Troxler 3430-M, Manual Of Operation And Instruction

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INTRODUCTION
The Model 3430 Surface Moisture-Density Gauge can quickly and
precisely determine the moisture and density of soils, soil bases,
aggregate, concrete and asphaltic concrete without the use of core
samples or other destructive methods.
Using direct transmission or backscattered gamma radiation, the
3430 gauge determines the density of materials by counting the
number of photons emitted by a cesium-137 source. Geiger-Mueller
(G-M) detectors located in the gauge base detect the gamma
radiation and a microprocessor converts the counts into a density
reading.
Using the principle of neutron thermalization, the Model 3430
determines the moisture content of soils and soil-like materials.
Hydrogen (water) in the material slows neutrons emitted from an
americium-241:beryllium source (or californium-252 in the Model
3430-M). Helium-3 detectors located in the gauge base detect the
slowed neutrons.
The nuclear method of testing density and moisture has been
approved by the American Society of Testing and Materials
(ASTM). The Model 3430 meets or exceeds all the requirements of
ASTM Standards C1040, D2922, D2950, and D3017.
Some information contained in this manual is used in training
courses offered by Troxler Electronic Laboratories, Inc. and to assist
purchasers in obtaining a Radioactive Materials License from the
U.S. Nuclear Regulatory Commission or an Agreement State.
Owners of this gauge must maintain a current radioactive materials
license as long as they own the gauge, even if it is in storage and not
actively being used.