standardization of na-22 by cnet method - lsc...

Standardization of Na-22

by CNET method

LIU Haoran1, LIANG Juncheng1and YUAN Daqing2

1. National Institute of Metrology ,China2. China Institute of Atomic Energy, China

Outline

Disscusion 1: Influence of tSIE

Results

Process of standardization

Sample preparation

Disscusion 2: Influence of kB

1

2

3

4

5

6 Conclusions

22Na master solution: Activity concentration of about 11.6 MBq/g Carrier: about 25μg/g NaCl in HCl (0.1 mol/L) Quenching agent: Nitromethane (CH3NO2) Scintillator: Ultima Gold LLT

Sodium -22

Preparation of LS Samples

Tritium（tracer） A set of 3H samples were prepared in the same way

0 2000 4000 6000 80001

10

100

1000

10000

100000

Channel

Coun

ts

Impurity check of 22Na solution

No γ-emitting impurity was detected.22Na: 511 keV

22Na: 1274.5 keV

40K: 1460.8 keV

22Na: (1274.5 +511) keV

Outline


Results


Sample preparation

Disscusion 2: Influence of kB values

1

2

3

4

5

6 Conclusions

The procedure of the CIEMAT/NIST Method

Tracer: 3H

Radionuclide to be analyzed: 22Na

2.1 Measurement details

LS spectrometers: PerkinElmer Tri-Carb 3100TR

• Quench indicating parameter : tSIE

• 5 cycles of 20 minutes per source

• At least 106 counts for each source

Decay scheme of Na-22

0.00098%

9.64% 90.3%

0.055%Stable

0.00524 ns

2.6029(8) a

EC β+

2+ 1274.577

0+ 0

3+ 0γ Emission intensities per 100 disintegrations

2.2 Efficiency calculation

Decay data of Na-22

Nuclear data of Na-22 (Cited from DDEP)


Atomic data of Na-22 for efficiency calculation using the KLM rearrangement model

Name of parameter Symbol Value ReferenceωK 0.0152ωL 0.0001

PKLL 1PKLM 0PKMM 0

Relative probabilities of the L Augerelectrons (sum=1) PLMM 0

PKL 1PKM 0

Relative probabilities of the L X-rays(sum=1) PLM 0 Firestone (1998)

EKLL 0.8268EKLM 0.8484EKMM 0.8701ELMM 0.0216 Larkins (1977)EKL 0.8486EKM 0.8701ELM 0.0216 Firestone (1998)

Larkins (1977)

Firestone (1998)

Average energies of the Augerelectrons

Average energies of the X-rays

Fluorescence yield Bambynek-1972

Relative probabilities of the K Augerelectrons (sum=1) E. Schönfeld and H. Janβ

en-1996

Relative probabilities of the K X-rays(sum=1) Firestone (1998)

Decay data of Na-222.2 Efficiency calculation

Sheet1

Name of parameterSymbolValueReference

Fluorescence yieldωK0.0152Bambynek-1972

ωL0.0001

Relative probabilities of the K Auger electrons (sum=1) PKLL1E. Schönfeld and H. Janβen-1996

PKLM0

PKMM0

Relative probabilities of the L Auger electrons (sum=1) PLMM0

Relative probabilities of the K X-rays (sum=1) PKL1Firestone (1998)

PKM0

Relative probabilities of the L X-rays (sum=1) PLM0Firestone (1998)

Average energies of the Auger electronsEKLL0.8268Larkins (1977)

EKLM0.8484

EKMM0.8701

ELMM0.0216Larkins (1977)

Average energies of the X-raysEKL0.8486Firestone (1998)

EKM0.8701

ELM0.0216 Firestone (1998)

Sheet2

Sheet3

Sheet4

3H• Decay type : Pure Bata deacy

• Code: CN2003

22Na• Decay type : β+/EC decay

• Code: CN2003• Electron-capture transition atomic

rearrangement model: KLM

• Computation of ionization quenching function

(1) The ionization quenching parameter：KB=0.075

(2) The stopping power values(default)

(3) Scintillator composition, density (modify to Ultima Gold LLT)


Code and parameters

1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

Effciency of H-3 Polynomial Fit of Effciency of H-3

Effc

ienc

y of

H-3

Free Parameter

Model PolynomialAdj. R-Square 0.99999

Value Standard ErrorEffciency of H-3 Intercept 93.5523 0.14887Effciency of H-3 B1 -48.09168 0.22889Effciency of H-3 B2 11.32439 0.11035Effciency of H-3 B3 -1.05462 0.01684

(a) The theoretical counting efficiency curve of 3H

The procedure to obtain the counting efficiency for Na-22

(b) Experimental quench-correction curve of 3H

320 340 360 380 400 420 440 460 480 5000.28

0.30

0.32

0.34

0.36

0.38

0.40

0.42

0.44


Effc

ienc

y of

H-3

tSIE


Value Standard ErrorEffciency of H-3 Intercept -0.04748 0.17964Effciency of H-3 B1 0.00146 0.00135Effciency of H-3 B2 -1.43251E-6 3.33152E-6Effciency of H-3 B3 8.22707E-10 2.72347E-9

(c) “Universal” curve

300 320 340 360 380 400 420 440 460 480 500

1.5

1.6

1.7

1.8

1.9

2.0

2.1

2.2

Free Parameter Polynomial Fit of Free Parameter

Free

Par

amet

er

tSIE

Model PolynomialAdj. R-Squa 0.99915

Value Standard ErFree Param Intercept 6.60128 0.92223Free Param B1 -0.02527 0.00691Free Param B2 4.51093E-5 1.71028E-5Free Param B3 -2.99366E- 1.39813E-8

(d) The theoretical counting efficiency curve of 22Na

1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4

0.906

0.907

0.908

0.909

0.910

0.911

0.912

0.913

Effciency of Na-22 Polynomial Fit of Effciency of Na-22

Effc

ienc

y of

Na-

22

Free Parameter

Model PolynomialAdj. R-Squar 0.99992

Value Standard ErrEffciency of Intercept 92.38282 0.02495Effciency of B1 -1.8608 0.05218Effciency of B2 0.98428 0.03899Effciency of B3 -0.25794 0.01239Effciency of B4 0.02494 0.00142

(e) Computed quench correction curve of 22Na

320 340 360 380 400 420 440 460 480 5000.28

0.30

0.32

0.34

0.36

0.38

0.40

0.42

0.44


Effc

ienc

y of

H-3

tSIE


Value Standard ErrorEffciency of H-3 Intercept -0.04748 0.17964Effciency of H-3 B1 0.00146 0.00135Effciency of H-3 B2 -1.43251E-6 3.33152E-6Effciency of H-3 B3 8.22707E-10 2.72347E-9

Outline

Disscusion 1: Influence of tSIE and kB

Results


Sample preparation


1

2

3

4

5

6 Conclusions

3.1 The stability of the counter

a. The stability of tSIE in the measurement

0 2 4 6 8 10

396.0

396.5

397.0

397.5

398.0

398.5

399.0

399.5

tSIE

Number of repeats

Sample H6

a. The stability of tSIE in the measurement

0 2 4 6 8 10

466.0

466.5

467.0

467.5 H1 Stirling of tSIE

tSIE

Number of repeats0 2 4 6 8 10

447

448

449

450 H2 ExpDec1 of tSIE

tSIE


433

434


tSIE

Number of repeats

0 2 4 6 8 10418

420


tSIE


413

414

415

416

H5 ExpDec1 of tSIE

tSIE


396

397

398

399


tSIE

Number of repeats

0 2 4 6 8 10385

386

387

388

389

H7 ExpDec1 of tSIE

tSIE


378

379

380

381

H8 ExpDec1 of tSIE

tSIE


366

367

368

369


tSIE

Number of repeats

3.1 The stability of the counter

0 2 4 6 8 10

153000

153500

154000

154500

155000 H1

tSIE


155500

156000

156500

157000

157500 H2

tSIE


191500

192000

192500

193000

193500 H3

tSIE

Number of repeats

0 2 4 6 8 10132500

133000

133500

134000

134500 H4

tSIE


127200

127400

127600

127800

128000

128200

128400

128600

128800

129000

129200 H5

tSIE


151800

152000

152200

152400

152600

152800

153000 H6

tSIE

Number of repeats

0 2 4 6 8 10

105800

106000

106200

106400

106600

106800

107000

107200

107400 H7

tSIE


92200

92400

92600

92800

93000

93200

93400 H8

tSIE


110500

111000

111500

112000

112500

113000 H9

tSIE

Number of repeats

b. The stability of counting rates in the measurement3.1 The stability of the counter

The activity concentration of 22Na

Sample No. tSIE EfficiencyCounting

rate(min-1) Mass(mg) A(kBq.g-1)

Blank 491.8 --- 258 --- ---N1 518.5 0.9106 550407 31.96 315.07N2 507.5 0.9105 601448 36.42 302.17N3 465.4 0.9102 386208 23.82 296.68N4 447.6 0.9101 360278 22.23 296.58N5 424.4 0.9099 509733 31.46 296.62N6 396.5 0.9097 373332 23.04 296.66N7 369.2 0.9095 341983 21.12 296.51

Relatively standard deviation of N3 to N7 0.02%

3.2 Results and uncertainty

360 380 400 420 440 460 480 500 520 5400.905

0.910

0.915

0.920

Efficiency

Effic

ienc

y

tSIE

N3 N1N2N4N5N6N7

360 380 400 420 440 460 480 500 520 540

294

300

306

312

318

N7 N6 N5 N4 N3

N2

N1

ActivityAc

ticity

Con

cent

ratio

n (k

Bq/g

)

tSIE

3.2 Results and uncertainty

3.2 Results and uncertaintyUncertainty components*, in % of the activity concentration, due to:

Factor U(a)/a in% Remarks

Counting statistics 0.05 Standard deviation of mean of 5 samples, including the source dispersion.

Weighing 0.09

Background 0.03

Dead time 0.10

Quenching 0.04

Tracer(H-3)

Outline


Results


Sample preparation


1

2

3

4

5

6 Conclusion

Sample No. tSIE CH3NO2(μl) Efficiency

Blank 491.8 0 ---N1 518.5 0 0.9106N2 507.5 20 0.9105N3 465.4 50 0.9102N4 447.6 70 0.9101N5 424.4 100 0.9099N6 396.5 150 0.9097N7 369.2 200 0.9095

(1) The tSIE seems to be affected by the γ rays from Na-22 source.

The problem of quench indicating parameter tSIE

The influence of quench(tSIE) for Na-22 effciencies

The contribution of γ-rays to overall effciency was taken into

account in efficiency calculation.

But the deviation of tSIE due to γ-rays was not considerded.

The influence of tSIE for Na-22 effciencies

The tSIE was varied over a range from 321-494, which correspondsto 22Na efficiencies from 90.95% to 91.06%.

320 360 400 440 480 5200.9075

0.9100

0.9125

Effic

iency

of N

a-22

tSIE

only a very small impact

300 320 340 360 380 400 420 440 460 480 500 5200.28

0.30

0.32

0.34

0.36

0.38

0.40

0.42

0.44

tSIE

Effc

ienc

y of

Mn-

55

The influence of tSIE for EC-γ nuclides

The tSIE was varied over a range from 321-494, which correspondsto 22Na efficiencies from 30.0% to 42.2%.

significant impact which can not be ignored

for example: Mn-54

(2) The tSIE of N1 and N2 are over the upper bound of quench correction curve

The problem of tSIE

320 340 360 380 400 420 440 460 480 500 520290

295

300

305

310

315

320

N1

N2

N3N4N6N7

tSIE upper bound:494

tSIE

Actic

ity C

once

ntra

tion

(kBq

/g) Acticity Concentration (kBq/g)

tSIE lower bound:321

N5

What can we do?

Outline

Disscusion: Influence of QIP tSIE

Results



Disscusion: Influence of kB values

1

2

3

4

5

6 Conclusions

The influence of kB values for CIEMAT/NIST method

In some of the early CIEMAT/NIST method literatures, differentvalues of Birks’ parameter, kB, have been reported by variousauthors.

But it doesn’t matter for pure β-emitters, because theefficiencies were calculated twice in the procedure and enabledus to establish a link between the counting efficiencies of thetwo radionuclides (tracer and nuclide under study).

Owing to cross-correlations, relative calculations are more likelyto exhibit less uncertainty than absolute estimations due to thecancelation effects.


For CIEMAT/NIST method, although sometimes the kB value usedin the calculation may be not the optimal one, but it has little effecton the result for pure β-emitters.

25 30 35 40 45 50 55 6089

90

91

92

93

94

95

96

kB=0.0075kB=0.012

Eff(C

-14)

Eff(H-3)

The effect of kB can be neglected


However, for EC decay nuclides:

0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65

0.05

0.10

0.15

0.20

0.25

0.30

Effc

ienc

y of

Ca-

41

Effciency of Fe-55

kB=0.0075 fe55trac kB=0.012 fe55trac kB=0.0075 CN2003 kB=0.012 CN2003

0.05 0.10 0.15 0.20 0.25 0.300.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

kB=0.0075 kB=0.012

Effc

ienc

y of

Ca-

41

Efficiency of H-3

for example: Ca-41

The effect of kB can be neglected The effect of kB is obvious

The influence of kB values for 22Na effciencies

0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.600.9070

0.9075

0.9080

0.9085

0.9090

0.9095

0.9100

0.9105

kB=0.0060 kB=0.0075 kB=0.0120 kB=0.0140E

ffcie

ncy

of N

a-22

Effciency of H-3

only a very small impact

There is a very small difference of using different kB values, within 0.03% in the whole interval..

Outline

Disscusion: Influence of tSIE

Results



Disscusion: Influence of kB values

1

2

3

4

5

6 Conclusions

Conclusions

Influence of tSIE

(1) If tSIE values are in the interval of quench correction curve,

the influence of tSIE to 22Na can be neglected.

(2) If tSIE values are out of range of quench correction curve, the

data could not be used.

Influence of kB values(1) The kB values are of only minor importance for 22Na effciency

calculation.

Thank you for your attention!

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standardization of na-22 by cnet method - lsc...

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