Chapter 2. Radiation 1. Radioactivity 2. Radiation interaction with matter 3. Radiation doses and hazard assessment
Chapter 2. Radiation 1.Radioactivity 2.Radiation interaction with Matter 3.Radiation Doses and hazard Assessment
2. 1 Radioactivit 1)Overview 2) Types of radioactive decay 3) Energetics of Radioactive Decay 4)Characteristics of Radioactive decay 5)Decay Dynamics 6) Naturally occurring Radionuclides
1) Overview 2) Types of Radioactive Decay 3) Energetics of Radioactive Decay 4) Characteristics of Radioactive Decay 5) Decay Dynamics 6) Naturally Occurring Radionuclides 2.1 Radioactivity
1)Overview Radioactive nuclei and their radiations have properties that are the basis of many of the ideas and techniques of atomic and nuclear physics 40 K
1) Overview Radioactive nuclei and their radiations have properties that are the basis of many of the ideas and techniques of atomic and nuclear physics. 40K
Radioactivity in Nature T1 pb Bi Po At Rn Fr 56 241d1.2min25 6/222Rn Is responsible for higher levels of background radiation in 226 1620 226 many parts of the world 38d 222 because it is a gas and Radon 218 can easily seep out of the earth into unfinished 27 min 20 min 164 214 basements and then into the house 3min 22 y 5d 138d 210 table 206 Z(Atomic Number) The uranium decay series
The uranium decay series. 222Rn is responsible for higher levels of background radiation in many parts of the world. because it is a gas and can easily seep out of the earth into unfinished basements and then into the house Radioactivity in Nature Radon
1)Overview Radioactive Decays transmutations of nuclides Radioactivity means the emission of alpha(a) particles, beta(B)particles, or gamma photons n) etc from atomic nuclei. The term radioactivity was actually coined by Marie Curie Radioactive decay is a process by which the nuclei of a nuclide emitα,βorγ rays etc In the radioactive process, the nuclide undergoes a transmutation, converting to another nuclide
5 Radioactive Decays transmutations of nuclides Radioactivity means the emission of alpha () particles, beta () particles, or gamma photons () etc. from atomic nuclei. The term radioactivity was actually coined by Marie Curie Radioactive decay is a process by which the nuclei of a nuclide emit , or rays etc. In the radioactive process, the nuclide undergoes a transmutation, converting to another nuclide. 1) Overview
Conservation of charge Conservation of the number of nucleons a Conservation of mass/energy (total energy) Conservation of linear momentum Conservation of angular momentum
Conservation of charge Conservation of the number of nucleons A Conservation of mass/energy (total energy) Conservation of linear momentum Conservation of angular momentum
2) Types of radioactive Decay Decay Type Reaction Description gamma(x) AP*- AP+y An excited nucleus decays to its ground state by the emission of a gamma photon alpha(a P A-4D+a An a particle is emitted leaving the daughter with 2 fewer neutrons and 2 fewer protons than the parent negatron(B-) 2P-2+AD+8-+D A neutron in the nucleus changes to a proton. An electron(6-)and an anti-neutrino(v)are emitted positron(+)分P→→z4D+B++ a proton in the nucleus changes into a neutron. A positron(B+)and a neutrino(v) are emitted
2) Types of Radioactive Decay
electron P+e--zAD"+y An orbital electron is absorbed by the capture(EC) nucleus, converts a nuclear proton into a neutron and a neutrino(v), and generally, leaves the nucleus in an excited state proton(p)2P→→ A-lD+p A nuclear proton is ejected from the nucleus neutron(n) P D+n A nuclear neutron is ejected from the nucleus internal con P*-+[ZP]++e- The excitation energy of a nucleus is version(IC) used to eject an orbital electron (usually a K-shell)electron
Photographic ate Magnetic Field T P XXXX XXXX Collimator Radioactive Element Apparatus similar to that used by henri becquerel to determine the magnetic deflection of radioactive decay products. The magnetic field is perpendicular to the direction of motion of the decay products
Apparatus similar to that used by Henri Becquerel to determine the magnetic deflection of radioactive decay products. The magnetic field is perpendicular to the direction of motion of the decay products
3 Energetics of radioactive decay The law of conservation of mass and energy covers all reactions Sum of mass before reaction Sum of mass after reaction +Q Q= Sum of mass before reaction- Sum of mass after reaction Energy in Radioactive Dec Before decay Interesting Items Spectrum(能谱) of particles Energy in gamma decay Energy in beta decay Energy in alpha decay Recoiling nucleus
The law of conservation of mass and energy covers all reactions. Sum of mass before reaction = Sum of mass after reaction + Q Q = Sum of mass before reaction - Sum of mass after reaction Energy in Radioactive Decay Before decay Recoiling nucleus Interesting Items: Spectrum（能谱） of particles Energy in gamma decay Energy in beta decay Energy in alpha decay 3) Energetics of Radioactive Decay