Model 43-68, 43-68/1, 43-68/2 Gas Proportional Detector
Ludlum Measurements, Inc.
Page 1
February 2011
General
The Ludlum Model 43-68, Model 43-68/1 and Model 43-68/2 are
gas proportional detectors, each having an open window area of
100 cm
2
. They are designed for alpha and beta survey and are
compatible with a number of counting instruments.
The three models are identical in performance specifications and
vary from each other only in the location of the quick disconnect
gas fittings. Both the Model 43-68 and Model 43-68/1 have the
two fittings “topside.” The Model 43-68 fittings are on the same
end as the cable connector, while the Model 43-68/1 has fittings on
opposite corners. The Model 43-68/2 fittings are on the narrow
side of the end of the detector opposite the handle. The cable
connector is also located there on the Model 43-68/2. (Refer to
individual assembly drawings for details.)
Instructions and procedures in this manual apply to all three
models
NOTE:
When changing the Mylar window on a detector, it is not
necessary to recalibrate the instrument as long as a functional
check is performed on the instrument and its readings are
consistent with the readings before the window was replaced
.
