BERTHOLD TECHNOLOGIES LB 444 Operating Manual Download

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04/03

347

LB 444

11.

RADIATION PROTECTION

11.1

Basics and Guidelines

Radioactive isotopes used for density measurements emit gamma radiation. Gamma ra-

diation consists of electromagnetic waves, i.e. a type of radiation which resembles light,
but has a much higher energy, so that it can pass through matter. This high-energy ra-

diation is hazardous to living beings; it can damage cells and cause mutations. To mini-
mize this hazard, one must be extremely careful when handling radioactive substances.
Radioactive sources which are used for density measurements are usually 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. An-

other check ensures that no radioactive particles are deposited on the surface of the cap-
sule. The user will receive an official certificate specifying these features of the radioac-

tive source.
In order to prevent health hazards due to working with radioactive substances, limits for

the maximum permissible radiation exposure of operating personnel have been agreed
upon on an international level. Appropriate measures in designing shieldings and arrang-

ing the measuring system at the measuring location ensure that the radiation exposure
of the personnel will remain 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 relat-
ing to radiation protection.
The Radiation Safety Officer will monitor handling of the radiometric measuring system
and, if necessary, formalize 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 explosion.

Any special event has to be reported to the Radiation Safety Officer immedi-
ately.

He will then investigate any damage and immediately take suitable precautions if

he detects defects that may adversely affect the operation or safety of the system.
The Radiation Safety Officer has to make sure that the provisions of the Radiation Protec-

tion Regulations will be observed. In particular, his duties include instructing the staff on
the proper handling of radioactive substances.
Radioactive sources that are no longer in use or have reached the end of their service life

have to be returned to the national radioactive waste disposal center or to the manufac-
turer.
Generally, every member of staff should endeavor to minimize any radiation exposure –
even within the permissible limits – by careful and responsible action and by observing

certain safety standards.
The total sum of the radiation dose absorbed by a body is dependent upon three factors.

Based on these factors, certain fundamental radiation protection rules can be derived: