Low energy measurement with helium micromegas tpc
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Low energy measurement with Helium micromegas µTPC. Olivier Guillaudin Frédéric Mayet, Daniel Santos, Charbel Koumeir , Cyril Grignon Laboratoire de Physique Subatomique et de Cosmologie Grenoble – Université Joseph Fourier - CNRS/IN2P3. MIMAC Collaboration.

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Low energy measurement with Helium micromegas µTPC

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Low energy measurement with helium micromegas tpc

Low energy measurement with Helium micromegas µTPC

Olivier Guillaudin

Frédéric Mayet, Daniel Santos, Charbel Koumeir , Cyril Grignon

Laboratoire de Physique Subatomique et de Cosmologie Grenoble – Université Joseph Fourier - CNRS/IN2P3


Low energy measurement with helium micromegas tpc

MIMAC Collaboration

LPSC (Grenoble) : D. Santos, F. Mayet, C. Koumeir, C. Grignon

Technical coordinator : O. Guillaudin

Team : O. Bourrion, G. Bosson, J-P. Richer, Ch. Fourel, T. Lamy, P. Sole, J.P. Scordilis, J. Angot, A. Pelissier

CEA-IRFU (Saclay): I. Giomataris, P. Colas, J. Pancin

IRSN (Cadarache) : A. Allaoua, L. Lebreton

O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


Outline

Outline

Final Goal : ionization measurement for low energy Helium ion

  • Calibrated Detector with X-Rays for Helium/Isobutane gaz mixture

  • A calibrated ion source (from 1 to 50 keV)

  • Gain Curve

  • Energy Resolution for X-Rays and low energy 3He and 4He ions

  • Quenching factor for MIMAC R&D project

    (Key point for Dark Matterto compute recoil energy )

O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


Detector bulk megas

Detector : Bulk µMegas

Standard bulk micromegas

fabricated at CERN-TS/DEM

  • Stainless steel mesh

  • 325 line/inch = 78 μm pitch

  • Wire diameter ~25 μm

  • Amplification gap = 128 μm

  • 100mm x 100mm active area

  • Pilar peach 2 mm

  • Drift gap: 3 cm

    HV ISEG

  • Ripple : 2 mV (p-p)

  • Resolution on voltage setting (10 mV)

  • LabView interface (voltage, current)

    Gain Reproductibility

O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


Calibration with helium isobutane mixture

Calibration with Helium / Isobutane mixture

  • Classical radioactive source :

    • 55Fe (5.97 keV)

  • Helium transparency for X > 2 keV

    High flux source (multicell detector!)

  • Production of fluorescence X-Rays on different targets with a Miniature X-Ray Generator (inside chamber)

    • Peak X-ray flux equivalent to a 2 mCi source (during few sec)

    • Target and X-ray

      • Al : 1.486 keV

      • Ti : 4.504 keV

      • Fe : 6.4 keV

      • Cu : 8.1 keV

  • O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Multi target spectrum

    Al (1,486 keV)

    Ti (4,504 keV)

    Multi-Target Spectrum

    • Target : Aluminium + Titanium

    • 700 mbar Helium + 5% Isobutane

    • E Drift = 130 V/cm

    • HV Detector = 430 V

    • Gain = 1,2 104

    • Energy Resolution FWHM

      • Aluminium 1,486 keV = 32,9 %

      • Titanium 4,504 keV = 19,6 %

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Multi target spectrum1

    Multi-Target Spectrum

    • Target : Aluminium + Iron

    • 1000 mbar Helium + 5% Isobutane

    • E Drift = 130 V/cm

    • HV Detector = 430 V

    Al (1,486 keV)

    Fe (6,4 keV)

    • Gain = 1,1 104

    • Energy Resolution FWHM

      • Aluminium 1,486 keV = 29,4 %

      • Iron 6,4 keV = 15,3 %

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Gain and energy resolution

    Gain and Energy resolution

    • Detector operated in sealed mode for 1 day (after outgazing during night)

    • Gain variation about ~ -0,2% / h

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Ecr ion source configuration design and build at lpsc ssi team

    He ions

    ECR ion source configuration(Design and build at LPSC SSI Team)

    • p, 3He and 4He from 1 to 50 keV

    • From 5 to 10 000 ions/s

    WIEN Filter (ion selection)

    Plasma source (gaz + HV)

    Henzel Lens

    Faraday Cup

    Membrane between vaccuum and gaz detector

    (Si3N4 or µm hole)

    Bulk Micromegas

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Ion source calibration with si 3 n 4 membrane time of flight under vacuum

    STOP

    He ions

    Mobile channeltron

    Ion source calibration with Si3N4 membrane Time of flight under vacuum

    Low energy secondary electron

    START

    Helium atom

    VACUUM

    Metallized Silicon Nitride membrane

    50 nm

    • Neutral atom after the Silicon nitride membrane

    • Method : measuring time of flight for 2 positions of the STOP channeltron

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Ion source calibration with si 3 n 4 membrane time of flight under vacuum1

    STOP

    He ions

    Mobile channeltron

    Ion source calibration with Si3N4 membrane Time of flight under vacuum

    Low energy secondary electron

    START

    Helium atom

    VACUUM

    Metallized Silicon Nitride membrane

    • Neutral atom after the Silicon nitride membrane

    • Method : measuring time of flight for 2 positions of the STOP channeltron

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Time of flight results

    Time of Flight Results

    • Ion : 4He

    • Membrane

      • 50 nm Si3N4

      • 10 nm Al

    • Others

      • Proton

      • 3He

    4He

    13,4 keV

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Ionisation measurement with si 3 n 4 interface

    55Fe (5,9keV)

    18 % FWHM

    26 % FWHM

    STRAGGLING!!!

    Al (1,486 keV)

    29,4 % FWHM

    Ionisation measurementwith Si3N4 Interface

    Calibration

    Helium + 5% Isobutane

    Pressure : 1 bar

    • 4He

    • Initial ion energy : 20 keV

    • 13,4 keV after membrane

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Ionisation measurement 1 m hole interface

    16 % FWHM

    Ionisation measurement1 µm Hole Interface

    Helium + 5% Isobutane

    Pressure : 1 bar

    Initial Ion energy : 13,4 keV

    Count rate : 25 cps/s

    Same resolution as X-Ray

    Energy resolution improvement with the hole

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Low energy measurement with helium micromegas tpc

    1 µm hole

    10 mm

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Quenching factor measurement

    Quenching factor @ 700 mbars

    Quenching factor measurement

    • Helium + 5% Isobutane

    • Pressure : 700 mbar

    • Count rate : 25 cps/s (no space charge effect)

    • Threshold :300 eV (ioni.) or 1 keV (recoil)

    4He

    New Micromegas (192 µm gap) for low pressure (< 500 mbar)

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Energy resolution ion vs x ray

    Energy resolution Ion vs X-Ray

    • Better resolution for X-Rays

    • Does not depend on pressure

    • Ion measurement down to 1 keV

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Ionisation and ion charge with hole

    H2 1+

    He 1+

    38,58 keV

    38,60 keV

    He 2+

    Ionisation and ion charge (with hole)

    Ion : He 1+

    Eacc = 50 keV

    Ec = 50 keV

    Ion : He 2+

    Eacc = 25 keV

    Ec = 50 keV

    Ionisation do not depend of state of charge

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    New ecr ion source for fluorine quenching factor measurement

    Henzel Lens 2

    Magnetic dipole

    Henzel Lens 1

    Faraday Cup

    New ECR ion source for Fluorine quenching factor measurement

    • Possibility to separate

      • p

      • 3He

      • 4He

      • 14N

      • 19F

    • Gaz : CF4

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Mimac tpc chamber

    MIMAC : µTPC chamber

    Ionisation

    and

    Track

    cathod

    Drift space : 15 cm

    Micromegas

    +pixellized anod (x,y)

    MIMAC ASIC

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    The tpc chamber

    He ions

    The TPC chamber

    Faraday cube

    • Design to be connected to the ECR ion source

    • Variable drift lenght to study diffusion effect on track

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Thanks for your attention

    Thanks for your attention

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Low energy measurement with helium micromegas tpc

    Drift velocity vs. Pressure

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Diffusion of primary electrons

    Diffusion of primary electrons

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Mimac source spectrum at 14kv

    MIMAC source spectrum at 14kV

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Low energy measurement with helium micromegas tpc

    Recoil energy distribution after a polypropilene foil of 0.44μg/cm2for acceleration energies of 45 and 50 keV

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    Time of flight measurement of the ion coming out of the mimac source at 50 kv

    Time of flight measurement of the ion coming out of the MIMAC source at 50 kV

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


    He3 tof measurement

    He3 -TOF measurement

    O. Guillaudin Low energy measurement with Helium micromegas - Paris - December 2008


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