Instrumentation and Measurements

This category covers radiation detection equipment, instrument selection, calibration, surveys and measurements, personnel monitoring, etc.

FAQs Developed by the HPS

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

  HPS FAQ   How Can You Detect Radiation?
  HPS FAQ   Measuring Occupational Exposures
  HPS FAQ   What Dosimeter Should I Use for Personnel Monitoring?
  HPS FAQ   What Radiation-Detecting Device Should I Use?

Relevant HPS Web Pages

The following HPS Web page also addresses this category:

  PDF   Particulate Air Monitoring Mathematical Sourcebook

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:
  •  Instrument Calibration (IC)
  •  Surveys and Measurements (SM)
  •  Personnel Monitoring (PM)
  •  Miscellaneous
Instrument Calibration (IC)
Q7150   –   Can I relate instrument calibration results obtained with plutonium-238 to plutonium-239 results?
Q7401   –   How do I determine efficiencies for NaI counting of environmental samples?
Q7972   –   How does detector get output converted to dose?
Q8371   –   Correlate gamma spectrum with dose
Q8495   –   Should this GM instrument meet any special requirements?
Q8505   –   What conversion factors should I use to convert between ambient dose equivalent and air kerma?
Q8629   –   Low Energy Response of GAFCHROMIC EBT Film
Q8813   –   Mock iodine-131 source
Q8865   –   TLD-100 for high-energy photons
Q8949   –   Relationship between absorbed dose and ambient dose equivalent
Q8983   –   Why are these personnel contamination monitors yielding excessive efficiencies?
Q9038   –   Do electronic personal dosimeters have to be calibrated?
Q9093   –   TLDs for entrance surface dose measurements.
Q9232   –   Interpret surface contamination levels from ionization chamber measurements
Q9278   –   Mock sources for Iodine-123 and Iodine-124
Q9321   –   What dose should be used for TLD calibration?
Q9367   –   How do I calibrate a flow-through chamber for airborne beta emitters?
Q9501   –   CR-39 response to 14 MeV neutrons
Q10110   –   How do I determine MDA in gamma spectrometry?
Q10132   –   Does it matter which side of the check source faces the detector?
Q10278   –   How do I set up this liquid scintillation counter for alpha/beta measurements?
Q10407   –   How do I calibrate TLDs for x-ray surface dose measurements?
Q10531   –   Is calibration necessary for this GM detector?
Q10548   –   Radon concentration produced by Pylon source
Q10686   –   What testing and/or calibration is required for this SCA/NaI(Tl) system?
Q10904   –   Can a point source be used to confirm activity in these volume sources?
Q10937   –   Are there any formal restrictions on repairing this detector Mylar window?
Q11077   –   Why do I get different activity estimates from gamma vs. beta counting?
Q11163   –   How do I determine minimum detectable dose for TLDs?
Q11421   –   TLD is suddenly overresponding to 6 MV x rays
Q11555   –   Is Pylon source a sealed source?
Q11875   –   Calibrating a TLD reader and determining ECCs
Q12504   –   Minimum detectable activity for multiple detector in-vivo system
Q12579   –   Is calibration of TLDs with this x-ray machine acceptable?
Q12587   –   Calibrating thermoluminescent dosimeters to high-energy field
Q13095   –   Is it possible to obtain a calibration for a depleted uranium surface source?
Q13219   –   Preparation of standards for alpha and beta self-absorption corrections
Q13273   –   Neutron instrument calibration
Q13343   –   How can I increase the calibration interval for GM instruments?
Q13624   –   Is ambient dose equivalent a good estimate of personal dose equivalent at x-ray energies?
Q13827   –   Why is the slope of the G-M plateau greater for halogen-quenched tubes compared to organic-quenched?
Q13832   –   How is this detector response related to x-ray dose?
Surveys and Measurements (SM)
Q4148   –   Convert from counts to dose
Q6701   –   How do I decide whether this object is contaminated?
Q6937   –   Alpha detector efficiency
Q7119   –   Instrumentation for measuring beta-gamma emitting contamination
Q7168   –   Can I separate these photon energies from 111In using a well counter?
Q7240   –   Can I convert the count rate on this detector to radon concentration?
Q7241   –   Is this GM probe able to measure this surface contamination level?
Q7387   –   How can I measure zinc 65 contamination?
Q7413   –   Are wireless environmental monitoring systems available?
Q7442   –   Small dimension alpha probes
Q7449   –   Measure x rays with GM detector
Q7500   –   Correlate count rate on GM with technetium-99m skin activity
Q7530   –   Spillover between alpha and beta channels in proportional counter
Q7546   –   Lead-214 and bismuth-214 gamma rays for radium-226 determination
Q7605   –   Surface contamination measurements and need for respiratory protection
Q7763   –   Why bother with the reduced chi-square value?
Q7823   –   Is radium-226 analysis by gamma spectrometry reliable?
Q7958   –   Does this chi-square value show significance?
Q7973   –   How is transport index determined?
Q7986   –   Is residual bomb radioactivity visible by satellite imaging?
Q8067   –   Why is the manufacturer's measurement range different from the display range for this GM?
Q8079   –   How do I correlate GM exposure rate and count rate on gamma camera?
Q8149   –   How does the guard ring reduce leakage in ion chamber?
Q8162   –   Multiuse contamination detector
Q8184   –   What GM response should I expect from this Na-22 source?
Q8227   –   How do I use this NaI detector to measure RDD ground contamination?
Q8263   –   Why are these package surface dose rates different?
Q8288   –   Is this attenuation method legitimate for beta radionuclide identification?
Q8308   –   What dosimeters can be used to measure reactor in-core doses?
Q8437   –   How do I obtain dose rate from count rate for this neutron instrument?
Q8446   –   Average photon energy from reactor pulse height distribution
Q8558   –   What 9-inch ball was used for the 9-inch/3-inch method for neutron energy assessment?
Q8597   –   Use of thorium-232 progeny to determine thorium activity
Q8600   –   Is the pancake detector suitable for screening purposes in leak testing?
Q8895   –   How do I interpret energy dependence of this GM detector?
Q8910   –   Where should I set the alarm point on this Inspector GM?
Q8948   –   How does this CsI detector measure dose?
Q8976   –   Are there radon monitors that provide very rapid response to airborne radon?
Q8995   –   Will magnesium chloride enhance or decrease the response of the neutron water content gauge?
Q9194   –   Can event detectors measure dose?
Q9287   –   What radiations from technetium-99m are causing the detector response?
Q9411   –   Is there a predictable relationship between GM reading and actual dose rate for LINAC measurements?
Q9431   –   Radionuclides that interfere with radium-226 quantification by gamma spectroscopy
Q9433   –   Using the 186 keV gamma ray from radium to assess uranium content
Q9568   –   What instruments are appropriate for beryllium-7 surveys?
Q9599   –   Is chi-square test appropriate for gamma camera?
Q9614   –   How should I perform this leak test?
Q9722   –   What impact does changing air particulate sampling flow rate have?
Q9806   –   How do I make survey measurements on the level gauge?
Q9862   –   Are these Japanese radiation levels significant?
Q9871   –   What is the procedure for doing a manual whole-body frisk?
Q9967   –   How should I sample for airborne iodine-125?
Q10000   –   How should I handle this variable data?
Q10004   –   Should I use liquid scintillation or gamma counting for leak test measurements?
Q10133   –   Why are these instrument readings on this package different?
Q10173   –   Is this flow rate suitable for a CAM?
Q10190   –   How do I show these measurements represent insignificant doses?
Q10281   –   Are these reading spikes on the GM a concern?
Q10330   –   Elevated GM reading on Maine seaweed
Q10336   –   Why might these dosimeter results be different from the survey instrument results?
Q10403   –   Should I expect terrestrial gamma dose rate and measured dose rate to agree?
Q10431   –   Does the LSC or an internal proportional counter have the highest Fe-55 counting efficiency?
Q10433   –   How are exposure readings related to effective dose, and when are count rate measurements appropriate?
Q10434   –   How low a reading is legitimate on these ion chambers?
Q10445   –   Can gamma spectrometry be used for analysis of uranium in water?
Q10452   –   Adjusting window thicknesses for instrument measurements of shallow, eye, and deep dose
Q10502   –   Air sampling for tritium
Q10514   –   What accounts for the shape of the energy response curve for this GM detector?
Q10557   –   Loss of tritium from volatility from wipes
Q10580   –   How do I correlate gamma activity results with gross alpha and beta results?
Q10722   –   Baseline measurements and gamma spectrometry
Q10738   –   Use of TLD reader for different phosphors
Q10748   –   Instruments for radionuclide identification
Q10761   –   Do readings at high altitudes with a pressurized ion chamber require corrections?
Q10966   –   Do these instrument readings refer to equivalent dose or effective dose?
Q10989   –   How should the critical level and MDA be used in assessing and reporting?
Q11024   –   How do I evaluate the measured dose rate from radiation through a narrow gap?
Q11050   –   How should I measure airborne tritium gas and calculate the dose from inhalation?
Q11103   –   What equipment do I need to analyze TENORM?
Q11219   –   What are the needs for a facility to provide thermoluminescent dosimetry services?
Q11228   –   Contamination assessment and control in the workplace
Q11258   –   Should I use TLDs or a Farmer chamber to assess occupational doses from therapeutic cobalt-60 and accelerator units?
Q11262   –   Requirements for using TLD-200 for environmental measurements
Q11577   –   Effect of helium-3 on flow-through air ionization chamber response
Q11641   –   Radon monitor spikes during jet descent
Q11645   –   Is my GM detector measuring x rays or RF from this RF source?
Q11729   –   Energy dependence of TLD-100 for iodine-125 compared to cobalt-60
Q11839   –   Critical level and lower limit of detection when count rates for two samples are added
Q11935   –   Correlating stack monitor count rate with air concentration
Q12023   –   What is the best compatible scintillator for tritium sampling using ethylene glycol?
Q12240   –   Factors in selecting portable, health physics dose-measuring instruments
Q12254   –   Inexpensive way to measure x-ray beam
Q12276   –   How do I interpret measurements at the low end of the manufacturer's energy range?
Q12319   –   Distance to measure dose rate from a sealed source
Q12326   –   Can this air-calibrated GM detector be used for underwater measurements?
Q12396   –   Cesium-137 in firewood
Q12402   –   Acceptable well counter background values
Q12704   –   GM detector response based on volume-averaging
Q12750   –   How do I calibrate this 3He detector?
Q12775   –   Can a thin-window GM be used as a survey meter for a PET-CT clinic?
Q13006   –   Check radiation in minerals
Q13023   –   Determination of average surface activity from measurements with this 15 cm2 probe.
Q13286   –   Use of TLDs in radiotherapy
Q13610   –   Possible alternatives to pressurized ion chambers
Personnel Monitoring (PM)
Q7249   –   Radium in the body
Q7624   –   Personnel dose measurement in medical facilities
Q7966   –   What TLD shape is appropriate?
Q8191   –   Is there a dosimeter I can use to measure my public exposure?
Q8622   –   Neutron albedo—men vs. women
Q8689   –   Training to remove the liquid scintillation counter external standard source
Q9328   –   Rationale for eye and skin doses
Q9333   –   Technologist's TLD badges from diagnostic x-ray procedures show no dose
Q9700   –   Reading of personnel dosimeters
Q9915   –   What are these TLD number designations and are they appropriate for neutron dosimetry?
Q9960   –   How can I differentiate among these TLD types?
Q10015   –   Can glow curve be constructed from individual light photon/PHA measurements?
Q10100   –   Why do these TLD 100 dosimeters show decreasing sensitivity with use?
Q10222   –   What might account for the high reading on this TLD?
Q10234   –   Does the angle of incidence affect the response of this TLD?
Q10237   –   Should this TLD be covered if used to evaluate Hp(10)?
Q10252   –   Why are these personnel dosimeters all crystalline materials?
Q10572   –   Why are TLD badges worn outside lead aprons?
Q10897   –   Do extremity dosimeters measure neutron dose?
Q11334   –   How do I use this Panasonic UD 809 dosimeter?
Q12114   –   Estimating effective dose from badges
Q12194   –   Why might the reference light source on this TLD reader be changing?
Q12503   –   Calibration of a TLD with a 6 MV beam or a positron emitter?
Q12535   –   Will portable x-ray machines swamp a pencil dosimeter?
Q12680   –   Vendor is reporting beta dose for CVL/x-ray technologist
Q13024   –   Is using a two-badge system for area monitoring in diagnostic x-ray rooms acceptable?
Q13252   –   Should I expect the same dose result for LiF dosimeters irradiated to a single dose in a single irradiation and the same dosimeters irradiated to the same total dose delivered in multiple lower dose irradiations?
Q14031   –   Bioassay for americium-241 and effect of DTPA on urinary excretion
Q14410   –   Personnel Monitoring (PM)
Q6886   –   Is CR-39 a tissue-equivalent dosimeter material?
Q7153   –   How do I convert tissue dose to silicon dose?
Q7531   –   Volume reduction to measure radioactivity in oil
Q7692   –   Response of MOSFET dosimeter
Q8032   –   Will light from this glass scintillator be visible?
Q8165   –   Will gamma radiation damage this glass scintillator?
Q8177   –   What container is suitable to analyze solid samples for radium?
Q8921   –   Why does CCD detect alpha, but not beta or gamma radiation?
Q8935   –   What are ion chamber guard rings made of?
Q8941   –   Will criticality monitors fail in high-radiation field?
Q9059   –   Bubblers for tritium collection
Q9341   –   How should Monte Carlo predicted count rates for the He-3 and glass scintillator detectors compare?
Q9530   –   How will bremsstrahlung from electrons on lead affect instrument response?
Q9605   –   How do I model a point detector for Monte Carlo simulation?
Q9651   –   What is the leakage source in semiconductors such as CdTe and how can I reduce it?
Q10036   –   Can we use wood as a tissue-equivalent material to make an ionization chamber?
Q10121   –   How do I determine filter collection efficiency?
Q10416   –   How should I recool this HPGE detector that has warmed up?
Q10421   –   Static electricity effect on GM detector
Q10654   –   Approved techniques/methods for testing HEPA vacuum cleaners
Q10838   –   Can light cause ionization?
Q11193   –   How do I predict air concentrations and wall deposition in hood and ducts?
Q11283   –   Is there an instrument for assessing package external radioactive contamination?
Q11300   –   Might this piece of metal be contaminated from work using a cesium irradiator?
Q11736   –   Software for recording and printing dose reports
Q12025   –   Survey instrument choice for low-energy x rays
Q12333   –   MCA gain
Q12462   –   How accurate was this Landsverk Roentgen meter?
Q12554   –   X-ray diffraction units and cancer
Q12760   –   Are these NaI instrument readings high enough to be a concern?
Q12829   –   Which MCNP tally do I use to evaluate a 3He detector response function?
Q12905   –   Do nano-sized microchips give off radiation? If they do, what would detect it?
Q12984   –   Minimum detection limit for a GM-based gamma monitor
Q13001   –   Why does this GM detector respond to light?
Q13085   –   Deciding between a scintillation detector and an ionization chamber
Q13274   –   Possible radiation damage to drone electronics from uranium tailings
Q13340   –   Calculating error in gamma spectrometric results
Q13443   –   Moving health physics counting system instruments
Q13561   –   Use of a GM detector to measure neutron-induced radioactivity in the body
Q13595   –   Dealing with a lost dosimetry badge
Q13630   –   Radiation from granite and detectors for measurements
Q13667   –   Electrostatic effects on PM-based scintillation detector
Q13808   –   Why are instruments calibrated and readings adjusted for a specific temperature and specific pressure?
Q13913   –   Are both liquid scintillation counting and liquid chromatography – mass spectrometry useful for analysis of radionuclides?
Q14000   –   How to reduce Compton scatter, backscatter, and escape peaks from occurring in a scintillation detector like a gamma camera or a well counter.
Q14030   –   What dosimeter would be suited to measuring cosmic radiation dose?
Q14132   –   Air sampling and analysis methods for nickel-63
Q14205   –   Evaluation of high activity by gamma spectrometry using increased distance to decrease dead time
Q14359   –   Optimization of an iodine monitoring system
Q14473   –   Possible damage to HPGe detectors from long-term storage at room temperature

Other Useful Websites

The following websites may also be useful:

  External website   Directory of Accredited Laboratories – National Institute of Standards and Technology
  External website   EML Procedures Manual – Oak Ridge Associated Universities
  External website   International Atomic Energy Agency Safety Reports Series No. 16, "Calibration of Radiation Protection Monitoring Instruments"
  External website   Radiation Detection and Measurement Textbook – Glenn F. Knoll
  External website   Radiation Protection – US Environmental Protection Agency/MARLAP
  External website   Radiation Protection – US Environmental Protection Agency/MARSSIM
  External website   Radiation Related Frequently Asked Questions – Idaho State University
  External website   Radiological Surveys for Controlling Release of Solid Materials – US Nuclear Regulatory Commission
  External website   Radionuclides in Analytical Chemistry – Wiley