Ludlum Measurements 2241-2, Руководство пользователя

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Model 2241-2RK Technical Manual
Section 1
Ludlum Measurements, Inc. Page 1-2 July 2012
Other features include: 1) Dead Time Correction (DTC) to compensate for
detector dead time, 2) audible click-per-event with programmable 1, 10, 100,
and 1000 divide-by; 3) LCD backlight with programmable
ON
time, 4)
programmable fixed or variable response time, and 5) count overflow visual
alarm, indicating that the counting circuitry is nearing the maximum
counting capability.
All of the features described above may be programmed manually using the
internal switch board or by computer through the RS-232 port. Two
different detector operating parameters may be stored in non-volatile
memory. The switch board can be removed after entering or changing
parameters to prevent tampering with setup parameters.
A regulated high-voltage power supply and two independent set-point
controls adjustable from 200 to 2500 volts with detector overload detection
and adjustable discrimination levels add versatility to the instrument. This
supports operation for a broad range of detectors and connecting cable
lengths. All of the calibration controls are covered to prevent any inadvertent
adjustment to the detector operating parameters.
The instrument is powered by two standard
˝
D
˝
cell batteries. The unit body
is made of cast-and-drawn aluminum with beige powder coating, which aids
in the decontamination of surfaces.
The Detectors
The Response Kit’s GM (Geiger-Mueller) Pancake Detector, Model 44-9,
will detect alpha, beta, and gamma radiation. Its size and shape provide easy
handling for surveying or personnel monitoring. The detector is energy
dependant, over-responding by a factor of 6 (to gamma radiation) in the 60
keV–100 keV range when normalized to 137
The Model 44-9 operates at 900 volts. The recommended
instrument input sensitivity (set at calibration) is
approximately 30
±
10 mV to prevent the detector from double pulsing.
Cs. The
response of this detector is nominally linear (within 10%)
from 1 mR/hr to 300 mR/hr.
The thin mica window in this detector is protected by a 79% open stainless
steel screen. The GM tube can be easily removed for replacement if
necessary. The GM tube face may rupture above 8000 feet altitude pressure.
Consequently, tube failure is likely if transported above this altitude in an
aircraft not pressurized.