Radiation and Radioactivity Units and Quantities www assignmentpoint
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Radiation and Radioactivity: Units and Quantities www. assignmentpoint. com
Introduction l Quantities (mass, volume, time, etc. ) vs. Units (grams, gallons, hours) l Units of exposure, radioactivity, and energy associated with ionizing radioactivity l As hours and minutes are to time. . . www. assignmentpoint. com
Objectives l Define – ROENTGEN, RAD, REM, CURIE, GRAY, SIEVERT, BECQUEREL. – SI units vs. Standard English units l Discuss the use and conversion of unit prefixes l Transform units using “unit analysis” www. assignmentpoint. com
Background l Early risk associated with use of ionizing radiation l skin erythema dose - 25 yrs l 1928 - ROENTGEN introduced by ICRP www. assignmentpoint. com
Roentgen www. assignmentpoint. com
Roentgen Named after Wilhelm C. Roentgen (thus the abbr. . . is capital “R”) l Pronounced rent’gen with a hard “g” l Limitations l – only applies to photons – only applies in air – only applies to energies less than 3 Me. V www. assignmentpoint. com
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rad l 1 rad = 1 Roentgen www. assignmentpoint. com
rem www. assignmentpoint. com
rem l Roentgen Equivalent Man l The unit of dose equivalent for any type of ionizing radiation absorbed by body tissue in terms of estimated biological effect - Unit of dose equivalent l Dose in health record is in units of rem l 1 rem = 1 Roentgen www. assignmentpoint. com
Quality Factor (Q) The specific value that accounts for the ability of different types of ionizing radiation to cause varying degrees of biological damage – X-rays, gamma rays, & beta particles – Neutrons & High energy protons – Alpha Particles www. assignmentpoint. com 1 10 20
Curie (Ci) l Named in honor of Pierre Curie l Radiation hazard does not solely depend on the activity. It also depends on the type of decay (alpha, beta, photon, etc. ) www. assignmentpoint. com
SI Radiation Protection Units l Becquerel (Bq) for Curie – 1 Ci = 3. 7 x 1010 Bq l Gray (Gy) for rad – 1 Gy = 100 rad l Sievert (Sv) for rem – 1 Sv = 100 rem www. assignmentpoint. com
Unit Analysis BASE UNIT CONVERSION TABLE Unit 1 Bq 1 Ci 1 Bq 1 dis/sec 1 Ci Unit Conversion 2. 7 x 10 -11 Ci 3. 7 x 1010 Bq 1 dis/sec 2. 7 x 10 -11 Ci 3. 7 x 1010 dis/sec www. assignmentpoint. com
Unit Analysis (Con’t. ) BASE UNIT CONVERSION TABLE Unit Conversion 1 rem 1 Sv 1 rad 1 Gy 1 R 1 meter 0. 01 Sv 100 rem 0. 01 Gy 100 rad 2. 58 x 10 -4 C/kg 3. 28 ft (39. 37 in) www. assignmentpoint. com
Summary l Radiation Protection unit definitions (including SI units) l Unit Prefixes l Unit conversions www. assignmentpoint. com
Old Terms l Roentgen-Based on the quantity of electrical charges produced in air by X or Gamma photons 1 R=2 billion pr l RAD-Radiation Absorbed Dose is the work energy resulting from the absorption of one ROENTGEN or 6. 24 E 5 Mev www. assignmentpoint. com
More Old Terms l REM- Roentgen Equivalent Mammal is equal to the absorbed does in RADS multiplied by a quality factor l Quality Factors l Beta = 1 l Gamma & X ray photons = 1 l Alpha = 10 l Neutrons = 20 www. assignmentpoint. com
New Terms sort of International Units have replaced the RAD and REM GRAY (Gy) = 100 RAD SIEVERT (Sv) = 100 REM Same Quality Factors apply to the Sv www. assignmentpoint. com
Units of Radioactivity Curie (Ci) = 2. 22 E 12 dpm or 3. 7 E 10 dps l Becquerel (Bq) = 1 dps l Maximum Dose/year = 5 REM or 50 m. Sv l Maximum Dose/year for Declared Pregnant Woman & Minors= 0. 5 REM or 5 m. Sv l www. assignmentpoint. com
Half Life Calculation www. assignmentpoint. com
Annual Dose Limits External/Internal Exposure Limits for Occupationally Exposed Individuals Adult ($18 yrs) Minor (< 18 yrs) Whole body* 5000 mrem/yr 500 mrem/yr Lens of eye 15000 mrem/yr 1500 mrem/yr Extremities 50000 mrem/yr 5000 mrem/yr Skin 50000 mrem/yr 5000 mrem/yr Organ 50000 mrem/yr www. assignmentpoint. com 5000 mrem/yr
Dose Response Relationships l 0 -150 rem—No or minimal symptoms l 150 -400 rem—Moderate to severe illness l 400 -800 rem—Severe illness deaths start above 500 rem l Above 800 rem—Fatal ***Acute whole body doses www. assignmentpoint. com
Your Annual Exposure Activity Smoking Typical Dose 280 millirem/year Radioactive materials use in a UM lab <10 millirem/year Dental x-ray Chest x-ray Drinking water Cross country round trip by air 10 millirem per xray 8 millirem per xray 5 millirem/year 5 millirem per trip 0. 165 Coal Burning power plant www. assignmentpoint. com millirem/year
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Estimated Exposure To The National Population l. Between 320 – 360 mr/yr www. assignmentpoint. com
Another Look at Sources www. assignmentpoint. com
Some Exposure Limits l l l l 2 mr/hr Dose rate to public / Federal 500 mr Emergency responder limit / State/BRC 5 r/yr Occupational /Federal 5 r/hr Turn back value / State/BRC 10 r Property / Federal 25 r Life saving / Federal >25 r Volunteers only / Federal Ref - 10 CFR PART 20, EPA 400, FL-SOP www. assignmentpoint. com
Security l All Radioactive Materials must be secured or under direct supervision at all times l There MUST be someone in the room at all times OR the door must be locked. www. assignmentpoint. com
Spill Response l On Skin—flush completely l On Clothing—remove l If Injury—administer first aid l Radioactive Gas Release—vacate area, shut off fans, post warning l Monitor all persons and define the area of contamination www. assignmentpoint. com
ALARA As Low As Reasonably Achievable—means making every reasonable effort to maintain exposures to radiation as far below the dose limits as is practicable consistent with the purpose for which the licensed activity is undertaken, taking into account the state of technology, the economics of improvements in relation to benefits to the public health and safety, and other societal and socioeconomic considerations, and in relation to utilization of nuclear energy and licensed materials in the public interest. www. assignmentpoint. com
Radiation Protection l Decrease Time l Increase Distance l Increase Shielding www. assignmentpoint. com