LUDLUM 44-9, Manual

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Model 44-9 Alpha, Beta and Gamma Detector
Ludlum Measurements, Inc. Page 1 December 2016
Introduction
The Ludlum Model 44-9 GM (Geiger-Mueller) Detector
detects alpha, beta, and gamma radiation. Its size and shape
(pancake) provide easy handling for surveying or personnel
monitoring. The detector is energy dependant, over-responding
by a factor of 6 in the 60 keV to 100 keV range when
normalized to
137
Cs.
The thin mica window is protected by a 79% open stainless
steel screen. The GM tube can be easily removed for
replacement if necessary.
This detector operates between 850-1000 volts, with a
recommendation from the tube manufacturer of approximately
900 Vdc. Recommended instrument input sensitivity is
approximately 30 mV or higher to prevent the detector from
double pulsing (where the detector “counts” a single pulse
from the instrument multiple times.)
Caution!
The GM tube face can rupture above 8000 feet in
altitude. When transporting this detector by air, use an
airtight container in order to avoid sudden atmospheric
changes resulting in tube failure.
The Ludlum Model 44-9 will operate with any Ludlum
instruments or equivalent instruments that provide 900 Vdc
and an input sensitivity of approximately 30 mV or higher.