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Radioisotope Laboratory Safety

Radioisotope Laboratory Safety. Conrad Sherman x9-3911 RSO/Health Physicist Marcus Balanky x9-5167 ARSO/ Health Physicist Vern Ares x9-5167 Assistant Health Physicist Environmental Health & Safety Radiation Safety (831) 459-3911. Introduction. Introduction Fundamentals Review

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Radioisotope Laboratory Safety

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  1. Radioisotope Laboratory Safety Conrad Sherman x9-3911 RSO/Health Physicist Marcus Balanky x9-5167 ARSO/ Health Physicist Vern Ares x9-5167 Assistant Health Physicist Environmental Health & Safety Radiation Safety (831) 459-3911

  2. Introduction • Introduction • Fundamentals Review • Radiation Survey Instruments Break • Controlling Radiation Exposure • Operating Procedures & Records • Emergency Procedures

  3. The ultimate goal of radiation safety training is the development of a safety culture. While the overall responsibility for the development of such a culture rests with management, the ultimate responsibility for the practice of safety rests with each individual.

  4. You are here

  5. Radiation Safety Training Required • The NRC considers training the most important way to control exposure to ionizing radiation. • This radiation safety class is all that is needed to work safely with radioactive material. (TRUE / FALSE)

  6. Fundamentals Review • Introduction • Fundamentals Review • Radiation Survey Instruments Break • Controlling Radiation Exposure • Operating Procedures & Records • Emergency Procedures

  7. Review of Fundamentals • Radiation and Radioactivity • Units • Activity • Exposure • Dose • Dose Equivalent

  8. Radiation Vs. Radioactivity • Radiation • Radiation is a process of emission of energy or particles. Various forms of radiation may be distinguished, depending on the type of the emitted energy/matter, the type of the emission source, properties and purposes of the emission, etc. • Radioactivity(Radioactive Decay) • Happens in parent nucleus and produces a daughter nucleus. This is a random process, i.e. it is impossible to predict the decay of individual atoms.

  9. Units

  10. Energy The electron volt is defined as the change in energy of a particle when it moves through a potential difference of one volt. 1 eV = (1.602 x 10-19 J) 1 MeV = one million electron volts 1 keV = one thousand eV

  11. Activity • A commonly used unit for measuring activity is the curie (Ci) (SI: becquerel Bq)1 Ci = 3.7 x 1010 dps 1 Bq = 1 dps • Typical activities found in a University lab are in the microcurie (mCi) to millicurie (mCi) range.

  12. Radiation vs. Radioactive Contamination • Radiation is particles or waves of energy emitted from unstable atoms. • Radioactive Contamination is radioactive material usually in any location you do not want it.

  13. Exposure • Exposure is a measure of ionization produced in air by photons (x and gamma rays) • Exposure meters report in units of exposure (mR/hr).

  14. Radiation Exposure External Gammas – 125I High energy betas – 32P. Internal Tritium Uptake of radioactive material via: • Ingestion • Absorption • Inhalation

  15. Dose An absorbed dose is the energy deposited in a unit mass by any radiation – rad(SI = grey Gy). Each type of radiationis assigned a QFwhich expressesthe biological risk.

  16. Dose Equivalent Dose equivalent is calculated as absorbed dose multiplied by a quality/weighting factor – rem (SI = sievert Sv).rad x QF = rem Gy x QF = Sv 1 Gray = 100 rad 1 Sievert = 100 rem

  17. Dose Limits http://www.ucsc.edu/ehs/

  18. Radiation Survey Instruments • Introduction • Fundamentals Review • Radiation Survey Instruments Break (Time Dependent) • Controlling Radiation Exposure • Operating Procedures and Records • Emergency Procedures

  19. Radiation Survey Instruments Radiation detection instruments are necessary to determine the effectiveness our exposure control program. Goal:We will provide information so that the radiation worker may: • Choose the correct radiation detection instrument. • Use the instrument properly.

  20. Background • Environmental ionizing radiation that can affect the radiation detection process • Several sources contribute to background • An acceptable range for background is determined for each instrument and each environment

  21. Efficiency • Counts per minute (CPM) the units that a survey instrument reports. • Since detectors aren’t 100% efficient...DPM = CPM / Detector Efficiency*(* the detector efficiency for the specific radioisotope only)

  22. Probe reading • DPM = CPM / Detector Efficiency* • We use dpm/100 cm2(* the detector efficiency for the specific radioisotope only) • Conversion = ccpm x ACF x Probe Factor

  23. Efficiency • GM meters have a relatively high efficiency for betas and low efficiency for x-rays and gammas. • For example GM efficiency for P-32 is approximately 32% and only 0.05% for I-125.

  24. Radiation Survey InstrumentsGM Detector • Self quenching gas filled chamber • Thin mica window • Central electrode • Walls form conductor and block unwanted radiation

  25. Radiation Survey InstrumentsGM Detector • 30-35 eV ionization energy produces charged pair formation • Current discharge causes pulse for counting

  26. GM Detector – Advantages and Limitations • Cannot distinguish type or energy of radiation electronically • Excellent for detecting small amounts of radioactivity • Respond to but is not suited to measure radiation fields • Possible paralysis of response at high count rates

  27. Calibration and Maintenance • Annual calibration required • Electronic calibration • Calibration in a known radiation field • Efficiency determination • Routine operational checks • Be sure to turn off the instrument when done.

  28. Liquid Scintillation Counter • Excellent choice for detecting and measuring low energy beta • Not portable - wipe or smears required for radiation survey use • Requires more training to prepare samples and interpret results than other instruments

  29. User Program 10 • EH&S Radiation Safety provides a user program for wipe surveys. • Please use this program for your routine laboratory wipe surveys. • We can provide an efficiency for the isotope you are using.

  30. General Tips LSC Wipe Survey • Survey discrete areas so that if contamination is found the spot will be easy to identify • Avoid cross contamination of samples • Artifacts may cause false positives • Static electricity • Chemoluminescence • Phosphorescence

  31. General Survey Information • Randomly survey selected areas outside of normal radioisotope use areas periodically. • Using a map of your lab can make documenting surveyed areas easier. • Look for levels >2X background. • Check for contamination wherever human hands normally go...

  32. 10. Soap/towel dispenser 9. Microwave oven 8. Radio dials 7. Phones 6. Pens/pencils 5. Chairs 4. Drawer handles 3. Refrigerator handles 2. Lab books Top 10 Most Often Contaminated Sites 1. Geiger counters

  33. Documenting Surveys • Contamination surveys must be documented • Record the following: • date performed • area(s) surveyed (a map helps!) • Results ccpm if < 2 x bkg • identity of surveyor • instrument used • action taken if contamination is found

  34. TLD Detector Personnel shall wear assigned dosimetry when handling radioactive materials or working near radiation producing machines

  35. Thermoluminescent Dosimeters • Thermoluminescent dosimeter (TLD) contain a lithium fluoride crystal. • If the crystal is heated after radiation exposure it will emit light that is proportional to the total exposure. • TLD will not detect low energy betas that cannot penetrate the plastic holder.

  36. Always: make available for exchange on the appropriate exchange date report contamination of dosimetry store away from radioactive sources Never: share dosimetry remove crystal from holder expose to heat take off campus intentionally expose to radiation The Care of Your Dosimeter

  37. Whole Body Wear between neck and waist Wear with name on badge facing outwards Extremity The label side of the ring should usually face the palm Wear gloves over the ring Wearing Dosimetry

  38. Missing Dosimetry If you lose, damage or fail to make dosimetry available for exchange you will be required to provide a detailed description of all radioactive sources in use during the wear period.

  39. Request Dosimetry • You may request your personal exposure history at anytime. • Write or e-mail the RSO your request and include you identification. • Annual report will be emailed

  40. Controlling Radiation Exposure • Introduction • Fundamentals Review • Radiation Survey Instruments Break • Controlling Radiation Exposure • Operating Procedures & Records • Emergency Procedures

  41. Radiation Protection The five main principles of radiation protection: Time Distance Shielding Contamination Control Administrative

  42. Avoid Ingesting Radioactive Material NO • Eating • Drinking • Smoking • Applying Cosmetics • Mouth Pipetting

  43. Protective Clothing • Gloves • Lab coat • Eyewear • Pants • Closed toe footwear

  44. Contamination Control • Wear PPE. • Watch out where you put your “hot” hands during an experiment. • Monitor yourself and your work area frequently • Wash your hands after finishing an experiment

  45. Monitor Yourself

  46. Removing Your Gloves

  47. D

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