Role of Quenching on Alpha/Beta Separation in Liquid Scintillation Counting for Several High Capacity Cocktails

Abstract

The optimization of alpha/beta separation in liquid scintillation using pulse shape analysis is convenient for the simultaneous determination of alpha and beta emitters in natural water and other samples. In this work, alpha/beta separation was studied for different scintillant/vial combinations and it was observed that both the optimum pulse shape discrimination level and the total interference value (that is, the summed relative interference between alpha and beta spectra) were dependent on the sample quenching and independent of the scintillant/vial combination. These results provide a simple method for modifying the counting configuration, such as a change in the cocktail, vial or sample characteristics, without the need to perform exhaustive parameter optimizations. Also, it was observed that, for our counting conditions, the combination of Ultima Gold AB scintillation cocktail with Zinsser low diffusion vials presented the lowest total interference, namely 0.94 ± 0.28%, which is insignificant for the counting of environmental samples.

References

1. F. Schönhofer, Analyst, 1989, 114, 1345.
2. L. Salonen, Sci. Total Environ., 1993, 130/131, 23.
3. R. Blackburn and M. S. Al-Masri, Analyst, 1993, 118, 873.
4. R. Blackburn and M. S. Al-Masri, Analyst, 1994, 119, 465.
5. APHA–AWWA–WEF, Standard Methods for the Examination of Water and Wastewater, American Public Health Association, Washington, DC, 18th edn., 1992.
6. SCA, Measurement of Alpha and Beta Activity in Water and Sludge Samples: Methods for the Examination of Waters and Associated Materials, Standing Committee of Analysts, London, 1986.
7. J. W. McKlveen and W. J. McDowell, Nucl. Instrum. Methods, 1984, 223, 372.
8. L. Kaihola, T. Oikari and J. Suontausta, in Liquid Scintillation Spectrometry, ed. Cook, G. T., Harkness, D. D., MacKenzie, A. B., Miller, B. F., and Scott, E. M., Radiocarbon, Tucson, AZ, USA, 1995.
9. J. A. Sanchez-Cabeza and Ll. Pujol, Health Phys., 1995, 68, 674.
10. Y. Yu-fu, B. Salbu, H. E. Bjørnstad and H. Lien, J. Radioanal. Nucl. Chem. Lett., 1990, 145, 345.
11. K. Rundt, PhD Thesis, Abo Akademi and Wallac Oy, Finland, 1989.
12. Ll. Pujol, PhD Thesis, Universitat Autònoma de Barcelona, 1996.
13. Ll. Pujol, Master Thesis, Universitat Autònoma de Barcelona, 1992.
14. J. Thomson, in Liquid Scintillation Counting and Organic Scintillators, ed. Ross, H. H., Noakes, J. E., and Spaulding, J. D., Lewis, Chelsea, MI, 1991, pp. 19–33.
15. J. M. Pates, G. T. Cook, A. B. Mackenzie and J. Thomson, J. Radioanal. Nucl. Chem. Articles, 1993, 172, 341.
16. L. Kaihola, in International Seminar on Low-level Counting in Environmental Radioactivity Monitoring, Estonian Academy of Sciencies, Tallinn, Estonia, 1990.
17. J. A. Sanchez-Cabeza, Ll. Pujol, J. Merino, L. León, J. Molero, A. Vidal-Quadras, W. R. Schell and P. I. Mitchell, in Liquid Scintillation Spectrometry 1992, ed. Noakes, J. E., Schönhofer, F., and Polach, H. A., Radiocarbon, Tucson, AZ, USA, 1993, pp. 43–50.
18. T. A. DeVol, D. D. Brown, J. D. Leyba and R. A. Fjeld, Health Phys., 1996, 70, 41.