辐射安全常识.ppt
《辐射安全常识.ppt》由会员分享,可在线阅读,更多相关《辐射安全常识.ppt(45页珍藏版)》请在三一文库上搜索。
1、,Principles of Radiation,Industrial Studies 4020 Topics in Industrial Studies Environmental Safety Management,Atomic number Atomic mass Number of Protons ONLY Number of Protons & Neutrons (weight),C,14,12,Chemical Symbol,Atomic Mass,Atomic Number,Review,So, what is it ?,H,3,Hydrogen 3 contains one p
2、roton + two neutrons. Its a radioactive isotope of hydrogen also known as tritium,Isotopes,Same number of protons; different number of neutrons Same chemical properties Different nuclear properties,Hydrogen 1 Proton,Deuterium 1 Proton, 1 Neutron,* Tritium 1 Proton, 2 Neutrons,H,1,1,* Note: Tritium i
3、s Radioactive,H,H,2,1,3,1,Radioactivity,Atoms with too many neutrons or protons are unstable and emit energy to become more stable. Energy is carried away by a- / b-particle or x- / g-ray. These atoms are called radioactive and the process is called radioactive decay,Radioactivity,Natural Uranium Th
4、orium Potassium-40 Carbon-14 (C-14) Hydrogen-3 (H-3) (tritium),Man made Phosphorus-32 (P-32) Sulfur-35 (S-35) Calcium-45 (Ca-45) Chromium-51 (Cr-51) Zinc-65 (Zn-65) Rubidium-86 (Rb-86) Iodine-125 (I-125),Background Radiation,mrem/yr Cosmic 27 Terrestrial 28 Inhaled 200 Internal 39 Man-made 63 Total:
5、 357,Radiation,Microwave light bulb cell phone UV lamp radio / TV laser heat lamp x-rays,Emission / propagation of energy through space or material medium as waves or particles,Ionizing Radiation,Alpha Particles,2 Protons + 2 Neutrons Short Range in Air Not an External Hazard Internal Hazard,Beta Pa
6、rticles,Negligible Mass Long Range in Air Internal/External Hazard Charged,Gamma Rays/Photons,Gamma photons & X-Ray both electromagnetic differ only by place of origin No mass or charge Highly-penetrating,Neutrons,Very Long Range Very Penetrating Difficult to detect,Other modes of Decay,Positron emi
7、ssion Electron capture Fission Electron,Activity,Decay is a statistical process. Cannot predict when a particular atom will decay. Can predict when certain amount (%) will have decayed.,Units of Activity,Curie (Ci) 1 Ci = 37,000,000,000 dps (3.7 x 1010 dps) or 1 Ci = 2.22 x 1012 dpm Becquerel (Bq) 1
8、 Bq = 1 dps 1 Ci = 37,000,000,000 Bq = 37 GBq (Giga Becquerel),Quantities & Units,Beta and gamma radiation about equally damaging: 1 R = 1 rad = 1 rem Alpha radiation causes greater cellular damage 1 rad of a = 20 rem,Decay Rate,Half-life, A= A0 e 0.693t/T A = A0 ()# of half-lives,Non-Ionizing Radia
9、tion,Questions?,Radiation Safety,Industrial Studies 4020 Topics in Industrial Studies Environmental Safety Management,Radiation Hazards,External Hazard (exposure from outside the body) High-energy beta (i.e., energy 300 keV or 0.3 MeV) Gamma and X-rays Neutrons Internal Hazard Radioactive material e
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 辐射 安全 常识
链接地址:https://www.31doc.com/p-3151102.html