Cih Radiation

Front 1

Atomic Nomenclature

Back 1

Mass Number (A) - the number of protons and neutrons
○ Atomic Number (Z) - the number of protons

Front 2

Alpha

Back 2

1) 4-8 MeV
2) Very Short Penetration
3) Easily Shielded- (paper, etc)
4) A(Z)→(A-4)(Z-2) + α alpha decay

5) QF= 20

Front 3

Beta

Back 3

1) Moderately penetrating (few meters in air, millimeters in tissue)

2) A(Z)→A(Z+1)- Beta goes up one Z

3) Three phase - one particle is 1/3 of the maximum beta energy. If you have 2 Mev of Energy, the average would be 1/3 of this

4) QF- 1

Front 4

Gamma

Back 4

1) Very penetrating

2) Different rays depending on what it is

Front 5

Activity Units

Back 5

1) SI Unit: Becquerel (Bq)
* 1 Bq=1 disintegration per second

* 1 Ci= 3.7 x10^10 Bq

* 1 micro Ci= 37 Kilo Bq

Front 6

Absorbed dose

Back 6

Dose is the absorption of radiation energy per unit mass of absorbed
Conventional dose is the Rad:

* The SI Unit is the Gray (Gy)- The international unit
* 1 Gy=1 joule per kilogram"
* 1 Gy=100 rad

Front 7

Equivallent Dose

Back 7

1) biological damage from a radiation dose
2) Rem= Dose equivalent, Rad=dose
3) Dose equivalent= (Dose in Rad* Quality factors):
* 1 rad of alpha= 20 rem Equivalent Dose

4) Expressed in REMs,
5) SI unit is Sievert
* 1 Sv=100 Rem"

Front 8

QF

Back 8

2) QF (X, Gamma, Beta)-1
3) QF (Alpha)= 20 (internal only)
4) QF (Neutron)=3--20 depending on energy

Front 9

Approximations and assumptions

Back 9

* 1 Reinken exposure = ~1 rad absorbed dose = ~1 rem equivalent dose

Front 10

mRem to mSv

Back 10

1mrem= .01mSv
1mSv= 100 mrem
1 rem= .01 Sv


1 rem= 10 mSv
* mSv are always 1 decimal place to the RIGHT of REM

Front 11

mRem to Rem, mSv to Sv

Back 11

1 rem is 1000 mrem
1 sv = 1000 mSeiverts

Front 12

Regulatory Limits

Back 12

1.public- .1 Rem/yr (1 mSv/yr)
2. Total effective dose equivalent 5 rem/yr (50mSv)
3. Single organ dose equivalent 50 rem/500mSv
4. Lens of the eye- 15 rem/150 mSv
5. Skin dose equivalent- 50 rem/500 mSv
6. Extremity dose equivalent- 50 rem/500 mSv
7. Fetal dose (declared pregnancy)- .5 rem/5 mSv

Front 13

Types of rad detectors

Back 13

1) Ionization chambers
2) Proportional counters
3) Geiger-Müller (GM) tubes
4) Scintillation detectors
5) Semiconductor detectors

Front 14

Radiation Quality- Low LET (Linear Energy Transfer)

Back 14

Energy Transfer)

"Low LET (X-rays, gamma rays)
1. Sparsely ionizing
2. Dose rate dependent
3. Modifiable by radical scavengers
4. Typical dose response function "Linear Quadratic"

Front 15

Radiation Quality- High LET

Back 15

"High LET (neutrons, a-particles)
1. Densely ionizing
2. Dose rate independent
3. Not modifiable by radical scavengers
4. Typical dose response function "Linear"

Front 16

Acute Radiation Symptoms

Back 16

Subclinical ........ 0 - 1 Gy
Hematopoietic......1 - 8 Gy- Survivable
Gastrointestinal......6 - 30 Gy- most of the time they don't make it
Neurovascular (CV/CNS)..10- 30 Gy or more- Always die
Pulmonary - > 10 Gy-

Front 17

Annual Limit of Intake

Back 17

○ Defined as the dose limit divided by the dose conversion factor
○ Dose limit may be either stochastic or non-stochastic
○ Different ALIs for inhalation and ingestion

Front 18

Derived Air Concentration (DAC)

Back 18

○ DAC= ALI/volume of air breathed in a year
○ Breathing Rate= 20 l/min
20L60 (hr) 40hrs *50 weeks per yer= 2400 m^3
○ DAC's are in Bq/m^3 or uCi/cm^3
○ There are separate DACs for submersion (noble gasses)

Front 19

DAC Hours

Back 19

2000 working hours = 1 ALI = 5 rem

Front 20

Shielding

Back 20

• Gamma Rays
○ Dl/I=-udx
○ I(x)=I0e^-ux

Front 21

Attenuation Coefficient

Back 21

Attenuation: (coefficient = μ (cm−1)):determines the decrease in beam
"intensity: due to a combination of absorption and scattering. (Linear attenuation coef.).

Front 22

Photoelectric, Compton and Pair Production

Back 22

1) Photoelectric- knocking out inner electron shell

2) Compton scattering- outer shell electron knocked off

3) Pair production- all energy above 1.022 transferred to electrons and abosorbed