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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

Resolve™ Filtersfor alpha source preparation

Charleston, SC

May 4, 2004


Resolve filters
Resolve™ Filters

0.1μ polypropylene

25mm disks

Uniform pore size distribution

Quality control appropriate for α-spectrometry


Product development validation
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


Reported lot to lot variability filter supplier 1 1500x

Known “poor” performing lot

Known “well” performing lot

Reported Lot-to-lot VariabilityFilter Supplier #1, 1500x


Sem comparison

Supplier #1: 1500 X

Supplier #2: 1500 X

Eichrom Filter: 1500 X

SEM Comparison


Various lots of eichrom filters

Eichrom lot A

Eichrom lot B

Eichrom lot D

Eichrom lot C

Various Lots of Eichrom Filters

1500x


Compared to poor performing lot

Eichrom lot B

Known “poor” performing lot

Eichrom lot D

Eichrom lot C

Compared to “Poor Performing” Lot

1500x

Eichrom lot A


Compared to well performing lot

Eichrom lot A

Eichrom lot B

Known “well” performing lot

Eichrom lot D

Eichrom lot C

Compared to “Well Performing” Lot

1500x


Filter blank comparison 1000 minute direct count measured activity pci in the u 232 region
Filter Blank Comparison1000 minute direct countMeasured activity (pCi) in the U-232 region


Alpha spectra lot 292218

Am-243

FWHM: 32 keV

Am-241

FWHM: 31 keV

U-232

FWHM: 23 keV

Alpha Spectra – lot 292218


Alpha spectra lot 264825

Am-243

FWHM:28 keV

Am-241

FWHM: 32 keV

U-232

FWHM:29 keV

Alpha Spectra: Lot 264825


Quality assurance program
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


A little background on filters
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.


0 1 micron pore size filter

“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


Resolve 0 1 micron pore size filter

Resolve “0.1 micron” pore size filter

15,000x


Two sides of the filter inside and outside of the roll stock 5 000x magnification
Two sides of the filter“Inside” and “Outside” of the Roll Stock(5,000x magnification)

Inside Lot 292218

Outside Lot 292218



External product evaluation
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



Summary
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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