Radiation Fundamentals

This category covers the fundamentals of radiation, including:  the different types of radiation, radiation quantities and units, basic terminology, radiation doses and dose calculations, etc.

FAQs Developed by the HPS

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

  HPS FAQ   Hair Analysis for Uranium
  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?

Relevant HPS Web Pages

The following HPS Web pages also address this category:

  PDF   ATE SI Conversion Chart
  PDF   Depleted Uranium Fact Sheet
  HTML page   Half-Life
  PDF   Polonium-210 Fact Sheet
  HTML page   Radiation Terms
  PDF   Shielding of Gamma Radiation
  PDF   Uranium Fact Sheet
  PDF   Uranium Primer

Questions Answered by HPS Experts

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:
  •  Alpha Radiation
  •  Beta Particles (negative and positive) and Electrons
  •  Doses and Dose Calculations
  •  Fission, Fusion
  •  Interaction Coefficients
  •  Neutrons
  •  Photons
  •  Radionuclides
  •  Radiation Quantities and Units
  •  Radiation Shielding
  •  Radiation Effects
  •  Miscellaneous
Alpha Radiation
Q9290   –   Surface contamination monitoring
Q9903   –   Solubility of transuranics
Q10849   –   Thorium in plants
Q11029   –   U-238 in a cornerstone
Q12703   –   Possible thorium poisoning
Beta Particles (negative and positive) and Electrons
Q6240   –   How do positron and electron ranges compare?
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
Doses and Dose Calculations
Q4025   –   Dose and properties of irradiated material
Q11233   –   Calculation of dose from inhalation of thorium-232
Q11413   –   What tissue weighting factors should be applied to remainder tissues?
Q11416   –   Is there a valid relationship between LET and RBE?
Q11931   –   External whole-body counting vs. biological excreta measurements
Q12529   –   Urine output value per day for internal dose calculation
Q12633   –   Beta dose rates in air at various distances
Q12635   –   Why are there differences between internal dose conversion factors for the public and workers?
Q12869   –   Can a 50-y dose commitment be divided by 50 to give an annual rate?
Q12910   –   Considerations in correlating thorium bioassay measurements with intakes
Q13633   –   Lifetime dose limits for nonstochastic effects
Q13647   –   Does the use of effective dose provide an accurate assessment of dose?
Q13818   –   What is the dose from inhaled tritium gas leaked from this device?
Q13901   –   How do I reconcile the external dose rate from this contaminated food with expected internal dose?
Q13910   –   Will 100 million people gathered together all die from an eight-hour exposure to natural radiation?
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?
Q12136   –   Correlation of neutron dose rate with gamma dose rate from americium-241-Be source
Q12241   –   What activation products might come from neutron irradiation?
Q12454   –   Activation products from neutron therapy
Q13014   –   Will neutron exposure during air flight activate the cobalt in my metallic implant?
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?
Q12285   –   Factors affecting observed Compton scatter in materials
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
Q12732   –   Zirconium 95 clearance classes
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?
Q12078   –   Differences between ambient dose equivalent and equivalent dose
Q12211   –   Can Hp(10) be used to approximate the eye lens dose?
Q12522   –   How does kerma differ from absorbed dose?
Q12600   –   Free-in-air karma measurement
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?
Q12133   –   Neutron dose through shield penetrations
Q13036   –   Why are high mass, high atomic number materials used for shielding even though the mass attenuation coefficients are smaller for high atomic number than for low atomic number materials?
Q13068   –   Attenuation of beta radiation in protective eyewear
Q14101   –   Polyethylene shield for neutrons
Radiation Effects
Q10942   –   Radiation sensitivity of women vs. men
Q11569   –   Risks from Carbon-11
Q12014   –   Fate of radiation after it interacts with shielding material
Q13187   –   Indirect radiation effects and indirectly ionizing radiation
Q13412   –   Radiation effects on metals
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
Q8186   –   Radiation terms
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?
Q12291   –   Calculating TEDE/CEDE from exposure to tritiated water
Q12299   –   Leakage x rays from electron microscopes
Q12357   –   Does the amount of radioactivity in a human stay constant during a life span?
Q12404   –   Radionuclide retention and clearance
Q12413   –   How can I convert environmental equivalent dose rate H*(10) (mSv/hr) to effective dose rate (mSv/hr)?
Q12659   –   Fukushima fallout
Q12800   –   What is an appropriate gamma ray dose rate constant for radium?
Q12845   –   What fraction of electron energy is converted into bremsstrahlung?
Q12968   –   Does radiation exposure cause objects to become radioactive?
Q13002   –   How do I show no x rays are coming from this 70-80 GHz body scanner?
Q13119   –   Using radiation from radioactivity in waste sites to generate electricity
Q13183   –   What are biological half-lives for lead and radium?
Q13223   –   Why are acute doses characterized in grays rather than sieverts?
Q13249   –   Understanding tritium bioassay results
Q13388   –   Can you eliminate man-made radiation exposure?
Q13419   –   How should I evaluate dose rate from sulfur-35?
Q13456   –   Spontaneous fission of natural uranium in everyday objects
Q13504   –   Why don't the effective dose conversion factors in ICRP 116 have any assigned uncertainties?
Q13807   –   How can we justify using water as a replacement for tissue in dosimetry applications?
Q14107   –   Decay correcting a mock 131-I source
Q14246   –   Dependence of ICRP committed dose coefficients on intake and f1 values
Q14414   –   Protection factors and gamma attenuation following an atomic weapon explosion
Q14423   –   Protection factors and gamma attenuation following an atomic weapon explosion

Other Useful Websites

The following websites may also be useful:

  External website   Basics about Radiation – Radiation Effects Research Foundation
  External website   Commonly Encountered Radionuclides – US 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 – US Environmental Protection Agency
  External website   Radioactive Isotopes – Lawrence Berkeley National Laboratory
  External website   Risks from Low Levels of Ionising Radiation – Public Health England