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Daniel Santos Laboratoire de Physique Subatomique et de Cosmologie Grenoble

MIMAC-He3 : Micro-tpc MAtrix of Chambers of 3 He + ( 19 F) Contribution to define a Large TPC for non baryonic Dark Matter search. Daniel Santos Laboratoire de Physique Subatomique et de Cosmologie Grenoble (CNRS/IN2P3-UJF-ENSPG). MIMAC-He3: (Micro-tpc MAtrix of Chambers of He3 +).

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Daniel Santos Laboratoire de Physique Subatomique et de Cosmologie Grenoble

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  1. MIMAC-He3:Micro-tpc MAtrix of Chambers of 3He + (19F)Contribution to define a Large TPC for non baryonic Dark Matter search Daniel Santos Laboratoire de Physique Subatomique et de Cosmologie Grenoble (CNRS/IN2P3-UJF-ENSPG) Daniel Santos

  2. MIMAC-He3: (Micro-tpc MAtrix of Chambers of He3 +) LPSC (Grenoble) : D. Santos, F. Mayet, R. Brissot Coordinateur technique : O. Guillaudin - Electronique : O. Bourrion, G. Bosson, J-P. Richer - Mécanique : Ch. Fourel, - Source d’ions : T. Lamy, P. Sole CEA-Saclay (Dapnia): I. Giomataris, P. Colas, D. Attié ILL (Grenoble) : B. Guerard, G. Manzin Daniel Santos

  3. 3He for axial detection of non-baryonic dark matter • spin 1/2 nucleus axial interaction • high “signal/noise” ratio : energy range ~ 1-5 keV • sensitive to M (WIMP) > 6 GeV • neutron capturesignature: n + 3He p + 3H + 764 keV • very low sensivity to -rays • in a gas form, the possibility to share a “patchy” matrix with other gases to follow the A cross section function Daniel Santos

  4. Cross section 3He-and event rate in MIMAC-He3 (10kg) • 0.02< Ωh2<0.15 • Accelerator constrains Exclusion curve for background 10-3 kg-1jour-1 Neutralino mass (GeV/c2) Daniel Santos

  5. Complementarity with scalar detection sSDandsSI not correlated E. Moulin et al, PLB 614 (2005)143 Daniel Santos

  6. Direct detection strategies (Drift) Daniel Santos

  7. MIMAC-He3: (Micro-tpc MAtrix of Chambers of He 3) • spatial • temporalresolution • energetic • recoil track • energy threshold ~ 200eV • electron/recoil discrimination Daniel Santos

  8. Quenching factor calculation(Lindhard theory) F. Mayet (2006) Daniel Santos

  9. Range vs. EnergyHe3 recoils Electrons Daniel Santos

  10. a/b ratio = f (pressure)L~10 cm Daniel Santos

  11. Time collection = f(pressure) Daniel Santos

  12. a/b ratio vs. Time collection E. Moulin (Ph.D. th.,2005) Daniel Santos

  13. Diffusion & Charge collectionD~ 200μm √ L[cm] => D~800 μm => 30 pixels( L ~15 cm and pixels~250 μm ) • He => 41 eV/ pair (e-ion) => 25 pairs/keV • With a gain G~3000 => 75000 e-/keV over 30 pixels => threshold ~ 2500e- “gassiplex” does the job…but we’ll try to do better ! Daniel Santos

  14. ASIC MIMAC16 « pixel » channels + mixer & shaper [energy] + double serialiser Process BiCMOS-SiGe 0.35mm Mixer & Shaper [2 gains] « pixel » channel [x 16] serialiser @ 400MHz [x 2] Daniel Santos

  15. ASIC MIMACOscillograms Serialiser outputs @ 320MHz “Z” measurement Time Over Threshold Energy measurement Mixer + shaper [2 gains] Daniel Santos

  16. Drift velocity vs. Pressure Daniel Santos

  17. Diffusion of primary electrons Daniel Santos

  18. Directionality at low pressure • Two different modes • High pressure (1, 2, 3 bars) to get WIMPs events !! • Low pressure (~100 mbar) to get directionality Range of recoils (x 10 ) (1bar to 100 mbar ) Diffusion (x 2) Drift velocity (x 2)  More suitable scenario (TBC by experiment) Daniel Santos

  19. Source 3He, 4He, 1H, (…) ( LPSC-Grenoble) Daniel Santos

  20. MIMAC source spectrum at 14kV Daniel Santos

  21. Interface (ion source – chamber)A thin foil (100 nm of Ni4Si3) Daniel Santos

  22. Time of flight measurement of the ion coming out of the MIMAC source at 50 kV Daniel Santos

  23. He3 -TOF measurement Daniel Santos

  24. Micromegas (100mmx100mm) Daniel Santos

  25. Ionization measured in the range of a few keV (in 4He ) Daniel Santos

  26. Daniel Santos

  27. Daniel Santos

  28. Internal conversion electrons and Auger electrons from the 57Co source Daniel Santos

  29. Auger & Internal Conversion Electrons from a « thin » 57Co source Daniel Santos

  30. Calibration (electron energies)from the 57Co source Daniel Santos

  31. Energy of He3 from the TOF measurementsat 15,17.5,20,22.5,30 kV Eout (keV) Ein (keV)  E (11keV) = 1.1 keV E(10.5keV) = 0.8 keV Daniel Santos

  32. He3 (1.1 keV) + e- (Co57) Daniel Santos

  33. He3 (E~ 0.8 keV) +e- (Co57) Daniel Santos

  34. 4He (10.5 kV) + 55Fe source(95% 4He + 5% isobutane) Daniel Santos

  35. Conclusions • The axial interaction should be explored • 3He is a very interesting target • High pressure (events) and low pressure (directionality) modes with the same detector • A matrix with different targets including 19F and H will allow to follow the p-n complementary and the cross section dependence • The quenching factor measurement in 3He and 4He is inminent • A collaboration with Drift collaboration and Zaragoza has started to define the Large TPC for nBDM search ! Daniel Santos

  36. Range of recoils (He3) vs. Recoil Energy(SRIM-2003) Daniel Santos

  37. The lightest neutralino • lowest mass linear superposition of superpartners of the gauge and higgs bosons: ~ ~ ~ ~ ~ = a1B + a2W3 + a3H1 + a4H2 • neutral, colorless, only weak interaction • stable with R-parity conservation • non-relativistic at decoupling  CDM • relic density can be compatible with cosmological observations Daniel Santos

  38. Direct Detection of SUSY particles • Elastic diffusion -quark : • spin dependent (axial) • SD(AX) αSD(p) × A2 • spin independent (scalar) • SI(AX) αSI (p) × A4 For 3He and 19F : SD » SI Daniel Santos

  39. H (E~ 5.9 keV) Daniel Santos

  40. Diffusion & Charge collectionD~ 200μm √ L[cm] => D~800 μm => 30 pixels( L ~15 cm and pixels~250 μm ) • He => 41 eV/ pair (e-ion) => 25 pairs/keV • With a gain G~3000 => 75000 e-/keV over 30 pixels => threshold ~ 2500e- “gassiplex” does the job…but we’ll try to do better ! Daniel Santos

  41. Spin-dependent WIMP-nucleus elastic cross-section OGA approximation: ap<Sp>  0 an<Sn>  0 Current technique: ap/an ratio = constant Generally, this ratio depends on the neutralino composition:  WIMP-model dependence Daniel Santos

  42. Spin-dependent exclusion plots (1) Tovey et al. PLB 488(2000)17 in the case of a single specie of nucleus. With: lim where sA is the experimental limit  3D exclusion plots: ap,an,m Daniel Santos

  43. Spin contributions to the axial interaction Daniel Santos

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