Radiation type

1. Alpha Particles: 2 neutrons and 2 protons
They travel short distances, have large mass
Only a hazard when inhaled
Four Primary Types of
Four Primary Types of
Ionizing Radiation:
Ionizing Radiation:
Alpha Particles
Alpha Particles

2. Four Primary Types of
Four Primary Types of
Ionizing Radiation:
Ionizing Radiation:
Beta Particles
Beta Particles
Beta Particles: Electrons or positrons having small mass and
variable energy. Electrons form when a neutron transforms into a
proton and an electron or:

3. Four Primary Types of
Four Primary Types of
Ionizing Radiation:
Ionizing Radiation:
Gamma Rays
Gamma Rays
Gamma Rays (or photons): Result when the nucleus releases
Energy, usually after an alpha, beta or positron transition

4. Four Primary Types of
Four Primary Types of
Ionizing Radiation:
Ionizing Radiation:
X-Rays
X-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

5. Four Primary Types of
Four Primary Types of
Ionizing Radiation:
Ionizing Radiation:
Neutrons
Neutrons
Neutrons: Have the same mass as protons but are uncharged
They behave like bowling balls

6. Four Primary Types of
Four Primary Types of
Ionizing Radiation
Ionizing Radiation
Alpha particles
Beta particles
Gamma rays (or photons)
X-Rays (or photons)
Neutrons

7. RADIATION
RADIATION
FUNDAMENTALS
FUNDAMENTALS
ATOMIC AND NUCLEAR
ATOMIC AND NUCLEAR
STRUCTURE
STRUCTURE
Bureau of Radiation Control

8. Radioactivity: Elements &
Radioactivity: Elements &
Atoms
Atoms
Atoms are composed of smaller particles
referred to as:
– Protons
– Neutrons
– Electrons

9. 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.

10. Types or Products of Ionizing
Types or Products of Ionizing
Radiation
Radiation


or X-
ray
neutron

11. Ionizing Radiation
alpha particle
beta particle
Radioactive Atom
X-ray
gamma ray

12. Ionizing Radiation
alpha particle
beta particle
Radioactive Atom
X-ray
gamma ray

13. Direct Ionization Caused By:
Direct Ionization Caused By:
Protons
Alpha Particles
Beta Particles
Positron Particles

14. Indirect Ionization Caused By:
Indirect Ionization Caused By:
Neutrons
Gamma Rays
X-Rays

15. DNA and Radiation
DNA and Radiation

16. Ionizing Radiation at the
Ionizing Radiation at the
Cellular Level
Cellular Level
 Causes breaks in
one or both DNA
strands or;
 Causes Free Radical
formation

17. Commonly Transported
Commonly Transported
Radioisotopes
Radioisotopes
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.

18. Radiation Measurement
Radiation Measurement
Terminology:
– Exposure rate = amount radiation possible to
receive per unit time.
– Dose = total amount of radiation received.

19. Radiation and Radioactivity:
Radiation and Radioactivity:
Units and Quantities
Units and Quantities
Department of Health
Bureau of Radiation Control

20. 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 ...

21. Objectives
Objectives
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”

22. Background
Background
Early risk associated with use of ionizing
radiation
skin erythema dose - 25yrs
1928 - ROENTGEN introduced by ICRP

23. Roentgen
Roentgen

24. Roentgen
Roentgen
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”)

25. rad
rad

26. rad
rad
1 rad = 1 Roentgen

27. rem
rem

28. rem
rem
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 rem
1 rem = 1 Roentgen
 Roentgen Equivalent Man

29. 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

30. 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

31. SI Radiation Protection Units
SI 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

32. Unit Analysis
Unit Analysis
BASE UNIT CONVERSION TABLE
Unit Unit Conversion
1 Bq 2.7 x 10-11
Ci
1 Ci 3.7 x 1010
Bq
1 Bq 1 dis/sec
1 dis/sec 2.7 x 10-11
Ci
1 Ci 3.7 x 1010
dis/sec

33. Unit Analysis (Con’t.)
Unit Analysis (Con’t.)
BASE UNIT CONVERSION TABLE
Unit Unit Conversion
1 rem 0.01 Sv
1 Sv 100 rem
1 rad 0.01 Gy
1 Gy 100 rad
1 R 2.58 x 10-4
C/kg
1 meter 3.28 ft (39.37in)

34. Summary
Summary
Radiation Protection unit definitions
(including SI units)
Unit Prefixes
Unit conversions

35. Old Terms
Old 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

36. More Old Terms
More Old Terms
REM- Roentgen Equivalent Mammal is equal to the
absorbed does in RADS multiplied by a quality factor
Quality Factors
Beta = 1
Gamma & X ray photons = 1
Alpha = 10
Neutrons = 20

37. New Terms
New Terms sort of
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

38. Units of Radioactivity
Units of Radioactivity
 Curie (Ci) = 2.22 E12 dpm or 3.7E10 dps
Becquerel (Bq) = 1 dps
Maximum Dose/year = 5 REM or 50 mSv
Maximum Dose/year for Declared Pregnant
Woman & Minors= 0.5 REM or 5 mSv

39. Half Life Calculation
Half Life Calculation

40. Annual Dose Limits
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 5000 mrem/yr

41. Dose Response Relationships
Dose Response Relationships
0-150 rem—No or minimal symptoms
150-400 rem—Moderate to severe illness
400-800 rem—Severe illness deaths start
above 500 rem
Above 800 rem—Fatal
***Acute whole body doses

42. Your Annual Exposure
Your Annual Exposure
Activity Typical Dose
Smoking 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/year
Cross country round trip by
air
5 millirem per trip
Coal Burning power plant
0.165
millirem/year

45. Estimated Exposure To The
Estimated Exposure To The
National Population
National Population
Between 320 – 360 mr/yr

46. Another Look at Sources
Another Look at Sources

47. Some Exposure Limits
Some 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

48. 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.

49. Spill Response
Spill Response
On Skin—flush completely
On Clothing—remove
If Injury—administer first aid
Radioactive Gas Release—vacate area,
shut off fans, post warning
Monitor all persons and define the area of
contamination

50. ALARA
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 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.

51. Radiation Protection
Radiation Protection
Decrease Time
Increase Distance
Increase Shielding