Application of CdTe (CdZnTe) detectors for radioactive waste characterization
The radiation detectors based on wide-zone semiconductor CdTe (CdZnTe) monocrystals have promising advantages for their application in investigation (characterization) of radioactive waste. Among these advantages there are the wide range of photons flux and energy, high registration efficiency and s...
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| Zitieren: | Application of CdTe (CdZnTe) detectors for radioactive waste characterization / N.A. Dovbnya, S.P. Karasyov, V.E. Kutny, A.V. Rybka, I.N. Shlyakhov, V.L. Uvarov // Вопросы атомной науки и техники. — 2002. — № 2. — С. 55-57. — Бібліогр.: 3 назв. — англ. |
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irk-123456789-801142015-04-13T03:02:10Z Application of CdTe (CdZnTe) detectors for radioactive waste characterization Dovbnya, N.A. Karasyov, S.P. Kutny, V.E. Rybka, A.V. Shlyakhov, I.N. Uvarov, V.L. Application of the nuclear methods The radiation detectors based on wide-zone semiconductor CdTe (CdZnTe) monocrystals have promising advantages for their application in investigation (characterization) of radioactive waste. Among these advantages there are the wide range of photons flux and energy, high registration efficiency and satisfactory energy resolution without deep cooling of the detector. This report discusses the obtained data concerning radiation stability of detectors, influence of different conditions (filters, collimators, registration channel fill etc.) on their energy resolution in spectrometric regime, as well as a dependence of radionuclide identification accuracy on detector size. 2002 Article Application of CdTe (CdZnTe) detectors for radioactive waste characterization / N.A. Dovbnya, S.P. Karasyov, V.E. Kutny, A.V. Rybka, I.N. Shlyakhov, V.L. Uvarov // Вопросы атомной науки и техники. — 2002. — № 2. — С. 55-57. — Бібліогр.: 3 назв. — англ. 1562-6016 PACS 07.85.-m, 07.88.+y, 81.70.Jb http://dspace.nbuv.gov.ua/handle/123456789/80114 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Application of the nuclear methods Application of the nuclear methods |
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Application of the nuclear methods Application of the nuclear methods Dovbnya, N.A. Karasyov, S.P. Kutny, V.E. Rybka, A.V. Shlyakhov, I.N. Uvarov, V.L. Application of CdTe (CdZnTe) detectors for radioactive waste characterization Вопросы атомной науки и техники |
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The radiation detectors based on wide-zone semiconductor CdTe (CdZnTe) monocrystals have promising advantages for their application in investigation (characterization) of radioactive waste. Among these advantages there are the wide range of photons flux and energy, high registration efficiency and satisfactory energy resolution without deep cooling of the detector. This report discusses the obtained data concerning radiation stability of detectors, influence of different conditions (filters, collimators, registration channel fill etc.) on their energy resolution in spectrometric regime, as well as a dependence of radionuclide identification accuracy on detector size. |
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Article |
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Dovbnya, N.A. Karasyov, S.P. Kutny, V.E. Rybka, A.V. Shlyakhov, I.N. Uvarov, V.L. |
| author_facet |
Dovbnya, N.A. Karasyov, S.P. Kutny, V.E. Rybka, A.V. Shlyakhov, I.N. Uvarov, V.L. |
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Dovbnya, N.A. |
| title |
Application of CdTe (CdZnTe) detectors for radioactive waste characterization |
| title_short |
Application of CdTe (CdZnTe) detectors for radioactive waste characterization |
| title_full |
Application of CdTe (CdZnTe) detectors for radioactive waste characterization |
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Application of CdTe (CdZnTe) detectors for radioactive waste characterization |
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Application of CdTe (CdZnTe) detectors for radioactive waste characterization |
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application of cdte (cdznte) detectors for radioactive waste characterization |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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2002 |
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Application of the nuclear methods |
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http://dspace.nbuv.gov.ua/handle/123456789/80114 |
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Application of CdTe (CdZnTe) detectors for radioactive waste characterization / N.A. Dovbnya, S.P. Karasyov, V.E. Kutny, A.V. Rybka, I.N. Shlyakhov, V.L. Uvarov // Вопросы атомной науки и техники. — 2002. — № 2. — С. 55-57. — Бібліогр.: 3 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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2025-07-06T04:02:16Z |
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A P P L I C A T I O N O F T H E N U C L E A R M E T H O D S
APPLICATION OF CdTe (CdZnTe) DETECTORS FOR RADIOACTIVE
WASTE CHARACTERIZATION*
N.A. Dovbnya, S.P. Karasyov, V.E. Kutny, A.V. Rybka, I.N. Shlyakhov, V.L. Uvarov
National Scientific Centre “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine
e-mail: karasyov@kipt.kharkov.ua
The radiation detectors based on wide-zone semiconductor CdTe (CdZnTe) monocrystals have promising
advantages for their application in investigation (characterization) of radioactive waste. Among these advantages
there are the wide range of photons flux and energy, high registration efficiency and satisfactory energy resolution
without deep cooling of the detector. This report discusses the obtained data concerning radiation stability of
detectors, influence of different conditions (filters, collimators, registration channel fill etc.) on their energy
resolution in spectrometric regime, as well as a dependence of radionuclide identification accuracy on detector size.
PACS 07.85.-m, 07.88.+y, 81.70.Jb
1. INTRODUCTION
The counting and spectrometric measurements are
widely used for determination of a partial activity of
radioactive waste.
Application of spectrometers based on Ge(Li)
detectors, having high sensitivity and energy resolution,
allows to solve the problems of analysis of the count
samples (see, for example, [1]). However, these
problems are solved mainly under conditions of
laboratories and measurement stands. The use of such
detectors for a remote monitoring is impeded or
impossible at all because of the necessity of their
cooling up to fluid nitrogen temperature. Besides,
Ge(Li) detector to be placed in a cryostat has the
considerable dimensions. Therefore a development of
spectrometers on a basis of CdTe (CdZnTe)
monocrystal having enough resolution and not requiring
severe cooling is an urgent problem of the field gamma-
spectrometry.
The purpose of this work is the improvement of
energy resolution of a spectrometer using CdZnTe
detector by means of a noise characteristics
improvement of the preamplifier and magnification as
much as possible of permissible statistical fill of the
spectrometer circuit.
2. DESIGN OF SPECTROMETER
Spectrometer is executed structurally as a block of
detection (it consists of CdZnTe detector, preamplifier
and feed filter) supplied with the thin (20 µm) Ве
window and block of the amplifier - shaper.
The basic problem faced during development of the
spectrometer was the improvement of its energy
resolution in a given range of the gammas energy.
A resolution of spectrometer with a semiconductor
detector is determined by a number of parameters. First
of all it depends on a collection efficiency of charge
carriers generated by gamma radiation in the detector
volume, on a performance of detector material (the
lifetime, mobility of charge carriers), its homogeneity,
and on a voltage applied to the detector. Other factor
giving the essential contribution to quantity of the
energy resolution, is the electric noise of detector-
preamplifier system connected with fluctuations of
detector current.
The measuring circuit of the spectrometer is
executed using Analog Devices elements. The block
diagram of the spectrometer is represented in Fig. 1.
2
3
4
5
6 71
Fig. 1. Block diagram of counter - spectrometer
(CS) with CdZnTe detector: 1 - detector; 2 -
preamplifier; 3 - high-voltage feed; 4 - pulse shaper-
amplifier; 5 – stabilizer of datum level; 6 - analogue-
digital converter (ADC); 7 - IBM-PC
A signal from CdZnTe detector output acts on the
preamplifier. From the latter a pulse acts on the shaper
amplifier with a stabilizer of datum level and a rejecter
of superimpositions. Then a signal is digitised in the 12
bits ADC. The detector is connected directly to gate of
first stage transistor of the preamplifier for elimination
of noise of the input capacitor.
A dependence of the CS energy resolution on
detector voltage Ud demonstrates the spectrums, which
are given in Fig. 2.
A collimating of gammas flux improves the energy
resolution of spectrometer (see Fig. 3). Its calibration
was carried out with use of standard Am-241 source.
* Work is supported by STCU under contract № 2185
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2002, № 2.
Series: Nuclear Physics Investigations (40), p. 55-57. 55
2. OPERATION OF SPECTROMETER
UNDER MAJOR FILL
Tacking into account the CS operation with high-
active samples its energy resolution dependence on
input pulse frequency is of a great importance. The
spectrums of high-active 99Mo sample (exposition dose
rate 100 mR/s) measured with CdZnTe detector are
submitted in Fig. 4.
0 100 200 300 400 500
N channel
0
200
400
600
800
1000 N count
a)
0 100 200 300 400 500
N channel
0
200
400
600
800 N count b)
0 100 200 300 400 500
N channel
0
200
400
600
800 N count
c)
The CS energy resolution was measured along the
line Еγ=140 keV (Tc-99m - daughter nucleus of the Мо-
99 isotope). It is visible from spectrums obtained that at
the fill less than 104s-1 the resolution does not change
practically. At the fill more than 2*104s-1 the resolution
is worsened, that can be explained by an overload of the
spectrometer (preamplifier and amplifier - shaper).
0 200 400
N channel
0
200
400
600
N count
d)
0 200 400 600
N channel
0
400
800
1200
N count
e)
Fig. 2. a) - Ud=50V; b) - Ud=75V; c) - Ud=100V;
d) - Ud=150V; e) - Ud=200V
The fill of the CS was varied by change of sample-
detector distance. Besides the various filter materials
were used (Fig. 5,6). The fill was checked using the
software of pulse analyzer.
CONCLUSIONS
As a result of carried out examinations the small-
sized not cooled counter - spectrometer with the
following specification is designed: CdZnTe
monocrystal size, mm − 6х6х1; rated detector
temperature t, °С − 25; detector noise at t, кeV − no
more than 1.6; maximum fill of spectrometer nmax, с-1 −
2*104
; resolution for energy of gammas Еγ=59.6 кeV
(Am-241) at nmax,% − no more than 10; detection block
size, mm − 30х40х35; maximum detection block-
amplifier-shaperdistance, m − not less than 50.
Last two parameters provide a possibility of detector
operation with the remote controllable manipulators for
analysis of the samples in hard-to-reach places or under
high-level irradiation.
56
0 200 400
N channel
0
200
400
600
N count
a)
0 200 400 600
N channel
0
200
400
600
N count
b)
Fig. 3. The same, that in Fig. 2 with 1.5 mm Fe
collimator
0 400 800 1200 1600
N channel
0
200
400
600 N count
Fig. 4. Spectrum of 99Мо sample (Cu filter of 2 mm
thick)
0 400 800 1200 1600
N channel
0
100
200
300
400 N count
Fig. 5. The same, that in Fig.4 with Al filter of 1mm
thick and 1.5 mm Fe collimator
0 400 800 1200 1600
N channel
0
400
800
1200
N count
Fig. 6. The same, that in Fig. 4, with Cu filter of 0.5 mm
thick
REFERENCES
1. B.N. Belayev, V.A. Babichev, E.A. Gromov et al.
Experimental examination of the spent RBMC-1000
fuel and use of radioactivity correlations in analysis of
the samples selected from Chernobyl zone.
Radiochemistry // 1991, № 4, p. 149-159
2. V.I. Ivanov, V.V. Kondrashov et al. CdTe
gamma-spectrometer with system of pulses-shape
discrimination // .PTE, 1999, № 3, p. 47-53
3. L.T. Jones and P.B. Woollam. Resolution
Improvement in CdTe Gamma Detectors Using Pulse-
Shape Discrimination. // NIM. 1975, v. 124, p. 591-595
57
N.A. Dovbnya, S.P. Karasyov, V.E. Kutny, A.V. Rybka, I.N. Shlyakhov, V.L. Uvarov
1. INTRODUCTION
CONCLUSIONS
REFERENCES
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