Lecture 5
Experimental Nuclear Physics
PHYS 741
Text
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References and Figures from:
- Basdevant et al., “Fundamentals in Nuclear Physics”
- Henley et al., “Subatomic Physics”
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From Rutherford to Neutrino Coherent Scattering
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Rutherford
• identified nucleus
• demonstrated scattering off nucleus (versus
electrons surrounding nucleus)
• measured nuclear radii
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Coherent Neutrino Nucleus Scattering
•
process at low energies, low momentum transfer
•
due to small momentum transfer neutrino interacts simultaneously
with all nucleons in nucleus -> amplitudes of wavefunctions are in
phase and add up coherently
•
CNNS cross-section very large but small momentum transfer makes it
very hard to detect
> CNNS can probe
physics beyond the
standard model
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A Slice of Matter - Classical View
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A Simplified by Typical Cross-Section Measurement
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Examples of Cross-Section
Which one of these cross-sections
is affected by Coulomb barrier?
cross-section
Energy
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Examples of Cross-Section
exothermic (n,γ) and (n,t) have
1/v dependence
(p,γ) suppressed at low E
because of Coulomb barrier
6Li(n,p)
has energy threshold
excited state of Li appears as a
resonance in n7Li elastic
scattering and in 6Li(n,t)
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Energy Levels of 7Li
resonance in 4th
excited state
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Elastic Scattering
of Neutrons
for low momenta:
> isotropic
for high momenta:
> angular distribution like
diffraction of disk R
anything surprising?
backward scattering from
exchange of charged pions
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Fragmentation and Fission
fragmentation
of 129Xe on 27Al
collission induced fission
of 238U on a Pb target
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Quark Gluon Plasma
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Quark Gluon Plasma
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Photodissociation
Eth=2.2 MeV
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giant resonance typical of
heavy nuclei
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Scattering in Repulsive Force
b = impact parameter
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Non-Relativistic Particles in Yukawa Potential
classical calculation
particle penetration to
about r0/10
Yukawa=solid line
Coulomb=dashed line
for b< r0
potential give nearly
same result
for b >>r0
Yukawa scattering less
than Coulomb scattering
because.... ?
Yukawa force drops much faster with distance
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Rutherford
1911
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