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Principles of Spectrometry. Principles of Spectrometry. What is this?. Principles of Spectrometry. Deconvolution. Principles of Spectrometry. Energy and efficiency calibration. Principles of Spectrometry. Select events. Compton suppression. “Anti-coincidences”. - PowerPoint PPT Presentation
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Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
1
Principles of Spectrometry
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
2
Principles of Spectrometry
What is this?
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
3
Principles of Spectrometry
Deconvolution.
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
4
Principles of Spectrometry
Energy and efficiency calibration.
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
5
Compton suppression.“Anti-coincidences”.
What if cascades are present? ► Coincidences.
Select events.Principles of Spectrometry
By software or by hardware.
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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Advanced background reduction
Cascade Cascade selectionselection
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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Compton Compton spectrometer.spectrometer.
Another example for Another example for coincidences.coincidences.
Principles of Spectrometry
cos11
cos1
20
20'
cmhcmh
hhhEe
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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• Peak area determination.• Peak-to-total ratio.• Peak-to-Compton ratio.• Relative efficiency.• Intrinsic efficiency.• Absolute efficiency.• Total efficiency.• Solid angle.• Energy Resolution (effect of number of charge carriers).• Dead time.• Resolving time.• Anti-coincidences.• Coincidences.• Summation effects and true coincidences.• Random coincidences.
• Attenuation coefficient.• Mass attenuation coefficient.• Mean-free path.
Principles of Spectrometry
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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Linear attenuation coefficientLinear attenuation coefficient(photoelectric) + (Compton) + (pair production)
1
0
0
dxe
dxxe
x
x
Mean free path
Mass attenuation coefficient Mass attenuation coefficient is independent of density and physical state.
Compounds and mixtures??Compounds and mixtures??Give examples.Give examples.Refer to XCOM.Refer to XCOM.
tt eIeII )/(00
Mass thicknessMass thickness
HW 7HW 7
Principles of Spectrometry
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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Self-AbsorptionSelf-Absorption
Photon AttenuationPhoton Attenuation
Valid for parallelphoton paths
or far geometries.
HW 8HW 8
t
eII
t
10
teII 0
1
Not realistic…!!Not realistic…!!
Principles of Spectrometry
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
11
Isotropic PhotonEmission
Solutions to self Solutions to self absorption at absorption at
close close geometries?geometries?
t
eII
t
10
MCMC
Principles of Spectrometry
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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Geometric correction factorGeometric correction factor
PointSource
Detector
ExtendedSource
Detector
THINKING QUIZTHINKING QUIZ
Principles of Spectrometry
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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• Cost• Room• Availability• Passive Shielding
Detector spheres for accelerators
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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BGO
L ead shield
Beam
BGOClover
T arget
P las tic sc intillator
An experimental setup for accelerators
R
1.27
1 2 3 4
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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An experimental setup for accelerators
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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An experimental setup for accelerators
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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An experimental setup for accelerators
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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An experimental setup for accelerators
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
20
An experimental setup for accelerators
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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An experimental setup for accelerators
• Low-energy ultra-weak resonance.• 10 days beam on target.
Accelerator Physics, JU, First Semester, 2010-2011 (Saed Dababneh).
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An experimental setup for accelerators
