ERROR ANALYSIS OF DUAL-ENERGY GAMMA-RADIATION MEASUREMENTS

被引：29

作者：

OOSTROM, M ^{[1
]}

DANE, JH ^{[1
]}

MISSILDINE, BC ^{[1
]}

LENHARD, RJ ^{[1
]}

机构：

[1] AUBURN UNIV, DEPT AGRON & SOILS, AUBURN, AL 36849 USA

来源：

SOIL SCIENCE | 1995年 / 160卷 / 01期

关键词：

D O I：

10.1097/00010694-199507000-00004

中图分类号：

S15 [土壤学];

学科分类号：

0903 ; 090301 ;

摘要：

Dual-energy gamma radiation systems are currently used to simultaneously determine either the dry bulk density of a porous medium and the volumetric content of one fluid, the volumetric fluid contents of two fluids, or the salt concentration and volumetric mater content. In this paper an error analysis based on the well-known error propagation formula is presented for all three types of measurements. For each application, formulae are derived that calculate the variance of a measured variable as a function of the observed count rates, attenuation coefficients, and path length. These formulae can be implemented in data acquisition or postprocessing programs. In addition, formulae are presented that relate the variance to the values of the measured variables, measurement counting time, calibration counting time, path lengths, source intensities, and attenuation coefficients. The latter formulae benefit experimental design. The effect of counting and calibration time, attenuation coefficients, source strengths, and path lengths on the probable error are demonstrated. For each type of measurement, experiments are conducted to test the validity of the presented theory. It was shown that, in general, the difference between the measured value and the true value of a variable is less than 1 standard deviation.

引用

页码：28 / 42

页数：15

共 14 条

[1]

Bevington P.R., Data Reduction and Error Analysis for the Physical Sciences, (1969)

[2]

Dane J.H., Oostrom M., Missildine B.C., An improved method for the determination of capillary pressure-saturation curves involving TCE, water and air, J. Cont. Hydrol., 11, pp. 69-81, (1992)

[3]

Ferrand L.A., Milly P.C.D., Pinder G.F., Dual-gamma attenuation for the determination of porous medium saturation with respect to three fluids, Water Resour. Res., 22, pp. 1657-1663, (1986)

[4]

Ferrand L.A., Milly P.C.D., Pinder G.F., Experimental determination of three-fluid saturation profiles in porous media, J. Cont. Hydr., 4, pp. 373-395, (1989)

[5]

Gardner W.H., Campbell G.S., Callissendorff C., Systematic and random errors in dual gamma energy soil bulk density and water content measurements, Soil Sci. Soc. Am. J., 36, pp. 393-398, (1972)

[6]

Grismer M.E., McWhorter D.B., Klute A., Monitoring water and salt movement in soils at low solution contents, Soil Sci., 141, pp. 163-171, (1986)

[7]

Hopmans J.W., Dane J.H., Calibration of a dual-energy gamma radiation system for multiple point measurements in a soil, Water Resour. Res., 22, pp. 1109-1114, (1986)

[8]

Knoll G., Radiation Detection and Measurement, (1979)

[9]

Lenhard R.J., Dane J.H., Parker J.C., Kaluarachchi J.J., Measurement and simulation of one-dimensional transient three-phase flow for monotonic drainage paths, Water Resour. Res., 24, pp. 853-863, (1988)

[10]

Lenhard R.J., Johnson T.G., Parker J.D., Experimental observations of nonaqueous-phase liquid subsurface movement, J. Cont. Hydr., 12, pp. 79-101, (1993)

← 1 2 →