Gamma-spectrometer for measurement characteristics of radionuclides
Describing and metrological characteristics of spectrometric stand intend for measurement characteristics of radionuclides and its identification are present. The results of measurements specific activity of any radionuclides using this spectrometer are present too.
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| Published in: | Вопросы атомной науки и техники |
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| Date: | 2002 |
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| Language: | English |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2002
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| Cite this: | Gamma-spectrometer for measurement characteristics of radionuclides / A.V. Torgovkin, B.I. Shramenko // Вопросы атомной науки и техники. — 2002. — № 2. — С. 69-71. — Бібліогр.: 4 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859825679840837632 |
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| author | Torgovkin, A.V. Shramenko, B.I. |
| author_facet | Torgovkin, A.V. Shramenko, B.I. |
| citation_txt | Gamma-spectrometer for measurement characteristics of radionuclides / A.V. Torgovkin, B.I. Shramenko // Вопросы атомной науки и техники. — 2002. — № 2. — С. 69-71. — Бібліогр.: 4 назв. — англ. |
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| container_title | Вопросы атомной науки и техники |
| description | Describing and metrological characteristics of spectrometric stand intend for measurement characteristics of radionuclides and its identification are present. The results of measurements specific activity of any radionuclides using this spectrometer are present too.
|
| first_indexed | 2025-12-07T15:28:40Z |
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GAMMA-SPECTROMETER FOR MEASUREMENT
CHARACTERISTICS OF RADIONUCLIDES
A.V. Torgovkin, B.I. Shramenko
National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine
e-mail: bshram@kipt.kharkov.ua
Describing and metrological characteristics of spectrometric stand intend for measurement characteristics of
radionuclides and its identification are present. The results of measurements specific activity of any
radionuclides using this spectrometer are present too.
PACS: 25.20.Lj
The spectrometric methods with the use of the
scintillation and semi-conductor detectors are more and
more applied at solving the problems connected with the
quantitative analysis. In most of the measurements that
are carried out the final goal is the data production of
the specific activity, the concentration and the substance
quantity. The identification of the radionuclides in the
complex spectrum by one, but more often by several
γ-lines is also an important problem. The γ-
spectrometer, used for isotope radioactive analysis, must
possess a rather high-resolution ability, great γ-quantum
registration efficiency at the range ≈60 keV-2 MeV and
have a small level of its own noise. The necessity to
combine these demands in one device became the goal
of this work.
GAMMA-SPECTROMETER HARDWARE
Primarily, for the radionuclide research we used
spectrometer on the basis of the IBM PC 386(387) and
ADC of the type 712 in CAMAC standard [1]. The
Ge(Li) ДГДК with the volume 50 sм3 was used as a
detector. The software allowed to carry out the spectra
obtaining under MS DOS and realize the simple
processing of the received data (to calculate the peak,
and subtract the phone) Feature of the work with the
CAMAC crate controller and limited quick-action of PC
did not allow to assume high charges. Specifically, the
counting error value reached 15-20 % at great charges
of the spectrometric channel. Such counting errors must
be taken into consideration by the programs on the
specific activity determination. Besides, ADC of the
712 type has 10-bit precision that leads to necessity to
change the amplification of the spectrometric channel
during the work, and, hence, the calibration of the
energy scales. Another configuration of the γ–
spectrometer was introduced with the consideration of
these remarks: PC386 was replaced by more powerful
Pentium-133, instead ADC-712 the 16-bit ADC, on the
AD976 basis produced by Analog Devices, is used. And
there is no need in the CAMAC crate controller. The
carried out substitution allowed working under the MS-
DOS and Windows-98.
As a γ–radiation detectors were chosen: a
semiconductor ДГДК-100 with the volume of 100 cm3
and scintillation БДИС3-05 with scintillator NaJ(Tl) ∅
63 mm × 63 mm. In addition, the spectrometer is
equipped with the scintillation detector NaJ(Tl) ∅
70 mm × 70 mm with well. It used during the work with
the low-active samples in the 4π geometry. Such a
spectrometer configuration provides a high resolution at
the Ge(Li) detector use, which is necessary at the
research of the isotopes with many γ–lines or at the
research of isotopes mixture. The scintillation detector
is used to the research of a single peak, for instance, in
isotopes 15О, 11С, 18F, 13N, 188Re. It has a sufficient
energetic range of the registered γ-quanta and to have a
spectrometer with a broadly varied registration
efficiency that is especially useful at the measurement
of the low-active and short-lived isotopes.
The spectrometric stand is equipped the end-window
counter МСТ-17 in order to have a β–radiation
registration of the analyzed samples and a contribution
rate of the β–activity into the irradiation dose. Besides,
the β–activity control of the measured devices allows to
detect the possible impurity of the sample targets, that
can distort the γ-spectra after the activation, especially
in low energy range. Spectrometers circuit is given at
Fig. 1.
The main tendency of the measurements perfection
is concluded in increasing of the device operating speed
and improving the measurement results accuracy. The
increase of the measurement accuracy is provided by
reduce of the statistical errors, and of the operating
speed – the device capability to work at great input
charges.
The error of the impulse miscalculation is one of the
main mistakes at the considerable input charges. It is the
consequence of the fact that the measurement channel
dead time is limited and the impulse distribution in time
is submitted to the statistic law [2]. The spectrometric
channel dead time is determined by the channel
capability not to assimilate the next impulse during
some time after the previous one. The value of this time
is determined by the detector characteristics, the
sharpener-amplifier characteristics, and the specification
of the interaction between the ADC and PC.
The counting errors that are concerned limited time
of charge absorption in the detector are observed at
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2002, № 2.
Series: Nuclear Physics Investigations (40), p. 69-71. 69
charges more than 105 s-1. The charge absorption time
fluctuations and the terminal time of the impulse
forming scheme occupation lead to the spectrum
deformation and sometimes increase the error counting.
Various scheme resolution of the rejecters that are
deformed according to the signal form and the added
impulses allow to reduce the spectrum deformation. The
most essential contribution to the counting errors is
carried in by the ADC and registration device [3].
Therefore, the main efforts were taken to optimize the
work of this spectrometric channel module. The main
approaches in this direction were: the ADC dead time
reducing, the impulse forming scheme occupation time
reducing, the spectrum correction with the high stable
impulse generator. The dead time for the spectrometer
(according to the scheme given at Fig. 1) was found by
the two sources method by the formula
21
1221
2 nn
nnn
⋅
−+
=τ ,
where n1, n2 and n12 – are the charges from the first,
second and both sources, accordingly. The average
meaning τ = 30 µs was received at the use of the БУС2-
47 with shaping time 1,6 µs.
When evaluating the sample activity, the detector
efficiency η is the essential factor. It was determined as
a relationship between the quantity of quanta detected in
the photopeak and the quantity of quanta radiated from
the γ-source with a known activity. With such
determination of the efficiency it was not necessary to
evaluate in each case a solid angle being covered by the
detector when changing the source position. To
determine η we used the set of the standard sources
composed of 22Na, 137Cs, 54Mn, 241Am, with γ-lines
energy 511, 1275, 661, 834, 59.5 keV, respectively.
Fig. 1. Spectrometers circuit
The measurement results of the Ge(Li) detector
efficiency dependence from γ-quanta energy at various
distances from the detector are shown at Fig. 2.
Table 1 shows the efficiency in % of the БДИС3-05
detector with the scintillator NaJ ∅63 mm × 63 mm.
Fig. 2 Detector efficiency as a function of
γ-quantum energy at different distances from the
source: 5,5 mm, 60 mm, and 100 mm
The measured energetic resolution of the
spectrometric channel with the semiconductor detector
on lines Со60 is 1,2 %, and on the line Со57
(136 keV) – 1,8 %. These factors allow to divide γ-lines,
and to identify, for instance, the radionuclides derivable
at the Re and Mo irradiation. The energetic resolution
on the line of 662 keV was measured for the
scintillation detector, that the meaning of 8,5 % is
received. The lower resolution than Ge(Li) will not be
hinder for the correct specific activity determination due
to the fact that the scintillation detector will be used
mainly for the spectra set from the sources possessing
single γ-lines.
Table 1
Energy,
keV
Efficiency at various distance from
the detector, %
0 13mm 23mm 34mm 43mm
60 23,4 14,7 10,1 6,9 5,0
511 9,3 5,3 3,7 2,7 2,1
662 9,0 4,7 3,2 2,2 1,7
835 7,1 3,5 - - -
1275 2,5 1,9 1,4 1,1 0,8
THE SOFTWARE AND DATABASE
The spectrometer software is written on the Borland
C++, Delphi 4.0 languages and allows to work under the
DOS and Windows-98 control. Unlike the software used
previously the applied programs allow to determine the
photo peak center, to subtract the phone and to estimate
the counting amount under the peak with a high
70
accuracy. It is decided to divide the programs according
to the spectrum accumulation and it’s processing to
have more flexibility in work. The database programs
used to identify the isotopes are taken out into separate
block. The spectra are accumulated either in the hand-
mode (only once) or in the automatic one with the set
time given beforehand and frequency. The data is kept
in the file on the hard disk in format combined with the
various program processing.
The program that allows producing the spectra
visualization, the calibration of the energy scale and
isotope identification according one or two γ-lines, was
written for the operative work with the spectrum. Fig. 3
shows the view of the program-working window. If it is
necessary this program counts the activity of the given
isotope inquiring the spectrum set parameters of the
working file and any characteristics of the applied
detector.
The radionuclide activity А0 at the instant of
irradiation stopping was calculated by the formula
t0
ekmIη
AA
⋅λ−⋅⋅⋅⋅
= ,
where η – is the efficiency of γ-quantum detection, I –
is the average current falling onto the sample, А0 – is
the specific activity of the sample at the instant of
stopping irradiation, m – is the target mass, k – is the
coeffcient of γ-quantum multiplicity, A – is the number
of γ-quanta detected in the time t after irradiation
stopping, λ – is the radionuclide decay constant.
Fig. 3. The view of the program working window
Miscalculations were counted by the following
formula:
( )1s
0 tN1
NN
τ⋅−
= ,
where N – is the number of photons in the photopeak
detected by the detector, N0 – is the real number of
photons, Ns – is the total number of pulses in the
spectrometric channel, τ – is the dead time of the
spectrometer, t1 – is the exposition time of spectrum.
The isotope identification is done by his γ-lines. The
identification program sends the SQL-request to the
database keeping the γ-lines energy meaning and the
allowable error in the energy determination. The table,
keeping the main characteristics of all isotopes that are
in the base, satisfying the given selection criteria, is
made on results of the request. The future selection
conditions formed on the data basis of the half-life of
the radionuclide and isotopic composition of target.
Such decision allows the stand operator to identify
correctly radionuclides as their constitution conditions,
are known.
Table 2
Isotope Specific activity Bq/g.µА
11C 2.25⋅106
13N 3.3⋅106
15O 2.5⋅106
18F 1⋅107
The activity research of the various radionuclides for
the medical application received on the linear
accelerator was carried out as a result of the work on the
spectrometric stand [4]. Table 2 shows the information
about the specific activity of some isotopes generated on
the linear accelerators NSC KIPT. Therefore, the
described spectrometric stand provides the measurement
of the various levels of γ-activity.
ACKNOWLEDGMENT
The authors thank to V.D. Ovchinnik and
V.I Kulibaba for the valuable remarks and for the help
in this work.
REFERENCES
1. G.L. Bochek, A.N. Dovbnya, А.S. Zadvorny
and all. Narabotka korotkozsuvuchih izitopov na
yskoritele EPOS NSC KIPT dlya positron-
emisionnoi tomografii // Problems of Atomic
Science and Tech. 1999, №1. Issue: Nuclear
Physics Researches (37), p. 66-67 (in Russian).
2. V.I. Gol’dansky, А.V. Kutsenko, M.I. Podgo-
retsky. Statistika otschetov pri registratsii
yadernyh shastits. Moscow:”Fizmatgiz”, 1959,
148 p. (in Russian).
3. V.B. Ivanov, Y.P. Sel’dyakov, V.I. Shepilov.
Prosheti v amplitudnoy spectrometrii impulsov //
PTE, 1979, №6, p. 14–29 (in Russian).
4. A.N. Dovbnya, N.P. Dikii, А.S. Zadvorny
and all. Issledovanie vozmozhnosti poluchenia
izotopov Re // The Journal of Kharkiv National
University, 2001, №510. Issue 1 /13/, p. 87-90 (in
Russian).
71
PACS: 25.20.Lj
GAMMA-SPECTROMETER HARDWARE
Fig. 1. Spectrometers circuit
THE SOFTWARE AND DATABASE
REFERENCES
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| id | nasplib_isofts_kiev_ua-123456789-80119 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T15:28:40Z |
| publishDate | 2002 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Torgovkin, A.V. Shramenko, B.I. 2015-04-12T06:26:47Z 2015-04-12T06:26:47Z 2002 Gamma-spectrometer for measurement characteristics of radionuclides / A.V. Torgovkin, B.I. Shramenko // Вопросы атомной науки и техники. — 2002. — № 2. — С. 69-71. — Бібліогр.: 4 назв. — англ. 1562-6016 PACS: 25.20.Lj https://nasplib.isofts.kiev.ua/handle/123456789/80119 Describing and metrological characteristics of spectrometric stand intend for measurement characteristics of radionuclides and its identification are present. The results of measurements specific activity of any radionuclides using this spectrometer are present too. The authors thank to V.D. Ovchinnik and V.I Kulibaba for the valuable remarks and for the help in this work. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Application of the nuclear methods Gamma-spectrometer for measurement characteristics of radionuclides Гамма-спектрометр для измерения характеристик радионуклидов Article published earlier |
| spellingShingle | Gamma-spectrometer for measurement characteristics of radionuclides Torgovkin, A.V. Shramenko, B.I. Application of the nuclear methods |
| title | Gamma-spectrometer for measurement characteristics of radionuclides |
| title_alt | Гамма-спектрометр для измерения характеристик радионуклидов |
| title_full | Gamma-spectrometer for measurement characteristics of radionuclides |
| title_fullStr | Gamma-spectrometer for measurement characteristics of radionuclides |
| title_full_unstemmed | Gamma-spectrometer for measurement characteristics of radionuclides |
| title_short | Gamma-spectrometer for measurement characteristics of radionuclides |
| title_sort | gamma-spectrometer for measurement characteristics of radionuclides |
| topic | Application of the nuclear methods |
| topic_facet | Application of the nuclear methods |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/80119 |
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