The Determination Of 226 Ra In Soil Samples Lawrence D. Morris General Engineering Laboratories, Inc. Anil H. Thakkar Eichrom Technologies, Inc.

General Engineering Laboratories, Inc. Charleston, SC Objective: Design a reliable method to measure 226 Ra in soil samples by Alpha Spectroscopy thus meeting the current need of our clients.  Faster Turn Around Times than current methods  This procedure utilizes Cation and Eichrom’s Ln Resin  Achieve Peak Resolution (FWHM) of less than 100keV

General Engineering Laboratories, Inc. Charleston, SC Anil Thakkar visited GEL in April  Discussed the Radium in Water procedure –Ran some test samples

General Engineering Laboratories, Inc. Charleston, SC Spectrum from Testing Water Procedure

General Engineering Laboratories, Inc. Charleston, SC  This brought up the question about how well the procedure would work with soils? Spectrum from Testing Water Procedure

General Engineering Laboratories, Inc. Charleston, SC Highlights of the Procedure: Radium in Water (RAW03) Eichrom Technologies, Inc.  Digest the sample  Dissolve the residue with dilute HNO 3  Pass sample through Cation resin column  Elute Ra and Ba with 8M HNO 3  Evaporate eluate to dryness  Dissolve residue with 0.095M HNO 3

General Engineering Laboratories, Inc. Charleston, SC  Pass through Ln Column collecting the eluate for determination of 226 Ra  Perform Barium Sulfate micro-precipitation  Filter  Count on Gamma for Tracer Recovery ( 133 Ba)  Count on Alpha for 226 Ra determination Highlights of the Procedure: Radium in Water (RAW03) Eichrom Technologies, Inc.

General Engineering Laboratories, Inc. Charleston, SC Test #1 Results SampleVolume (g) % Yield ( 133 Ba) Activity (pCi/g) Uncertainty 2-Sigma (pCi/g) MDA (pCi/g) FWHM (keV) % Recovery 1 (Sample) (Sample) (Sample) (Blank) (Matrix Spike) (Lab Control Sample)

General Engineering Laboratories, Inc. Charleston, SC Test #1 Spectra Sample 1

General Engineering Laboratories, Inc. Charleston, SC Test #1 Spectra Sample 3

General Engineering Laboratories, Inc. Charleston, SC Test #1 Spectra Sample 6 (LCS)

General Engineering Laboratories, Inc. Charleston, SC Problem with initial testing:  Resolution exceeded 100keV –Suspected cause was from natural Barium in the soil.

General Engineering Laboratories, Inc. Charleston, SC Proposed solutions: Use less sample Use less Barium Carrier –100  L of 0.75 mg/mL Barium Carrier was used for Test #1 Use less Seeding Suspension

General Engineering Laboratories, Inc. Charleston, SC Test #2  Analyze 3 samples with No Barium Carrier  Analyze 3 samples with 50  L of Barium Carrier  Vary aliquot size from 0.1g to 0.5g

General Engineering Laboratories, Inc. Charleston, SC Test #2 Results SampleVolume (g) % Yield ( 133 Ba) Activity (pCi/g) Uncertainty 2-Sigma (pCi/g) MDA (pCi/g) FWHM (keV) 1 No Barium No Barium No Barium µL Barium µL Barium µL Barium

General Engineering Laboratories, Inc. Charleston, SC Problem with Test #2:  Resolution on samples with reduced Barium Carrier continue to exceed 100keV

General Engineering Laboratories, Inc. Charleston, SC Test #2 Spectra Sample 1

General Engineering Laboratories, Inc. Charleston, SC Test #2 Spectra Sample 3

General Engineering Laboratories, Inc. Charleston, SC Test #3  Used 0.1mL of the seeding suspension 0.2mL used previously  No Barium Carrier was used

General Engineering Laboratories, Inc. Charleston, SC Test #3  No Barium Yields FAILURE

General Engineering Laboratories, Inc. Charleston, SC Test #4  Comparison of Alpha Spec vs. Emanation  Alpha Spec –Used 0.2g of sample –50  L of Barium Carrier  Emanation used 0.5g of sample

General Engineering Laboratories, Inc. Charleston, SC Test #4 Results SampleVolume (g) % Yield ( 133 Ba) Activity (pCi/g) Uncertainty 2-Sigma (pCi/g) MDA (pCi/g) FWHM (keV) Alpha Spec Run Emanation Run

General Engineering Laboratories, Inc. Charleston, SC Test #4 Spectra Sample 1

General Engineering Laboratories, Inc. Charleston, SC Test #4 Spectra Sample 2

General Engineering Laboratories, Inc. Charleston, SC Update to the Objective  Further discussions with the client revealed they were never able to achieve resolution <100keV –They re-set their requirement to <250keV  Current testing Average FWHM –149keV –Consistently <200keV

General Engineering Laboratories, Inc. Charleston, SC Changes to 226 Ra Water Procedure  Ensure that 0.5g or less of soil used –Minimizes natural Barium introduced  Reduce Barium carrier used –50µL 0.75mg/mL

General Engineering Laboratories, Inc. Charleston, SC In Conclusion  Original FWHM Goal (<100keV) not achieved –Client changed their requirement to <250keV Average FWHM for soils 149keV  Faster Turn Around Times accomplished –Soils can be run in 2 days Emanation 3 day minimum Gamma 7-30 day minimum –Waters can be run in 1 day