ORNL is managed by UT-Battelle, LLC for the US Department of Energy

Development of Revised Radioanalytical Procedure for 210Po in Urine

and more…

Dosimetry Services Group

Oak Ridge National Laboratory

Hiromu Kurosaki

22

In Vitro Radiobioassay Program at ORNL• Routine Analyses – 24 Hour Void Urine– PAS (Personal Air Sampler) Filters for 227Ac

• Incident (Emergency) Analyses– Urine, Fecal, etc.

• Analytes of Interest– Alpha (225Ac, 241Am, 243Am, 242Cm, 244Cm, 248Cm, 252Cf, 237Np,

210Po, 238Pu, 239Pu, 242Pu, 244Pu, 226Ra, 228Th, 229Th, 230Th, 232Th, 232U, 234U, 235U, 238U)

– Beta (227Ac, 249Bk, 14C, 36Cl, 3H, 63Ni, 241Pu, 35S, 89/90Sr, 99Tc)– Gamma Emitters– ICP-MS (235U, 238U, Ratio)

33

Auto Deposition onto Ag/Cu/Ni Disks

• Simple and Quick

HEAT

44

Auto Deposition onto Ni Disks

24 Hour Urine(1.5 – 2 L)

Aliquot of 100 mL

Auto Deposition4 Hours

AlphaSpectrometry

Acidify with HCL

HEAT

55

0

10

20

30

40

50

60

70

80

90

100

4400 4600 4800 5000 5200 5400Energy keV

Auto Deposition onto Ni Disks

• Simple and Quick

• Poor Ni disks resolution– ROI setting difficulty

209Po

210Po

66

0

10

20

30

40

50

60

70

80

90

100

4400 4500 4600 4700 4800 4900 5000 5100 5200 5300 5400Energy keV

Setting ROI automatically is difficult.

209Po 210Po

ROI

77

Auto Deposition onto Ni Disks

• Simple and Quick

• Poor Ni disks resolution– ROI setting difficulty

• Sub-sampling required– Another source of uncertainty

88

How would you take sub-sample from these ?

Precipitate

99

We tried three sampling methods for 238U.

Supernate From the Bottom Entire Sample

1. Take 25 mL from the top2. Take 25 mL from the bottom3. Take remaining entire sample (950 mL)

1 2 3

1010

238U Activity: 3 > 1

y = 0.4188x

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04

Sub-

Sam

ple

/ dp

m/L

Entire Sample / dpm/L

1

3

1:1 line

1111

238U Activity: 2 > 3 > 1

y = 0.4188x

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04

Sub-

Sam

ple

/ dp

m/L

Entire Sample / dpm/L

2

1

3

1:1 line

1212

Another Source of Uncertainty

• Sub-sampling uncertainty can be critical.– Good Sub-sampling procedure is necessary.

• Or process entire samples.– Eliminates sub-sampling uncertainty.– Provides better detection limit.

1313

Auto Deposition onto Ni Disks

• Simple and Quick

• Poor Ni disks resolution– ROI setting difficulty

• Sub-sampling required– Another source of uncertainty

• Sequential analysis difficult– Extraction chromatography makes it easy!

1414

Po Analysis with Separation

Entire Urineor Sub-sample

Pre-Concentration

Ce-OH Precipitation

AlphaSpectrometry

3M HCl

Po fraction

SR

8M HNO3

1515

After Column Separation, Takes < 30 Minutes

TRU

Po

Add Ce Carrier

Add H2O2

Add pH Indicator

Elute

Filter

Adjust pH

1616

Sequential Analysis Possible

3M HCl

SRTR

UDG

A

Pu/Np/Th/U

Am/Cm/Cf

Po/Sr

Entire Urineor Sub-sample

Pre-Concentration

1717

Fe may Follow Po

Entire Urineor Sub-sample

Pre-Concentration

Ce-OH Precipitation

AlphaSpectrometry

3M HCl

Po fraction

SR

8M HNO3

Fe

1818

TRU Removes Fe upon Po Elution

Entire Urineor Sub-sample

Pre-Concentration

Ce-OH Precipitation

AlphaSpectrometry

3M HCl

TRU

SR

8M HNO3

FePo fraction

1919

0

50

100

150

200

250

4400 4500 4600 4700 4800 4900 5000 5100 5200 5300 5400Energy keV

Sharper Peak, Greater RecoveryRecovery range:

EXC + Ce-OH70 – 90 %

Auto-Deposition30 – 60%Ce-OH ppt

Auto-Deposition

209Po 210Po

2020

Who cares about accurate alpha detector efficiency?

• If alpha tracer is used, efficiency cancels.

• It only affects recovery calculation.

• But beta tracers (234Th and 239Np) are used at ORNL

• So correct detector efficiency is required.

2121

How do we calculate efficiency?

• Use NIST traceable source (Electroplated)

• Are the efficiencies the same for ED and PPT?

Disk Filter

2222

242Pu

1

239Pu

Filter

2

Filter

Alpha Spec

How do you calculate efficiency of PPT?

Ce-OH ppt

Ce-OH ppt

242Pu

239+242Pu

2323

0

100

200

300

400

500

600

700

800

900

4700 4800 4900 5000 5100 5200 5300Energy / keV

Pu on Filter #1

0

20

40

60

80

100

120

4700 4800 4900 5000 5100 5200 5300Energy keV

Pu in Filtrate (Filter #2)

242Pu

242Pu

239Pu

Added 242Pu

242Pu left in filtrate (Calculated from filter #2)

242Pu on filter #1

minus

Should be equivalent to

1 2

2424

0

100

200

300

400

500

600

700

800

900

4700 4800 4900 5000 5100 5200 5300Energy / keV

Pu on Filter #1

0

20

40

60

80

100

120

4700 4800 4900 5000 5100 5200 5300Energy keV

Pu in Filtrate (Filter #2)

242Pu

242Pu

239Pu

Added 242Pu

242Pu left in filtrate (Calculated from filter #2)

242Pu on filter #1

minus

Should be equivalent to

1 2

ED > PPT ?

2525

Summary

• The new 210Po procedure provides– Sharper Peak– Greater Recovery– No Sub-Sampling Uncertainty– Sequential Analysis

• How are you handling efficiency of micro-precipitation?

2626

Acknowledgement

• Group Leader (Dosimetry)– Govind Rao

• Radiobioassay Lab– April Tucker– Kim Johnson– John Keaton Jr.– Michelle Kinnebrew– Pam McConkey– Jamie Daum– Hayden Nelson

• Counting Room– Joe Conner– Susan Lambert

ORNL is managed by UT-Battelle, LLC for the US Department of Energy

Thank you!

kurosakih@ornl.gov