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ROUNDED MODERATOR
DIGITAL
READOUT
DIGITAL
CALIBRATION
RS232 OUTPUT
REMOVABLE
DISPLAY
BORON LOADED
MODERATOR
ENERGY
RESPONSE GRAPH
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The Model
5085 Meridian is a highly evolved neutron REM meter of classic
design. It is an ideal portable instrument for measuring neutrons
in reactors, laboratories and hospitals. The Meridian has a wide
energy response and closely conforms to the ICRU REM response
curve.
The autoranging display has both a digital readout and a bargraph
that simulates a moving pointer. The display is mounted on top
of the moderator which makes it easy to see when it is being carried.
The display also rotates in 2 axes and can be placed at either
end of the moderator; it can be separated for a remote readout.
No matter where you place the moderator, you can usually move
the display so you can read it.
The moderator is a classic boron loaded Anderson Braun design.
One end of the moderator is rounded to give better directional
response. In the moderator, the detector cable passes through
a labyrinth to eliminate streaming. The standard Meridian has
a Bf3 detector; a He3 detector is also available which offers
more sensitivity. The instrument may be carried with the rounded
end or the flat end toward the front with the display moved accordingly.
Specifications
Mechanical
Size overall: 8.5 in. (22 cm) W x 9.5 in. (24 cm) L x 17.5 in.
(45 cm) H. Gasketed splashproof aluminum enclosure. Top panel
is milled and anodized with non-eraseable nomenclature. Bottom
painted. LCD window is acrylic. Handle is acrylic.
Weight:
20.5 lbs (9.3 kg) with batteries.
External
controls: 4 pushbuttons, Power, Mode, Speaker and light. Power
button when held down for 5 seconds resets the microprocessor.
Internal
construction: Circuit board hinges for easy access. Batteries
are mounted on an aluminum panel in nylon holders. ICs are socketed.
All components are standard types.
Electrical
Detectors: Bf3 Standard, He3 available.
Detector
Sensitivity: Bf3: ~12kc/mrem,
He3:~50Kc/mrem,
both with Cf252
Display:
2 line x 20 character alphanumeric supertwist LCD with backlight.
Contrast adjustable from front panel.
Audio:
Built in piezo beeper at 2.4 kHz
Adjustments:
Threshold, HV and contrast digitally set.
High voltage:
Adjustable from 300 to 1800 Volts.
Batteries:
6 AA cells for 100 hour life. Battery condition displayed at turn
on and turn off. Low battery warning during operation. Instrument
will automatically turn off when batteries are too low for proper
operation. May be set for auto turn off.
Calibration
and parameter storage: Data stored in permanent memory for minimum
of 40 years. Batteries not required for storage.
Operational
Modes: 2 modes available, Rate, and Integrate, others programmable.
Calibration, Setup, and Maintenance mode also available.
Units:
Conventional and SI units
Menu selection:
Only one menu.
Rate mode:
Shows numeric value of rate. Updated every second. Limited to
3 significant digits. Autoranging.
Integrate
mode: Shows Integrated dose and integration time. Count-down and
count-up for time.
Bargraph:
Moving digital pointer on background of scale markings. Updated
10 times every second. Bargraph width is 3 in (7.6 cm). Full scale
markings are actively shown on the display.
Calibration:
Calibration accessed through front panel or through battery compartment.
Response
Range: 0.01 to 10,000 mrem/h.
Accuracy:
Within 1% or 2 digits for Count rates independent of detector.
Within 15% for detector. Timebase is crystal controlled.
Time constant:
Dynamically set depending on count rate but has additional settings
of short, med and long.
Dead time
correction: Corrects up to 4 times actual rate.
Gamma Response:
No response up to 500 R/h Cs137.
Environmental
Temperature range: -20°C to 50°C
Humidity
range: 0 to 95% non condensing
Option/equipment
Options: Repair manual, He3 detector, extended range 2GeV moderator
, many different setup configurations, scales and units.
Equipment:
Supplied w/ manual, batteries,
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