Formation of uniform electron beams on large-area targets
The report describes the results of calculations and experimental studies of the system for scanning the beam on outside targets of electron accelerators by magnetic quadrupole lenses.
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2004
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| Series: | Вопросы атомной науки и техники |
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| Cite this: | Formation of uniform electron beams on large-area targets / A.N. Dovbnya, N.A. Dovbnya, Z.M. Kolot, V.A. Popenko, A.N. Savchenko, D.L. Styopin, V.A. Shendrik // Вопросы атомной науки и техники. — 2004. — № 1. — С. 120-121. — Бібліогр.: 4 назв. — англ. |
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nasplib_isofts_kiev_ua-123456789-789632025-02-23T20:25:49Z Formation of uniform electron beams on large-area targets Формування однорідних пучків електронів на мішенях з великою площею Формирование однородных пучков электронов на мишенях с большой площадью Dovbnya, A.N. Dovbnya, N.A. Kolot, Z.M. Popenko, V.A. Savchenko, A.N. Styopin, D.L. Shendrik, V.A. Элементы ускорителей The report describes the results of calculations and experimental studies of the system for scanning the beam on outside targets of electron accelerators by magnetic quadrupole lenses. Представлені результати розрахунків та експериментальних досліджень системи розгортки пучка на вихідних мішенях прискорювачів електронів магнітними квадрупольними лінзами. Представлены результаты расчета и экспериментальных исследований системы развертки пучка на выходных мишенях ускорителей электронов магнитными квадрупольными линзами. 2004 Article Formation of uniform electron beams on large-area targets / A.N. Dovbnya, N.A. Dovbnya, Z.M. Kolot, V.A. Popenko, A.N. Savchenko, D.L. Styopin, V.A. Shendrik // Вопросы атомной науки и техники. — 2004. — № 1. — С. 120-121. — Бібліогр.: 4 назв. — англ. 1562-6016 PACS: 07.55.+k https://nasplib.isofts.kiev.ua/handle/123456789/78963 en Вопросы атомной науки и техники application/pdf Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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Элементы ускорителей Элементы ускорителей |
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Элементы ускорителей Элементы ускорителей Dovbnya, A.N. Dovbnya, N.A. Kolot, Z.M. Popenko, V.A. Savchenko, A.N. Styopin, D.L. Shendrik, V.A. Formation of uniform electron beams on large-area targets Вопросы атомной науки и техники |
| description |
The report describes the results of calculations and experimental studies of the system for scanning the beam on
outside targets of electron accelerators by magnetic quadrupole lenses. |
| format |
Article |
| author |
Dovbnya, A.N. Dovbnya, N.A. Kolot, Z.M. Popenko, V.A. Savchenko, A.N. Styopin, D.L. Shendrik, V.A. |
| author_facet |
Dovbnya, A.N. Dovbnya, N.A. Kolot, Z.M. Popenko, V.A. Savchenko, A.N. Styopin, D.L. Shendrik, V.A. |
| author_sort |
Dovbnya, A.N. |
| title |
Formation of uniform electron beams on large-area targets |
| title_short |
Formation of uniform electron beams on large-area targets |
| title_full |
Formation of uniform electron beams on large-area targets |
| title_fullStr |
Formation of uniform electron beams on large-area targets |
| title_full_unstemmed |
Formation of uniform electron beams on large-area targets |
| title_sort |
formation of uniform electron beams on large-area targets |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2004 |
| topic_facet |
Элементы ускорителей |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/78963 |
| citation_txt |
Formation of uniform electron beams on large-area targets / A.N. Dovbnya, N.A. Dovbnya, Z.M. Kolot, V.A. Popenko, A.N. Savchenko, D.L. Styopin, V.A. Shendrik // Вопросы атомной науки и техники. — 2004. — № 1. — С. 120-121. — Бібліогр.: 4 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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2025-11-25T06:03:02Z |
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| fulltext |
FORMATION OF UNIFORM ELECTRON BEAMS
ON LARGE-AREA TARGETS
A.N. Dovbnya, N.A. Dovbnya, Z.M. Kolot, V.A. Popenko, A.N. Savchenko, D.L. Styopin,
V.A. Shendrik
National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine
The report describes the results of calculations and experimental studies of the system for scanning the beam on
outside targets of electron accelerators by magnetic quadrupole lenses.
PACS: 07.55.+k
Extension of the class of radiation works on the ex-
ternal electron beam from the accelerator KUT-20 [1]
has given rise to a problem of searching new devices for
beam extraction and irradiation field formation. For the
long-term treatment of large-scale objects one uses suc-
cessfully electromagnetic scanners we have developed
[2,3], but for the isotope production one needs an ex-
tracted electron beam of a maximum density (power)
and, respectively, of a minimum cross-section that, as a
rule, leads to failure in the foil of the exit window.
Therefore, besides development of special exit windows
of a small area providing the works with converters on a
not scanned beam it is necessary to have a device for
formation of electron beams with a large area (≈
1000 cm2) for diverse technological tasks at the target
disposed at some distance (≈100 cm) from the exit win-
dow (during works with the target the converter taken
away).
When using the electromagnetic scanner, the scan-
ning is performed so that every pulse gets into the cer-
tain part of an object, and, as a result, this part gains a
higher specific power and overheats. Furthermore, the
shape of a dose field depends on dimensions of the exit
windows of the scanner and can change slightly with
changing the scanner current. In addition, to form a dose
field one applied “scatters”, i.e. the field is formed due
to the electron scattering on the foil. In this case it is not
possible to control the dose field shape. However, the
main problem consists in that, at high currents of accel-
erated electrons, a large energy spread takes place and
in both cases the major higher-energy part of the beam
stays closely to the center, and the minor one takes
place near the dose field periphery. In the beam center
there generated is the bremsstrahlung with a higher
maximum energy and, naturally, there occurs the
stronger activation of irradiated materials than at the
edges. Moreover, the accelerator is used for diverse
technological tasks and, therefore, a quick replacement
of a scanner is required.
Existing beam scanners allow beam scanning with a
maximum frequency ≈ 3 Hz. At the same time, by in-
creasing this frequency to the pulse repetition frequency
≈100…300 Hz with simultaneous increasing its area
one should decrease proportionally the amplitude of
cyclic stresses and, thereby the effect caused by the
charge accumulation in dielectrics and semiconductor
materials being under irradiation. To decrease the mean
beam density it is necessary, on the one hand, to con-
struct large-area target units, and, on the other hand, to
realize the methods of formation of large-size beams. In
the principal plane it can be realized with the use of a
duplet or a triplet of quadrupole lenses having a large
aperture. However, expenditures of energy for operation
of such a system will be considerable. Therefore, we
have realized at the accelerator EPOS several simpler
variants using available equipment, additional
quadrupole lens and beam “scatters”. This combination
makes it possible to join accelerator regimes of irradia-
tion of semiconductors and dielectrics (high-density
beam) and a regime of generation of radionuclides for
medicine (low-density beam).
At the accelerator KUT-20 the electron beam extrac-
tion is performed through the double window (cooling
water flows between foils) without a beam scanner. As
the water layer is sufficiently thick (4…8 mm), the win-
dow is a natural beam “scatter”. In this connection, a
problem has appeared, namely, to form a dose field with
the help of a quadrupole lens.
For calculation of a dose field on the object under ir-
radiation the Monte-Carlo method was used. A program
for beam scanning simulation was developed. Initial
conditions for a particle at the accelerator exit are cho-
sen from experimentally-known beam distributions by
coordinates, angles and energies. Multiple beam scatter-
ing at the exit foil was taken into account also for the
particle passing in the air. The lens parameters and the
distance between the lens and the target were varying
[4]. Fig. 1,2 presents the results of calculations of elec-
tron distribution corresponding to the target center
(electron energy 22 MeV, lens length 10 cm, field gradi-
ent 700 Oe/cm, lens-target distance 80 cm, behaviour of
106 electrons was considered).
Similar plots of electron distribution can be obtained
easily for all distances from the target center.
Basing on the calculation results obtained one can
forecast with a higher precision the dose field distribu-
tion on the object under irradiation for a particular tech-
nological process.
Experiments on studying the dose field distribution
were carried out. At a distance of 60 cm from the accel-
erator exit the glass dosimeters were installed for mea-
surement of the electron beam density distribution (dos-
es) in different cross-sections of the target. In fig.3 the
results of experimental measurements are given.
_________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.120-121. 120
Fig.1. Electron distribution on the horizontal corre-
sponding to the target center
Fig.2. Electron distribution on the vertical corre-
sponding to the target center
Fig.3. Longitudinal dose distribution in different cross-
sections of the target (l = 40 cm, h = 17.5 cm)
It is seen, that the electron beam covers fully the tar-
get with an effective area ≈ 800 cm2 and some uniformi-
ty of beam distribution. Thus, a uniform field distribu-
tion is reached due to the choice of the irradiation condi-
tions and the target unit design.
Analysis of experimental measurements shows that
they confirm the calculation results.
The results of investigations allow us to conclude
that the quadrupole lens can be used as a device of scan-
ning high-energy electrons for formation of dose fields
with a given area. When working with pulsed beams the
quadrupole lens scans every pulse of accelerated parti-
cles and, as a result, the uniform activation and gradual
heating of materials under irradiation are attained. Using
the quadrupole lens for field steering (changing the cur-
rent in coils) one can change with comparative ease the
beam shape that is very important for technological pro-
cesses. Unlike a scanner a quadrupole lens does not re-
quire to perform pumping down that allows one to pass
more quickly onto other accelerator operation programs
(the lens can be easy and quickly replaced). All the
above provides a lens with a number of advantages
against traditional methods of beam scanning.
REFERENCES
1. A.N. Dovbnya, A.E. Tolsltoj, V.A. Shendrik. For-
mation of Scanner Magnetic-Optical Characteristics
in the NSC KIPT New-Generation Electron Linak
KUT 20 // Voprosy Atomnoj Nauki i Tekhniki. Se-
ries: “Yaderno-Fizicheskie Issledovaniya” (38).
2001, N 3, p.124-125.
2. A.N. Dovbnya, A.I. Kosoj, A.E. Tolstoj,
V.A. Shendrik. Scanning and formation of the
beam extracted from multipurpose electron acceler-
ators // Voprosy Atomnoj Nauki i Tekhniki. Series:
“Yaderno-Fizicheskie Issledovaniya” (28). 1997,
N 1, p.114-121.
3. V.N. Boriskin, A.E. Tolstoj, V.A. Shendrik. Skan-
ning of the extracted beam and monitoring of elec-
tron energy at technological linear accelerators //
Voprosy Atomnoj Nauki i Tekhniki. Series “Yader-
no-Fizicheskie Issledovaniya” (31, 32). 1997,
N 4,5, v. 2, p.57-59.
4. V.I. Kotov, V.V. Miller. Focusing and mass-sepa-
ration of high-energy particles. M.: “Atomizdat”,
1969.
ФОРМИРОВАНИЕ ОДНОРОДНЫХ ПУЧКОВ ЭЛЕКТРОНОВ НА МИШЕНЯХ
С БОЛЬШОЙ ПЛОЩАДЬЮ
А.Н. Довбня, Н.А. Довбня, З.М. Колот, В.А. Попенко, А.Н. Савченко, Д.Л. Степин, В.А. Шендрик
Представлены результаты расчета и экспериментальных исследований системы развертки пучка на вы-
ходных мишенях ускорителей электронов магнитными квадрупольными линзами.
ФОРМУВАННЯ ОДНОРІДНИХ ПУЧКІВ ЕЛЕКТРОНІВ НА МІШЕНЯХ З ВЕЛИКОЮ ПЛОЩЕЮ
А.М. Довбня, Н.А. Довбня, З.М. Колот, В.О. Попенко, А.М. Савченко, Д.Л. Стьопін, В.А. Шендрик
Представлені результати розрахунків та експериментальних досліджень системи розгортки пучка на
вихідних мішенях прискорювачів електронів магнітними квадрупольними лінзами.
_________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1.
Series: Nuclear Physics Investigations (42), p.120-121.121
National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine
REFERENCES
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