1. Nuclear Size Depends on probe and relevant physics.
Different experiments give different results  Radius not well defined.
Depends on probe and relevant physics.
Probes should be close to the order of the size of the nucleus ~ m.
Visible light?  much larger.
1 MeV ?  = ?? x m. But interacts with orbital electrons.
Suitable probes: p, n, , e, X. Charge distribution. Mass distribution.
All experiments agree qualitatively and somehow quantitatively.
Project ….
R  A⅓ Why? In a while ……
R = r0 A⅓ with r0 dependent on the method.
Matter distribution  charge distribution. [Recently some halo
nuclei, e.g. 11Li, found]. What is that?
Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh).

2. Nuclear Size HW 4 HWc 3 Experiments show that
t = (2.4 ± 0.3) fm for all nuclei 
t/R  A-1/3
Is surface effect the same for all nuclei?
HWc 3
Compare for A = 4, 40, 120 and 235.
0 = nucleon density near the center.
t = “skin” thickness.
a = thickness parameter.
R = Half-density radius.
Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh).

3. Nuclear Size R = r0 A⅓ Why? 0 decreases with A? No Yes
High-energy e scattering
Constant  R  A⅓
Light nuclei?
From some experiments….!
Charge distribution: r0 = 1.07 fm. a = 0.55 fm.
Matter distribution: r0 = 1.25 fm. a = 0.65 fm.
R = r0 A⅓
Why?
Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh).

4. Nuclear Size 40Ca ….. ….. 59Co ….. ….. 115In ….. ….. 197Au ….. …..
HW 5
Nucleus Z/A Charge density
40Ca … …..
59Co … …..
115In … …..
197Au … …..
Charge radius ~ nuclear radius, even though heavy nuclei have more neutrons than protons. Explain…
Density of ordinary atomic matter ~ 103 kg/m3. Density of nuclear matter
~ 1017 kg/m3.
Neutron stars, 3 solar masses, only 10 km across ….. !!!
Surface effect?
Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh).

5. Short range of nuclear force
Nuclear Size
Three conclusions can be drawn:
Inside the nucleus the density is fairly uniform.
The transitional surface layer is thin.
The central density has a similar value for different nuclei.
Liquid Drop
Short range of nuclear force
Saturation?
Get an estimate for nuclear density and thus inter-nucleon distance.
Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh).

6. Nuclear Size HW 6 How can we get r0 from the graph?
1 Ci Pu-Be Neutron Source
Neutron
Detector
Absorber
Beam
From Optical Model
Dimensions
Different
targets
HW 6
How can we get r0 from the graph?
Preferably low 
Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh).

7. Nuclear Size Quite old!!! Not exactly for Au!!!
Alpha particle (+2e)
Gold nucleus (+79e) d
Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh).

8. Nuclear Size Closest approach “d”. E = ECoulomb  d = 2kZe2/E
What about the recoil nucleus?
HW 7 Show that
where mN : mass of the nucleus
m : mass of alpha
What are the values of d for 10, 20, 30 and 40 MeV  on Au?
How does this explain … ?
Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh).

9. Nuclear Shape
Crude Nucleons in the nucleus are confined to an approximately spherically symmetric structure  Nuclear radius.
Deformations…! Consequences….!!
Is there a sharp spherical wall…???!!!
HW 8
if it is assumed that the charge is uniformly spherically distributed in a nucleus, show that the electric potential energy of a proton is given by:
Nuclear and Radiation Physics, BAU, First Semester, (Saed Dababneh).