Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly
An electron-neutron converter was optimized to ensure effective usage of generated neutrons in a subcritical assembly. Проведена оптимизация нейтронно-производящей мишени с целью максимально эффективного исполь- зования произведенных нейтронов в подкритической ядерной сборке. Проведено оптимізацію...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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| Дата: | 2006 |
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| Формат: | Стаття |
| Мова: | Англійська |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2006
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly / M.I. Aizatskiy, A.M. Dovbnya, I.M. Prokhorets, S.I. Prokhorets, Y.V. Rudychev, M.A. Khazhmuradov // Вопросы атомной науки и техники. — 2006. — № 2. — С. 28-30. — Бібліогр.: 8 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859633639390707712 |
|---|---|
| author | Aizatskiy, M.I. Dovbnya, A.M. Prokhorets, I.M. Prokhorets, S.I. Rudychev, Y.V. Khazhmuradov, M.A. |
| author_facet | Aizatskiy, M.I. Dovbnya, A.M. Prokhorets, I.M. Prokhorets, S.I. Rudychev, Y.V. Khazhmuradov, M.A. |
| citation_txt | Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly / M.I. Aizatskiy, A.M. Dovbnya, I.M. Prokhorets, S.I. Prokhorets, Y.V. Rudychev, M.A. Khazhmuradov // Вопросы атомной науки и техники. — 2006. — № 2. — С. 28-30. — Бібліогр.: 8 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | An electron-neutron converter was optimized to ensure effective usage of generated neutrons in a subcritical assembly.
Проведена оптимизация нейтронно-производящей мишени с целью максимально эффективного исполь-
зования произведенных нейтронов в подкритической ядерной сборке.
Проведено оптимізацію нейтроноутворюючої мішені з метою максимально ефективного використання
нейтронів в підкритичній ядерній зборці.
|
| first_indexed | 2025-12-07T13:13:30Z |
| format | Article |
| fulltext |
MATHEMATICAL MODELING OF A NEUTRON PRODUCTION TAR-
GET OF AN ELECTRON ACCELERATOR DRIVEN SUBCRITICAL
ASSEMBLY
M.I. Aizatskiy, A.M. Dovbnya, I.M. Prokhorets, S.I. Prokhorets, Y.V. Rudychev, M.A. Khazh-
muradov
NSC KIPT, Kharkov, Ukraine
E-mail: khazhm@kipt.kharkov.ua
An electron-neutron converter was optimized to ensure effective usage of generated neutrons in a subcritical as-
sembly.
PACS: 61.20.ja
1. INTRODUCTION
At present, neutron physics becomes a powerful tool
for solving various applied and fundamental problems.
Some fields of neutron application became classical. ear
energetic is one of such applications. For example, new
safe reactors based on fast neutrons are used, and nucle-
ar facilities using spallation neutrons with external irra-
diation of an active zone by protons [1] are created. Ele-
ment transmutation is also the classic field of neutron
application. This field is directly connected with nuclear
energetic because it becomes possible to load reactors
with other kind of fuel. Neutrons are widely used in
medicine, e.g., for cancer treatment [2]. Science
progress in techniques, biochemistry and biology makes
it necessary to use new physical methods which give
possibility to obtain complex information about molecu-
lar structure and molecular dynamics of composite crys-
tal and molecular-biology systems in natural conditions
[3,4]. The modern methods in neutron physics are
unique because information obtained by these methods
could not be obtained by other methods. Application of
the above-mentioned methods is limited because neu-
tron sources with high intensity and required spectrum
characteristics are not always available. Creation of a
hybrid nuclear facility (accelerator – target – subcritical
assembly) also known as Accelerator Driven Systems
(ADS) is one of the ways to obtain neutron source with
required characteristics [5]. Therefore, to develop such
kind of facilities it is important and necessary to opti-
mize parameters of all facility units.
The aim of this work is optimization of the parame-
ters of the neutron source target for an electron accelera-
tor driven assembly.
2. OPTIMIZATION OF THE ELECTRON-
NEUTRON CONVERTER
Neutrons are generated as a result of so-called pho-
tonuclear reactions. Photonuclear reaction model must
take into account the different nuclear reaction mecha-
nisms involved in the initial photonuclear excitation
process and subsequent decay of the excited nucleus by
particle and gamma-ray emission. All these processes
were taken into account for modeling of neutron genera-
tion by Monte-Carlo method. Detailed description of
such processes can be found in [6]. The GEANT4
physical tools were used for numerical modeling.
The typical curves of neutron yield for several ele-
ments are shown in Fig.1 and Fig.2. [7].
5 20 30 E , eVМ
0
0.5
1.0
1.5
2.0
2.5
3.0
Ni
Та Ag Fe Al
Cu
γ mC
Ba
Au
Pb
W
U C
Al
Ni
FeCu
Ag
Ba
Pb
Ta
Au
W
U
γ,
re
l.
un
.
Fig. 1. Photonuclear reaction yields
0 4020 60 80 Z
10 3
10 4
10 5
10 6
10 7
(γ ,n)
(γ ,2n)
(γ ,p)
(γ ,pn)
(γ ,3n)
(γ α, )
Y
ie
ld
, m
ol
р-1
-1 .
Fig. 2. Photonuclear reaction yields versus nucleus
atomic numbers
___________________________________________________________
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2006. № 2.
Series: Nuclear Physics Investigations (46), p.28-30. 28
These curves show that for obtaining high intensity
neutron source it is necessary to choose target with high
atomic number. Besides, a material for electron-neutron
converter must be refractory and easy to treat. Tungsten
meets all these requirements and it was chosen as the
material for electron-neutron converter.
The initial geometry was following: we used the
cylindrical converter and parallel electron beam normal
to the target face surface. The diameter of initial beam
was 5 mm and energy was 100 MeV. It is also necessary
to note that neutron generation reactions are threshold
ones. It means that if the energy of gamma is less than
given threshold energy, then all secondary particles can
not be able to generate neutrons. The threshold energy
value depends on a material. As it has been mentioned
above, tungsten is the material for our converter. Then
for this material all gammas with energy less than
6.19 MeV can not generate neutrons. Therefore, such
gammas are background and have an influence only on
converter temperature. Thus, in this case gammas with
such energies are ignored under modeling.
Choosing a target thickness is the first step of opti-
mization. Having analyzed the obtained data, the thick-
ness of our converter was chosen as 6.5 cm.
About 99.84% of gammas created as a result of in-
teraction between initial electron beam and converter
material are adsorbed in the converter of such thickness.
On the other hand, 99.98% of distributed gamma fluxes
participate in process. So, nearly all gammas can gener-
ate neutrons.
The neutron energy spectrum is shown in Fig.3. This
spectrum shows that most of neutrons have energies up
to 6 MeV. These neutrons are conceivably generated as
a result of ( )n,γ and ( )n2,γ reactions in a Giant Dipole
Resonance (GDR) region. Threshold energies for these
reactions are 6.19 and 13.6 MeV, respectively.
1 2 3 4 5 6 7 8 9 10 11 12
10-5
10-4
10-3
10-2
N
eu
tro
n
Y
ie
ld
, n
/e
Energy, MeV
Fig. 3. Energy spectrum of neutrons generated by tung-
sten target irradiated with 100 MeV electrons
These reactions have a maximum cross-section in
GDR region. At the higher neutrons energies the yield
decreases more than order of the magnitude that corre-
sponds to appropriate cross-sections. Besides, the num-
ber of gammas decreases exponentially with increasing
of their energy.
Angular distribution of generated neutrons is shown
in Fig.4. This distribution indicates that scattered neu-
tron yield probability has a maximum at the angle more
than 100°, i.e. in backward direction to the initial beam,
as forward scattered neutrons is gone from large materi-
al thickness. This distribution has such shape as neutron
yield is isotropic in any direction, and the maximum of
generated neutrons lies in the thickness up to 3 cm.
0 4 8 12 16 20 24 28 32 36
0.0
0.4
0.8
1.2
1.6
Cylinder
Cylinder+well
N
eu
tro
n
Y
ie
ld
, n
/e
·1
0-3
Theta, dergee
Fig. 4. Angular distributions of neutron yield for cylin-
drical target (cylinder, solid line) and for cylindrical tar-
get with channel (cylinder + well, dashed line)
It is obvious that the given configuration of the neu-
tron fluxes is not optimized, as there is a probability to
have a leakage of backward scattered neutrons because
of the subcritical assembly construction,
To optimize our neutron yield, we modified the con-
verter geometry by adding a small channel inside the
cylinder, which is denoted as a “well” in our figures.
The similar modification for spherical geometry was
used by Kovalev [8].
Diameter of this channel is practically equal to the
initial beam diameter; in our case it is equal to 5.1 mm.
The channel depth influence on neutron yields
change was calculated. In particular, the dependence of
neutron yields from lateral and face cylinder surfaces on
channel depth was investigated. Results are shown in
Fig.5.
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
Bottom
Top
Tube
N
eu
tr
on
fr
ac
tio
n
Well Depth, cm
Fig. 5. Neutron yields versus channel depth for lat-
eral and face cylinder surfaces normalized by total neu-
tron yield from converter surface
___________________________________________________________
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2006. № 2.
Series: Nuclear Physics Investigations (46), p.28-30.28
From the obtained data we can conclude that the
maximal neutron yield lies at the 3.5 mm of the channel
depth. Also dependence of the neutron flux angular dis-
tribution has been obtained for given geometry as it is
shown in Fig.4 (cylinder + well, dashed line). The maxi-
mum of the angular distribution lies near 90°. Thus, the
optimized converter geometry ensures more effective
neutrons yield. In our case the maximum of neutron
yield from the neutron source target lateral surface is an
optimization criterion.
After optimization procedure the geometrical config-
uration of electron-neutron, converter was following:
cylinder of 10 cm thickness with channel of 3.5 cm
depth.
So, it can be concluded that this optimized configu-
ration of electron-neutron converter ensures effective
usage of the generated neutrons for neutron multiplica-
tion in the subcritical assembly.
3. CONCLUSION
The electron-neutron converter irradiated with elec-
trons with energy 100 MeV was simulated by using
Monte-Carlo method based on the GEANT4 physical
tools. It is necessary to note, that in the GEANT4, it is
possible to use different physical models depending on
the problem solved. Also the usage of the quark-level
model ensured in our case more accurate description of
energy and angular neutron distributions both at high
and low energies. All models in the GEANT4 were veri-
fied by experimental data.
The converter geometry and material was optimized
to obtain maximum neutron yield with the assumption
of converter using together with the subcritical assem-
bly.
Obtained results allowed defining the optimal geom-
etry of the electron-neutron converter with taking into
account the converter material. It was shown that after
converter geometry modification from cylindrical shape
to the cylinder with a channel, the neutron yield fraction
from cylinder lateral surface increased from 35% up to
53%. This fact ensures more effective usage of the gen-
erated neutrons in the subcritical assembly. The angular
and energy neutron flux distributions were simulated
and optimized according to the listed above conditions.
REFERENCES
1. Yu.M. Ado. NPP operating at the subcritical reactor
with external neutron irradiation (impossibility of the
reactor runaway): Preprint IPHE 93-24 OKU. Protvino:
1993 (in Russian).
2. B.F. Bayanov et al. Accelerator-based neutron source
for the neutron-capture and fast neutron therapy at hos-
pital // Nucl. Instrum. and Methods. 1998, A413, p. 397-
426.
3. G.E. Bacon. Neutron Diffraction. “Clarendon Press”,
1975.
4. Yu.A. Alexandrov et al.: Preprint JINR P-14-5358.
Dubna, 1970.
5. M. Prome. Major project for the Use of High Power
Linac. Proc. of Linac96. 1996, v.1, p.9-11.
6. GEANT4 Physics Reference Manual. GEANT4 Work-
ing Group CERN. June 21, 2004.
7. W.P. Swanson Calculation of neutron yields released by
electron incident on selected materials // Health Physics.
1978, v.35, p.353-367.
8. V.P. Kovalev. Secondary radiation of the electron ac-
celerators. M:. “Atomizdat”, 1979 (in Russian).
МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ НЕЙТРОНОПРОИЗВОДЯЩEЙ МИШЕНИ
ПОДКРИТИЧЕСКОЙ ЯДЕРНОЙ СБОРКИ, УПРАВЛЯЕМОЙ УСКОРИТЕЛЕМ ЭЛЕКТРОНОВ
Н.И. Айзацкий, А.Н. Довбня, И.М. Прохорец, С.И. Прохорец, Е.В. Рудычев, М.А. Хажмурадов
Проведена оптимизация нейтронно-производящей мишени с целью максимально эффективного исполь-
зования произведенных нейтронов в подкритической ядерной сборке.
МАТЕМАТИЧНЕ МОДЕЛЮВАННЯ НЕЙТРОНОУТВОРЮЮЧОЇ МІШЕНІ ПІДКРИТИЧНОЇ
ЯДЕРНОЇ ЗБОРКИ, КЕРОВАНОЇ ПРИСКОРЮВАЧЕМ ЕЛЕКТРОНІВ
М.І. Айзацький, А.М. Довбня, І.М. Прохорець, С.І. Прохорець, Є.В. Рудичев, М.А. Хажмурадов
Проведено оптимізацію нейтроноутворюючої мішені з метою максимально ефективного використання
нейтронів в підкритичній ядерній зборці.
20
Н.И. Айзацкий, А.Н. Довбня, И.М. Прохорец, С.И. Прохорец, Е.В. Рудычев, М.А. Хажмурадов
|
| id | nasplib_isofts_kiev_ua-123456789-78699 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T13:13:30Z |
| publishDate | 2006 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Aizatskiy, M.I. Dovbnya, A.M. Prokhorets, I.M. Prokhorets, S.I. Rudychev, Y.V. Khazhmuradov, M.A. 2015-03-20T08:51:27Z 2015-03-20T08:51:27Z 2006 Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly / M.I. Aizatskiy, A.M. Dovbnya, I.M. Prokhorets, S.I. Prokhorets, Y.V. Rudychev, M.A. Khazhmuradov // Вопросы атомной науки и техники. — 2006. — № 2. — С. 28-30. — Бібліогр.: 8 назв. — англ. 1562-6016 PACS: 61.20.ja https://nasplib.isofts.kiev.ua/handle/123456789/78699 An electron-neutron converter was optimized to ensure effective usage of generated neutrons in a subcritical assembly. Проведена оптимизация нейтронно-производящей мишени с целью максимально эффективного исполь- зования произведенных нейтронов в подкритической ядерной сборке. Проведено оптимізацію нейтроноутворюючої мішені з метою максимально ефективного використання нейтронів в підкритичній ядерній зборці. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Линейные ускорители заряженных частиц Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly Математическое моделирование нейтронопроизводящeй мишени подкритической ядерной сборки, управляемой ускорителем электронов Математичне моделювання нейтроноутворюючої мішені підкритичної ядерної зборки, керованої прискорювачем електронів Article published earlier |
| spellingShingle | Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly Aizatskiy, M.I. Dovbnya, A.M. Prokhorets, I.M. Prokhorets, S.I. Rudychev, Y.V. Khazhmuradov, M.A. Линейные ускорители заряженных частиц |
| title | Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly |
| title_alt | Математическое моделирование нейтронопроизводящeй мишени подкритической ядерной сборки, управляемой ускорителем электронов Математичне моделювання нейтроноутворюючої мішені підкритичної ядерної зборки, керованої прискорювачем електронів |
| title_full | Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly |
| title_fullStr | Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly |
| title_full_unstemmed | Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly |
| title_short | Mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly |
| title_sort | mathematical modeling of a neutron production target of an electron accelerator driven subcritical assembly |
| topic | Линейные ускорители заряженных частиц |
| topic_facet | Линейные ускорители заряженных частиц |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/78699 |
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