Standardization of Na-22 by CNET method - LSC...
Transcript of Standardization of Na-22 by CNET method - LSC...
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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
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Outline
Disscusion 1: Influence of tSIE
Results
Process of standardization
Sample preparation
Disscusion 2: Influence of kB
1
2
3
4
5
6 Conclusions
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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
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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
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Outline
Disscusion 1: Influence of tSIE
Results
Process of standardization
Sample preparation
Disscusion 2: Influence of kB values
1
2
3
4
5
6 Conclusions
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The procedure of the CIEMAT/NIST Method
Tracer: 3H
Radionuclide to be analyzed: 22Na
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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
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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
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Decay data of Na-22
Nuclear data of Na-22 (Cited from DDEP)
2.2 Efficiency calculation
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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
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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)
2.2 Efficiency calculation
Code and parameters
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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
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(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
Effciency of H-3 Polynomial Fit of Effciency of H-3
Effc
ienc
y of
H-3
tSIE
Model PolynomialAdj. R-Square 0.99915
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
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(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
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(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
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(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
Effciency of H-3 Polynomial Fit of Effciency of H-3
Effc
ienc
y of
H-3
tSIE
Model PolynomialAdj. R-Square 0.99915
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
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Outline
Disscusion 1: Influence of tSIE and kB
Results
Process of standardization
Sample preparation
Disscusion 2: Influence of kB values
1
2
3
4
5
6 Conclusions
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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
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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
Number of repeats0 2 4 6 8 10
433
434
435 H3 ExpDec1 of tSIE
tSIE
Number of repeats
0 2 4 6 8 10418
420
422 H4 ExpDec1 of tSIE
tSIE
Number of repeats0 2 4 6 8 10
413
414
415
416
H5 ExpDec1 of tSIE
tSIE
Number of repeats0 2 4 6 8 10
396
397
398
399
400 H6 ExpDec1 of tSIE
tSIE
Number of repeats
0 2 4 6 8 10385
386
387
388
389
H7 ExpDec1 of tSIE
tSIE
Number of repeats0 2 4 6 8 10
378
379
380
381
H8 ExpDec1 of tSIE
tSIE
Number of repeats0 2 4 6 8 10
366
367
368
369
370 H9 ExpDec1 of tSIE
tSIE
Number of repeats
3.1 The stability of the counter
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0 2 4 6 8 10
153000
153500
154000
154500
155000 H1
tSIE
Number of repeats0 2 4 6 8 10
155500
156000
156500
157000
157500 H2
tSIE
Number of repeats0 2 4 6 8 10
191500
192000
192500
193000
193500 H3
tSIE
Number of repeats
0 2 4 6 8 10132500
133000
133500
134000
134500 H4
tSIE
Number of repeats0 2 4 6 8 10
127200
127400
127600
127800
128000
128200
128400
128600
128800
129000
129200 H5
tSIE
Number of repeats0 2 4 6 8 10
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
Number of repeats0 2 4 6 8 10
92200
92400
92600
92800
93000
93200
93400 H8
tSIE
Number of repeats0 2 4 6 8 10
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
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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
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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
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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)
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Outline
Disscusion 1: Influence of tSIE
Results
Process of standardization
Sample preparation
Disscusion 2: Influence of kB values
1
2
3
4
5
6 Conclusion
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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
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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.
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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
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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
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(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?
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Outline
Disscusion: Influence of QIP tSIE
Results
Process of standardization
Preparation of LS Samples
Disscusion: Influence of kB values
1
2
3
4
5
6 Conclusions
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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.
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The influence of kB values for CIEMAT/NIST method
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
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The influence of kB values for CIEMAT/NIST method
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
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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..
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Outline
Disscusion: Influence of tSIE
Results
Process of standardization
Preparation of LS Samples
Disscusion: Influence of kB values
1
2
3
4
5
6 Conclusions
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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.
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Thank you for your attention!
Standardization of Na-22 �by CNET methodSlide Number 2Slide Number 3Slide Number 4Slide Number 5Slide Number 6Slide Number 7Slide Number 8Slide Number 9Slide Number 10Slide Number 11Slide Number 12Slide Number 13Slide Number 14Slide Number 15Slide Number 16Slide Number 17Slide Number 18Slide Number 19Slide Number 20Slide Number 21Slide Number 22Slide Number 23Slide Number 24Slide Number 25Slide Number 26Slide Number 27Slide Number 28Slide Number 29Slide Number 30Slide Number 31Slide Number 32Slide Number 33Slide Number 34Slide Number 35Slide Number 36Slide Number 37