GB1259771A - Improvements in radiometric analysis - Google Patents

Abstract

1,259,771. X-ray fluorescence analysis. HILGER & WATTS Ltd. Jan.27, 1969 [Oct.27, 1967], No.49024/67. Heading G1A. In X-ray fluorescence analysis of a slurry, besides the fluorescence analysis measurement itself, separate measurements of absorption are carried out on the slurry so as to correct the fluorescence measurement for variations in the value of the sum (Áe + Áf) of the absorption coefficients for incident and fluorescent radiation respectively. One absorption measurement comprises measuring the absorption, by the slurry, of a beam of y -radiations in the energy range 600-3, 000 KeV. In this measurement the apparatus used may be similar to the absorption measurement device disclosed in Specification 1,103, 562 for measuring the density of slurry, and involves passing the beam through a column of the slurry. The other absorption measurement is carried out with a reflex or backscatter geometry set-up, Fig. 2, and utilizes a target D on the side of the sample cell C remote from the radiation source B which is mounted on the window of a detector A in shielded relation thereto. In this way, characteristic (fluorescent) radiation from the target (which is of the material to be determined in the sample) is absorbed by the slurry sample as it passes therethrough to the detector. In obtaining the latter measurement accurately, certain corrective measurements are necessary: the background radiation is measured, the target not being in position, Fig. 1 (not shown); also standardizing measurements using firstly, Fig. 3 (not shown) a standard absorber alone, and then, Fig.4 (not shown), the standard absorber plus the target, are carried out, this providing a calibration or standardization for each sample and thereby obviating the effects of drift in the detector circuitry which might occur during a sequence of measurements on sequential portions of the sample. The measurement carried out using reflex geometry is dependent on Áe and Áf. This measurement is combined with that for absorption of gamma rays to determine (Áe + Áf) which is then used in order to correct the main fluorescence measurement.