Radiation Pager-S User’s Manual
Copyright 2023 Sensor Technology Engineering, LLC. All rights reserved.
2
2OPERATION
The user interface of the Radiation Pager-S consists of a multicolor Indicator LED and a single digit
numerical Level Display. Together, these two indicators show the status of the instrument and
communicate the intensity of any detected gamma radiation (see Figure 2).
Figure 2: Radiation Pager-S User Interface
The Radiation Pager-S is activated by a three-position rotary Mode Switch. The middle position turns the
instrument off. By rotating the knob right, the instrument is turned on and enables the audible alarm mode.
Conversely, by rotating the knob left, the instrument is turned on and the silent (vibration) alarm mode is
enabled.
When the Radiation Pager-S is turned on, the middle segment of the Level Display flashes while a self-test
is conducted. At the successful conclusion of the self-test the outer segments of the Level Display will light
in a clockwise rotation for 10 seconds while the instrument measures the ambient gamma radiation
background. After the background radiation level has been measured, the instrument is ready for use. The
Radiation Pager-S is now measuring ambient gamma radiation and will alarm if the detected radiation
exceeds the alarm threshold. Every 20 seconds, the period in the Level Display will flash to let the user
know that the instrument is operating properly.
When the detected radiation level exceeds the stored background level by a significant margin, the
Radiation Pager-S will alarm. The alarm is indicated by an illumination of the Level Display, and by either
an audible alarm or vibration, depending on the operating mode of the device. As the Radiation Pager-S is
moved closer to the radiation source, the duty-cycle of the audible alarm or vibration will increase, and the
value on the Level Display will increase. The Level Display readout will range in value from 1 - 9. These
values are a relative indication of the ambient gamma radiation field; no absolute exposure rate data can be
inferred from this readout.
The background radiation level will change as the operator moves from one physical location to another.
When the Update Button is pressed, the Radiation Pager-S alarm threshold is recalculated based on
measurements over the previous six seconds. The Update Button should be pressed:
1) Whenever a ‘U’ appears on the Level Display;
2) When the Radiation Pager-S alarms randomly after having moved to an area of higher background
radiation (i.e. after moving from wood building to brick or concrete building);
3) To increase the dynamic range of the Radiation Pager-S. When the instrument is near a radiation
source, the Level Display and alarm duty-cycle may be maxed out. Pressing the Update Button in
It is important to not turn on the Radiation Pager-S in the vicinity of a radiation source. This will affect
the alarm threshold calculation and will reduce the device’s sensitivity. The alarm threshold can always
be reset, however, by pressing the Update Button.
