Radiation Safety Capt. David Ayre CAP, SWR-TX-176

Radiation SafetyCapt. David Ayre CAP, SWR-TX-176

RADIATION

The definition of radiation is the emission (sending out) of waves and/or particles thru space.

TYPES OF RADIATION

TYPES OF RADIATION

• heat

• light

• radio waves

• x-rays

• nuclear

IONIZING OR

NON - IONIZING

• non -ionizing• non - ionizing• non - ionizing• ionizing• ionizing

Nuclear Radiation

One source of radiation is the nuclei of an unstable atom. These radioactive atoms become more stable when the nuclei ejects or emits subatomic particles and/or high-energy photons (gamma rays).

This Is the Way the Atom Probably Looks

NucleusProton

Neutron

Electron

Atomic StructureAtomic Structure

Atomic NumberAtomic number (Z number)

is the number of PROTONS in the nucleus of an atom.

Atomic MassAtomic Mass

(A number),

is the number of PROTONS plus

the number of NEUTRONS in

the nucleus of an atom.

Mass and Charges of Basic Atomic Particles

MassMass ChargeCharge

Proton 1 amu + 1

Neutron 1 amu0 or

neutral

Electron1/2000 amu

- 1

ISOTOPEAtoms with the same atomic number,

but different atomic mass.

6 Protons

6 Neutrons

6 Protons

7 Neutrons

6 Protons

8 Neutrons

Carbon-12(6P + 6N)

Atomic Mass = 12

Carbon-13(6P + 7N)

Atomic Mass = 13

Carbon-14(6P + 8N)

Atomic Mass = 14

IODINE ISOTOPE EXAMPLE

Isotope Atomic MassAtomic Number

Number of Neutrons

I 123 123 53 70

I 125 125 53 72

I 131 131 53 78

Discovery of RadiationHenri Becquerel 1896

Marie Curie-To describe the behavior of uranium and thorium she invented the word “radioactivity” --based on the Latin word for ray.

Ernest Rutherford

Wilhelm Roentgen 1895

RUTHERFORD’S EXPERIMENT

Photographic Plate

TYPES OF RADIATION

Types of Radiation

Mass Charge Stopped By

Alpha 4 + 2 Thin Sheet of Paper

Gamma Ray

No Mass No Charge Several Inches of Lead or Steel

X Ray No Mass No Charge Several Inches of Lead or Steel

Beta 1/2000 - 1 Thin Aluminum

Neutron 1 0 High Hydrogen Content

Electromagnetic Spectrum

INDUSTRIAL USES OF RADIOACTIVE MATERIALS

Power Plants

Medical

Farming

Ranching

Textile

Auto

Soda Can

CASES OF HIGH OCCUPATIONAL EXPOSURE TO RADIATION

Early Scientists

Watch Dial Painters

Nuclear Weapons Research

Military Personnel

Emergency/Medical Personnel

Giga (G) = 1 billion

Mega (M) = 1 million

kilo (k) = 1 thousand

milli (m) = 1 thousandth

micro (u) = 1 millionth

COMMON PREFIXES

The SI UNIT is the_____Becquerel____

which is one nuclear transformation or one disintegration

per second.

Curie

A UNIT used to measure

the activity of a

radioactive source and

equals

37,000,000,000

disintegration's per

second.

UNITS OF MEASUREMENTUNITS OF MEASUREMENT

RoentgenA measure of theionization effect

Gammaand

X radiation have in AIR.

UNITS OF MEASUREMENT

REMA measure of the

biological effect

radiation has on man.

REM

stands for

Roentgen Equivalent Man

UNITS OF MEASUREMENT

Half-LifeThe time required for the amount of

radioactive material to decrease by one

half.

Original Material

Material after one Half-Life

Material after two Half-Lives

HALF-LIVES OF VARIOUS ISOTOPES

IsotopeHalf-Life

Am 241 454 Years

Cs 137 30 Years

Ra 226 1602 Years

I 131 8 Days

Co 60 5.2 Years

FILM BADGES

Radiation will expose film just as

light will.

The greater the dose of radiation the darker the film

will become.

Detecting Radiation and thePHOTOGRAPHIC PROCESS

0561420 T

N JAN 01, 1997 Z1

030000 T29 07469

John DoeLANDAUERLANDAUER

TLD’s use three chips that when

exposed to radiation store the energy.

When the chip is heated it gives off

light proportional to the radiation

absorbed.

THERMOLUMINESCENT THERMOLUMINESCENT DOSIMETERDOSIMETER

OSL’s use two thin Al2O3 strips which when exposed to radiation record Photons (X & d Rays) in the 5 keV / 40 MeV range & Beta Particles in the 150 keV / 10 MeV range.

During analysis, the Al2O3 is stimulated with selected frequencies of laser light, which cause it to become luminescent in proportion to the amount of radiation exposure received.

A third component, for the measurement of Neutrons, is also enclosed. This is a Neutrak 144 Allyl Diglycol carbonate solid state track detector. In this case measurement is made by chemical etching followed by track counting. Energies measured are between 100 keV / 30 MeV.

JOHNDOE

TRAINING

luxelLANDAUER

®

FRONT

OPTICALLY STIMULATED LUMINESCENCE (OSL) OPTICALLY STIMULATED LUMINESCENCE (OSL) DOSIMETERDOSIMETER

Dose Measurement Range

Photon 1 mREM to 1000 REM

Beta Particle 10 mREM to 1000 REMNeutron 20 mREM to 25 REM

Accuracy

Deep DoseDeep Dose = ±15% at the 95% confidence interval for photons above 20 keV

Shallow DoseShallow Dose = ±15% at the 95% confidence interval for photons above 20 keV and beta particles above 200 keV

01 - 01 - 99

0030000 T29 04839

Whole Body (chest)

0554677A2

3073

719

BACK

OPTICALLY STIMULATED OPTICALLY STIMULATED LUMINESCENCE (OSL) LUMINESCENCE (OSL)

DOSIMETERDOSIMETER

OPTICALLY STIMULATED OPTICALLY STIMULATED LUMINESCENCE (OSL) DOSIMETERLUMINESCENCE (OSL) DOSIMETER

The OSL is the principle deviceused to measure radiation exposure personnel.

The OSL will only measure what your body will receive and does not

“protect” from radiation.

A OSL will simply measure what you have been exposed to and willallow us to determine if you havereceived to much radiation.

JohnDoe

TRAINING

luxelLANDAUER

®

RADIATION MONITORING

Radiation Quality is an indication

of the type of radiation received

Radiation Quality Type of Radiation Received

P Gamma Only

CPN Combination Gamma and Neutron

NF Fast Neutron

M Minimal (Less than 1.0 mR)

MAXIMUM PERMISSIBLE MAXIMUM PERMISSIBLE EXPOSURESEXPOSURES

5 REM per Year

Lifetime Dose – ( Age - 18 ) * 5 REM

Recommended exposure while pregnant

500 mREM

Average exposure for Wireline

Logging & Perforating Personnel

150 - 250 mREM per Quarter

Detecting Radiation and the ENCLOSED GAS VOLUME PROCESS

Geiger-Mueller Counters

An enclosed tube has an anode and a cathode and usually an inert gas inside the tube. The radiation enters the tube ionizing the gas thus creating a current flow. The amount of radiation is proportional to

the current flow.

Electrical Current

Measuring Device

Anode +

Cathode -

+ -Voltage Source

Inert Gas

Incident Ionizing Radiation

Detecting Radiation and the SCINTILLATION CRYSTAL PROCESS

e-

e- e- e-

e-e-

P

Optical CouplingGrease

Scintillating Crystal

Preamp

HighVoltage

Dynodes

Photo-Cathode

GlassVacuum Tube

e- ElectronsP Photons

Gamma Ray

Photo-MultiplierTube

A

Milliroentgens

50 100 150 2000

EYEPIECE

D

LENS

C

B

+ +

+ +- -

- -

DIRECT - READING POCKET DOSIMETER

A. Charging Rod

B. Metal Support for Fibers

C. Movable Fine Metal Coated Quartz Fiber

D. Transparent Scale

LENS

Detecting Radiation and the Direct-Read Pocket Dosimeter

493VICTOREEN

mR/h

0

0.1

0.2 0.3

0.4

0.5VICTOREEN

c/m

PHONE

Switch positions are:

• Off

• bat.

• x100• x10• x1

Scale reads from0 to 0.5

VICTOREEN MODEL 493

Ludlum Model 2

01

2 34

5mR/h

ON F

OFF S

HV

OFF

LUDLUMMEASUREMENTS, INC.

SWEETWATER,TEXASMODEL 2

SURVEY METER

BAT

X 10

X 1

X 0.1

Scale Reads from:0 to 5

LUDLUM MODEL 2SURVEY METER

Switch Position Are:• OFF• BAT• X 10• X 1• X 0.1

AUD

What exposure rate is this meter reading?

X 1 _______mREM/hour

X 10 _______mREM/hour

X 100_______mREM/hour

What exposure rate is this meter reading?

X 0.1 ______mREM/hour

X 1.0 ______mREM/hour

X 10 ______mREM/hour

0

0.1

0.30.2

0.4

0.5

mR/h

VICTOREEN 493

LUDLUM MODEL 2

0

2 34

5

1

EXPOSURE RATE

_____ mREM/hour

100 mREM/year (General Public)

500 mREM/year (If Attended Awareness Training)

5 REM/year

OCCUPATIONAL DOSE RATES

BACKGROUND RADIATION DOSE

Source Radiation Received

Radon Gas 200 mREM/year

Daughter Products 28 mREM/year

Food & Water 40 mREM/year

Cosmic Rays 28 mREM/year

Medical Radiation 53 mREM/year

T.V. Consumer Products 7 mREM/year

TOTAL 356 mREM/year

RADIATION DOSES FROM OTHER SOURCES

SOURCE EXPOSURE• One Hour of Jet Flight at 37,000 Feet 2 mREM/hour

• Chest X-Ray or Dental Exam 10 mREM/hour

• Dose to Unborn Child Due to Background 200 mREM/hour

• Pelvic Exam 600 mREM/hour

• Lower GI Series 700 mREM/hour

• Areas of High Background Up to 5000 mREM/year

Biological Effects Due to ExposureCan Be Divided Into Two Groups

EARLY EFFECTS LATE EFFECTS

(ACUTE) (DELAYED)

Blood Count Changes Genetic Damage

Vomiting Increased Cancer Risk

Nausea Shortened Life Span

Death

Some Acute Effects of High Exposure Over a Short Period Are

DOSE (1 week)EFFECT (30 days)

• 30-150 REM Detectable changes in blood counts

• 150-250 REM Nausea and vomiting within 24 hours

• 250-350 REM Death may occur

• 350 REM 50% will Die within 30 days

• 350-600 REM Death will probably occur

• over 600 REM 100% will die within 30 days

Estimated Loss of Life Expectancy From Health Risks

HEALTH ESTIMATES OF DAYS OF

RISK LIFE EXPECTANCY

LOST, AVERAGE

Smoking 20 2370 (6.5 years)

Cigarettes/Day

OVERWEIGHT 435 (1.2 years)

(by 20 %)

RISK CHART CONTINUED

AUTO ACCIDENTS

200 DAYS

ALCOHOL CONSUMPTION

130 DAYS

RISK CHART CONTINUED

HOME ACCIDENTS

95 DAYS

DROWNINGS’

41 DAYS

RISK CHART CONTINUED

SAFEST JOBS

(SUCH AS ………………..)

30 DAYS

NATURAL

BACKGROUND

RADIATION (Calculated)

8 DAYS

RISK CHART CONTINUED

1 REM Occupational Radiation Dose

Calculated (Industry Average Is 0.34 REM/year)

1 DAY

1 REM/year for 30 Years, Calculated

30 DAYS

5 REM/year for 30 years, Calculated

150 DAYS

Everyday Items Containing Radioactive Materials

Scale Found on Oil Field Pipe

Brazil NutsSmoke DetectorsLantern MantlesSome CeramicsSalt Substitutes

ALARA PRINCIPLE

ALARA

stands for AS LOW AS REASONABLY

ACHIEVABLE

REDUCING YOUR EXPOSURE

The three most important safety rules to remember while

working with radiation areTimeTime

Distance Distance

ShieldingShielding

The Effect of Time on Radiation Exposure

EXPOSURE = DOSE RATE X TIME

For Example: 495 mREM per hour

1 HOUR = 495 mREM

2 HOURS = 990 mREM

3 HOURS = 1485 mREM

The Effect of Distance on Radiation Exposure

The Equation for Calculating

Radiation Exposure as a

Function of Distance:

I 1 x ( D1 ) 2 = I 2 x ( D 2 ) 2

OR

I 2 = I 1 x ( D 1 ) 2

( D 2 ) 2

SHIELDINGSHIELDINGDEFINITION

OF

SHIELDINGUsing some material as a

shield to reduce the radiation

exposure.

SHIELD

GAMMA RAYS

SHIELDING MATERIALS

ALPHA PAPER SKIN SEVERAL

INCHES OF

AIR

GAMMA LEAD STEEL GOLD

BETA TIN THIN DEPLETED

ALUMINUM URANIUM

NEUTRONS WATER WAX PARAFFIN