Service manual

STP 11-25R13-SM-TG
T - 16
b. RF potentials induced in metal objects may be sufficient to cause electric shock when contacted
by personnel. Although usually insufficient to electrocute personnel directly, the shock may cause the
person involved to react violently and thereby cause injury by falling or striking some object. Smokestack
guys, railings, aircraft, lengths of wire cable, and antennas may have sufficient voltage induced in them to
constitute an electric shock hazard. Personnel working near such objects should be aware of the
potential hazard and ground the object when possible. It should be noted that several grounds may be
needed to provide a RF ground for all surfaces of a large metallic object.
T-21. X-Ray Hazards.
When high velocity electron beams strike metal or certain other materials, X-rays are produced. The
operation of some electronic devices depends on the acceleration of electrons, and when the
accelerating voltage approaches or exceeds 10,000 volts the production of X-rays may become a hazard
to personnel. Examples of such electronic devices are magnetrons, klystrons, thrystons, CRTs, and high
voltage rectifier tubes. Currently radar and CRTs are the primary electronic equipment that uses
sufficient voltage to constitute a hazard. As the accelerating potentials become greater than 10,000 volts,
the X-rays produced have much greater energy and the difficulty of providing adequate shielding
increases appreciably.
T-22. Servicing Electronic Devices That Produce X-Ray Hazards.
When performing preventive or corrective maintenance on electronic devices that produce
hazardous X-ray radiation as an undesirable by-product, maintenance personnel should observe the
following precautions:
a. Observe all warning signs on the equipment and all written safety precautions in the instruction
manuals for the equipment that deals with X-ray hazards.
b. Do not use jumper interlocks that permit the servicing of operating equipment with the
protective X-ray shielding removed, unless such procedures are called for in the instruction manuals.
c. Be sure to replace all protective X-ray shielding when servicing complete so that operating
personnel or others will not unknowingly be subjected to harmful X-ray radiation.
d. When bench testing X-ray-producing electronic devices, be sure that adequate X-ray shielding
is provided to protect all personnel in the testing area.
e. Determine the latest safety precautions, including the use of the latest approved dosimeters, by
consulting the post safety officer, health physicist, or the industrial hygienist at post installations.
f. The local Radiological Protection Officer will be requested to determine if X-rays are produced
and the extent of the hazard. Film badges will be worn when required by AR 40-14.
g. Electronic devices that produce an X-ray hazard will be labeled to warn personnel of this
hazard.
h. Warning placards will be properly posted in the vicinity of X-ray hazards.