16: Requirements and Precautions For the Use of "Radiation Producing
Machines and Devices"
Radiation can be produced by certain pieces of electronic apparatus,
including high voltage power supplies and other high voltage equipment
with an associated vacuum, as a by-product of operation. Questions concerning
the suspected emission of radiation from equipment should be directed
to the "Health Physicist."
Analytical X-ray Installations (top)
The State of New Jersey has set forth requirements for "analytical
x-ray equipment" in Subchapter 21 of N.J.A.C. 7:28, and the "Authorized
User" is responsible to insure that these requirements are met.
"Analytical x-ray equipment" means any device or combination
of devices utilizing x-rays to determine the microscopic structure
or composition of material, including but not limited to, x-ray diffraction,
x-ray spectroscopy, x-ray fluorescence or fluorescence x-ray spectroscopy
equipment. Electron microscopes are not regarded as analytical x-ray
2. General Requirements
a. Warning Signs and Lights
All "analytical x-ray equipment" must have the following
- A clearly visible label, near any switch energizing an x-ray
tube, which bears the radiation symbol and the words: "Caution:
This Equipment Produces X-rays When Energized. To Be
Operated Only By
- A clearly visible label, near the x-ray tube housing, which
bears the radiation symbol and the words: "Caution:
High Intensity X-ray Beam."
- A clearly visible fail-safe* warning light, near any switch
energizing an x-ray tube, labeled with these words: "X-ray
- A clearly visible fail-safe warning light in a conspicuous
the x-ray tube which indicates when the x-ray tube
is producing x-rays.
*As used for the purposes of Section 16, "fail-safe" means
that all failures of warning and safety systems that can reasonably
be anticipated will cause the equipment to fail in a mode such
are safe from exposure to radiation.
b. Operating Procedures and Dose Limits
All analytical x-ray equipment must have the following items and meet
the following requirements:
- Written operating and alignment procedures provided by the manufacturer
or the person in charge of the unit.
- Procedures such that the dose received by the operator during
operation and alignment does not exceed 37.5 mrem in one hour to
hands and forearms and 2.5 mrem in one hour to the whole
body or lens
- A radiation survey to insure that the dose rates transmitted
through the beam stop or from other components of the unit, such
as high voltage rectifiers, do not exceed the limits set
the N.J. Radiation Protection Code.
- Finger or wrist personnel monitors for all persons who operate,
repair or align this equipment.
- A radiation survey each time a new installation is placed into
operation or each time changes are made that could affect
the degree of
- All safety devices, either required by the regulations or provided
at the time of the equipment's installation, must be
maintained in a fully
- Safety devices must be tested
at least once every six months and records kept of the testing.
3. Requirements for Open Beam X-ray Systems
An open beam system is a system for which it is possible to place any
part of the body in any possible x-ray path. In addition to the general
requirements found in paragraph 2 below, the following requirements must
a. Safety Devices
The following items are required:
- A clearly visible warning indicator near each x-ray tube shutter,
which indicates when the shutter is open.
- A barrier between the "Radiation
Area" and the "Restricted
- For new x-ray equipment acquired after February 1, 1980, and
for older equipment transferred from one user to another after
there must be:
- A guard or interlock to prevent entry of any part of the
body into the primary beam
- A beam shutter for each port of the tube housing. The shutter
must be interlocked so that the port will be open
only when the collimator
or apparatus coupling is in place. Shutters
at unused ports must be
b. Dose Rates
- All parts of the system, except the tube housing, shall be constructed
so that, with all shutters closed, the stray radiation
measured 5 cm from any surface does not exceed 0.25 mrem/hour.
- The x-ray tube housing shall be constructed so that, with all
shutters closed, the leakage radiation measured 5 cm from its surface
does not exceed 2.5 mrem/hour.
4. Requirements for Enclosed Beam X-ray Systems
An enclosed beam system is a system in which all possible x-ray paths
are fully enclosed so that any part of the body cannot enter the enclosure.
In addition to the general requirements found in paragraph 2 above, the
following requirements must be met:
a. Safety Devices
There must be:
- Enough interlocks to prevent the generation of x-rays or the
emergence of the primary beam when any section of the enclosure
is opened during
routine operation, alignment or maintenance.
- A chamber or coupled chambers enclosing the radiation source,
sample, detector and analyzing crystal, which cannot be entered
part of the body during normal operation.
- A sample chamber closure with a fail-safe interlock so that no
x-ray beam can enter an open sample chamber.
b. Dose Limits
The equipment must be so constructed that the dose rate due to
leakage radiation at 5 cm from any accessible surface does not
mrem/hour during normal operation.
General Labeling and Warning Sign Requirements (top)
- Any "Radiation
Producing Machine or Device," even if
the production of radiation is incidental to the device or machine's
purpose, must be
labeled on the control panel or a conspicuous surface with a label
stating that ionizing radiation is produced when the machine or
operation. Labels may be obtained from the Office of Environmental
Health and Safety.
- The provisions of Section 9 apply to
Producing Machines and Devices."
General Precautions (top)
- Analytical x-ray equipment is capable of producing primary or diffracted
beams of radiation that are hazardous because of the extremely high exposure
rates. Data on the radiation hazards from such equipment is included
in Appendix I.
- Analytical x-ray equipment should be placed in a room separate
from other work areas whenever possible.
- When not in operation, equipment whose primary purpose is the production
of radiation should be secured in such a way as to be accessible
to, or operable by, authorized personnel only.
- Equipment whose primary purpose is the production of radiation
should not be left operating unattended unless there are suitable
present to show that the equipment is switched on. Open beam
equipment should never be left unattended during operation
without adequate safeguards.
- Tampering with interlocks is strongly discouraged, but it is recognized
that there may be times when such tampering is unavoidable. Explicit
steps must be taken to inform all "Users" of the machine
or device that the particular interlock is inoperable, and a
sign with the individual's name and description of the status
interlock must be placed on the equipment.
- When "Radiation
Producing Machines or Devices" are used
by several people, there must be effective communication on the status
of the machine or device, particularly during repair and modification
- Radiation surveys should be made after each modification
- It is strongly recommended that a suitable ratemeter
with audible output be present in any area in which open beam analytical
is used. A properly placed ratemeter may provide an audible
warning that such equipment is producing radiation.