Magnetic coupled accelerating structure
This paper presents the results of a survey study that analyzed the possibility of using a magnetic coupled disk-loaded waveguide as an accelerating structure in travelling wave (TW) regime. The electrodynamics parameters of such a structure at various modes in C-band for a wide range of phase veloc...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2010
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| Cite this: | Magnetic coupled accelerating structure / S.V. Kutsaev, N.P. Sobenin, A.A. Zavadtsev, R.O. Bolgov, P.K. Davydov // Вопросы атомной науки и техники. — 2010. — № 3. — С. 48-50. — Бібліогр.: 2 назв. — англ. |
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| author | Kutsaev, S.V. Sobenin, N.P. Zavadtsev, A.A. Bolgov, R.O. Davydov, P.K. |
| author_facet | Kutsaev, S.V. Sobenin, N.P. Zavadtsev, A.A. Bolgov, R.O. Davydov, P.K. |
| citation_txt | Magnetic coupled accelerating structure / S.V. Kutsaev, N.P. Sobenin, A.A. Zavadtsev, R.O. Bolgov, P.K. Davydov // Вопросы атомной науки и техники. — 2010. — № 3. — С. 48-50. — Бібліогр.: 2 назв. — англ. |
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| description | This paper presents the results of a survey study that analyzed the possibility of using a magnetic coupled disk-loaded waveguide as an accelerating structure in travelling wave (TW) regime. The electrodynamics parameters of such a structure at various modes in C-band for a wide range of phase velocities as a function of aperture radii and coupling slot sizes are presented. This accelerating structure is applicable for forward or backward wave operation modes. The version of a 10 MeV combined accelerator with a standing wave (SW) coupler and a TW magnetic coupled accelerating structure is proposed.
Приведены электродинамические характеристики круглого диафрагмированного волновода с магнитной связью в СВЧ-диапазоне на разных видах колебаний и разных значениях фазовой скорости волны в функции радиуса апертуры и размеров щелей связи. Ускоряющая структура такого типа может работать в режиме прямой или обратной волны. Рассмотрен вариант комбинированного ускорителя на энергию 10 МэВ с группирователем, работающим в режиме стоячей волны, и ускоряющей частью на основе структуры с магнитной связью с положительной дисперсией.
Наведено електродинамічні характеристики круглого діафрагмованого хвилеводу з магнітним зв'язком в СВЧ-діапазоні на різних видах коливань і різних значеннях фазової швидкості хвилі у функції радіусу апертури і розмірів щілин зв'язку. Прискорююча структура такого типу може працювати в режимі прямої або зворотної хвилі. Розглянуто варіант комбінованого прискорювача на енергію 10 МеВ з групувачем, що працює в режимі стоячій хвилі, і прискорюючою частиною на основі структури з магнітним зв'язком з позитивною дисперсією.
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MAGNETIC COUPLED ACCELERATING STRUCTURE
S.V. Kutsaev1, N.P. Sobenin1, A.A. Zavadtsev2, R.O. Bolgov1, P.K. Davydov1
1Moscow Engineering Physics Institute, Moscow, Russia;
2Nano Invest, Reutov, Russia
E-mail: s_kutsaev@mail.ru
This paper presents the results of a survey study that analyzed the possibility of using a magnetic coupled disk-
loaded waveguide as an accelerating structure in travelling wave (TW) regime. The electrodynamics parameters of
such a structure at various modes in C-band for a wide range of phase velocities as a function of aperture radii and
coupling slot sizes are presented. This accelerating structure is applicable for forward or backward wave operation
modes. The version of a 10 MeV combined accelerator with a standing wave (SW) coupler and a TW magnetic cou-
pled accelerating structure is proposed.
PACS 29.17.+w, 29.27.Eg
1. INTRODUCTION
As one knows, one of the most popular accelerating
structures for linear accelerators is a disk-loaded struc-
ture (DLS) working on an E01 travelling wave (TW)
with electric and biperiodical accelerating structure
(BAS) working on standing wave (SW) a with magnetic
coupling.
Fig.1. Magnetic-coupled disk-loaded structure
The TW magnetic coupled DLS presented at Fig.1
possesses the advantages of both classical DLS (small
filling time) and BAS (high shunt impedance and cou-
pling coefficient). As the coupling of such a structure is
affected by magnetic field, its dispersion would be
negative. This kind of structure would be compactly
called a negative dispersion structure (NDS).
____________________________________________________________
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2010. № 3.
Series: Nuclear Physics Investigations (54), p.48-50. 48
Increasing the period D we can achieve working
modes higher than π. In this case the dispersion of the
structure would be positive again. This kind of structure
would be compactly called a positive dispersion struc-
ture (PDS) [1,2].
It is of interest to calculate the electrodynamical pa-
rameters of these structures (first of all shunt imped-
ance, group velocity and attenuation) as functions of
mode and some geometrical dimensions (accelerating
gap, aperture and coupling gaps).
2. ELECTRODYNAMICAL PARAMETERS
2.1. STRUCTURE WITH NEGATIVE DISPERSION
The structures working on modes close to π are per-
spective to use in linear accelerators with a high accel-
eration temp. Increasing shunt impedance while having
a high coupling coefficient is the general aim of struc-
ture optimization.
The resonant model of the NDS designed for 4π/5
mode and electric field distribution are shown at Fig.2.
The structure has been tuned to work at 5712 MHz re-
sonant frequency.
Fig.2. Resonant model and E-field distribution
of 4π/5 mode NDS
The dependence of principal electrodynamical pa-
rameters to phase velocity is presented at Table 1. These
results have been obtained for coupling gap span angle
90o and normalized aperture a/λ=0.04.
Table 1
Electrodynamical parameters of the NDS with different
phase velocity
Phase Velocity 1.0 0.8 0.6 0.4
Shunt Impedance,
MΩ/m
143
132
69
67
Coupling coefficient, % 12.0 13.7 18.0 27.3
Attenuation, 1/m 0.11 0.12 0.11 0.12
Group Velocity, % -6.1 -6.5 -8.0 -10.5
Shunt impedance of this structure appears to be quite
high, this is because of a small aperture what is undesir-
able. Thus, the dependence of these parameters with a
respect to aperture size is a question to research. The
results are presented in Table 2. The phase velocity is
considered to be 1.0 and coupling gap span angle is 75°.
Table 2
Electrodynamical parameters of the NDS
with different aperture
Normalized aperture 0.04 0.07 0.1 0.14
Shunt Impedance, MΩ/m 85 73 56 39
Coupling coefficient, % 7.7 7.3 7.2 6.6
Attenuation, 1/m 0.14 0.15 0.16 0.17
Group Velocity, % -5.9 -5.7 -5.5 -5.4
The values of shunt impedance now are comparable
to the DLS ones, while the group velocity and coupling
coefficient are much higher and could be increased by
expanding the coupling gap.
2.2. STRUCTURE WITH POSITIVE DISPERSION
For this structure it is interesting to research the de-
pendences of electrodynamical parameters of the geo-
metrical dimensions and operating modes in fact to ob-
tain its optimal performance.
First the aperture size has been varied from 0.04 to
0.14 like in NDS, while the operating mode was consid-
ered to be 6π/5, phase velocity 1.0 and other geometri-
cal dimensions were fixed. Another important depend-
ence is of the phase velocity, as the TW buncher con-
sists of different phase velocity cells. The dependence
diagram of shunt impedance can be observed on Fig.3,
while the one of group velocity is presented on Fig4.
49
Fig.3. The dependence of PDS shunt impedance
vs aperture size
Thus, the values of shunt impedance and group ve-
locity are high enough in the whole range of the aper-
ture radius. It is important because this size varies much
both in TW buncher and in accelerating part with con-
stant gradient to obtain the necessary field strength.
Fig.4.The dependence of group velocity vs aperture size
Fig.5. The dependence of PDS shunt impedance
vs operating mode
Now it is necessary to determine what operating
mode is optimal. The dependences of this structure’s
shunt impedance of an operating mode for the cases of
two different coupling coefficients are presented on
Fig.5. The normalized aperture size is considered to be
0.1. The maximum of the shunt impedance is achieved
on modes near 4π/3.
Comparing the electro dynamical parameters of PDS
working on 4π/3 mode, NDS working on 3π/4 and DLS
working on classical 2π/3 mode with a/λ =0.1 and the
coupling gap span size was chose such to obtain group
velocity around 4.5%, we see that PDS has the highest
shunt impedance and group velocity. This comparison
results are presented in Table 3, where Q stands for
quality factor and α for attenuation.
Table 3
Parameters of different TW structures
a/λ Type rsh, MΩ/m Q α, 1/m βgr, %
0.04 PDS
NDS
173
86
11500
7400
0.108
0.145
4.8
5.9
0.07 PDS
NDS
159
73
11500
7520
0.116
0.151
4.5
5.5
0.10 PDS
NDS
DLS
140
56
87
11300
7130
9070
0. 120
0.156
0.660
4.4
5.7
1.0
0.12 PDS
NDS
DLS
103
39
65
9800
6710
9000
0. 139
0.173
0.208
4.4
5.4
3.2
0.14 PDS
NDS
DLS
79
39
65
8600
6710
9000
0.166
0.173
0.208
4.2
5.4
3.2
3. COMBINED ACCELERATOR
3.1. HYBRID STRUCTURE
Consider using PDS as an accelerating structure in
electron linac designed for cargo inspection systems.
This linac should have an output energy equaled to
10 MeV. To achieve this flexibility the beam loading
should be used, thus the output current should be high
enough.
Such an accelerator should have the particle capture
as high as possible, while being as short as possible.
This can be reached by using a hybrid accelerating
structure with a 3 cell SW BAS buncher, which allows
to achieve high capture on a short length and TW accel-
erating part. For this accelerator PDS structure working
on 4π/3 mode with a/λ= 0.1 has been chosen.
3.2. INPUT COUPLER
The RF power is input into the first TW cell. To en-
sure symmetry of the field in this cell, opposing WR187
waveguides are connected. One of these waveguides is
short-circuited by the metal pin and is used for vacuum
pumping. Fig.6 shows the model of this coupler as well
as the electric field intensity.
Fig.6. Input coupler in the hybrid structure
The SW buncher was considered to be identical to
the one used in the SW cargo inspection accelerator.
The parameters of the cells are shown in Table 4.
Table 4 3.3. ELECTRON DYNAMICS
SW structure parameters
Cell
number
Phase
velocity
Effective shunt
impedance,
MΩ/m
Coupling
coefficient,
%
Q-
factor
1 0.67 50.3 38.9 5540
2 0.42 28.2 13.5 5680
3 0.78 97.6 10.9 6800
For this coupler geometry the following distribution
of the electric fields normalized to the one in the first
TW cell has been achieved.
Table 5
Electric Field Distribution
N 1 2 3 4 5 6 7 8 9 10
E/Etw 0.42 0.98 1.65 0.9 1 1 1 1 1 1.1
For this data the dynamics of the electrons in such
an accelerator has been calculated with a help of
PARMELA and Hellweg codes. The input and output
parameters of the accelerator are presented in Table 6.
The input coupler has been tuned to provide a TW re-
gime in the accelerating part at the 5712 MHz operating
frequency. The output cell radius and coupler gap width
have been chosen so that a complex electric field on the
axis would be equal in the centers of each cell (Fig.7). Table 6
Combined Accelerator Parameters
Input Power, MW 4.5
Pperating Frequency, MHz 5712
Number of Cells 3 + 28
Output Energy, MeV 10.8
Input Current, mA 200
Output Current, mA 135
Capture Coefficient, % 67.5
Energy Spectrum, % 4.8
Phase Length, grad 35
Length, m 0.98
Fig.7. Complex electrical field distribution on the axis
of the structure
Then, the input cell radius and coupler gap have
been tuned so, that there would be no reflection to the
input port. The S11 parameter distribution is shown at
Fig.8. The peaks near the resonant frequency stand for
the resonances excited on the nearest modes.
CONCLUSIONS
The electrodynamics parameters for the magnetic
coupled disk loaded structure have been calculated both
for positive and negative dispersions for the 5712 MHz.
The possibility of using a PDS in the combined ac-
celerator been considered. The RF input coupler for this
accelerator has been developed and tuned. The electron
dynamics for this structure has been calculated.
Fig.8. Frequency characteristic
REFERENCES
1. M. Ferderer, A. Zavadtsev, S. Kutsaev, et al. Accel-
erating Structure For C-Band Electron Linear Accel-
erator Optimization // Proc. LINAC’08. 2008,
p.2746-2749.
2. V. Pirozhenko. Efficient Traveling-Wave Accelerating
Structure For Linear Accelerators // Proc. EPAC’08.
2008, p.921-923.
Статья поступила в редакцию 23.09.2009 г.
УСКОРЯЮЩАЯ СТРУКТУРА С МАГНИТНОЙ СВЯЗЬЮ МЕЖДУ ЯЧЕЙКАМИ
С.В. Куцаев, Н.П. Собенин, А.А. Завадцев, Р.О. Болгов, П.К. Давыдов
Приведены электродинамические характеристики круглого диафрагмированного волновода с магнитной
связью в СВЧ-диапазоне на разных видах колебаний и разных значениях фазовой скорости волны в функ-
ции радиуса апертуры и размеров щелей связи. Ускоряющая структура такого типа может работать в режи-
ме прямой или обратной волны. Рассмотрен вариант комбинированного ускорителя на энергию 10 МэВ с
группирователем, работающим в режиме стоячей волны, и ускоряющей частью на основе структуры с маг-
нитной связью с положительной дисперсией.
ПРИСКОРЮЮЧА СТРУКТУРА З МАГНІТНИМ ЗВ'ЯЗКОМ МІЖ КОМІРКАМИ
С.В. Куцаєв, Н.П. Собєнін, А.А. Завадцев, Р.О. Болгов, П.К. Давидов
Наведено електродинамічні характеристики круглого діафрагмованого хвилеводу з магнітним зв'язком в
СВЧ-діапазоні на різних видах коливань і різних значеннях фазової швидкості хвилі у функції радіусу апер-
тури і розмірів щілин зв'язку. Прискорююча структура такого типу може працювати в режимі прямої або
зворотної хвилі. Розглянуто варіант комбінованого прискорювача на енергію 10 МеВ з групувачем, що пра-
цює в режимі стоячій хвилі, і прискорюючою частиною на основі структури з магнітним зв'язком з позитив-
ною дисперсією.
50
УСКОРЯЮЩАЯ СТРУКТУРА С МАГНИТНОЙ СВЯЗЬЮ МЕЖДУ ЯЧЕЙКАМИ
|
| id | nasplib_isofts_kiev_ua-123456789-17012 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T13:26:24Z |
| publishDate | 2010 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Kutsaev, S.V. Sobenin, N.P. Zavadtsev, A.A. Bolgov, R.O. Davydov, P.K. 2011-02-18T10:28:47Z 2011-02-18T10:28:47Z 2010 Magnetic coupled accelerating structure / S.V. Kutsaev, N.P. Sobenin, A.A. Zavadtsev, R.O. Bolgov, P.K. Davydov // Вопросы атомной науки и техники. — 2010. — № 3. — С. 48-50. — Бібліогр.: 2 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/17012 This paper presents the results of a survey study that analyzed the possibility of using a magnetic coupled disk-loaded waveguide as an accelerating structure in travelling wave (TW) regime. The electrodynamics parameters of such a structure at various modes in C-band for a wide range of phase velocities as a function of aperture radii and coupling slot sizes are presented. This accelerating structure is applicable for forward or backward wave operation modes. The version of a 10 MeV combined accelerator with a standing wave (SW) coupler and a TW magnetic coupled accelerating structure is proposed. Приведены электродинамические характеристики круглого диафрагмированного волновода с магнитной связью в СВЧ-диапазоне на разных видах колебаний и разных значениях фазовой скорости волны в функции радиуса апертуры и размеров щелей связи. Ускоряющая структура такого типа может работать в режиме прямой или обратной волны. Рассмотрен вариант комбинированного ускорителя на энергию 10 МэВ с группирователем, работающим в режиме стоячей волны, и ускоряющей частью на основе структуры с магнитной связью с положительной дисперсией. Наведено електродинамічні характеристики круглого діафрагмованого хвилеводу з магнітним зв'язком в СВЧ-діапазоні на різних видах коливань і різних значеннях фазової швидкості хвилі у функції радіусу апертури і розмірів щілин зв'язку. Прискорююча структура такого типу може працювати в режимі прямої або зворотної хвилі. Розглянуто варіант комбінованого прискорювача на енергію 10 МеВ з групувачем, що працює в режимі стоячій хвилі, і прискорюючою частиною на основі структури з магнітним зв'язком з позитивною дисперсією. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Физика и техника ускорителей Magnetic coupled accelerating structure Ускоряющая структура с магнитной связью между ячейками Прискорююча структура з магнітним зв'язком між комірками Article published earlier |
| spellingShingle | Magnetic coupled accelerating structure Kutsaev, S.V. Sobenin, N.P. Zavadtsev, A.A. Bolgov, R.O. Davydov, P.K. Физика и техника ускорителей |
| title | Magnetic coupled accelerating structure |
| title_alt | Ускоряющая структура с магнитной связью между ячейками Прискорююча структура з магнітним зв'язком між комірками |
| title_full | Magnetic coupled accelerating structure |
| title_fullStr | Magnetic coupled accelerating structure |
| title_full_unstemmed | Magnetic coupled accelerating structure |
| title_short | Magnetic coupled accelerating structure |
| title_sort | magnetic coupled accelerating structure |
| topic | Физика и техника ускорителей |
| topic_facet | Физика и техника ускорителей |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/17012 |
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