. NEWAGE -- A direction-sensitive dark matter search (New generation WIMP search with an advanced gaseous trackerexperiment) Kentaro Miuchi （Kyoto University) H. Nishimura T. Tanimori, H. Kubo, S. Kabuki, K. Tsuchiya, A. Takada, Y. Okada, K. Hattori, K. Ueno, S. Kurosawa A. Takeda (ICRR), H. Sekiya (ICRR)

  2. OUTLINE DirectionsensitiveDMsearch Micro-TPC NEWAGEsurfacerun FUTUREPLANS & SUMMARY June11 2007 DBD07

  3. １.DirectionsensitiveDMsearch“WIMP-wind”detection PLB 578 (2004) 241 SOLAR SYSTEM220 km/s WIMPV0 =230 km/s The WIMP-wind

  4. WIMP WIND γ F • WHY “Direction-sensitive” ? • Large mass for exclusion （and indication） • BUT Annual modulation is not enough… • Direction-sensitive for detection Annualmodulation direction

  5. sensitivity • Sensitivities • Goal: Detect the WIMP-wind　（2010~） • underground・low pressure ( CF4 0.05 bar )・large volume （1m3 × N） • CURRENT: • surface・CF4 0.2 atm ・30cm cube

  6. 2 micro-TPC (3D tracking device) 23×28×31cm3 Preprints: physics/0701085 K.Miuchi et.al TPC Particle tracks 40cm TPC e X readout（768ch） GEM(×10) Y readout（768ch） m-PIC (×5000) FAGA position encoder（1536ch） Position Encoder Feb.20, 2007 APPEAL07

  7. Particle tracks 30cm TPC e GEM 5mm m-PIC 2D imaging device Takada et. Al. PSD7 • GEM (gas gain 10) • 140mm pitch • 70mm diameter Large area GEM(scienergy) 30cm μPIC(Toshiba) 28cm 23cm • m-PIC (gas gain 5000) • 400mm pitch • 589824 pixels • 768+768 readout

  8. TPCsystem Kubo et. al. IEEE/NSS 2005 • Gas volume • DRIFT length 31cm • CF4 0.2bar gas gas volume TPC system 31cm • 100MHz, pipeline ASD • + Summed analog signal • for energy ENCODER • Readout electronics • 768 anode + 768 cathode • Digital (LVDS) signals at ASD • (X,Y,T) at the position encoder • for tracking Feb.20, 2007 APPEAL07

  9. n q p Proton tracks 30cm 252Cf n • CF4+C4H10(9:1) 0.2 atm • n -> p forward scattering (emulation of WIMP -> F scatterings) Z(drift) • TPC performance1: nuclear tracks, imaging 15cm 0cm -15cm -15cm 15cm X Y 252Cf（NE45°zenith35°） CF4+C4H10252Cf run 0 Recoil directionimage 1 Cos q Jan 27, 2007 3rd MPGD workshop

  10. TPC performance 2:gamma-ray rejection • energylengthcorrelation • gamma-rays from 137Cs neutron（BG） neutron（BG）

  11. gamma-ray rejection（continued） • spectrum,BGsubtrucction Energy spectrum thick: 137Cs run hatched: no source Subtractedenergy spectrum consistentwith0（>100keV） neutron（BG） • gamma rejection ＜　2e-4　（statistics limited）

  12. TPC performance: nuclear track efficiency • neutrons from 252Cf • 0.4 @ 100keV June11, 2007 DBD07

  13. 3 Surface run • Surface run① • 2006 Nov.1st ~ Nov.27th • exposure 0.15 kg days (=0.0089kg ×16.7days) • @Kyoto university (N35.03E135.783） • Energy spectrum（conventional method） Energy spectrum

  14. Surface run ② • The sky map (by nuclear recoil tracks) • flat neutron background is seen North sky view seen by C and F nuclei(100-400keV) • DM direction

  15. Surface run ③ • Cosθ distribution • consistent with a flat distribution Cosθ分布 (100-400keV) WE AREHERE DM limit • First step to theNEWAGE Jan 27, 2007 3rd MPGD workshop

  16. 4 Next step… KAMIOKA LAB-B2007/1/19 Kamioka Kyoto • Gounderground • JUSTstarted Osaka KAMIOKA LAB-B2006/12/12 Jan 27, 2007 3rd MPGD workshop

  17. SUMMARY • μTPC：30cm cube in operation • direction-sensitive method works! • NEWAGE：underground run just started

  18. TPCperformance ② stability • Drift velocity: fast drop ⇒ slow decrease after 1 day • gain, energy resolution ：　stable withinthe systematic error

  19. 検出器応答 a a+Li • エネルギー校正 • ガラスに蒸着した10B( 厚さ0.6μm ) • ドリフトケージ内部にセット、外から252Cfの中性子を減速して照射 • 10B(n,a)7Li 反応　 (Q=2.70MeV 1.8MeV for a) • 原子核による校正、低エネルギーへの線形性は別途確認示す必要あり • 現状では、校正には6時間程度、見せれる絵には12時間程度かかっている XYイメージ スペクトル スペクトル(GEANT4） keV エネルギー vs 飛跡長 2000 keV

  20. 検出器応答 • 位置分解能から角度分解能 • アルファ線の飛跡を直線フィット、残差を求める：0.8mm • BG runのC,F recoilでの　飛跡長 / (nhit-1) = 1mm(サンプリング密度) • 上記二つのパラメータをもちいてsimulation振る。 • NHIT=3　で直線FITすると左の様になる。 • ローレンツィアンでFITして、γ=25°(=HWHM)

  21. 検出器応答 • エネルギー分解能 • 高エネルギー（5-8MeV）ではラドンのピークを使ってモニタ • 40％FWHM • これは検出器固有の数字（ゲインのばらつきが効いている） • 低エネルギーでは、以前のArでの実測60％FWHM@60keV • これが電子数統計とすると、W値、エネルギーで外挿すると、60×sqrt((54/26)×(60/100))=70％FWHM@100keV 60%@59.5keV

  22. TPCperformance (with Ar+C2H6 gas) • Gas gains • operation gain for MIPs ~50,000 Gain curves • Gain uniformity • Maximum / minimum = 2.2 Gain map

  23. June11, 2007 DBD07

  24. Preprints: physics/070118 K.Miuchi et.al • TPC performance①tracking • 400mm digital “HIT” ( for tracking) + summed analog ( for energy) Z projection X,Y image F,C tracks 30cm trigger n Z(drift) 252Cf 30 cm 15cm Trigger：z=0 0cm X Y -15cm 15cm -15cm • Fidutial24×21.5×31cm3(CF4 8.9g)FLAT response • F 500keV 5~6mm in 0.2atm CF4 • gamma rejection ＜　2e-4　（statistics limited）

  25. シミュレーション sim 測定値 測定値 • データ Input: エネルギーBIN、絶対検出効率 × 「DMの風」 検出器の方向依存感度マップ Input: エネルギー分解能、角度分解能、WIMP質量、エネルギーBIN 比較 = WIMP質量、エネルギーBIN ごとに用意 クロスセクション sim For givenWIMP質量、反跳エネルギー sim Expected cosθ分布（DM） Expected 「DMの風」

  26. June11, 2007 DBD07

  27. 241Am 109Cd 133Ba • Spectra • Energy spectra from the whole volume(with energy corrections) Cu-Ka,b 8keV Cu-Ka,b Cs-Ka,b 31keV Cu-Ka,b 59.5keV Ag-Ka,b 22.2+24.9keV Energy resolution linearity 60%@59.5keV Jan 27, 2007 3rd MPGD workshop

  28. muons Cosmic ray muons Protons (~2MeV) • Particle Tracking Neutrons（252Cf） Electrons (~100keV) 511keVg‘s（22Na） 30cm Jan 27, 2007 3rd MPGD workshop

  29. Residual (long drift) Fitted line data • 3D Spatial resolution • Fit muon tracks with straight lines • plot the residuals residual Drift length r [cm] data s dependence on drift length m-PIC Residual (short drift) Residual muon tracks r [cm] Jan 27, 2007 3rd MPGD workshop ｌ [cm]

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