THERMAL NEUTRON ABSORPTION BY ELEMENTS IN SOIL AND CORRECTION OF MOISTURE CONTENT MEASURED BY NEUTRON MOISTURE METER

Journal Article · Tue Jan 01 04:00:00 EST 1963 · Proc. Japan Conf. Radioisotopes

OSTI ID:4690974

Ono, H

It is a characteristic feature of a neutron moisture meter that measured values are more or less influenced by the composition of the material. The counting rate of thermal neutrons decreases in this meter when a measured material contains elements of large absorption cross section for thermal neutrons. It is necessary in such cases to correct the moisture content measured by the moisture meter. Chlorine's absorption cross section is especially large, compared with other elements found in soil, and even a small amount has much influence on the indication of the meter. There are some cases when the existence of nitrogen and iodine cannot be considered negligible. It is very troublesome to prepare various samples which contain proper amounts of these elements so that one may obtain correction factors from experiment. Thermal neutron flux incident into a detector can be calculated from the two group diffusion equations of neutrons. Accordingly, the decrease of thermal neutron counting rate due to the existence of special eiements can be calculated, too. A correcting method by calculation is offered in this paper. A good agreement is found between experiments and calcuiations for various concentrations of chlorine in salt water. This correcting method was successfully applied to a field test exercised in the reclaimed formation near the coast. (JAIF)

• Research Organization: Central Research Inst. of Electric Power Industry
• NSA Number: NSA-17-030091
• OSTI ID: 4690974
• Journal Information: Proc. Japan Conf. Radioisotopes, Journal Name: Proc. Japan Conf. Radioisotopes Vol. Vol: 5th, No. 3
• Country of Publication: Country unknown/Code not available
• Language: Japanese

Related Subjects

ABSORPTION
CHLORINE
CROSS SECTIONS
DIFFUSION
ELEMENTS
EQUATIONS
GENERAL AND MISCELLANEOUS
HUMIDITY
IODINE
NEUTRON FLUX
NEUTRONS
NITROGEN
QUANTITY RATIO
RADIATION DETECTORS
SALTS
SOILS
WATER