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Resolve ™ Filters for alpha source preparation

Resolve ™ Filters for alpha source preparation . Charleston, SC May 4, 2004. Resolve ™ Filters. 0.1μ polypropylene. 25mm disks. Uniform pore size distribution. Quality control appropriate for α-spectrometry. Product Development/Validation. Evaluation of Resolve Filters

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Resolve ™ Filters for alpha source preparation

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  1. Resolve™ Filtersfor alpha source preparation Charleston, SC May 4, 2004

  2. Resolve™ Filters 0.1μ polypropylene 25mm disks Uniform pore size distribution Quality control appropriate for α-spectrometry

  3. Product Development/Validation • Evaluation of Resolve Filters • Comparison with commercially available filters • Supplier #1 • Supplier #2 • Evaluate performance (alpha spec) and appearance (SEM) • Validate lot-to-lot variability of supplier • Assurance of filter quality

  4. Known “poor” performing lot Known “well” performing lot Reported Lot-to-lot VariabilityFilter Supplier #1, 1500x

  5. Supplier #1: 1500 X Supplier #2: 1500 X Eichrom Filter: 1500 X SEM Comparison

  6. Eichrom lot A Eichrom lot B Eichrom lot D Eichrom lot C Various Lots of Eichrom Filters 1500x

  7. Eichrom lot B Known “poor” performing lot Eichrom lot D Eichrom lot C Compared to “Poor Performing” Lot 1500x Eichrom lot A

  8. Eichrom lot A Eichrom lot B Known “well” performing lot Eichrom lot D Eichrom lot C Compared to “Well Performing” Lot 1500x

  9. Filter Blank Comparison1000 minute direct countMeasured activity (pCi) in the U-232 region

  10. Am-243 FWHM: 32 keV Am-241 FWHM: 31 keV U-232 FWHM: 23 keV Alpha Spectra – lot 292218

  11. Am-243 FWHM:28 keV Am-241 FWHM: 32 keV U-232 FWHM:29 keV Alpha Spectra: Lot 264825

  12. Quality Assurance Program • Screening of filter material roll stock • SEM • Visual evaluation • Pore size uniformity: subjective determination • Alpha Spectrometry • Am-241/243; 50µg Ce • FWHM each peak <= 50 keV

  13. A little background on filters • Design and specification set on “removal” of particles from liquids. • Nominal “pore size” related to the size of particles removed from the liquid. • In alpha spec source prep the major consideration should be a uniform pore size to give the best source. • “Shiny side” apparent on some types of filters indicating different performance each side.

  14. 1µ “0.1 micron” pore size filter 15,000x Designed to remove 99.98% of particles >0.1µ Surface pores > 0.1µ will occur Goal of Eichrom product is uniform pore size

  15. 1µ Resolve “0.1 micron” pore size filter 15,000x

  16. Two sides of the filter“Inside” and “Outside” of the Roll Stock(5,000x magnification) Inside Lot 292218 Outside Lot 292218

  17. Peak Resolution EvaluationFWHM (keV)

  18. External Product Evaluation • Barry Stewart, Carlsbad EMRC • “These filters are superb for use in making sources for alpha spectroscopy.” • Am 241/243 • With and without substrate • ASTM C1163-98, LaF3 ppt., 50 µg La carrier • “Glossy side” up and down

  19. External Results

  20. Summary • Eichrom now supplies a 0.1µ polypropylene filter for alpha spec source prep • Pore size uniformity is monitored by SEM analysis and performance is measured by FWHM of Am-243/241 (specification <= 50 keV.) • Performance demonstrated at Eichrom and externally. • Both sides of filter are equivalent: no need to “put the shiny side up.”

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