CHECK
EYE FOR CARRYING STRAP
FUNCTION
SWITCH
GAMMA
BETA
METER
METER
SWITCH
METER
500
CAL
HEADSET
HANDLE
CONNECTOR
500
CAL
OFF
BAT
RANGE SWITCH
CAP
OFF
500
BAT
RANGE
500
5
.5
SWITCH
50
50
5
500
50
5
POTENTIOMETERS
LIGHT
METER
.5
LIGHT
BATTERY COVER
5
SWITCH
CAL
BATTERY
COVER
BATTERIES
BATTERIES
CAPTIVE SCREWS
PROBE ASSEMBLY
DCf1102
DCf1101
Figure 11-2. AN/PDR-43F radiac meter.
Figure 11-1. AN/PDR-27S radiac meter.
dose rates at any location inside the ship can be
AN/PDR-43
The AN/PDR-43 shown in figure 11-2 is a
2. The RADIAC METER. The radiac meter is
installed on the bridge. One or more auxiliary readouts
battery-powered, high-range, beta-gamma RADIAC
are located in DCC and other prime locations. The
set used for low- and high-level surveys and, in some
radiac meter has two types of displays--one is for dose
cases, personnel monitoring. It uses a GM detector and
rate and the other is for accumulated dose. The primary
has a built-in Krypton-85 source to check for proper
meter displays the dose rate. The small counter registers
operation on all three operating ranges: 0-5 R/hr
the accumulated dose in rads by counting the rad pulses
(gamma), 0-50 R/hr (gamma), and 0-500 R/hr
from the detector. Each time a dose of 1 rad is
(gamma). GM detectors, such as the AN/PDR-43
accumulated, the radiac meter sounds a loud beep. The
adjust quickly to changes in the level of radiation
range of the small counter is 0 to 9,999 rad. Gamma
intensity. Even when shifting to a different range scale,
intensity is indicated on one of the following four
ranges: 0 to 10 rad/hr, 0 to 100 rad/hr, 0 to 1,000 rad/hr,
only 1 second is required for meter adjustment. At
and 0 to 10,000 rad/hr.
intensities above 500 R/hr, the meter pegs but does not
become saturated. It is calibrated to an accuracy of
For normal operation, the AN/PDR-65 is powered
by the 115-volt alternating current (vac) ship's power.
20 percent.
In an emergency, the radiac operates on four internal,
rechargeable, nickel-cadmium, C-cell batteries, which
AN/PDR-65
are on floating charge. The batteries can power the
The AN/PDR-65 shown in figure 11-3 is designed
radiac for approximately 20 hours.
to detect and measure gamma radiation. The set
Dosimeters
consists of two primary elements as follows:
1. The DETECTOR UNIT. The detector unit
A number of types of radiation dose-indicating
must be located at or near a masthead. The field of view
devices (dosimeters) are in the Navy radiac system.
for the detector of an enveloping base surge cloud and
Dosimeters of interest to the Damage Controlmen are
resultant fallout must be relatively unobscured. As a
the DT-60/PD, the CP-95A/PD, the IM-9/ PD, and
result, if suitable scaling factors are available, gamma
the IM-143/PD.
11-3
