Use of a non-linear method for including the mass uncertainty of gravimetric standards and system measurement errors in the fitting of calibration curves for XRFA freeze-dried UNO/sub 3/ standards
A sophisticated nonlinear multiparameter fitting program was used to produce a best fit calibration curve for the response of an x-ray fluorescence analyzer to uranium nitrate, freeze dried, 0.2% accurate, gravimetric standards. The program is based on unconstrained minimization subroutine, VA02A. The program considers the mass values of the gravimetric standards as parameters to be fit along with the normal calibration curve parameters. The fitting procedure weights with the system errors and the mass errors in a consistent way. The resulting best fit calibration curve parameters reflect the fact that the masses of the standard samples are measured quantities with a known error. Error estimates for the calibration curve parameters can be obtained from the curvature of the ''Chi-Squared Matrix'' or from error relaxation techniques. It was shown that nondispersive XRFA of 0.1 to 1 mg freeze-dried UNO/sub 3/ can have an accuracy of 0.2% in 1000 s.
- Research Organization:
- California Univ., Livermore (USA). Lawrence Livermore Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6760766
- Report Number(s):
- UCRL-81180; CONF-780522-7; TRN: 78-014697
- Resource Relation:
- Conference: ANS topical meeting, Williamsburg, VA, USA, 15 May 1978
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
URANIUM NITRATES
X-RAY FLUORESCENCE ANALYSIS
X-RAY FLUORESCENCE ANALYZERS
CALIBRATION
CALIBRATION STANDARDS
ERRORS
LEAST SQUARE FIT
NONLINEAR PROBLEMS
RESPONSE FUNCTIONS
ACTINIDE COMPOUNDS
CHEMICAL ANALYSIS
FUNCTIONS
MAXIMUM-LIKELIHOOD FIT
NITRATES
NITROGEN COMPOUNDS
NONDESTRUCTIVE ANALYSIS
NUMERICAL SOLUTION
OXYGEN COMPOUNDS
STANDARDS
URANIUM COMPOUNDS
X-RAY EMISSION ANALYSIS
400103* - Radiometric & Radiochemical Procedures- (-1987)