Dose distribution in the heterogeneous materials irradiated by electron beams
The simulation of the absorbed depth-dose distribution (DDD) near the boundary of contacting materials with a different density and/or by effective atomic numbers of materials irradiated by a scanning electron beam was fulfilled. The experimental validation of the obtained theoretical predictions...
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| Zitieren: | Dose distribution in the heterogeneous materials irradiated by electron beams / I. Kaluskab, V.T. Lazurika, V.M. Lazurika, G.F. Popova, Y.V. Rogova, Z. Zimek // Вопросы атомной науки и техники. — 2004. — № 1. — С. 184-186. — Бібліогр.: 3 назв. — англ. |
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irk-123456789-790682015-03-26T03:01:55Z Dose distribution in the heterogeneous materials irradiated by electron beams Kaluska, I. Lazurik, V.T. Lazurik, V.M. Popov, G.F. Rogov, Y.V. Zimek, Z. Применение ускоренных пучков The simulation of the absorbed depth-dose distribution (DDD) near the boundary of contacting materials with a different density and/or by effective atomic numbers of materials irradiated by a scanning electron beam was fulfilled. The experimental validation of the obtained theoretical predictions related with abnormal behavior of the DDD in heterogeneous materials was fulfilled on the radiation-technological lines with Linac LAE 13/9, INCT. Проведено моделювання розподілу поглиненої дози (РПД) на границі контактуючих матеріалів з різними щільностями і/чи атомними номерами, що опромінюються скануючим електронним пучком. Експериментальну перевірку теоретичних передбачень аномальної поведінки РПД у гетерогенних матеріалах проводили на радіаційно-технологічній лінії з лінійним прискорювачем електронів LAE 13/9, ІЯХТ, Варшава, Польща. Проведено моделирование распределения поглощенной дозы (РПД) на границе раздела веществ с различными плотностями и/или атомными номерами, облучаемых сканирующим электронным пучком. Экспериментальную проверку теоретических предсказаний аномального поведения РПД в гетерогенных материалах проводили на радиационно-технологической линии с линейным ускорителем электронов LAE 13/9, ИЯХТ, Варшава, Польша. 2004 Article Dose distribution in the heterogeneous materials irradiated by electron beams / I. Kaluskab, V.T. Lazurika, V.M. Lazurika, G.F. Popova, Y.V. Rogova, Z. Zimek // Вопросы атомной науки и техники. — 2004. — № 1. — С. 184-186. — Бібліогр.: 3 назв. — англ. 1562-6016 PACS: 81.70.-q http://dspace.nbuv.gov.ua/handle/123456789/79068 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Применение ускоренных пучков Применение ускоренных пучков |
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Применение ускоренных пучков Применение ускоренных пучков Kaluska, I. Lazurik, V.T. Lazurik, V.M. Popov, G.F. Rogov, Y.V. Zimek, Z. Dose distribution in the heterogeneous materials irradiated by electron beams Вопросы атомной науки и техники |
| description |
The simulation of the absorbed depth-dose distribution (DDD) near the boundary of contacting materials with a different
density and/or by effective atomic numbers of materials irradiated by a scanning electron beam was fulfilled. The experimental
validation of the obtained theoretical predictions related with abnormal behavior of the DDD in heterogeneous materials was
fulfilled on the radiation-technological lines with Linac LAE 13/9, INCT. |
| format |
Article |
| author |
Kaluska, I. Lazurik, V.T. Lazurik, V.M. Popov, G.F. Rogov, Y.V. Zimek, Z. |
| author_facet |
Kaluska, I. Lazurik, V.T. Lazurik, V.M. Popov, G.F. Rogov, Y.V. Zimek, Z. |
| author_sort |
Kaluska, I. |
| title |
Dose distribution in the heterogeneous materials irradiated by electron beams |
| title_short |
Dose distribution in the heterogeneous materials irradiated by electron beams |
| title_full |
Dose distribution in the heterogeneous materials irradiated by electron beams |
| title_fullStr |
Dose distribution in the heterogeneous materials irradiated by electron beams |
| title_full_unstemmed |
Dose distribution in the heterogeneous materials irradiated by electron beams |
| title_sort |
dose distribution in the heterogeneous materials irradiated by electron beams |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2004 |
| topic_facet |
Применение ускоренных пучков |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/79068 |
| citation_txt |
Dose distribution in the heterogeneous materials irradiated by electron beams
/ I. Kaluskab, V.T. Lazurika, V.M. Lazurika, G.F. Popova, Y.V. Rogova, Z. Zimek // Вопросы атомной науки и техники. — 2004. — № 1. — С. 184-186. — Бібліогр.: 3 назв. — англ. |
| series |
Вопросы атомной науки и техники |
| work_keys_str_mv |
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| first_indexed |
2025-07-06T03:10:25Z |
| last_indexed |
2025-07-06T03:10:25Z |
| _version_ |
1836865474661449728 |
| fulltext |
DOSE DISTRIBUTION IN THE HETEROGENEOUS MATERIALS
IRRADIATED BY ELECTRON BEAMS
I. Kaluskab, V.T. Lazurika, V.M. Lazurika, G.F. Popova, Y.V. Rogova, Z. Zimekb
aKharkov National University, Kharkov, Ukraine;
bInstitute of Nuclear Chemistry and Technology, INCT, Warsaw, Poland;
E-mail: popov@univer.kharkov.ua
The simulation of the absorbed depth-dose distribution (DDD) near the boundary of contacting materials with a different
density and/or by effective atomic numbers of materials irradiated by a scanning electron beam was fulfilled. The experimental
validation of the obtained theoretical predictions related with abnormal behavior of the DDD in heterogeneous materials was
fulfilled on the radiation-technological lines with Linac LAE 13/9, INCT.
PACS: 81.70.-q
1. INTRODUCTION
The numerical investigations of a dose distribution
in heterogeneous targets irradiated on radiation-techno-
logical lines (RTL) by a scanned electron beams on
moving conveyer were carried out with use of software
ModeRTL [1]. The software ModeRTL (Modeling of
the Radiation-Technological Line) is developed for sim-
ulation of radiation processes and calculation of the ab-
sorbed dose, temperature, and charge distribution within
products irradiated by a scanning electron beam with the
electron energy range from 0.1 to 20 MeV on industrial
RTL.
Investigations were fulfilled in the two-dimensional
geometrical model, in which the target on a conveyor
line was represented as a set of parallelepipeds unlimit-
ed on length along a motion of the conveyor (axis Z). It
is supposed, that the parallelepiped sides are oriented
only in parallel and perpendicularly to scanning direc-
tion of an electron beam (axis Y), and the material of
each element of target (represented as separate paral-
lelepiped) is homogeneous. Dose fields in a plane of
scanning of an electron beam (plane XY) were calculat-
ed. Depth-dose distributions (depth is measured from an
irradiated surface of object along an axis X perpendicu-
lar to axis Y) were compared on various distances from
a boundary of materials with different densities and/or
atomic numbers.
The comparison and analysis of the results have al-
lowed one to bring out a series of features in behavior of
dependence of a depth-dose distribution near to bound-
ary of two different materials. Let us note, that an
anomaly dose which appear near the boundaries of two
materials with different atomic numbers are well
known. As a rule, the consideration of these effects is
perform for a case of normal falling of an electron beam
and at a uniform irradiation of a boundary of contacting
materials, i.e. in one-dimensional model. In this case,
the influence of density of the contacting materials on
value of boundary effects can be neglected. This report
is focused mainly to boundary effects of another sort,
namely, boundary effects appearing due to difference of
densities of contacting materials.
2. THEORETICAL PREDICTIONS
The heterogeneous target consisting of two blocks
was chosen for an illustration of some theoretical pre-
dictions, obtained on the basis of results analysis of
computer experiments. Blocks of contacting materials
have identical chemical composition and different densi-
ties. For example, such target can be easily implemented
with use of homogeneous (PE density of 0.94 g/cm3) and
granules (PE2 bulk density of 0.3 g/cm3) polyethylene.
The geometrical parameters of a target were chosen so
that the curves of depth-dose distribution at center of
blocks corresponded to an extreme case of a semi-infinite
target. It is implemented when the sizes of blocks greater
than r0 – continuous slowing-down approximation range
of electrons in material of the block.
The key features of simulation results of an electron
dose distribution in targets consisting of two materials
with different density are the following:
1. Depth-dose distribution near to boundaries of the
contacting materials with different density differs under
the shape from a depth-dose distribution in semi-infinite
target for each of contacting materials.
2. The values of doses near to boundary of two ma-
terials which differed only in density coincide on a sur-
face of a target and can differ in depth of a target,
3. The value of a dose in material with smaller den-
sity is greater than in material with greater density on all
depth of an irradiated target,
4. Maximal values of a dose near to a boundary of
the contacting materials with different density can ex-
ceed maximal values of a dose in semi-infinite target for
each of contacting materials,
5. The local minimum in depth-dose distribution can
appear on small distances from a surface of a target in
material with greater density,
6. Depth-dose distribution near to boundaries of con-
tacting materials with different density have the similar
shapes on considerable distances from a surface of a tar-
get.
The theoretical analysis of mentioned above general
features allows to make a conclusion about a determina-
tive role of electrons, which move along boundary, in
process of formation of a boundary effect.
It is important for development of theoretical models
to utilize an experimental validation of basic features of
boundary effects predicted on the basis of computer
simulation of an irradiation process. The quality of an
irradiation process in radiation technologies are deter-
mined by values of the dose limits - Dmin and Dmax. The
practical recommendations and conclusions obtained on
the basis of the mentioned above basic features of
boundary effects are important for radiation technolo-
gies. Thus, the theoretical predictions require experi-
___________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.184-186. 184
mental validation on actual RTL.
3. EXPERIMENTAL
The experimental investigations of the absorbed
depth-dose distribution near to boundary of two materi-
als with different density and/or by effective atomic
number which were irradiated by a scanning electron
beam with energy 10 МеV were fulfilled. The absorbed
dose for irradiated materials was delivered in the range
of 40…60 kGy. The experiments were performed on the
RTL with Linac LAE 13/9 at the INCT, Warsaw,
Poland [2]. Dose effects near to boundary of two con-
tacting materials with different density and atomic num-
ber such as Al with density 2,7 g/cm3, high density
polyethylene (PE) block with density 0.94 g/cm3, PE1
granules with bulk density 0.66 g/cm3, and wood with
density 0,44 g/cm3 were investigated. The materials
were represented as parallelepipeds at which the con-
tacting boundaries are in parallel with an axis of elec-
trons beam. Cellulose Triacetate (CTA) dosimetric film
(FTR-125) with thickness 0.125 mm, density 1.32 g/cm3
was used for measurement of a depth-dose distribution.
4. RESULTS AND DISCUSSION
Results of the specially carried out dose distribution
measurements in CTA films inserted in the standard Al
dosimetric wedge (the points) and obtained with use of
the software ModeRTL (histograms) are presented in
Fig.1,a. Results of Monte Carlo simulation of the depth-
dose distributions in homogeneous materials (his-
tograms with points +) and obtained by semi-empirical
model [3] for semi-infinite medium (dash line) are pre-
sented for comparison in Fig. 1,a,b.
As it is seen from Fig. 1,a, the ratio of calculated
values of a dose in CTA film to a dose in Al on a sur-
face of a target (x=0, see values in the first cells of two
histograms) corresponds to the ratio of values of a dose
measured by Al dosimetric wedge (Experiment 1) to
calculated values of a dose in Al (histogram with points
+) on any depth in a target.
Difference of a dose profile in a CTA film from a
dose profile in target material are determined by two
factors: by change of a dose profile due to differences of
stopping powers of materials (first factor) and change of
a dose profile due to differences of materials density
(second factor).
The smaller density and greater stopping power of
CTA film material relatively Al corresponds to a case,
when both factors work in one direction, that lead to
considerable excess of a dose distribution in CTA films
relatively a dose in Al (greater than 20%). The differ-
ence in density of a film material and the target materi-
als lead to appreciable distortion of a dose profile in a
film (compare curves of a dose - measured by Al dosi-
metric wedge (Experiment 1) and calculated (or mea-
sured) in CTA films).
It essentially distinguishes a case, when there is a
difference in densities of contacting materials from a
case, when there is a difference only in stopping powers
of material.
The conclusions formulated on the basis of the visu-
al analysis presented on Fig.1,a are agreed with experi-
mental and simulation results for PE granules (See
Fig. 1,b). The ratio of a stopping power of CTA film
material to a stopping power of PE is less than 1 and
density of CTA film material more than PE density.
Fig.1. Depth-dose distribution in the target consisting of
two Al blocks (a) and PE1 blocks (PE1 density 0.66
g/cm3) (b): Histograms - results of calculations by a
method Monte Carlo of the dose distribution in Al and
PE1 blocks (points +) and in CTA film placed between
two Al and PE1 blocks; Dashed line - dose distribution
calculated with the use semi-empirical model at the cen-
ter of Al and PE1 blocks. Experimental results for dose
distribution measured by CTA film placed between two
Al and PE1 blocks are shown by points
Differences of a dose profile in a CTA film from a
dose profile in bulk PE are determined by two factors,
as well as for a case of CTA film in Al. However, in this
case, action of the factors is opposite and the values of
difference of doses in CTA film and in bulk PE less on
an absolute value and has an opposite sign.
Results of Monte Carlo simulation (histograms) of
the depth-dose distributions on the boundary of two
contacting blocks consisting of different materials and
obtained by semi-empirical model for semi-infinite
medium (solid line) are presented in Fig. 2,a and b.
Experimental results for depth-dose distribution
measured by CTA film placed between materials with
different density in Fig. 2,a and b are shown by points.
The relative accuracy of experimental data did not ex-
ceed 5% for values of doses greater than 10 kGy. The
uncertainty of the depth value of all curves is 0.125 cm
and the average size in each point is 0.1см. It is sup-
posed, that the process of an irradiation can be described
in one-dimensional model, i.e. the effects of lateral
boundaries of a target can be neglected.
___________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.184-186.185
The requirements for experiments and computer
modeling were chosen so that in dedicated range of
depths the level of precision for an experimental and
calculation data (relative deviation) of measuring no
greater than 5%, relative root-mean-square statistical er-
ror no greater than 5%) was supplied sufficient for car-
rying out of the comparative analysis.
Fig.2. Depth-dose distribution in the target consists of
PE-Al (a) (PE density 0.94 g/cm3) and wood-PE blocks
(b) (wood density 0.44 g/cm3): Histograms – results of
calculations by a method Monte Carlo of the depth-dose
distribution near to boundary of Al, PE, and wooden
blocks; Solid curves – depth-dose distribution at the
center of Al, PE, and wooden and PE blocks calculated
with the use semi-empirical model. Xopt is the optimum
target thickness for PE and wooden blocks at one-sided
irradiation respectively
As it is seen in Fig.2,a and b in dedicated range of
target depths the measurement results are satisfactorily
agreed with results obtained on the basis of simulation
of an irradiation process by a Monte-Carlo method.
It is possible to conclude, that basic features of
boundary effects which were described in items 1,3,4,6
(part «Introduction») obtained theoretically with using
the software ModeRTL are experimentally validated.
The established fact of strong distortion of a dose pro-
file in thin dosimetric film (see Fig.1,a and b) specifies
necessity of modernization of a measurement principles
for experimental validation of items 2,4 for the list of
general features of boundary effects.
The results represented in Fig.2,a and b concerned to
a case when the sizes of the contacting materials in a di-
rection perpendicular to a boundary of target are great
and it is possible to suppose a target by unlimited.
5. CONCLUSIONS
The experimental and theoretical examinations of
boundary anomalies of a dose distribution are per-
formed on model samples. Both used materials (Al, PE,
wood, CTA film) and radiation facility on basis of the
LAE 13/9 are typical for a series of radiation technolo-
186
gies. As it is seen from comparison of experimental re-
sults with data, obtained by simulation methods, fol-
lows, that the theoretical predictions of behavior of a
dose near to a boundary of two materials with different
density are correct. It was established, that the boundary
anomalies of a dose can be realized at radiation process-
ing of heterogeneous materials. Investigation of those
anomalies can be used to estimate the quality of an irra-
diation fulfilled on RTL.
It is shown that an application of designed software
model for planning of irradiation on RTL and interpreta-
tion of results obtained by dosimetric film is correct, is
useful and, in a series of cases it is necessary in practice.
REFERENCES
1. V.T. Lazurik, V.M. Lazurik, G. Popov, Yu. Rogov.
Proc. of EBT’03 Conf. Varna, Bulgaria, p.616-622.
2. Z. Zimek, S. Kołyga, V.M. Levin, V.M. Nikolaev,
V.V. Rumyantsev, L.P. Fomin. An Institute of Nuc-
lear Research Electron Linac. // Nukleonika, 1972,
v. 17, № 1-2, р. 67-75.
3. V.M. Lazurik, T. Tabata, V.T. Lazurik // Radiat.
Phys. Chem. 2001, v. 60, р. 161-162.
РАСПРЕДЕЛЕНИЕ ДОЗЫ В ГЕТЕРОГЕННЫХ МАТЕРИАЛАХ,
ОБЛУЧАЕМЫХ ПУЧКАМИ ЭЛЕКТРОНОВ
И. Калуска, В.Т. Лазурик, В.М. Лазурик, Г.Ф. Попов, Ю.В. Рогов, З. Зимек
Проведено моделирование распределения поглощенной дозы (РПД) на границе раздела веществ с раз-
личными плотностями и/или атомными номерами, облучаемых сканирующим электронным пучком. Экспе-
риментальную проверку теоретических предсказаний аномального поведения РПД в гетерогенных материа-
лах проводили на радиационно-технологической линии с линейным ускорителем электронов LAE 13/9,
ИЯХТ, Варшава, Польша.
РОЗПОДІЛ ДОЗИ В ГЕТЕРОГЕННИХ МАТЕРІАЛАХ,
ЩО ОПРОМІНЮЮТЬСЯ ПУЧКАМИ ЕЛЕКТРОНІВ
І. Калуска, В.Т. Лазурік, В.М. Лазурік, Г.Ф. Попов, Ю.В. Рогов, З. Зімек
Проведено моделювання розподілу поглиненої дози (РПД) на границі контактуючих матеріалів з різними
щільностями і/чи атомними номерами, що опромінюються скануючим електронним пучком.
Експериментальну перевірку теоретичних передбачень аномальної поведінки РПД у гетерогенних
матеріалах проводили на радіаційно-технологічній лінії з лінійним прискорювачем електронів LAE 13/9,
ІЯХТ, Варшава, Польща.
___________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.184-186.187
3. EXPERIMENTAL
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