AM-801 Rev 1 Serial #221 - 268 Operation/Technical Manual
W B Johnson July 30, 2018
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2.0 DESCRIPTION
The Model AM-801 is a ruggedized, portable monitor that can be utilized to screen large numbers of persons quickly for low
levels of gamma and beta radiation. The AM-801 utilizes 4 large area plastic scintillators totaling 672 cubic inches to meet
and exceed the measuring requirements of FEMA standard for portable portal monitors. The instrument is weather resistant,
light weight, and easy to assembly without tools. The AM-801 comes with a durable carrying case, complete with wheels.
The system automatically counts the person passing through the portal and is equipped with a real time clock, which displays
the correct date, time and year. All of the data for the system is stored in a non-volatile memory, capable of maintaining the
data for 10 years.
3.0 THEORY OF OPERATION
3.1 GENERAL
The AM-801 utilizes the latest field proven, microprocessor circuitry and large area plastic scintillators to accurately and
rapidly measure beta (above 500 keV) radiation and gamma radiation from 60 keV to 2MeV. The instrument is very user
friendly and can be utilized by persons with minimal training. Radiation detection is by 4 plastic scintillators with a total
volume of 672 cubic inches. Each Scintillator has a 0.031 aluminum window that permits the AM-801 to measure higher
energy beta and gamma radiation to 60 keV. The scintillators are contained in a durable aluminum housing that is very
weather resistant and can be quickly disassembled without tools. The readout and data entry are accessed through a large
area color monitor that utilizes a touch sensitive screen for all data input. FIGURE 1 shows the VGA monitor doing the
BACKGROUND INITILIZATION prior to normal operation. The most pertinent measuring and diagnostic data is
continuously displayed on the monitor. The operator can see some of the data that is to be displayed i.e Detector high voltage
and BKG CPS. Parameters that are or can be displayed include the background count, date and time, number of persons who
have passed through the portal, high voltage, battery voltage, counting rate of each detector, relative energy distribution of
the incoming radiation and software version of each detector. An outline of the monitor and the relative strength of the
radiation field striking each detector is displayed on the green vertical bars. The count rate is displayed by each detector.
Touching the graphic of each detector displays a course spectrum of the radiation energy striking the detector and the signal
with and without background subtract as shown in FIGURE 2. During the startup period, the instrument is automatically
running systems checks, establishing background and verbally stating that the unit is not ready for operation. The upper
center of the portal displays the OPERATIONAL CONDITION of the portal i.e. background initialization, too fast, alarm
etc. and the block below displays the seconds remaining before normal operation can begin.
FIGURE 1 FIGURE 2
