Particles and Radiation
- Created by: henry freston
- Created on: 04-03-15 15:17
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- Particles and Radiaton
- Constituents of the atom
- Proton: Relative- Charge= +1 Mass= 1 Actual: Charge= 1.6x10^-19 Mass= 1.67x10^-27
- Electron: Relative- Charge= -1 Mass= 0.0005 Actual- Charge= -1.6x10^-19C Mass= 9.11x10^-31
- Key Facts: - An atom has a diameter of ~1x10^-10m -The proton and neuton are 2000x the size of the electron -Most of an atom is empty space
- Strong Nuclear Force
- The primary force holding together the constituents of the atom- it stops the nucleus from disentigratiing
- It holds the protons and neutrons together
- Overcomes the electrostatic force between the protons in the nucleus
- Has a range of 3-4 femtometres (x10^-15) and it only has an attractive force down to o.5fm (below this distance it acts as a repulsive force to prevent protons and neutrons being pushed into eachother
- Radioactive Decay
- Alpha Decay: Nucleon number decreases by 4 and Atomic number decreases by 2 and an alpha particle is emitted
- Beta Radiation: A neutron changes to a proton. The nucleon number increases by 1. An anti neutron is emitted.
- Gamma Radiation: Electromagnetic radiation emitted by and unstable nucleus. Can pass through thick metals. Emitted by a nucleus with too much energy after an alpha or beta emission.
- Particles and Antiparticles
- Particle annihilation: A particle and it's corresponding antiparticle collide. Momentum and energy must be conserved and because the two particles have opposite quantum numbers, their mass gets converted into photons
- Pair production: Opposite of Particle annihilation. A photon with sufficient energy suddenly changes into a particle and its antiparticle.
- Particle interactions
- Weak nuclear force: Responsible for radioactive decay. For example it causes a proton to change into a neutron
- Electron Capture: a proton rich nuclide absorbs and inner atomic electron, changing a proton to a neutron
- Primary decay for istopes
- Occurs when a nucleus does not have sufficient energy to decay by positron emission
- An X-ray photon is also emitted because the nucleus is in an excited state until the electron is replaced by an outer electron
- Classificaton of particles
- Leptons
- Fubdamental particles
- Interact using weak force but if charged will interact via gravitational and electronmagnetic
- Electrons, Muons and Taus
- Muons and Taus are very unstable and eventually decay into electrons
- Each lepton has a neutrino. These have almost zero mass and zero charge
- Antileptons: each lepton and neutrino has an antiparticle with opposite charge
- Lepton Number: Each lepton is given a lepton number +1 and antileptons -1
- Hadrons
- Strong Nuclear Force
- Made up of quarks (not fundamental particles)
- Baryons
- Neutrons + Protons (baryon no. = 1)
- All unstable with the exception of the proton and anti
- Antiprotons and antineutrons are antibaryons (baryon no. = -1)
- Baryon number must be conserved
- Mesons
- All are unstable
- Pions
- Lighter than Kaons
- More stable than Kaons
- Kaons
- Heavier than pions
- Less stable than pions
- interact with Baryons via strong nuclear force
- Leptons
- Quarks
- Up, Down and strange
- Fundamental particles that make up baryons
- Constituents of the atom
- Neutron: Relative- Charge= 0 Mass= 1 Actual- Charge= 0 Mass= 1.67x10^-27
- Constituents of the atom
- Proton: Relative- Charge= +1 Mass= 1 Actual: Charge= 1.6x10^-19 Mass= 1.67x10^-27
- Electron: Relative- Charge= -1 Mass= 0.0005 Actual- Charge= -1.6x10^-19C Mass= 9.11x10^-31
- Key Facts: - An atom has a diameter of ~1x10^-10m -The proton and neuton are 2000x the size of the electron -Most of an atom is empty space
- Constituents of the atom
- Electron Capture: a proton rich nuclide absorbs and inner atomic electron, changing a proton to a neutron
- Primary decay for istopes
- Occurs when a nucleus does not have sufficient energy to decay by positron emission
- An X-ray photon is also emitted because the nucleus is in an excited state until the electron is replaced by an outer electron
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