The performance and radiation exposure of some neutron probes in measuring the water content of the topsoil layer

Soil Research ◽  
1997 ◽  
Vol 35 (6) ◽  
pp. 1397 ◽  
Author(s):  
A. Arslan ◽  
A. K. Razzouk ◽  
F. Al-Ain
Keyword(s):  
Radiation Exposure ◽  
Water Content ◽  
Soil Surface ◽  
Surface Probe ◽  
Neutron Probe ◽  
Depth Probe ◽  
Straight Line ◽  
In Situ Calibration ◽  
Percentage Water Content

The use of neutron scattering technique for determining the soil surface water content is not popular due to the radiation escaping from the soil surface and the large errors in measurement. To compare the radiation exposure and the performance of different techniques statistically, 3 sites were selected. Five different neutron probe models and different adaptors were used with the depth probes. Exposure to neutrons and γ radiations, at various distances from the probes, were determined. In situ calibration curves were determined using different models of depth probes with a Solo surface reflector block, CPN surface adaptor, and different numbers of plastic Teflon parallelepiped, as well as surface Troxler 3401-B probes. Depth neutron probe readings increased with increasing number of Teflon plastic blocks deposited on the soil surface. The intercept of the straight line regression analysis of CR (count ratio, surface count over standard count) u. percentage water content on a volume basis decreased with increasing number of blocks deposited on the soil surface at all sites. The determination coefficient values of any depth probe with a Solo surface reflector or a block of 4·8 cm thickness were higher than those of a Troxler 3401-B surface probe or CPN 503 depth probe with its surface adaptor. The least exposure to radiation was with a depth probe with surface reflectors. This study proves the possibility of measuring the moisture content of the soil surface by using a depth neutron probe with a block laid on the surface, without danger of receiving the threshold dose of radiation.

Analysis of Water Budgets in Semi-Arid Lands from Soil Water Records

1995 ◽  
Vol 31 (2) ◽  
pp. 131-150 ◽  
Author(s):  
C. J. Pilbeam ◽  
C. C. Daamen ◽  
L. P. Simmonds
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Surface ◽  
Total Evaporation ◽  
Growing Seasons ◽  
Neutron Probe ◽  
Unsaturated Hydraulic Conductivity ◽  
Probe Measurements

SUMMARYFour components of the water budget for a growing season, namely storage, drainage, transpiration and direct evaporation from the soil surface, were estimated using a suite of techniques. The only data requirements were rainfall, neutron probe measurements of soil water content and microlysimeter measurements of evaporation from the soil. Data from four growing seasons at Kiboko, Kenya between 1990 and 1992 were used to provide examples of the estimations. Drainage was significant (about 10% of rainfall) in one season only; in the other seasons, total evaporation comprised at least 95% of the seasonal rainfall.Drainage was determined using a relationship between unsaturated hydraulic conductivity and soil water content that was determined during the early part of the rainy season when water was penetrating to depth. This analysis made it possible to identify a critical water content at the base of the soil profile, above which there would be significant drainage. However, there are large errors associated with estimation of drainage if significant drainage occurs.Estimates of direct evaporation from the soil surface were used as the basis of distinguishing transpiration from total evaporation. Microlysimetry was used to develop a model of evaporation from these sandy soils, which was based on the assumption that the evaporation from the soil surface following heavy rainfall is a unique function of time from rainfall, and little influenced by the presence of a sparse crop. This method showed that direct evaporation from the soil accounted for between 70 and 85% of total evaporation in seasons when total evaporation estimates ranged from 150 to 325 mm.

scholarly journals Neutron probe measurement of soil water content close to soil surface

1993 ◽  
Vol 50 (3) ◽  
pp. 333-337 ◽  
Author(s):  
M.C. Falleiros ◽  
A. Ravelo Sanchez ◽  
M.Dornelas de Souza ◽  
O.O.S. Bacchi ◽  
J.E. Pilotto ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Surface ◽  
Slow Neutron ◽  
Neutron Probe ◽  
Points Of View ◽  
Red Latosol ◽  
Sphere Of Influence

The problem of neutron probe soil water content measurements close to soil surface is analysed from the spatial variability and also from the slow neutron "loss" to the atmosphere points of view. Results obtained on a dark red latosol of the county of Piracicaba,SP, indicate the possibility of precisely measuring the neutron "sphere of influence" when different media are used on soil surface.

scholarly journals Performance of the SoLid reactor neutrino detector

2019 ◽  
Vol 219 ◽  
pp. 08003
Author(s):  
Maja Verstraeten
Keyword(s):  
Quality Control ◽  
Energy Resolution ◽  
Neutrino Detector ◽  
Channel Response ◽  
In Situ Calibration ◽  
Reactor Neutrino ◽  
Li Isotope ◽  
Better Than

The SoLid Collaboration is currently operating a 1.6 ton neutrino detector near the Belgian BR2 reactor. Its main goal is the observation of the oscillation of electron antineutrinos to previously undetected flavour states. The highly segmented SoLid detector employs a compound scintillation technology based on PVT scintillator in combination with LiF-ZnS(Ag) screens containing the 6Li isotope. The experiment has demonstrated a channel-to-channel response that can be controlled to the level of a few percent, an energy resolution of better than 14% at 1 MeV, and a determination of the interaction vertex with a precision of 5 cm. This contribution highlights the major outcomes of the R&D program, the quality control during component manufacture and integration, the current performance and stability of the full-scale system, as well as the in-situ calibration of the detector with various radioactive sources.

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