Fundamentals of Radiation

The process of emission of radiation or particles

Atomic Model (Main Particles)Nucleus (Nucleons)Proton, p, positive chargemass = 1.67262x10-27 kgNeutron, n, no chargemass = 1.67929x10-27 kgElectron Shell/CloudElectron, e, negative chargemass = 9.10939x10-31 kg

Atomic (Bohr) Model

Other Basic ParticlesPhotonElectromagnetic waveNo mass or chargeNeutrino (Antineutrino)No mass or chargeAppears during decay of certain nucleiMany more that Physicists like

Atomic DefinitionsAtomic Number, ZNumber of Protons/ElectronsAtomic Mass Number, ATotal Number of NucleonsAtomic WeightMass of a Neutral Atom Relative to the Mass of 12CElementNuclide with Unique Atomic NumberIsotopesNuclides with Same Atomic Number but Different Atomic Mass Numbers

Common Isotopeshttp://www.eccentrix.com/

Atomic DefinitionsIsotope Identification or X-A ActivityNumber of disintegrations (decays) per unit timeHalf-LifeTime for half of the material to decay away

Radiation Decay

Radiation UnitsBecquerel, BqOne disintegration per secondRate at which radiation of some type is emitted from a collection of isotopes Curie, Ci3.7x1010 BqAmount of radiation emitted from 1 g of Ra-226

Common Radioactive DecayAlpha, a++Helium Nucleus (4 n, 2 p)Captures 2 eBeta, b-ElectronPositron, b+Gamma, gPhoton

Atomic Stability CurveAlpha DecayBeta DecayPositron Decay

Decay Chains

3 Things to Reduce RadiationDistanceShieldingTime

Distance: Inverse Square Law

Visualizing Distance

Shielding: Attenuationm is a function of radiation energy and shielding material

Shielding Radiation

Visualizing Shielding

Time: Duration of Exposure

Common RadioisotopesCarbon-14, Organic MaterialPotassium-40, BananasTechnetium-99, Medical DiagnosisCesium-137, Industrial GaugesLead-210, GroundRadium-226,-228, Brazil NutsUranium-234,-235,-238, GroundThorium-232, GroundPlutonium-238, PacemakersAmericium-241, Smoke Detectors

Examples and Problems 1.2Pumped Storage Scheme:Reservoir Containing 6.7 million m3 H2O 500 m above the Lower ReservoirCan Supply 1800 MWeAssume No LossesHow Long Can the Plant Remain in Operation?

Examples and Problems 1.2SolutionFind the Total Potential EnergyMass = Volume * Density r = 1000 kg/m3, m = 6.7x109 kgPE = Mass * Height * Gravity (9.81 m/s2)PE = 32.8x1013 JOperational Time = PE/PowerOT = 5 hours

Examples and Problems 1.2Other Problems using Same EquationsWhat is the Volume of the Upper Reservoir for a Set Power Supply and Operational Time?Account for Additional Power Losses using Efficiency TermsCompare Reservoir Sizes and Heights for Desired Power RatingsAdditional AnalysisEnergy Costs to Fill Upper Reservoir versus Revenue Generated from Energy Produced

Radiation Decay ExampleIf you had a vial containing 9x1012 Bq each of carbon-14 and Bq of tritium, what would the activity be 100 years later? How many grams of each would be in the container?(The isotopes decay into nitrogen-14 and helium-3, respectively)

Radiation Decay Example

IsotopeA(100y)N(100y)m(100y)3H3.2x1010 Bq5.7x1011 atoms2.8 pg14C8.9x1012 Bq7.4x1016 atoms1.5 mg