THE HOMOGENEITY CONTROL OF REFERENCE MATERIALS BY PHOTON ACTIVATION
Instrumental photon activation analyses can present two aspects: the bulk determination of trace elements with good sensitivity in the sub- ppm levels for some elements and the homogeneity control of reference materials with high precision. For the non-destructive and multi-element control of homogeneity by photon activation, the reference materials are activated in the 44 MeV Bremsstrahlung produced by the GELINA electron linear accelerator using two irradiation arrangements. (a) In the case of Ce, Co reference samples and NBS SRM-1645 river sediment samples; the samples (400 mg each) and standards (In and Sn) are placed around the rotation axis of the sample holder so that each sample or standard is alternatively rotated through the centre of the photon beam and activated.(b) In the case of Bessines mineral samples and natural Moroccan phosphate rock samples BCR CRM 32, the central position irradiation arrangement is used and a stack of samples (250 mg each) and standards are activated together continuously. The inhomogeneity found in the five reference samples is less than 1 % at the 99.73 % confidence level.
Bibliographic Reference: INTERN. J. ENVIRON. ANAL. CHEM, VOL. 16 (1983), PP. 227- 236
Record Number: 1989122067400 / Last updated on: 1987-01-01
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