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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
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
A. Manalaysay, 2/8/06 2
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
