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Detección Direccional de Materia OscuraMIMAC

MIcro-tpc MAtrix of Chambers

Daniel SantosLaboratoire de Physique Subatomique et de Cosmologie

(LPSC-Grenoble)(UJF Grenoble 1 -CNRS/IN2P3-INPG)

« Thermal History » of our Universe…

t = 380 000 ans

D. Santos (LPSC Grenoble)Tandar (CNEA)-Buenos Aires – 10 /11/ 2010

Cosmic Microwave Background (CMB)

oCOBE : T3K & large scale anisotropies → hot BBo Balloons & ground-based experiments : intermediate scale fluctuations → inflationo WMAP : large to med. scale T & large scale TE anisotropies → concordance modelo PLANCK will measure large to small scale T & E anisotropies & constrain B-mode fluctuations

↓?

WMAP 2 yearsWMAP 8 years

Planck 1 year

94 GHz - 15’ FWHM217 GHz - 5’ FWHM

5 x 5 deg. FieldT anisotropies

Tandar (CNEA)-Buenos Aires – 10 /11/ 2010 D. Santos (LPSC Grenoble)

T Power spectra

WMAP 4 years

From

pur

e C

MB

map

s

Planck - 15 months

Blue book simulationsTandar (CNEA)-Buenos Aires – 10 /11/ 2010 D. Santos (LPSC Grenoble)

Tandar (CNEA)-Buenos Aires – 10 /11/ 2010

• densité de matière ΩM = ΩB + ΩNB•déterminée par CMB

SNIa« clusters » de galaxies

0.0 0.2 0.4 0.6 0.8 1.0 1.2ΩM

ΩΛ

1.0

0.8

0.6

0.4

0.2

0.0

Am

as d

e ga

laxi

es

⇒ Concordance en faveur de ΩΛ ~ 0.7ΩM ~ 0.3

ΩM » ΩB » Ωlum

Ωtot = Ωr + ΩΛ + ΩM

⇒ existence de matière sombre (MS) :- baryonique (MSB) : résidus stellaires…ΩMSB ≤ 10% ΩMS (EROS, MACHO)

- non-baryonique (MSNB)D. Santos (LPSC Grenoble)

Non-baryonic Dark Matter

• DM hot (relativistic) : neutrinos Ωνh2 < 0.0067 (95% CL) (WMAP+2dFGRS)

• DM cold (not relativistic) : WIMPs, Mχ ~ O(GeV)

Most favorable candidate : • heavy : from 1 GeV to 1 TeV• stable• neutral

For WIMPs :

avec Mχ = O(100 GeV) ⇒ Ωχh2 = O(0.1)

( )><

=Ω−−

vGeVOhAσχ

292 10


Materia oscura no bariónica : « pruebas »

Escala local « nuestra Galaxia »

Incompatibilidad entre

la ley de Newton

y las observaciones astrofísicas

… salvo si se supone un halo de materia oscura englobando nuestro disco galactico

)/1( rv∝


Y en nuestra Via Lactea ?

Disco galáctico sólo

Disco galáctico +

Halo de materia oscura

Un halo de materia oscura no bariónica alrededor de nuestro disco galáctico

Sol


A escala de cúmulos

La materia no bariónica domina (~ 6 veces) la materia bariónica

(1E0657-558) Z= 0.296


• Détection directe : diffusion du neutralino surle noyau cible

- Cryogénique : Ge, CaWO4, INa, 3He- Non-cryogénique : Gel (Freon), Fluor

Directionnelle : CS2 (Drift), CF4 (DMTPC, MIMAC)

• Détection indirecte : détection des produits d’annihilation de neutralinos

- Télescopes à neutrinos : Super-K, ANTARES, IceCube, …- Expériences spatiales : AMS, Pamela, GLAST (FERMI)

• Accélérateurs (LEP,Tevatron,LHC) :⇒ limites directes sur les masses

des particules SUSY chargées⇒ LHC : découverte?

MACHe3

Cresst

AMS

Super-K

ANTARESGLAST

MIMAC


Estrategias de detección …

Direct detectionDirect detection

Elastic collision of a Wimp with a gas target nucleus :

Differential rate as a function of the recoil energy

Galactic halo

Particle Physics

Nuclear Physics

r : reduced mass



Direct Detection Strategies

D. Santos (LPSC Grenoble)

Detección directa : modulación anual

DAMA

Rotación de la Tierra =>

~7% de variación en amplitud

Medida a 9σ !!

Sin embargo… : excluida por Edelweiss, CDMS, … Observation : medida del flujo de µ ( MINOS)

Directional detection : principle

« A wind of WIMPS coming from the Cygnus constellation »


b) Le halo de matière noireThree models for isothermal halo:• Isotropic sphere• Oblate ellipsoid • Triaxial ellipsoid (3 axes différents)

Dispersion of velocity linked to V0(r→∞) ≈ 220 km.s-1

Boltzmann Eq. for a collissionless gas particles

Poisson Eq. for the gravit.field

Direct DetectionDirect Detection

Maxwell Distribution


Direct detectionDirect detection

e) Quelques ordres de grandeursProfil de vitesse des WIMP:• Distribution maxwellienne

• Mean velocity 300 km/s

• Cold matter (not relativistic)

Taux d’événement par énergie de recul:• Recoil energy ~ keV

• Energy threshold MIMAC ~ 5 keV •(recul) (19F)

WIMP velocity

Eve

nt ra

te

Recoil energy (keV)

f 1(v)

D. Santos (LPSC Grenoble)Tandar (CNEA)-Buenos Aires – 10 /11/ 2010

c) Distribution spatiales des reculs

Recoil simulation: ZW

XG

YG

ZG

lW

bW

YW

XW

ϕR

θR

WIMP

Recoil

• Collision isotrope dans le CDM:108 Events with ER = [5,50] keV

Recoil MapRecoil Map

Recoils in the earth reference in galactic coordinates (HealPix)


a) Simulation d’une mesure réaliste

Wimp recoilsBackground

Example of a MIMAC map measurement:100 WIMP evts + 100 Background evts

Méthode de vraisemblance


Directional PhenomenologyDirectional Phenomenology

b) Identification du signal WIMP« likelihood », without priors

S: WIMP signal theoretical distributionB: Background theoretical distribution (isotropic)M: MIMAC measurements

Poisson statistics

« Discovery » parameter:: Coordinates of the Wimp wind=> Signature of the galactic origin

« Discovery » parameter:: Coordinates of the Wimp wind=> Signature of the galactic origin


c) Résultat


Input:M = 100 GeV/c^2Lambda = 0.5L = 90°B = 0°


J.Billard, F.Mayet et D.S, PLB(2010)

Section efficace axiale WIMP-noyau :

La limite obtenue sur un noyau peut être convertie en limite sur le nucléon (->comparaisons)

Section efficace axiale WIMP-nucléon :

Approximation :

l’interaction est dominée par un des nucléons (ap =0 ou an=0)

Détection directe : interaction axiale


Direct detection : scalar vs axial

Scalar Interaction :

Axial Interaction : (spin coupling)

Very weakly correlated…Complementary searches…

4)()( ApX SIA

SI ×∝σσ

2)()( ApX SDA

SD ×∝σσ

Heavy nuclei : Ge, Xe, …

Odd nuclei : 1H, 3He, 19F,

Or… (73Ge, 129Xe)

WIMP-quark interaction :


Cross section 3He-χand event rate in MIMAC-He3 (10kg)

• 0.02< Ωχh2< 0.15• Accelerator constrains

Exclusion curve for background 10-3 kg-1jour-1

Neutralino mass (GeV/c2)


Complementarity with scalar detection

σSD and σSI not correlated

E. Moulin et al, PLB 614 (2005)143


WIMP

WIMP

3He

e-

cathode

micromesh

anode

E = 200 V/cm

E = 30 kV/cm

Gaz: 3He + 5% isobutane

pixels

strip readout

Charge sensitive preamplifier

MIMACStrategy :

Matrix of micro-TPCDirectional detection (energy and 3D track)Multi-targets (1H,3He, 19F) σ(A) Axial interaction3He, CH4, C4H10, CF4

TPC low pressure (~50 mbar)Micromegas (CEA Saclay)Tracks of a few mm and keV

Rejection based on :Energy and range : e-/nuclei Correlation of µTPCs (neutrons)

n

19FCF4

Tested !


A µ-TPC for Dark Matter…

Drift space : 16,5 cm ( up to 25 cm)

Micromegas pixellisée (x,y)

Pixel = 350µm

4 cm x 4 cm

Measured energy ≠ EreculAnd

Projected track ≠ 3D Track

cathode

WIMP

e-

Main problems !!

10 cm x 10 cm : soon…Tandar (CNEA)-Buenos Aires – 10 /11/ 2010 D. Santos (LPSC Grenoble)


Quenching factor measurement

He ions

ECR source •Low energy ion source

1 to 50 keV

•Developped @LPSC


Detection of 4He (recoils) of 1.5 keV !!( 95% 4He + 5% iso) at 700mbars


QF measurement !!

Measurement of 4He

in 95% 4He + 5% C4H10

Quenching factor @ 700 mbars

Range of interest for Dark Matter

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

•The response of this 4He detector is fully understood from 1 to 50 keV

•Dark Matter range : covered


IQF Measurement of 4He in 95% 4He + 5% C4 H10as a function of the pressureD. Santos et al. arXiv:astro-ph0810.1137

3D Track reconstruction :

C. Grignon et al. 2010

3D track built form many 2D images

L, θ and φ

t=0 ns

t=25 ns

t=50 ns

σDiff = 200 μm √L(cm)vdiff = 16 μm/ns

Anode ReadAnode Read--outoutevery 25 ns

We only need the drift velocity…



MIMAC chips integrated in the electronics of the prototype

96+96=192 channelsCovering 4x4 cm2

AutotriggeredRead out every 25ns

J.P. Richer, G.Bosson,O. Bourrion et al.NIM (2010)

New version (v2)64 channels ready to be tested

3D track : Alpha 5,5 MeV (222Rn)

He + 5% iC4H10

350 mbar,

150 V/cm


3D Track : 5.9 keV electron (55Fe)

He + 5% iC4H10

350 mbar,

150 V/cm

Typical background in DM detection



MIMAC : recoil track measurementsApril 2009 – June 2010

@ IRSN Cadarache

Amande facility :

•Neutron field with energies down to a few keV


MIMAC prototype at Cadarache(detecting neutrons by nuclear recoil)

electrons

Recoils

Preliminary resultsHe + 5% iC4H10

350 mbar,

150 V/cm

Discrimination e/recoil : measurements…

•High power rejection

•Low energies ( 10 keV)

Neutrons 144 keV

144 keVTandar (CNEA)-Buenos Aires – 10 /11/ 2010 D. Santos (LPSC Grenoble)


Energy (ADC)

Recoils from 144 keV neutronsPure

isobutane

100 mbar

150 V/cm

Amande facility @ IRSN Cadarache-> Neutron field with energies down to a few keV

Leng

th (c

m)

recoils

electrons

•Possibility to have H as a target

•Background discrimination from recoils

144 keV)


New degree of freedom to discriminate recoils from electrons from 3D tracks

Normalized Integrated Straggling (NIS)(Sum of partial deflections along the measured track, normalized by its total energy)(J. Billard et al. (2009) in preparation)


NIS (for recoils)

Entries 534

Mean 0.1258

RMS 0.06629

NIS0 0.5 1 1.5 2 2.5 30

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

0.22Entries 534

Mean 0.1258

RMS 0.06629

NIS(for electrons)

Entries 188Mean 1.075RMS 0.5518

NIS0 0.5 1 1.5 2 2.5 30

0.01

0.02

0.03

0.04

0.05

Entries 188Mean 1.075RMS 0.5518


3D Tracks: Reconstruction & simulation

He + 5% iC4H10

100 mbar,

60 V/cm C. Grignon et al, 2010

SRIM + Magboltz ( electron diffusion) + detector response simulation (DAQ ...)

p 8 keV


3D Track: proton 8 keV in He + 5% iC4H10

He + 5% iC4H10

350 mbar,

150 V/cm


70 % CF4 + 30% CHF3

55 mbar, 170 V/cm

~40 keV (ionization), ~3 mm

Trak in 3D : 19F in 70 % CF4 + 30% CHF3 !!!

X-Y (anode)

X-Z

Y-ZTandar (CNEA)-Buenos Aires – 10 /11/ 2010 D. Santos (LPSC Grenoble)


Recoil of 19F(Eion~40 keV)in 55 mbar ofCF4 + CHF3 (30%)


A small part of the 10x10 cm2 pixelized anode(Saclay-MIMAC)

J-P. Mols et al.October 2009


MIMAC unit (1m3) in 2013…

Chambers (green)MIMAC Electronics (brown)

Discovery plot (significant number of Wimp events (~50))


J.Billard, F.Mayet et D.S. PRD (2010)


Exclusion plot for directionaldetection

J.Billard, F.Mayet ,D.S.PRD (2010)


Input: • Halo isotrope: σ_Vi = 155 km/s• masse: 50 GeV• section efficace: 10-3 pb• Bckg rate: 10 evts/kg/year

Masse

Section efficace

l

b

σ_Vx

σ_Vy

σ_Vz

Bdf rate

Physique des particules

Découverte de la DM

Physique du halo galactique

Markov Chain Calculation…J.Billard et al.(to be published…)


MIMAC:(MIcro-tpc MAtrix of Chambers )

LPSC (Grenoble) : F. Mayet , D. Santos, C. Grignon (post-doc),J. Billard (Ph.D )

Technical Coordination : O. Guillaudin- Electronics : G. Bosson, J-L. Bouly, O.Bourrion, J-P. Richer- Gas detector : O. Guillaudin, A. Pellisier- Data Acquisition: O. Bourrion- Mechanical Structure : Ch. Fourel- Ion source : T. Lamy, J. Angot, P. Sole

CEA-Saclay (IRFU): I. Giomataris, P. Colas,E. Ferrer, J-P. Mols, F. Iguaz

IRSN (Cadarache): L. Lebreton, C. Golabek

Direct Detection : spin contents

19F : spin contents …


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