XENON
Emily Altiere
Nevis Lab, Columbia University
August 6,2009
Emily Altiere
0
Acknowledgements
Elena Aprile, Guillaume Plante, Rafael
Lang, Luke Goetzke, Kyungeun Lim,
Bin Choi, and Mike Sheavitz
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Emily Altiere
Main Goal
Measure the ionization and scintillation
yield as a function of energy deposition
in Liquid Xenon (LXe)
W.W.Moses: Scintillator Non-Proportionality: Present
Understanding and Future Challenges
Emily Altiere
B.D.Rooney: Benchmarking the Compton Coincidence
Technique for Measuring Electron Response NonProportionality in Inorganic Scintillators
2
Current Picture
• Charge and light
signals for electron
and nuclear recoils
as a function of
energy for Xenon10
• Difficult to introduce
LE gamma rays
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Emily Altiere
Topics
•
•
•
•
•
•
•
•
•
•
Interactions of Gamma-rays with Matter
Compton Scattering
Compton Coincidence Technique (CCT)
Sodium Iodide (NaI(TI)) Detector
Calibrating and Energy Resolution for NaI(TI)
CCT with NaI(TI)
High Purity Germanium (HPGe) Detector
CCT with HPGe
CCT with Xenon
XeMini
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Emily Altiere
Interactions of Gamma-rays
with Matter
1. Photoelectric Absorption
•
•
Incident photon is fully absorbed by an electron,
which is then ejected from its shell
Low energy range
2. Compton Scattering
•
•
Incident gamma ray photon is deflected off an
electron at an angle, , transferring only part of
its energy.
Medium energy range
3. Pair Production
•
Emily Altiere
•
Gamma-ray is absorbed and replaced by an
electron-positron pair
Energies 1.02MeV and higher
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Compton Scattering
e
hv 

hv’
e
hv
1 (
)(1 cos( ))
mec 2
(2)
For =, backscattering occurs
hv

Eerecoil  hv  hv
hv
(1)
hv    
hv
2hv
1 (
)
2
mec
(3)

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Emily Altiere
Compton Coincidence
Technique (CCT)
Detector 2

h ’
Detector 1
h
Use Compton Scattering to
measure electron response
and measure light yield
non-proportionality for LE in
a material/detector 1.
Cs137
Lead Brick
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Emily Altiere
NaI(Tl) Scintillation Detector
• Inorganic scintillator
• Used in gamma-ray
spectroscopy
PMT 3” Diameter
• Non-proportional light response
with energy deposition
NaI(TI) Crystal
3”dia. X 3” thick
NaI(TI) crystal scintillator. Model 3M3/3
B.D.Rooney: Benchmarking the Compton Coincidence
Technique for Measuring Electron Response NonProportionality in Inorganic Scintillators
Emily Altiere
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Calibration Setup
Research Amp 1
Detector 1
MCA/
Computer
h
High
Voltage
(1keV)
Cs137
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Emily Altiere
Calibration
• Sources
• Radioactive (eg. Cs137, Ba133,
Co57, Co60)
• Known energies
• Gamma-rays with energies
between 80keV-1.3MeV
• MCA
• 1024 channels
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Emily Altiere
NaI(TI) Spectrum of Cs137
662 keV
FWHM
7.12%
Backscatter Peak
Compton Edge
NaI(TI) spectrum of Cs137
Emily Altiere
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Energy Resolution
Cs137:662keV
W.W.Moses: Scintillator Non-Proportionality:
Present Understanding and Future Challenges
Energy resolution with NaI(TI) crystal
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Emily Altiere
Experimental Setup
Preamp
TC Amplifier
Dual Gate
Generator 1
Research Amp 2
Detector 2

High
Voltage
(1.8keV)
h ’
Divider
Detector 1
Discriminator
4-input
Logic
Research Amp 1
Spectroscopy
Amplifier
h
High
Voltage
(1100keV)
Cs137
Lead Brick
Delay
Amp
Dual Gate
Generator 2
MCA/
Computer
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Emily Altiere
Experimental Setup
Preamp
TC Amplifier
Dual Gate
Generator 1
Research Amp 2
Detector 2

High
Voltage
(1.8keV)
h ’
Divider
Detector 1
Discriminator
4-input
Logic
Research Amp 1
Spectroscopy
Amplifier
h
High
Voltage
(1100keV)
Cs137
Lead Brick
Delay
Amp
Dual Gate
Generator 2
MCA/
Computer
14
Emily Altiere
Experimental Setup
Preamp
TC Amplifier
Dual Gate
Generator 1
Research Amp 2
Detector 2

High
Voltage
(1.8keV)
h ’
Divider
Detector 1
Discriminator
4-input
Logic
Research Amp 1
Spectroscopy
Amplifier
h
High
Voltage
(1100keV)
Cs137
Lead Brick
Delay
Amp
Dual Gate
Generator 2
MCA/
Computer
15
Emily Altiere
Experimental Setup
Preamp
TC Amplifier
Dual Gate
Generator 1
Research Amp 2
Detector 2

High
Voltage
(1.8keV)
h ’
Divider
Detector 1
Discriminator
4-input
Logic
Research Amp 1
Spectroscopy
Amplifier
h
High
Voltage
(1100keV)
Cs137
Lead Brick
Delay
Amp
Dual Gate
Generator 2
MCA/
Computer
16
Emily Altiere
Experimental Setup
Preamp
TC Amplifier
Dual Gate
Generator 1
Research Amp 2
Detector 2

High
Voltage
(1.8keV)
h ’
Divider
Detector 1
Discriminator
4-input
Logic
Research Amp 1
Spectroscopy
Amplifier
h
High
Voltage
(1100keV)
Cs137
Lead Brick
Delay
Amp
Dual Gate
Generator 2
MCA/
Computer
17
Emily Altiere
Experimental Setup
Preamp
TC Amplifier
Dual Gate
Generator 1
Research Amp 2
Detector 2

High
Voltage
(1.8keV)
h ’
Divider
Detector 1
Discriminator
4-input
Logic
Research Amp 1
Spectroscopy
Amplifier
h
High
Voltage
(1100keV)
Cs137
Lead Brick
Delay
Amp
Dual Gate
Generator 2
MCA/
Computer
18
Emily Altiere
Experimental Setup
Preamp
TC Amplifier
Dual Gate
Generator 1
Research Amp 2
Detector 2

High
Voltage
(1.8keV)
h ’
Divider
Detector 1
Discriminator
4-input
Logic
Research Amp 1
Spectroscopy
Amplifier
h
High
Voltage
(1100keV)
Cs137
Lead Brick
Delay
Amp
Dual Gate
Generator 2
MCA/
Computer
19
Emily Altiere
CCT with NaI(TI)
MCA Saturation
Backscatter Peak
Background
Expected 100keV peak
Monte Carlo Simulation for 30 Degrees with NaI(TI)
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Emily Altiere
HPGe Ionization Detector
HPGe
Preamp
•
•
•
•
Semiconductor
Ionization
High resolution
3 keV-1Mev
Liquid Nitrogen Dewar
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HPGe Spectrum of Cs137
662 keV
662 keV
Backscatter Peak
Compton Edge
FWHM
1.10%
FWHM
7.12%
HPGe spectrum of Cs137
NaI(TI) spectrum of Cs137
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Emily Altiere
CCT with HPGe
Background
662 keV
Backscatter
Monte Carlo Simulation for 24.4 Degrees with HPGe
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Emily Altiere
CCT with LXenon
• Will replace LE
NaI(TI) detector with
a LXenon detector.
• We want to produce:
• Scintillation efficiency
vs energy deposition
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Emily Altiere
XeMini
• Important features:
• 4 top PMT’s allow for
position reconstruction,
which gives increased
resolution allowing for
precise measurements of
LE’s.
• Dual phase (liquid /gas) to
understand electron recoil
energy
Top Mesh
Anode
Bottom Mesh
Cathode
Level Meter
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Emily Altiere
Conclusion
• Gamma-rays interact with
electrons in three ways,
photoelectric absorption,
Compton scattering and pair
production.
• NaI(Tl) detector and nonproportional light response
• Compton Coincidence Technique
to measure low energies in a
detector
• Future goals of CCT with LXe to
measure the light and charge
efficiency as a function of
electron recoil energy
• XeMini detector
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Emily Altiere