Introduction; Intended Use - Fluke 481 Operator's Manual

Introduction

The Model 481 Ion Chamber Survey Meter (the Survey Meter) is a hand-held,
battery operated meter designed to measure beta above 100 keV and gamma
and x-ray radiation above 7 keV, using the latest CMOS and LCD technology.
The Survey Meter case is constructed of high strength ABS plastic. A gasket and
desiccant pack seal moisture out of the Survey Meter and provide a cushion for
the internal components. The readout consists of a 2½ digit liquid crystal display
and a 100 segment analog bar graph. The bar graph contains a zero segment
and 20 groups of five segments each. A permanent scale is located on the
display screen. The major divisions of the scale indicate the units corresponding
to the range that the meter is measuring. The units of measurement show next to
the 2½ digit display. LOW BAT and FREEZE appear on the display when the
Survey Meter is operating in these modes. External controls consist of an
ON/OFF button and a MODE button. The Survey Meter is auto-ranging and auto-
zeroing. The auto-on circuit for the backlight is enabled when twilight conditions
occur. The Survey Meter has an audio alarm that can be set by the user. Two
9 volt batteries, located in the back of the Survey Meter, provide over 200 hours
of continuous operation. A 440 mg/cm2 phenolic shield is provided as a beta
shield. The shield also serves as an equilibrium thickness for photon
measurements & protects the Mylar window.

Intended Use

The 481 Ion Chamber Survey Meter is a hand-held, battery operated unit
designed to measure beta radiation above 100 keV and gamma and x-ray
radiation above 7 keV.
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