Radiation Basics

The following FAQs have been developed by our topic editors for this category:

  HPS FAQ   How Can You Work Safely Around Radiation?
  HPS FAQ   Radiation Basics
  HPS FAQ   Radiation Dose Units
  HPS FAQ   Radioactivity Units
  HPS FAQ   Relationship Between Radionuclide Gamma Emission and Exposure Rate
  HPS FAQ   What Is Dose? What Units Are Used for Dose?
  HPS FAQ   What Is Radiation?
  HPS FAQ   What Is Radioactive Contamination?
  HPS FAQ   What Types of Radiation Are There?
  HPS FAQ   Where Do Atoms Go When They Decay?

The following HPS Web pages also address this category:

  PDF   ATE SI Conversion Chart
  HTML page   Radiation Terms
  PDF   Shielding of Gamma Radiation

The following health physics questions have been answered by an expert and approved by our editors for inclusion in our "Ask the Experts" feature. Click on the question to see the answer.

Questions in this Category Are in the Following Subcategories:
  •  Beta Particles (negative and positive) and Electrons
  •  Fission, Fusion
  •  Interaction Coefficients
  •  Neutrons
  •  Photons
  •  Radionuclides
  •  Radiation Quantities and Units
  •  Radiation Shielding
  •  Radiation Effects
  •  Miscellaneous
Beta Particles (negative and positive) and Electrons
Q7770   –   Is this beta radiation or bremsstrahlung from this strontium-90 source?
Q9260   –   Where can I find tables of beta emitters by maximum beta energy?
Q9707   –   Difference between mean range and max range
Fission, Fusion
Q10097   –   Why are cesium-137, strontium-90, and iodine-131 the fission products that get most talked about when many more fission products are produced in reactors?
Interaction Coefficients
Q8659   –   Why does the attenuation coefficient change with field size?
Q8192   –   Neutron decay and residual activity from nuclear bomb
Q8216   –   Am I receiving dose from this Pu-Be source?
Q8536   –   How do I obtain neutron attenuation cross sections?
Q9869   –   How do I calculate dose from this Pu-Be source?”
Q4817   –   Average gamma energy of Ra-226
Q7385   –   Current gamma ray dose constants
Q9016   –   Are these hard or soft x rays from this RF generator?
Q9118   –   Does positron kinetic energy go to annihilation photons?
Q10388   –   Are these very low energy photons really producing this notable increase in exposure rate?
Q10579   –   How do these multiple x-ray energies originate?
Q11545   –   Why don't I get expected results using the Rad Pro Calculator?
Q11989   –   Is the gamma-ray dose-rate constant defined for water, and how does one account for attenuation?
Q8270   –   How does one obtain the half-life for long-lived radionuclides?
Q8820   –   How can activity increase with radioactive decay?
Q9852   –   Exposure from technetium-99
Q11530   –   Beta and gamma emissions from 232Th progeny decay
Q11727   –   Products for cleaning up radioactive iodine
Radiation Quantities and Units
Q7868   –   Is effective dose a practical quantity in operational health physics?
Q10010   –   Why is the term stopping power being used for photons?
Q11309   –   Is it REM or rem?
Q11491   –   How may I adjust ICRP Publication 72 dose conversion factors for insoluble plutonium oxide?
Radiation Shielding
Q8135   –   How do I determine HVL for brass?
Q8929   –   Depleted uranium as shielding
Q9724   –   What boron-based buffer is available for neutron shielding?
Q11377   –   Characteristic x rays from interactions in leaded gloves
Q11704   –   Could an old lead pig be contaminated?
Radiation Effects
Q10942   –   Radiation sensitivity of women vs. men
Q11569   –   Risks from Carbon-11
Q12014   –   Fate of radiation after it interacts with shielding material
Q7283   –   How do I interpret these radon concentration numbers from early hot springs measurements?
Q7434   –   Radionuclide abundance, branching fraction, and radiation yield
Q7462   –   Why liquid, solid, or gaseous targets for cyclotron radionuclide production?
Q7613   –   X-ray energy deposited, energy fluence, and dose in silicon
Q7843   –   Alterations of a radionuclide's half-life
Q7878   –   Convert mass concentration in soil to area concentration
Q7923   –   Can nonionizing radiation be converted to ionizing radiation?
Q8340   –   How much dose might I be getting from this x-ray diffraction unit?
Q8344   –   What is the effect of kVp on x-ray intensity?
Q8353   –   Preparation of aqueous radionuclide standard
Q8542   –   When and why are high doses expressed as absorbed doses?
Q8671   –   Are these GM readings from uranium metal realistic?
Q8724   –   What is the effective atomic number of glass fiber filter?
Q8966   –   What weighting factor is used in converting organ dose to effective dose?
Q8974   –   Health physics concerns with nanoparticles
Q9281   –   How long before radium reaches equilibrium with uranium in plant leaves?
Q9291   –   Is this well water with uranium safe to drink?
Q9399   –   Ionization from lightning, Tesla coils, gamma rays, and x rays
Q9434   –   Why are photons and neutrons described as indirectly ionizing?
Q9498   –   Methods to track transport of particles in the environment and in the body
Q9503   –   Is it appropriate to project cancer risk for background exposure?
Q9635   –   What is the source of the gamma emission from this Po-210 source?
Q9646   –   Why is energy released in decay so important?
Q9658   –   How much ionization would this gamma ray yield in a cell?
Q9678   –   Do levels of radioactivity in the United States follow the levels being released from the Japanese reactor site?
Q9715   –   Should I be concerned with rain water contaminated with Fukushima radioactivity?
Q9723   –   What is the concrete TVL for thallium-201?
Q9776   –   Are radioactive lightning rods a potential contamination hazard?
Q9782   –   Explain why adult and child doses from CT scans differ
Q9800   –   Why does NRPB ImPact software require NRPB SR-250 organ dose data?
Q9828   –   How to determine dimensions or shielding for storage room for Troxler gauges.
Q9832   –   How do I evaluate risks from inhalation exposures?
Q9866   –   Why do we use both distance and attenuation to calculate reduction in photon dose rate?
Q9921   –   What are the requirements for using the radiation warning symbol?
Q10176   –   Are knock-on ions produced by radiation interactions a hazard?
Q10341   –   What is the significance of half-life in radiation control?
Q10370   –   How much of a lead equivalent is 3/8-inch tempered glass?
Q10372   –   How should I evaluate natural radionuclides in water, and how do I determine doses from exposures?”
Q10396   –   Is stainless steel acceptable for this laboratory sink?
Q10438   –   Concern with radium plateout on walls of water cleanup pressure vessel
Q10463   –   Release of iodine from charcoal cleanup systems
Q10781   –   Are skin dose and eye dose part of effective dose?
Q10795   –   Can we transform these radioactive atoms to stable atoms?
Q10976   –   How long a line segment should I select to simulate a very long line source?
Q11321   –   Concern with exposure from this Cs-137/Ba-137m generator
Q11517   –   Can I use dose to calculate activity?
Q11547   –   Determining secular equilibrium in radium-226 sample
Q11637   –   Effect of diseases on organ radioactivity
Q12008   –   Can electricity deactivate radioactive atoms?
Q12012   –   What is the fate of alpha particles and beta particles after they are emitted by nuclei?

The following websites may also be useful:

  External website   Basics about Radiation – Radiation Effects Research Foundation
  External website   Commonly Encountered Radionuclides – U.S. Environmental Protection Agency
  External website   Definitions and Units – Oak Ridge Associated Universities
  External website   Ionizing Radiation – Occupational Safety and Health Administration
  External website   National Nuclear Data Center – Brookhaven National Laboratory
  External website   Radiation and Radioactivity – The University of Michigan
  External website   Radiation Emergencies – Centers for Disease Control and Prevention
  External website   Radiation Related FAQs – Idaho State University
  External website   Radiation Shielding Textbook – J. Kenneth Shultis and Richard E. Faw
  External website   Radiation Terminology – The University of Michigan
  External website   Radiation, Radioactivity and Risk Assessment Poster
  External website   Radiation: Non-Ionizing and Ionizing – U.S. Environmental Protection Agency
  External website   Radioactive Isotopes – Lawrence Berkeley National Laboratory
  External website   Risks from Low Levels of Ionising Radiation – Public Health England