XENON10: Searching For Dark Matter with a Noble Liquid TPC Aaron Manalaysay Dept. of Physics,...

XENON10: Searching For Dark Matter with a Noble

Liquid TPC

Aaron Manalaysay

Dept. of Physics, University of Florida

August 31, 2006

RWTH Aachen Graduate College – Bad Honnef

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OVERVIEW

•Background

•Detection

•Using Liquid Xenon

•UFXenon

•XENON10

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Evidence and Motivation

Galactic rotation curves

Gravitational Lensing

Cosmic Microwave Background

0009.00224.0

135.02

008.0009.0

2

h

h

b

M

Big Bang Nucleosynthesis

003.0002.0

2 020.0 hb

BACKGROUND

D. Clowe, et al , astro-ph / 0608407

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BACKGROUND

Content of the Cosmos

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Thermal Relics from Freezout

Leaving equilibrium as universe expands:

BACKGROUND

In equilibrium:

X + X Y + Y

vh

AX

-13272 scm103

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Some Properties of Dark Matter

•Distributed in spherical halo throughout galaxy

•Electrically neutral

•Non-relativistic (“cold”)

•Weak cross section

•Non-baryonic

Candidate: WIMP

(Weakly Interacting Massive Particle)

BACKGROUND

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+ q + q

q scattering

WIMP Detection Scheme

+q + q

annihilation

0-50 keV nuclear recoils

DETECTION

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DETECTION

WIMP interactions: expected 5-50 keV nuclear recoils

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•Intrinsic Scintillator

•Large target nuclei (z=54, a~130-ish)

•Easily scaled up in mass

•Inert gas: safe and easy to work with (and obtain)

•Easy Cryogenics at ~180K

•Suitable for spin-dependent and spin-independent WIMP interactions

•No long-lived radio isotopes

•Self-shielding

•Allows for nuclear recoil discrimination

Why Xenon?

Using LXe

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Rel. Scintillation Yield

56.5 keV n-recoils

5.5 MeV alphas

122 keV gammas

Ionization yield from alphas

Aprile et al.

Interaction Process

S. Kubota et al.

+Xe

+e-

Xe*

Xe++e-

Xe2+

Xe2*

Xe**+ Xe

2Xe

+Xe

2Xe

178nmSinglet (3ns)

178nmTriplet (27ns)

Excitation

IonizationEr

Nevis Lab data

Using LXe

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LXe

GXe

PMT PMT

Es

Ede-

e- e-

e-

Cathode

Anode Grid

Gate Grid

Dual Phase TPC

Nuclear recoils

Inelastic (40keV+NR)

Inelastic (80keV+NR)

Using LXe

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UFXENON Detector Design

UFXenon

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Monte Carlo simulations

Simulated energy spectrum and position info.

Need to simulate light collection efficiency.

Ba133

Cou

nts

Energy [keV]

UFXenon

Ba133

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LXe

EJ301

n

)cos1()(

22

Xen

Xennr mm

mmEE

Studying Nuclear Recoils

Study nuclear recoils down to 5keV recoils. Absolute recoil energy inferred from recoil angle and ToF.

AmBe

UFXenon

neutrons

gammas

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Scintillation and Ionization Yields

These measurements are essential for performing nuclear recoil discrimination.

Ionization yield

UFXenon

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Additional Scintillation Efficiency Measurement

Lopes et al

Preliminary data from Lopes et al indicates possible departures from the predictions of the Hitachi model.

UFXenon

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XENON

XENON Collaboration

Columbia University

Brown University

Rice University

Case Western Reserve University

RWTH Aachen / University of Florida

Yale University

Lawrence Livermore National Laboratory

Laboratori Nazionali del Gran Sasso

Universidade de Coimbra

Rick Gaitskell, Peter Sorensen, Luiz de Viveiros, Simon Fiorucci

Tom Shutt, Alexander Bolozdyna, Paul Brusov, John Kwong, Eric Dahl

Jose Matias, Joaquim Santos, Luis Coelho

Elena Aprile, Karl Giboni, Masaki Yamashita, Guillaume Plante, Maria Monzani

Laura Baudis, Joerg Orboeck, Jesse Angle, Aaron Manalaysay

Francesco Arneodo, Alfredo Ferella

Adam Bernstein, Norm Madden, Celeste Winant, Chris Hagmann

Dan McKinsey, Richard Hasty, Angel Manzur, Taritree Wongjirad, Kaixuan Ni

Uwe Oberlack, Roman Gomez, Peter Shagin

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XENON10, 100, 1TGran Sasso

Lead Shield

XENON10

XENON100

XENON1T

CDMSII (current)

XENON10

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XENON10XENON10

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XENON10 Background MC SimulationsXENON10

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XENON10

Current Status/Future Plans•Energy threshold ~10 keV

•First data (post shield construction) was dominated by Kr contamination (~25ppm)

•Replaced with Xe of low Kr (<1ppm) for calibration (the current status)

•Neutron calibration starting in September

•Fill with ultra-low Kr level Xe (<1ppb) in September/October

•Low-background data Corno Grande, Gran Sasso