Density Meter LB 444 SECTION 9. RADIATION PROTECTION
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9. RADIATION PROTECTION
9.1 Basics and Guidelines
The radioactive isotopes used for density measurements emit gamma radiation.
Gamma radiation consists of electromagnetic waves, i.e. it is a type of radiation
which resembles light, but has a much higher energy, so that it can pass through
matter. This high-energy radiation is hazardous to living beings; as it can dam-
age cells and cause mutations. To minimize this hazard, one must be extremely
careful when handling radioactive substances.
The radioactive sources used for density measurements are sealed sources, i.e.
the actual radioactive substance is surrounded by at least one, often several
sealed layers made of stainless steel, each of which is checked individually for
leaks. Another check ensures that no radioactive particles are deposited on the
surface of the capsule. The user receives a certificate specifying these features
of the radioactive source.
In order to prevent adverse health effects caused by working with radioactive
substances, limits for the maximum permissible radiation exposure of operating
personnel have been agreed upon at an international level. Appropriate meas-
ures in designing the shieldings and arranging the measuring system at the
measuring location ensures that the radiation exposure of persons remains well
below the maximum permissible value of 5 mSv (500 mrem) per year.
A Radiation Safety Officer has to be appointed who is responsible for all
questions relating to radiation protection. Depending on the nature of the
license covering the installation, he or she is on site in the case of a Spe-
cific License or at PerkinElmer Berthold USA in the case of a General Li-
cense.
The Radiation Safety Officer monitors handling of the radiometric measuring
system and, if necessary, formalize the safeguards and any special precautions
applicable to a given establishment in formal procedural instructions, which in
special cases may serve as a basis for radiation protection guidelines.
These may stipulate that access to the vessel shall only be permitted after the
active beam is shielded. Radiation protection zones outside the shielding must
be - if they are accessible - marked and guarded.
These instructions should also include checks of the shutter device of the
shielding and measures for serious operational trouble - such as fire or explo-
sion.
Any special event has to be reported to the Radiation Safety Officer imme-
diately.
He/she will immediately take suitable precautions if he/she detects de-
fects that may adversely affect the operation or safety of the system.
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