1. THE NUCLEUS OF THE ATOM

2. Components of the Atomic Nucleus
Protons
Neutrons and Isotopes
Radioactivity
Development of Nuclear Weapons
Nuclear Energy
Particle Physics
Standard Model
Four Fundamental Froces

3. Potential Energy of any Body of Mass

4. The Proton Rest Mass =1.007276466812awu
Average Lifetime ≥2.1X1029 years
Discovered, described, and named by Ernest Rutherford over a three-year period ( )

5. James Chadwick Student of Rutherford
Designed an experiment with Polonium and Beryllium target. Detected an uncharged form of radiation that had a mass approximately equal to the proton.
He called it the neutron.
; Britain

6. The Neutron Rest Mass =1.0086649160043awu
Average Lifetime = sec
Chadwick’s experimental design

7. Isotopes
Following the discovery of neutrons, the disagreement between atomic number and atomic mass for the elements became clear.
Also, the disagreement between different forms of the same element could be explained.

8. Antoine Henri Becquerel
Discovered penetrating radiation by uranium salts that exposed photographic plates in the absence of visible light.
Reported in 1896.
; France

9. Marie & Pierre Curie
Following report of invisible radiation, Pierre and Marie worked on characterizing the radiation and finding other radioactive elements (e.g. Radium).
Maria (Marie) Salomea Sklodowska-Curie;
; Poland and France
Pierre Curie; ; France

10. Types of Radiation
Paper
Aluminum
Lead M

11. Alpha Radiation (α-decay)
Discovered and named by Rutherford
Reduces the atomic number by 2 and atomic mass by 4
Equivalent to a helium nucleus

12. Beta Radiation (β-decay)
Discovered by Becquerel and named by Rutherford
Neutron decays to a proton, an electron, an electron neutrino
Initiated in the nucleus by neutron spontaneously changing to proton (mediated by the weak nuclear force)

13. Gamma Radiation (γ-decay)
Discovered by Villard and named by Rutherford
Type of photon – high energy x-ray with frequency >1019 Hz
Potassium-40 good source
γ-decay in association with α and/or β decay

14. Half-Life Probabilistic nature Exponential decay
Rutherford suggested it as a way to date minerals.

15. Radiometric Dating Based on two decay sequences:
238U to 206Pb (half-life 700 million years)
235U to 207Pb (half-life 4.5 billion years)
Usually taken from very stable zircon crystals

16. Decay Chains

17. Controlled Nuclear Fission
Friedrich Wilhelm ‘Fritz’ Strassman
; Germany
Otto Hahn
; Germany
Lise Meitner
; Austria, Germany
Sweden, UK

18. Leo Szilard
Tuesday, September 12, The stoplight changed to green. Szilárd stepped off the curb. As he crossed the street time cracked open before him and he saw a way to the future, death into the world and all our woes, the shape of things to come. (Rhodes 1986)
; Hungary and USA

19. Pile-1; University of Chicago 2 December 1942
Enrico Fermi
Began to bombard elements with neutrons and transmutated them into different elements
In USA built first reactor to create a sustained nuclear reaction
Developed theory of β-decay
; Italy and USA
Pile-1; University of Chicago 2 December 1942

20. Letter to FDR

21. The Manhattan Project

22. Little Boy, The Uranium Bomb

23. Fat Man, The Plutonium Bomb
Plutonium bred from U-238 in reactors at Hanford, WA
At Trinity Test Site
Left: J. Robert Oppenheimer, scientific leader of Los Alamos
Right: Gen. Leslie Groves

24. The Only Uses of Atomic Devices in War
Little Boy at Hiroshima,
6 August 1945
Yield: 16 kt
Casualties: >90,000 dead
Fat Man at Nagasaki,
9 August 1945
Yield: 21 kt
Casualties: >60,000 dead

25. The Cold War and Destruction Unlimited
10.4mt
MIKE
1952
Edward Teller ( )
Hungary and USA
W-88
Warhead
For Trident II missiles
475kt

26. Nuclear Energy

27. Accidents TMI unit 2 28 March 1979 Chernobyl 26 April 1986
Fukushima-1 11 March 2011

28. Accelerators Tevatron at Fermilab, near Chicago
Large Hadron Collider, CERN
Appearance of the spray of subatomic particles from a high energy collision

29. The Standard Model of Particle Physics

30. The Four Fundamental Forces of Nature
Strong Nuclear Force: short range but very strong in attracting quarks (exchange of gluons changes color) within hadrons (e.g. protons and neutrons)
Weak Nuclear Force: short range and weaker than all forces except gravity. Exchange of W and Z bosons between quarks changes their flavor (e.g. U or D).
Electromagnetic Force: long distance and obeys inverse square law. Photons carry force which is exchanged between leptons.
Gravitational Force: long distance and obeys inverse square law. Gravitons attract all particles that have mass.

31. Strong Nuclear Force ~100X stronger than EM force u = +2/3
Binds hadrons (protons & neutrons) in nucleus
Binds quarks to form hadrons
u = +2/3
d = -1/3
Gauge particle is gluon

32. Weak Nuclear Force Reprise β-decay with quarks and W- boson
Results of weak nuclear interactions
Radioactive decay
Beta decay
Burning of sun
Initiating the process of hydrogen fusion in stars.
Production of deuterium
Formation of other heavy nuclei
Radiocarbon dating
W & Z bosons ~100 times as massive as a proton

33. Antimatter
Every particle has an anti-particle (e.g. electron vs. positron)
Electron-positron annihilation yields gamma radiation