Particles and radiation

Particles and radiation

1. Particles and anti-particles

   • Nucleon
     • Proton
       • Charge: 1.6 x 10^-19 Mass: 1.67 x 10^-27
     • Nuetron
       • Charge: 0 Mass: 9.11 x 10^-31
     • Antiproton
       • Charge: -1.6 x 10^-19 Mass: 1.67 x 10^-27
     • Antineutrino
       • Charge: 0 Mass: 9.11 x 10^-31
   • Have opposite charge
   • same mass and energy
   • • Electron
     • Positron

2. Isotope

   • DIFFERENT number of NUETRONS
   • SAME number of PROTONS
   • Unstable nuclei
     • Decay
   • Isotopic data- the amount of different isotopes of an element present in a substance
   • Used for carbon dating as the half life of carbon 14 can indicate the age

3. Alpha decay

   • Strong nuclear force cannot keep big atoms stable
   • Alpha particle emitted
   • Nucleon number decreases by 4 as 2 protons and 2 nuetrons lots
     • Nuetron number decreases by 2
     • Proton number decreases by 2

4. Beta minus decay

   • Emission of electron and antineutrino
   • Happens in neutron rich isotopes
   • Beta particle emitted (electron) and neutron becomes a proton
     • Hence proton number decreases
     • Nucleon number stays the same as neutron is lost but proton is gained
   • Caused by weak intereaction

5. Hypothesis - Neutrino

   • Energy appeared to have been lost does not fit with conservation laws
     • Must be more than electron emitted
       • Neutral (conserve charge)
       • zero or almost zero mass (as not detected)

6. Pair production

   • Mass converts to energy
   • Energy converts to mass
     • Produces matter and antimatter
       • Due to conservation laws
         • Annihilation
           • Mass is converted back to energy
             • In form of two gamma ray particles
   • Needs enough energy to produce masses called total rest energy
     • Min energy=2 x rest energy of particle

7. Forces

   • Nucleons
     • Electromagnetic force
       • Protons repel each other
       • extends over larger range
     • Gravitational force
       • Nucleons are attracted to each other due to their mass
     • Strong nuclear force
       • Keeps nucleus together because if it was only electromagnetic or gravitational
       • Attractive force
       • The range
         • repulsive at less than 0.5 fm
           • Bigger than 0.5fm it becomes attractive force
             • Maximum attractive value, at about 3fm
               • Then it drops to 0fm

8. Hadrons and leptons

   • Hadrons affected by strong force
     • Non-fundamental particles
       • Baryons
         • Neutrons
         • Protons
         • Antibaryons
           • Antiproton
           • Antineutrino
         • Must be conserved to exist
       • Mesons
         • Pions
           • Exchange particles of the strong force
           • Lighter
         • Kaons
           • Unstable and heavier also have short lifetime and decay into pions
   • Lepton
     • Fundamental particles
       • Electron
       • Muon
       • Electron neutrino
       • Muon neutrino

9. Strangeness

   • CREATED via STRONG force (strangeness conserved)
   • Strange particles can only be created in pairs
   • DECAY through WEAK force

10. Conservation laws

    • Energy and momentum ALWAYS conserved in particle INTEREACTION
    • Baryon number
      • ALWAYS
    • Charge
      • ALWAYS
    • Lepton number
      • electron and muon numbers conserved seperately
        • Insert table stating electron and muon lepton number
    • Strangeness
      • ONLY conserved for strong intereactions
      • Sometimes in weak intereaction
        • Beta decay

11. Quarks and antiquarks

    • Baryon
      • two types of quarks up and down
      • particle
        • Proton
        • Neutron
        • Made up of three quarks
      • anti partcile
        • Anti proton
        • Antineutrino
        • Made up of three antiquark
    • Insert table for quarks
    • Insert table for anti quarks
    • Mesons
      • Insert diagram

12. Particle Intereaction

    • All forces caused by particle exchange
      • Attraction
        • The two particles have an exchange particle which acts similar to a lasso or a boomerang forcing them towards each other
      • Repulsion
        • Exchange takes place between two particles which carriers momentum causing them to move apart
        • Electrostatic repulsion
          • Virtual photons
      • Virtual particles- short lifespan exist long enough to transfer energy, momentum etc.
      • Insert table
    • Feynman diagrams
      • Electromagnetic repulsion
      • Electron-proton collision
      • Electron capture
      • Beta minus/plus decay

13. Photon

    • E=hf
      • E= Energy of one photon (J)
      • H= Planck's constant
      • F= Frequency of light (Hz)
    • Black body radiation investigation