NAA ko method

Proceedings of the International Graduate on Engineering and Science (IGCES'08)
Fundamental Science 23 - 24 December © 2008 IGCES

Technical development of Instrumental Neutron
Activation Analysis (INAA) based on ko method at The National Nuclear
Agency of Indonesia

Nursama Heru Apriantoro*, Sutisna£, Ahmad Termizi Ramli*
£
The National Nuclear Energy Agency of Indonesia (BATAN), Serpong, Tangerang, Indonesia.
* Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor,
Malaysia

ABSTRACT Key word : ko INAA, bi-isotopic, tripe bare
method
Quantitative multi-element determination using
1. Introduction
Instrumental Neutron Activation Analysis (INAA)
technique based on ko method was implemented
As a multi-element analytical technique, neutron
experimentally in INAA laboratory. Parameters
activation analysis based on relative method has
of canal irradiation and counting geometry were
been applied widely in many
studied and determinated in the experiment. The
activities[1],[2],[3],[4]. This method has relative
f parameter was obtained by bi-isotropic
good accuracy, especially for trace elemental
method, while for parameter by bare triple
analysis. However, this technique hardly
monitor technique. The determination of P/T and
depends on the availability of comparator which
reference position was taken in primary and
is usually in the form of standard primer
secondary application. The validation of ko was
solution, and also requires a long time for
conducted using SRM/CRM based on SNI 2000-
preparation and data analysis [5]. These are the
17025. Efficiency curve characteristic for
main constraint, especially for analyzing
detector was found to be in-line with HPGe
numbers of samples.
detector characteristic. Canal irradiation
characteristic of RS01 to RS04 facility yielded to
Various experiments have been done to increase
thermal neutron flux average and fast neutron
the effectiveness and efficiency of this method,
around 1.33 x 1017 nm-2 s-1 and 2.20 x 1016 nm-2
one of which was with single comparator or
s-1 respectively, while for f and parameter was
automatization system. Recently, a method with
41.9 and 0.02 respectively. Validation result of
special concern from various NAA laboratories
precision test, accuracy test and reputability
is the use of composite nuclear constant ko for
linearity obtained with standard reference
elements quantity calculation [6],[7]. The
materials and certificate reference material is
members of Forum of Nuclear Cooperation in
presented. Elements of Al, As, Br, Co, Cl, Cu,
Asia (FNCA), at annual meeting in Bangkok,
Fe, I, K, Na, Rb, Sc, U and Zn were suitable for
Thailand have agreed to apply INAA based on ko
precision test, while the materials for accuracy
method as standard procedure in NAA laboratory
test were As, Ag, Br, Co, Cl, Fe, I, K, Na, Rb, Sb,
[8]. The same attention was also given by IAEA
Sc, Se, U and Zn. Thus, as a conclusion, the ko
with the releasing of ko-IAEA software to
method offer better identification ability than the
calculate quantity of elements in any samples
comparability method. The technique of ko-INAA
based on ko method [9].
nuclear was successfully implemented in The
National Nuclear Energy Agency of Indonesia
Several publications show that usage of the ko
(BATAN). This technique increases the Neutron
constant, which is then called ko-INAA method,
Activation Analysis ability for quantitative
can increase ability of INAA laboratory support
determination of elements in various materials
system, by eliminating the usage of chemicals
by eliminating the dependency of standard
for comparator without a long preparation time.
materials usage as well as the improvement of
This method also has high selectivity and
analysis time efficiency.
sensitivity if combined with reliable -spectrum


analysis, with relative good accuracy and Some important parameters that have to be
precision compared to comparability method [6]. determined experimentally accurately are the
Thus, this method could be used in trace efficiency of counting geometry and the
elements analysis because of its high accuracy characteristic of irradiation canal, as well as the
and precision. software capability for -spectrum peak fitting.
Quantitative element determination based on ko
In the ko-INAA method, in contrast to method was calculated using equation proposed
comparability method, the parameters of reactor by Frans de Corte [10] ;
canal, counting geometry, efficiency detector and
peak-to-total ratio should be accurately
determined before running the analysis. Two
important parameters, f and are determined (1)
experimentally, for those are dependent on
reactor type and irradiation facility. The f
parameter is determined by bi-isotopic method
using 94Z(n, )95Zr and 96Zr(n, )97Zr. On the other Thus, the p, f and parameters would depend
hand the triple bare monitor method based on at on the condition of irradiation canal and the
95
Zr , 97Zr and 198Au was used to determine detector used.
parameter, as presented by De Coerte [10].
2.1 Detector efficiency
This research studied the usage of ko method of
INAA, for environmental monitoring study, Detection efficiency p, was determined at
health and industry application. The study coincidence- free reference position, usually at a
included the determination of reactor parameter, distance more than 10 times detector diameter
stipulating of reference position, calculation of from detector surface. To calculate correction
geometry efficiency, validation to SNI-17025- factor caused by "summing out" true-coincidence
2000, and applying of ko method for pre- effect, the total detection efficiency parameter, t,
elementary study. was obtained from conversion of P/T ratio
toward peak efficiency, p, according to equation
2. Methods (2).

Determination of f and canal irradiation
parameters was obtained by bi-isotopic and triple (2)
bare method using isotopes of 95Zr, 97Zr and
198
Au as result of reaction (n, ). The efficiency
of counting geometry in the reference was
determined using a number of standard sources. 2.2 Canal irradiation of rabbit facility
Total efficiency was calculated through characteristic
geometry efficiency conversion and peak-to-total
ratio using secondary standard. Zr and Au Different from comparability method, the ko-
irradiation for determination of flux, f and INAA method was largely based on the value of
parameters was done at all irradiation canals in f and for every position of irradiation canal. At
rabbit facility P2TRR (RSO1 to RS04). For
this experiment, f and parameters was
quantitative element determination in standard
determined by triple bar method and bi-isotopic
material, each sample and comparator (Al-0.1%
technique as recommended by de Corte and
Au) were irradiated simultaneously for ten times.
Blaauw [11].
The average results were then calculated using
weighted mean.
The f parameter determination with bi-isotopic
technique used reaction of 94Zr(n, )95Zr and
According to IAEA method and SNI-17025- 96
2000, SRMCRM of sea biota and sediments Zr(n, )97Zr from the foil target of Zr (Nilaco,
were used to validate the method. The validation 99.98%). Furthermore f value was calculated
included the tests for precision, accuracy, using equation:
detection limit, repeatability and linearity.


(3) 2.4 Detection Limit

Table 1 shows detection limit of elements
measurement in standard material. Detection
limit is determined based on formula from Currie
by the equation:
Meanwhile, the a parameter was determined by
triple-bar-method technique not only with
previous reaction but also with 197Au(n, )198Au, (8)
then a value was calculated using equation (4).

where NB is background count, m is number of
(4) channels selected before and after peak, and n is
number of channels below the peak.
or qo, a and b parameter was calculated using
equation (5) – (7), respectively: As many as 19 elements could be selectively
identified within detection limit value based on
(5) sample type that was analyzed.

(6) 2.5 Validation Method

(7) Based on SNI 17205-200, some examination
criteria must be fulfilled for validation of
nonstandard method, that are the precision test,
accuracy test, linearity, repeatability, detection
limit and reproducibility. For this purposes, the
IAEA examination method was held.
2.3 Element quantification in SRM sediment
and sea biota

For elemental identification, standard samples
was used that are SRM NIST 1566b Oyster
Tissue for 22 elements identification, CRM
NIES No.9 Sargasso for 22 elements
identifications and CRM NMIJ 7302a Sediment
for 18 elements identifications. Not all detected
elements could be validated, due to uncompleted
validation requisites. The detected elements for
SRM NIST 1566b were Ag, Al, Ace, Cl, Co, Cu,
Fe, Na, Se, U and Zn, while for CRM NIES No.
9 Sargasso were Ag, Al, Ace, Br, Co, Fe, I, K,
Na, Rb, Sc, U, and Zn. For CRM NMIJ 7302a
limited sediment of elements As, Co, Fe, Mn,
Rb, Sb and Zn were detected.


Table 2. Detection limit of ko INAA measurements for standard elements using fluks neutron thermal
3.9 x 1013 n cm-2 s-1, iradiation time 2 h, time decay 2 – 3 weeks, and counting time 0.5- 2
hours.

Standard samples
SRM NIST 1566b CRM NIST CRM NMIJ 7302a
Elements Unit
Oyster Tissue No.9 Sargasso Sediments
Na mg kg-1 50.91 622 16,850
Co mg kg-1 0.48 0.25 0.3
Zn mg kg-1 14.56 7.58 11.38
As mg kg-1 0.86 4.73 35.08
Se mg kg-1 4.1 1.73 6.18
Ag mg kg-1 1.8 1.83 0.91
U mg kg-1 0.25 1.85 12.6
Fe mg kg-1 216 164 259
Br mg kg-1 0.53 2.02 10.74
Rb mg kg-1 17.48 12.27 20.47
Sb mg kg-1 0.15 0.42 0.51
Sc mg kg-1 0.02 0.01 0.02
Zr mg kg-1 151.4 202.7 520.6
Cd mg kg-1 8.43 25.34 69.81
La mg kg-1 0.13 0.55 1.99
Ce mg kg-1 1.78 2.35 2.8
Au mg kg-1 0.003 0.02 0.04
Hg mg kg-1 0.97 0.97 6.54
Th mg kg-1 0.38 1.85 0.35

2.6 Precision test where Ns and Na are values from the certificate
and measurement result, respectively, Us and Ua
Precision test was conducted based on IAEA expressed uncertainty for 95 % (2 ) confidence
standard formula, by using F1 and F2 indicators level, H is Howitzh constant ( H = 0.02. c0.8495),
defined as: and c is recommended concentration from the
certificate. Based on this criteria, analysis results
is acceptable if F1 value is lower than F2.

(9) 2.7 Accuracy test

The accuracy test was conducted based on IAEA
standard procedure, as well as the precision test.
(10) At this examination the F3 and F4 parameters are
defined as follows:


(11) recommended has average accuracy of 78.47%
except Ag (12.90%). CRM NMIJ 7302a
sediment, all element recommended has average
accuracy of 85.22% except Mn (70.44%).
(12)
The precision test result for elements
recommended to 3 standard materials in test as
shown in table 4. From 11 elements evaluated at
SRM NIST 1566b Oyster Tissue that is Ag, Al,
As, Cl, Co, Cu, Fe, Na, Se, U and Zn, three
All the test results are acceptable if F3 value is elements (Ag, Co and Se) were rejected as they
smaller than F4. failed the precision test. In the case of CRM
NIES NO. 9 Sargasso, from 13 evaluated
elements, two 2 elements were rejected (Co and
Ag). The majority of elements have been
2.8 Linearity evaluated and fitted with precision test standard.
In case of CRM NMIJ 7302a sediments, only
As one of validation criteria, linearity test was one element (Sb) was rejected from precision
observed on representative elements i.e. Cr, Br, test.
Sc, Fe, As and Zn. Number of measurement
varied from 4 to 7 point of observation. Linear
regression values R2 were in the range of 0.81 –
0.96 for evaluated elemen

3 RESULTS AND DISCCUSION

Table 2 shows irradiation canal characteristic in
all position, including th, fast , f and for RS01
to RS04 canals. These data indicates that the
averages of thermal neutron flux and fast neutron
are 1.33 x1017 nm-2 s-1 and 2.20 x1016 nm-2 s-1
respectively, while for f and are 41.9 and 0.02
respectively.

Table 2 shows irradiation canal characteristic in
all position, including th, fast , f and for RS01
to RS04 canals

Canal fth ffast f a
(n m-2 s-1) (n m-2 s-1)
RS01 1.33 x 1017 1.07 x 1016 41.6 0.02
RS02 9.75 x 1016 9.31 x 1015 40.6 0.02
RS03 1.62 x 1017 4.68 x 1016 41.61 0.02
RS04 1.39 x 1017 2.29 x 1016 43.95 0.02

The analysis result of elements recommended by
SRM NIST 1566b Oyster Tissue, CRM NIES 9
SARGASO and CRM NMIJ 7302a sediment,
respectively shown in Tables 3. For SRM NIST
1566b Oyster Tissue, all element recommended
has average accuracy more than 79.36% except
Cu (32.82%), Al (56.85%) and Co (56.76%).
For CRM NIES 9 SARGASO, all element


Table 4 Precision test of elements measurement in standard samples

Standard sample Element Precision Test
SRM NIST 1566b Oyster Tissue F1 F2 F1 < F2 Conclusion
Ag 8.6 1.6 No rejected
Al 3.5 241.6 Yes accepted
As 9 11.5 Yes accepted
Cl 4.4 2801.5 Yes accepted
Co 4.6 1.2 No rejected
Cu 7.5 116.5 Yes accepted
Fe 5.3 201.3 Yes accepted
Na 2.8 1810 Yes accepted
Se 8.7 3.3 No rejected
U 198.8 392.2 Yes accepted
Zn 3.3 957.9 Yes accepted
CRM NIST No.9 Sargasso Ag 16.4 1.5 No rejected
Al 7.3 400.4 Yes accepted
As 8.2 105.4 Yes accepted
Br 6.1 218.6 Yes accepted
Co 8.9 0.9 No rejected
Fe 5.3 167.1 Yes accepted
K 11.1 2,183.80 Yes accepted
l 5 118.7 Yes accepted
Na 5 6,356.60 Yes accepted
Rb 9.1 26.3 Yes accepted
Sc 333.3 1,111.10 Yes accepted
U 158.8 250 Yes accepted
CRM NMIJ 7302a Sediments Na 1.7 6,838.60 Yes accepted
Co 13 15.7 Yes accepted
As 9.6 23.7 Yes accepted
Sb 8.8 2.3 No rejected
Rb 11.9 70.4 Yes accepted
Fe 1 17.665.7 Yes accepted
Mn 3.8 424.00 Yes accepted

matrix were rejected in examination, whereas the
Table 5 show the accuracy test result for
remains (Zn, As, Se, Ag, U, Fe and Cl) could be
elements which passed the precision test using
accepted. From 13 elements evaluated at
standard material SRM NIST 1566b Oyster
Sargasso. about 50 % of elements (Na, Co, Ag,
Tissue, CRM NIES NO9 SARGASO, and CRM
Al, K and I) were is unaccepted in this
NMIJ 7302a sediments. From precision test, the
examination while the remains accepted. For
elements Na, Co, Al, and Cu at Oyster Tissue
CRM NMIJ 7302a sediment, only 3 elements
were unaccepted for this test (Na, Fe and Mn).


Table 5 Accuration results of elements measurement in standard samples.

Standard sample Accuration Test
SRM NIST 1566b Oyster Tissue F3 F4 F3 < F4 Conclusion
0.11 0.13 Yes accepted
85.3 14.9 No rejected
274 171.30 No rejected
0.3 0.3 No rejected
0.3 1 Yes accepted
CRM NIST No.9 Sargasso 0.4 0.2 No rejected
4 20.7 Yes accepted
57,229.10 3,976.60 No rejected
3,736.70 1,613.80 No rejected
CRM NMIJ 7302a Sediments 4,545 514.60 No rejected
9,822,1 925.5 No rejected
162,3 52.70 No rejected

From the result of precision and accuracy tests, many material types by eliminating dependency
determination of elements with short decay time of standard materials usage, as well as the
(obtained through short time irradiation ~ 1 improvement of analysis time efficiency. The
minute) such as Mn, Na, Al, Cu and I, still have existence of irradiation canal parameter value
technical constrain. The irradiation time was and proper irradiation handling subsequently
believed as the constraint factor for this problem increased performance of ko technique. In
yet to be determined in accurate figure. contrast with relative method, this technique was
mainly influenced by the availability of accurate
CONCLUSION irradiation canal parameter data and loading -
unloading precision time.
The ko-INAA nuclear technique was Based on test result obtained, the sampling
successfully implemented in NAA laboratory of matrix was significant to accuracy and precision
Indonesia’s National Nuclear Energy Agency result of measurement. As a conclusion, this
(BATAN). The technique increases the ability of method is better in element identification
NAA for quantitative elements determination in compared to comparative method.


[8]. FNCA (Forum of Nuclear Cooperation in
Acknowledgement Asia)., 2004., Proceedings of The 2004 FNCA
Workshop on the Utilization of Research
This project used various facilities provided by Reactors, Bangkok, Thailand, January 13 – 21,
Universiti Teknologi Malaysia and The National 2005
Nuclear Energy Agency of Indonesia (BATAN).

References
[9]. Freitas, MC, and Martinho, E., 1989.
Determination of trace elements in reference
[1]. Lyon, W.S., 1982. Practical applications of materials by the k0-standardization method
activation analysis and other nuclear techniques. (INAA), Talanta 36 (1989) (4), pp. 527–531
Proc. Int. Sym. Appl. Technol. Ion. Rad. 2, 871–
883. [10]. De Corte, F., and A. Simonits, A. 1994.
Vademecum for ko users, addendum to the
[2]. Tsoulfanidis, N., 1987. Measurements and Kayzero, Solcoi Software Package, DSM
Detection of Radiation. Hemisphere Publishing Research, 1994.
Corporation, Washington, New York, London
(Chapter 15, pp. 467–476).

[3]. Djojosubroto, H. Present Status on the
application of NAA in Indonesia, Proceeding of
Indonesia-German Symposium on
Environmental Monitoring on Speciment Bank,
Yogyakarta, Indonesia, December 12-13, 1995

[4]. Chung, YS., Kim, SH., Hwa, MJ., Kim,
YJ., Lim JM., and Jin-Hong Lee, JH., 2006.
Quantitative analysis of urban dust (PM2/PM10-
2) in Daejeon city by instrumental neutron
activation analysis, Journal of Radioanalytical
and Nuclear Chemistry 267, pp. 95–107

[5]. Sutisna, Yusuf S, Fisli A, Rukihati,
Wardhani S, and Thrina M, The role INAA in
the environmental studies : Quantitative
determination of heavy metal pollutant on
environmental samples, Proceeding of the 2001
workshop on the utilization of research reactors,
Beijing, China, November 5 – 9, 2001.

[6]. Jingye, A., Chen DA., Jing, T., Weishi, C.,
Wenshu, Z., Daohua, W., 2001. An Analytical
software for NAA by Using ko method.
Proceeding of the 2001 workshop on the
utilization of research reactors, Beijing, China,
November 5 – 9.

[7]. De Corte, F., 1987. The k0-standardization
method — a move to the optimization of neutron
activation analysis, Agregé thesis, University of
Ghent, Belgium

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