1. ? Nuclear Reactions Categorization of Nuclear Reactions
According to: bombarding particle, bombarding energy, target, reaction product, reaction mechanism.
Bombarding particle:
Charged particle reactions. [ (p,n) (p,) (,) heavy ion reactions ].
Neutron reactions. [ (n,) (n,p) ….. ].
Photonuclear reactions. [ (,n) (,p) … ].
Electron induced reactions………….
Bombarding energy:
Thermal.
Epithermal.
Slow.
Fast.
Low energy charged particles.
High energy charged particles. ?
Neutrons.
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).

2. Nuclear Reactions Pickup Resonant Stripping Non-resonant Targets:
Light nuclei (A < 40).
Medium weight nuclei (40 < A < 150).
Heavy nuclei (A > 150).
Reaction products:
Scattering. Elastic 14N(p,p)14N
Inelastic 14N(p,p/)14N*
Radiative capture.
Fission and fusion.
Spallation.
…..
Reaction mechanism:
Direct reactions.
Compound nucleus reactions.
More in what follows ….
What is a transfer reaction….?????
Pickup
Resonant
Stripping
Non-resonant
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).

3. Reaction Cross Section(s) (Introduction)
Probability.
Projectile a will more probably hit target X if area is larger.
Classically:  = (Ra + RX)2.
Classical  = ??? (in b) 1H + 1H, 1H + 238U, 238U + 238U
Quantum mechanically:  =  2.
Coulomb and centrifugal barriers  energy dependence of .
Nature of force:
Strong: 15N(p,)12C  = 0.5 b at Ep = 2 MeV.
Electromagnetic: 3He(,)7Be  = 10-6 b at E = 2 MeV.
Weak: p(p,e+)D  = b at Ep = 2 MeV.
Experimental challenges to measure low X-sections..
HW 33
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).

4. Reaction Cross Section(s) (Introduction)
Detector for particle “b” d Ia
“b” particles / s
,
cm2
“X“ target Nuclei / cm2
“a” particles / s
Typical nucleus (R=6 fm): geometrical R2  1 b.
Typical : <b to >106 b.
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).

5. Reaction Cross Section(s) (Introduction)
Many different quantities are called
“cross section”.
Krane Table 11.1
Angular distribution
Units … !
“Differential” cross section
(,) or ( )
or “cross section” …!!
Doubly differential
t for all “b” particles.
Energy state in “Y”
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).

6. Nuclear and Radiation Physics, BAU, Second Semester,
Coulomb Scattering
Elastic or inelastic.
Elastic  Rutherford scattering.
At any distance:
V = 0
Ta = ½mvo2
l = mvob
vmin vo
rmin b d
Nuclear and Radiation Physics, BAU, Second Semester,
(Saed Dababneh).
No dependence on 

7. Coulomb Scattering
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).

8. Coulomb Scattering b   < b  >  db  d HW 34
n  target nuclei / cm3
x  target thickness (thin).
nx  target nuclei / cm2
HW 34
Show that
and hence b
Rutherford cross section
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).

9. Coulomb Scattering HW 35 Study Fig. 11.10 (a,b,c,d) in Krane
See also Fig in Krane.
HW 35
Show that the fraction of incident alpha particles scattered at backward angles from a 2 m gold foil is 7.48x10-5.
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).

10. Coulomb Scattering Elastic  Rutherford scattering.
Inelastic  Coulomb excitation.
See the corresponding alpha spectrum of Fig in Krane.
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).

11. Coulomb Scattering
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).

12. Nuclear Scattering Elastic or inelastic. Analogous to diffraction.
Alternating maxima and minima.
First maximum at
Minimum not at zero (sharp edge of the nucleus??)
Clear for neutrons.
Protons? High energy, large angles. Why?
Inelastic  Excited states, energy, X-section and spin-parity.
Nuclear and Radiation Physics, BAU, Second Semester, (Saed Dababneh).