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Alpha Particles: 2 neutrons and 2 protonsThey travel short distances, have large massOnly a hazard when inhaled
Four Primary Types of Four Primary Types of Ionizing Radiation:Ionizing Radiation:
Alpha ParticlesAlpha Particles
Four Primary Types of Four Primary Types of Ionizing Radiation:Ionizing Radiation:
Beta ParticlesBeta ParticlesBeta Particles: Electrons or positrons having small mass and variable energy. Electrons form when a neutron transforms into a proton and an electron or:
Four Primary Types of Four Primary Types of Ionizing Radiation:Ionizing Radiation:
Gamma RaysGamma Rays
Gamma Rays (or photons): Result when the nucleus releases
Energy, usually after an alpha, beta or positron transition
Four Primary Types of Four Primary Types of Ionizing Radiation:Ionizing Radiation:
X-RaysX-Rays
X-Rays: Occur whenever an inner shell orbital electron is removed
and rearrangement of the atomic electrons results with the release of
the elements characteristic X-Ray energy
Four Primary Types of Four Primary Types of Ionizing Radiation:Ionizing Radiation:
NeutronsNeutrons
Neutrons: Have the same mass as protons but are uncharged
They behave like bowling balls
Four Primary Types of Four Primary Types of Ionizing RadiationIonizing Radiation
Alpha particlesBeta particlesGamma rays (or photons)X-Rays (or photons)Neutrons
RADIATION RADIATION FUNDAMENTALS FUNDAMENTALS
ATOMIC AND NUCLEAR ATOMIC AND NUCLEAR STRUCTURESTRUCTURE
Bureau of Radiation Control
Radioactivity: Elements & Radioactivity: Elements & AtomsAtoms
Atoms are composed of smaller particles referred to as:
– Protons
– Neutrons
– Electrons
Ionization Ionization Ionizing radiation is produced by unstable
atoms. Unstable atoms differ from stable atoms because they have an excess of energy or mass or both.
Unstable atoms are said to be radioactive. In order to reach stability, these atoms give off, or emit, the excess energy or mass. These emissions are called radiation.
Types or Products of Ionizing Types or Products of Ionizing RadiationRadiation
or X-
rayneutron
Ionizing Radiation
alpha particle
beta particle
Radioactive Atom
X-ray
gamma ray
Ionizing Radiation
alpha particle
beta particle
Radioactive Atom
X-ray
gamma ray
Direct Ionization Caused By:Direct Ionization Caused By:
Protons
Alpha Particles
Beta Particles
Positron Particles
Indirect Ionization Caused By:Indirect Ionization Caused By:
Neutrons
Gamma Rays
X-Rays
DNA and RadiationDNA and Radiation
Ionizing Radiation at the Ionizing Radiation at the Cellular LevelCellular Level
Causes breaks in one or both DNA strands or;
Causes Free Radical formation
Commonly Transported Commonly Transported RadioisotopesRadioisotopes
Americium-241= Diagnose thyroid disorders, smoke detectors.
Cesium-137= Cancer treatment.Iodine-125,131= Diagnosis & treatment
liver, kidney,heart, lung and brain.Technetium-99m=Bone and brain imaging;
thyroid and liver studies; localization of brain tumors.
Radiation MeasurementRadiation Measurement
Terminology:
– Exposure rate = amount radiation possible to receive per unit time.
– Dose = total amount of radiation received.
Radiation and Radioactivity: Radiation and Radioactivity: Units and QuantitiesUnits and Quantities
Department of HealthBureau of Radiation Control
Introduction Introduction
Quantities (mass, volume, time, etc.) vs. Units (grams, gallons, hours)
Units of exposure, radioactivity, and energy associated with ionizing radioactivity
As hours and minutes are to time ...
ObjectivesObjectives
Define – ROENTGEN, RAD, REM, CURIE, GRAY,
SIEVERT, BECQUEREL.– SI units vs. Standard English units
Discuss the use and conversion of unit prefixes
Transform units using “unit analysis”
Background Background
Early risk associated with use of ionizing radiation
skin erythema dose - 25yrs1928 - ROENTGEN introduced by ICRP
RoentgenRoentgen
RoentgenRoentgen
Pronounced rent’gen with a hard “g”Limitations
– only applies to photons– only applies in air– only applies to energies less than 3 MeV
Named after Wilhelm C. Roentgen (thus the abbr... is capital “R”)
radrad
radrad1 rad = 1 Roentgen
remrem
remrem
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
Dose in health record is in units of rem1 rem = 1 Roentgen
Roentgen Equivalent Man
Quality Factor (Q)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 1– Neutrons & High energy protons 10– Alpha Particles 20
Curie (Ci)Curie (Ci)
Radiation hazard does not solely depend on the activity. It also depends on the type of decay (alpha, beta, photon, etc.)
Named in honor of Pierre Curie
SI Radiation Protection UnitsSI Radiation Protection Units
Becquerel (Bq) for Curie– 1 Ci = 3.7 x 1010 Bq
Gray (Gy) for rad– 1 Gy = 100 rad
Sievert (Sv) for rem– 1 Sv = 100 rem
Unit AnalysisUnit Analysis
BASE UNIT CONVERSION TABLE
Unit Unit Conversion1 Bq 2.7 x 10-11 Ci1 Ci 3.7 x 1010 Bq
1 Bq 1 dis/sec1 dis/sec 2.7 x 10-11 Ci1 Ci 3.7 x 1010 dis/sec
Unit Analysis (Con’t.)Unit Analysis (Con’t.)BASE UNIT CONVERSION TABLE
Unit Unit Conversion
1 rem 0.01 Sv1 Sv 100 rem1 rad 0.01 Gy1 Gy 100 rad1 R 2.58 x 10-4 C/kg1 meter 3.28 ft (39.37in)
SummarySummary
Radiation Protection unit definitions (including SI units)
Unit PrefixesUnit conversions
Old TermsOld Terms
Roentgen-Based on the quantity of electrical charges produced in air by X or Gamma photons 1R=2 billion pr
RAD-Radiation Absorbed Dose is the work energy resulting from the absorption of one ROENTGEN or 6.24 E5 Mev
More Old TermsMore Old Terms
REM- Roentgen Equivalent Mammal is equal to the absorbed does in RADS multiplied by a quality factor
Quality FactorsBeta = 1
Gamma & X ray photons = 1Alpha = 10
Neutrons = 20
New Terms New Terms sort ofsort of
International Units have replaced the RAD and REM
GRAY (Gy) = 100 RADSIEVERT (Sv) = 100 REM
Same Quality Factors apply to the Sv
Units of RadioactivityUnits of Radioactivity
Curie (Ci) = 2.22 E12 dpm or 3.7E10 dpsBecquerel (Bq) = 1 dpsMaximum Dose/year = 5 REM or 50 mSvMaximum Dose/year for Declared Pregnant
Woman & Minors= 0.5 REM or 5 mSv
Half Life CalculationHalf Life Calculation
Annual Dose LimitsAnnual Dose LimitsExternal/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
5000 mrem/yr
*Effective dose equivalent
Dose Response RelationshipsDose Response Relationships
0-150 rem—No or minimal symptoms150-400 rem—Moderate to severe illness400-800 rem—Severe illness deaths start
above 500 remAbove 800 rem—Fatal
***Acute whole body doses
Your Annual ExposureYour Annual ExposureActivity Typical DoseSmoking 280 millirem/year
Radioactive materials use in a UM lab <10 millirem/year
Dental x-ray 10 millirem per x-ray
Chest x-ray 8 millirem per x-ray
Drinking water 5 millirem/yearCross country round trip by air 5 millirem per trip
Coal Burning power plant 0.165 millirem/year
Estimated Exposure To The Estimated Exposure To The National PopulationNational Population
Between 320 – 360 mr/yr
Another Look at SourcesAnother Look at Sources
Some Exposure LimitsSome Exposure Limits 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 >25r Volunteers only / Federal
Ref - 10CFR PART 20, EPA 400, FL-SOP
Security Security
All Radioactive Materials must be secured or under direct supervision at all times
There MUST be someone in the room at all times OR the door must be locked.
Spill ResponseSpill Response
On Skin—flush completelyOn Clothing—removeIf Injury—administer first aidRadioactive Gas Release—vacate area,
shut off fans, post warningMonitor all persons and define the area of
contamination
ALARAALARA
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 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.
Radiation ProtectionRadiation Protection
Decrease Time
Increase Distance
Increase Shielding