BERTHOLD TECHNOLOGIES LB4710-050, User Manual

Page: 100 / 227

Chapter 11 Radiation Protection
Mini-Switch LB 471
100
Distance
This means the distance between the radioactive source and the
human body. The radiation intensity (dose rate) decreases – like
light – in proportion to the square of the distance: doubling the
distance to the source reduces the dose rate to one quarter.
Conclusion:
If work is to be performed in the vicinity of facilities containing
radioactive substances, maximum distance has to be maintained.
This is especially true for persons who are not directly involved in
this work.
Time
The total time a person stays in the vicinity of a radiometric meas-
uring system and the body is exposed to radiation. The effect is
cumulative and increases therefore with the duration of the radia-
tion exposure.
Conclusion:
Any work in the vicinity of radiometric measuring systems has to
be prepared carefully and organized such that it can be carried out
in the shortest time possible. Having the proper tools and aids
handy is of particular importance.
Shielding
The material surrounding the source provides the shielding effect.
As the shielding effect depends, following an exponential function,
on the product of thickness multiplied by the density, it follows
that material with a high specific weight is used for shielding pur-
poses. The shielding supplier usually calculates suitable dimen-
sions.
Conclusion:
Before mounting or dismounting the shielding, make sure that the
radiation exit channel is
locked in the closed position.
You may not remove the source from the shielding!
Distance
Time
Shielding



