Measurement of thermal neutron constants of the soil: application to the calibration of neutron moisture gauges and to the pedological study of soil

Conference · Wed Oct 01 04:00:00 EDT 1975 · Natl. Bur. Stand. (U.S.), Spec. Publ.; (United States)

OSTI ID:7276200

Couchat, P ^[1]; Carre, C; Marcesse, J; Le Ho, J

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1. CEN Cadarache, Saint-Paul-les-Durance, France

The neutronic method for measuring the water content of soils is more and more used by agronomists, hydrogeologists and pedologists. On the other hand the studies on the phenomena of slowing down and diffusion process have shown a narrow relation between the thermal absorption (..sigma../sub a/) and diffusion (..sigma../sub d/) constants and the thermal flux developed in the soil around a fast neutron source like Am-Be. Then, the authors present two original applications of the direct measurement of ..sigma../sub a/ and ..sigma../sub d/. The method described consists in the measurement, in a cube of graphite with an Am-Be source in the middle, on one side of the perturbation of the thermal flux, obtained by the introduction of 300 g of soil, and on the other side of the transmitted thermal flux measured through the same sample of soil, on a side of the cube. After calibrating the device, these two parameters give ..sigma../sub a/ and ..sigma../sub d/ which are easily introduced in the calibration equation of neutron moisture gauge. also these two values are useful for the pedologists because ..sigma../sub d/ is connected to clay content in the soil and ..sigma../sub a/ is connected to the type of clay by the way of rare earth contents.

• OSTI ID: 7276200
• Conference Information: Journal Name: Natl. Bur. Stand. (U.S.), Spec. Publ.; (United States) Journal Volume: 425
• Country of Publication: United States
• Language: English

Related Subjects

440105* -- Radiation Instrumentation-- Radiometric Instruments-- (-1987)
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
510101 -- Environment
Terrestrial-- Basic Studies-- Radiometric Techniques-- (-1989)
54 ENVIRONMENTAL SCIENCES
ABSORPTION
BARYONS
CALIBRATION
CLAYS
DIFFUSION
ELEMENTARY PARTICLES
FERMIONS
HADRONS
MEASURING INSTRUMENTS
MINERALS
MOISTURE
MOISTURE GAGES
NEUTRAL-PARTICLE TRANSPORT
NEUTRON TRANSPORT
NEUTRONS
NUCLEONS
RADIATION TRANSPORT
RADIOMETRIC GAGES
SOILS
THERMAL NEUTRONS