charged particle interactions - detection
DESCRIPTION
Charged Particle Interactions - Detection. Interaction of heavy charged particles Electronic or nuclear (Rutherford, nuclear reactions, …). Detectors mainly designed to make use of electronic interactions. - PowerPoint PPT PresentationTRANSCRIPT
Excitation Ionization ion-pair, suppress recombination in detectors.
Energy loss
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
Interaction of heavy charged particles
• Electronic or nuclear (Rutherford, nuclear reactions, …).
• Depletion layer.• Delta rays and secondary electrons.• Electron suppression for charge integration.• Faraday Cup.• Tracks.
Detectors mainly designed to make use of electronic interactions.
SRIMhttp://www.srim.org
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
2
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220
20
24
1ln2
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dx
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Stopping power Stopping power Bethe-Bloch formula
Minimum ionizing particles
~1/E
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Electron pick-up. ~1/E
Charged Particle Interactions - DetectionWhat about fission fragments?????What about fission fragments?????
Bragg curve
• Energy loss is a stochasticstochastic process, thus energy straggling.energy straggling.
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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eV / Å keV / m MeV / mm keV / (g/cm2) MeV / (mg/cm2) keV / (mg/cm2) eV / (1x1015 atoms/cm2)
Charged Particle Interactions - Detection
UnitsUnits
(conversion)(conversion)You will encounter this when you run SRIM
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
Range of charged particles Range of charged particles Compare to gamma … !!!Compare to gamma … !!!Range straggling?Range straggling?
Mean and extrapolated range.
• An “old” idea to measure energy..!• Surface barrier, PIPS.• For a detector to register the full energy of charged particles, its thickness should be more than the range at that energy.• Sometimes we look for partial energy.• E-E detection. • Energy and position position sensitive detectors.sensitive detectors.• Radioactive ion beams.Radioactive ion beams.
Counts number
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
Use SRIMData to
reproduce the
graphs.
Energy deposited in an Energy deposited in an absorber (or detector).absorber (or detector).
Or, if “thin” absorber:Or, if “thin” absorber:
Both are not accurate. Both are not accurate. Why?Why?You can do it better with You can do it better with SRIM.SRIM.
tdx
dEE
ave
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
E-E detection.
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
Stopping timeStopping time
Problem…!!
• Effect on Doppler shift and broadening in nuclear reactions.
Compare the application of scaling laws and Bragg-Kleeman rule with SRIM.Work out many examples.
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
Fast Electron Interactions.Fast Electron Interactions.
• CollisionalCollisional
• Radiative (Bremsstrahlung)Radiative (Bremsstrahlung)
What is the main difference for positrons?
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
Range .. !
Ra
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x d
ens
ity
Mon
oene
rget
ic
What about electrons?
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
nteI
I 0
Radiation Detection and Measurement, JU, 1st Semester, 2008-2009 (Saed Dababneh).
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Charged Particle Interactions - Detection
BackscatteringBackscattering
Fra
ctio
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ack
sca
ttere
d• Detector entrance window or dead layer.• Source backing.