1.11 - EXTERNAL EXPOSURE
CONTROL questions & answers
What are the four basic methods for minimizing personnel
external exposure? - answer 1. Reduce the amount of source
material
2. Reduce the amount of time of exposure to source of radiation.
3. Increase the distance from the source of radiation.
4. Reduce the radiation intensity by using shielding between
source and personnel.
How do you determine gamma radiation field intensity ? - answer
I = R/hr at one foot from a radioactive point source
C= source activity in Curies (Ci)
E= gamma energy in MeV
N= number of gammas per disintegration (photon yield).
*Accurate within +/- 20% for gamma energies between 0.05 MeV
- 3 MeV.
*If N isn't give assume 100% photon yields (1.00
photons/disintegration)
* If more than one photon energy given take sum of each photon
x by its percentage
CONTROL questions & answers
What are the four basic methods for minimizing personnel
external exposure? - answer 1. Reduce the amount of source
material
2. Reduce the amount of time of exposure to source of radiation.
3. Increase the distance from the source of radiation.
4. Reduce the radiation intensity by using shielding between
source and personnel.
How do you determine gamma radiation field intensity ? - answer
I = R/hr at one foot from a radioactive point source
C= source activity in Curies (Ci)
E= gamma energy in MeV
N= number of gammas per disintegration (photon yield).
*Accurate within +/- 20% for gamma energies between 0.05 MeV
- 3 MeV.
*If N isn't give assume 100% photon yields (1.00
photons/disintegration)
* If more than one photon energy given take sum of each photon
x by its percentage
