Tuning irregular intedigital accelerating structure with RF field focusing
The results of investigations on tuning the cells of interdigital accelerating structure of a new prestripping section of the multicharge ion linear accelerator (MILAC) are presented in the paper; for this purpose an alternating phase focusing with stepped changing of a synchronous phase is used....
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2006
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| Цитувати: | Tuning irregular intedigital accelerating structure with RF field focusing / V.A. Bomko, A.F. Dyachenko, B.V. Zajtsev, A.F. Kobets, Ye.V. Ivakhno, Z.E. Ptukhina, S.S. Tishkin, E.D. Marynina // Вопросы атомной науки и техники. — 2006. — № 3. — С. 78-80. — Бібліогр.: 6 назв. — англ. |
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irk-123456789-794412015-04-02T03:02:08Z Tuning irregular intedigital accelerating structure with RF field focusing Bomko, V.A. Dyachenko, A.F. Zajtsev, B.V. Kobets, A.F. Ivakhno, Ye.V. Ptukhina, Z.E. Tishkin, S.S. Marynina, E.D. Ускорители заряженных частиц The results of investigations on tuning the cells of interdigital accelerating structure of a new prestripping section of the multicharge ion linear accelerator (MILAC) are presented in the paper; for this purpose an alternating phase focusing with stepped changing of a synchronous phase is used. In this case, the focusing period consists of a series of cells which lengths vary irregularly due to the synchronous phase change. The procedure of tuning the cells of the accelerating structure to the specified resonant frequency is described, that provides the required electric field distribution between drift tubes. The works were performed by numerical simulations; the results were checked experimentally on test-benches. Приводятся результаты исследований по настройке ячеек встречно-штыревой ускоряющей структуры новой предобдирочной секции линейного ускорителя многозарядных ионов (ЛУМЗИ), в которой применяется переменно-фазовая фокусировка с шаговым изменением синхронной фазы. В этом случае период фокусировки состоит из ячеек, длина которых изменяется нерегулярно. Описана методика настройки ускоряющей структуры на заданную резонансную частоту, обеспечивающая при этом требуемое распределение электрического поля вдоль зазоров. Работы выполнялись путем численного моделирования, результаты которого проверялись на экспериментальном стенде Приводяться результати досліджень по настройці комірок зустрічно-штирьової прискорюючої структури нової передобдиркової секції лінійного прискорювача багатозарядних іонів (ЛУМЗІ), в якій використовується варіант змінно-фазового фокусування. Прискорююча структура складається із послідовності комірок з дуже нерегулярною довжиною трубок дрейфу. Описана методика настройки таких комірок на робочу частоту і процес формування розподілу прискорюючого поля. Роботи виконувались методом чисельного моделювання, результати перевірялись на експериментальному стенді. 2006 Article Tuning irregular intedigital accelerating structure with RF field focusing / V.A. Bomko, A.F. Dyachenko, B.V. Zajtsev, A.F. Kobets, Ye.V. Ivakhno, Z.E. Ptukhina, S.S. Tishkin, E.D. Marynina // Вопросы атомной науки и техники. — 2006. — № 3. — С. 78-80. — Бібліогр.: 6 назв. — англ. 1562-6016 PACS: 27.17.+w http://dspace.nbuv.gov.ua/handle/123456789/79441 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| topic |
Ускорители заряженных частиц Ускорители заряженных частиц |
| spellingShingle |
Ускорители заряженных частиц Ускорители заряженных частиц Bomko, V.A. Dyachenko, A.F. Zajtsev, B.V. Kobets, A.F. Ivakhno, Ye.V. Ptukhina, Z.E. Tishkin, S.S. Marynina, E.D. Tuning irregular intedigital accelerating structure with RF field focusing Вопросы атомной науки и техники |
| description |
The results of investigations on tuning the cells of interdigital accelerating structure of a new prestripping section
of the multicharge ion linear accelerator (MILAC) are presented in the paper; for this purpose an alternating phase
focusing with stepped changing of a synchronous phase is used. In this case, the focusing period consists of a series
of cells which lengths vary irregularly due to the synchronous phase change. The procedure of tuning the cells of the
accelerating structure to the specified resonant frequency is described, that provides the required electric field distribution
between drift tubes. The works were performed by numerical simulations; the results were checked experimentally
on test-benches. |
| format |
Article |
| author |
Bomko, V.A. Dyachenko, A.F. Zajtsev, B.V. Kobets, A.F. Ivakhno, Ye.V. Ptukhina, Z.E. Tishkin, S.S. Marynina, E.D. |
| author_facet |
Bomko, V.A. Dyachenko, A.F. Zajtsev, B.V. Kobets, A.F. Ivakhno, Ye.V. Ptukhina, Z.E. Tishkin, S.S. Marynina, E.D. |
| author_sort |
Bomko, V.A. |
| title |
Tuning irregular intedigital accelerating structure with RF field focusing |
| title_short |
Tuning irregular intedigital accelerating structure with RF field focusing |
| title_full |
Tuning irregular intedigital accelerating structure with RF field focusing |
| title_fullStr |
Tuning irregular intedigital accelerating structure with RF field focusing |
| title_full_unstemmed |
Tuning irregular intedigital accelerating structure with RF field focusing |
| title_sort |
tuning irregular intedigital accelerating structure with rf field focusing |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2006 |
| topic_facet |
Ускорители заряженных частиц |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/79441 |
| citation_txt |
Tuning irregular intedigital accelerating structure with RF field focusing / V.A. Bomko, A.F. Dyachenko, B.V. Zajtsev, A.F. Kobets, Ye.V. Ivakhno, Z.E. Ptukhina,
S.S. Tishkin, E.D. Marynina // Вопросы атомной науки и техники. — 2006. — № 3. — С. 78-80. — Бібліогр.: 6 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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2025-07-06T03:29:21Z |
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| fulltext |
TUNING IRREGULAR INTEDIGITAL ACCELERATING STRUC-
TURE WITH RF FIELD FOCUSING
V.A. Bomko, A.F. Dyachenko, B.V. Zajtsev, A.F. Kobets, Ye.V. Ivakhno, Z.E. Ptukhi-
na, S.S. Tishkin, E.D. Marynina
NSC KIPT, Kharkov, Ukraine
E-mail: bomko@kipt.kharkov.ua
The results of investigations on tuning the cells of interdigital accelerating structure of a new prestripping section
of the multicharge ion linear accelerator (MILAC) are presented in the paper; for this purpose an alternating phase
focusing with stepped changing of a synchronous phase is used. In this case, the focusing period consists of a series
of cells which lengths vary irregularly due to the synchronous phase change. The procedure of tuning the cells of the
accelerating structure to the specified resonant frequency is described, that provides the required electric field distri-
bution between drift tubes. The works were performed by numerical simulations; the results were checked experi-
mentally on test-benches.
PACS: 27.17.+w
1. INTRODUCTION
To solve some scientific and applied problems, a
task of accelerating a high current beam of light ions on
the Kharkov multicharge ions linear accelerator MILAC
[1, 2] is set. In this connection it is necessary to modern-
ize some accelerator systems especially in its initial
part. The existing prestripping section PSS-15 [3] is de-
signed for accelerating heavy ions with mass-to-charge
ration of A/q≤15. It does not fit for acceleration of in-
tense beams of heavy ions (protons, deuterons, helium).
Therefore, presently next to this section a new initial
part of the accelerator (PSS-4) is being constructed for
accelerating only light ions from 30 keV/u to 1 MeV/u
meant for significant increase of pulse number of the
beam current. After recharging (stripping) this beam
will be output on the acceleration line of the main MI-
LAC section and accelerated up to 8.5 MeV/u.
2. CALCULATION OF CELL LONGITUDI-
NAL DIMENSIONS
As the PSS-4 accelerating structure we chose a mod-
ification of the cavity of interdigital type which is
presently in use in the main and prestripping sections of
MILAC [2,3]; the cavity is being excited on H111 wave.
The advantages of this structure in the energy range un-
der discussion lie in its compactness, high acceleration
rate, and high electrodynamic characteristics providing
stable operation and power-saving mode of RF-power
supply. The interdigital accelerating structure is also fa-
vorable for the simplest and efficient method for provid-
ing phase and radial stability of the beam along the ac-
celerating channel which the alternating phase focusing
is in the version with the stepped changing of the syn-
chronous phase [4,5].
Efficiency of this method depends strongly on con-
figuration of each focusing period. The structure of the
focusing period in the construction being discussed con-
tains a number of cells (see Table 1) where the syn-
chronous phase changes discretely from the cells with
negative (grouping) phases passing the cells having the
phase smaller in absolute value through ϕs=0 to the zone
of positive (focusing) phases and ends with transition to
the zone of negative phases.
Table 1. The structure of the focusing period in the con-
struction
Cell
number
Tube
length, cm
Synchr.
phases, deg.
Tube di-
ameter,
cm
0 12,61 -90 22
1 12,62 -90 22
2 36,27 75 22 (26)
3 9,74 50 26
4 6,56 0 31
5 4,59 -65 48
6 12,59 -90 52
7 50,62 75 36 (50)
8 13,71 50 43
9 9,31 0 45
10 10,50 -50 65
11 15,64 -85 62
12 73,48 75 61
13 23,19 60 55
14 9,96 0 60
15 9,22 -65 72
16 33,17 -70 69
17 96,23 75 45 (46)
18 31,97 60 72
19 13,58 0 77
20 14,93 -60 94
21 41,83 -70 87
22 127,75 75 65 (74)
23 42.05 60 88
24 17,58 0 96
25 18,98 -60 110
26 39,44 -90 110
27 167,81 75 69 (85)
28 50,41 60 108
20 48,69 40 129 (140)
30 36,69 0 156
31 78,22 10 156
32 36,21 150
Such arrangement of synchronous phases provides
the capture of high current ion beam being injected in
the phase angle of 120o and its radial and phase stability
____________________________________________________________
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2006. № 3.
Series: Nuclear Physics Investigations (47), p.78-80.
78
along the accelerating structure, and gives a possibility
to hold the acceleration rate at rather high level.
The PSS-4 accelerating structure is designed for low
input energy of ions (30 keV/u) and high pulsed beam
current (12 mA); therefore, accelerating field distribu-
tion in the initial part of the structure was taken as in-
creasing from cell to cell in order to provide the maxi-
mum capture of particles in the mode of stable longitu-
dinal motion. In this case the width and depth of the po-
tential well in which the particles move increases signif-
icantly.
A LINACV2 computer code was written in FOR-
TRAN90 [5] for calculation of the longitudinal cell di-
mensions and ion beam dynamics; this code gives a pos-
sibility to work in dialogue mode. The geometric sizes
of tubes are given in the Table 1.
Taking into account all the listed above aspects a
task is set to optimize the design of all the elements of
the PSS-4 accelerating structure; such optimization
would provide tuning the accelerating structure on the
specified frequency and required accelerating field dis-
tribution.
3. CALCULATION OF GEOMETRIC AND
ELECTRODYNAMIC CHARACTERISTICS
Calculations of constructive and electrodynamic
characteristics were carried out in 3D version. The pro-
cedure of ‘manual control’ was used which means that
the geometrical sizes were sequentially changed for ob-
taining the required values of necessary characteristics.
In the process of optimization parameters for the ele-
ments of the structure (cavity diameter, cavity shape the
drift tube diameters, diameters of the rods of the drift
tube holders) were adjusted to the required values. In
the process of tuning the end resonance tuning elements
were used [2] which represent quarter wave oscillators;
on the side of the oscillator facing the side wall of the
cavity a control piston is placed which can move in lon-
gitudinal direction. Such systems are installed on the in-
put and output ends of the cavity.
The optimization process appeared to be very com-
plicated due to a difference in synchronous phases (as it
is seen from the Table 1) and, therefore, differences in
drift tube lengths along the focusing periods which is an
intrinsic feature of the alternating phase focusing (APF
with SCP) which we used. The number of calculation
cycles was several tens. As a result of these calculations
the data were obtained which ensured completion of the
task.
The results of calculations of geometric and electro-
dynamic characteristics are presented in the Table 2.
The general view of the PSS-4 accelerating structure
is given in the Fig.1. The octahedral cavity having the
diameter of the inscribed circle 1075 mm is a compound
structure consisting of two lengthwise halves connected
with safe electrical and thermal contacts.
The most arduous was curried out on determination
of the drift tube diameters which should provide the
necessary inductive and capacitive characteristics of the
cells of the accelerating structure. In the Fig.2 the end
section of the accelerating structure with end tuning ele-
ment is shown.
Table 2. Geometric and electrodynamic characteris-
tics of the structure
Input ion energy 30 keV/u
Output ion energy 975 keV/u
Operating frequency 47.2 MHz
Accelerating field 9…85 kV/cm
Total acceleration rate 1.6 MeV/m
Cavity length 239 m
Number of accelerating cells 32
Cavity diameter 107.5 cm
Pulsed current of accelerated ions 10 mA
Angle of beam capture 120o
Q-factor of the cavity 20000
Shunt impedance 150 MΩ/m
Pulse repetition rate 12.5 Hz
Fig.1.The general view of the PSS-4 accelerating struc-
ture
Fig.2. The end section of the accelerating structure
with end tuning element
The obtained distribution of accelerating field along
the gaps is shown in the Fig.3. Growing field in the ini-
tial part of the structure and constant field in the follow-
ing one is achieved with accuracy sufficient for stable
dynamics of the high current ion bunches being acceler-
ated.
____________________________________________________________
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2006. № 3.
Series: Nuclear Physics Investigations (47), p.78-80.
79
Fig.3. The obtained distribution of accelerating field
along the gaps
4. CONCLUSION
By the present time calculations have been complet-
ed; technical documentation has been prepared for all
the PSS-4 constructive units. According to the Project
schedule, manufacture, assembling and adjustment will
have been finished by spring of 2006.
REFERENCES
1. V.A. Bomko, A.P. Kobets, Yu.P. Mazalov,
B.I. Rudyak. Heavy ion linear accelerator at NSC
KIPT // Ukrainian Physical Journal, 1998, v.43,
№9, p.1144
2. V.A. Bomko, A.F. Dyachenko, A.F. Kobets et al.
Interdigital Accelerating H-structure in Multy
Charged Ion Linac (MILAC) // Rev. of Scientific
Instruments and Methods, 1998, v. 69, №10, p.35.
3. V.A. Bomko, B.I. Rudyac, A.F. Kobets et al. Pre-
stripping Section of the Multycharged Ion LINAC
with A/q =15 // Problems of Atomic Science and
Technology. Series: Nuclear Physics Investiga-
tions. 1997, №6(6), p.23.
4. V.A. Bomko, A.P. Kobets, B.V. Zaitsev et al. New
developments of the ion beams RF- focusing //
Problems of Atomic Science and Technology. Se-
ries: Nuclear Physics Investigations. 2003, №4(3),
p.274-278.
5. V.A. Bomko, A.P. Kobets, Z.E. Ptukhina,
S,S, Tishkin. Variant alternation phase focusing
with step change of the synchronous phase // Prob-
lems of Atomic Science and Technology. Series:
Nuclear Physics Investigations. 2004, №2(43),
p.153-154.
6. V.A. Bomko, Z.E. Ptukhina, S.S. Tishkin. Variant
of the accelerating and focusing structure of the
high current linear ion accelerator // Problems of
Atomic Science and Technology. Series: Nuclear
Physics Investigations. 2006, №8(46), p.100-102.
НАСТРОЙКА НЕРЕГУЛЯРНОЙ ВСТРЕЧНО-ШТЫРЕВOЙ УСКОРЯЮЩЕЙ СТРУКТУРЫ
С ФОКУСИРОВКОЙ ВЧ-ПОЛЕМ
В.А. Бомко, А.Ф. Дьяченко, Б.В. Зайцев, А.Ф. Кобец, Е.В. Ивахно, З.Е. Птухина, С.С. Тишкин, Е.Д. Ма-
ринина
Приводятся результаты исследований по настройке ячеек встречно-штыревой ускоряющей структуры
новой предобдирочной секции линейного ускорителя многозарядных ионов (ЛУМЗИ), в которой применя-
ется переменно-фазовая фокусировка с шаговым изменением синхронной фазы. В этом случае период фоку-
сировки состоит из ячеек, длина которых изменяется нерегулярно. Описана методика настройки ускоряю-
щей структуры на заданную резонансную частоту, обеспечивающая при этом требуемое распределение
электрического поля вдоль зазоров. Работы выполнялись путем численного моделирования, результаты ко-
торого проверялись на экспериментальном стенде.
НАСТРОЙКА НЕРЕГУЛЯРНОЇ ЗУСТРІЧНО-ШТИРЕВOЇ ПРИСКОРЮЮЧОЇ СТРУКТУРИ
З ФОКУСУВАННЯМ ВЧ-ПОЛЕМ
В.О. Бомко, А.Ф. Д’яченко, Б.В. Зайцев, А.П. Кобець, Є.В. Івахно, З.Є. Птухіна, С.С. Тішкін, Е.Д. Марині-
на
Приводяться результати досліджень по настройці комірок зустрічно-штирьової прискорюючої
структури нової передобдиркової секції лінійного прискорювача багатозарядних іонів (ЛУМЗІ), в якій
використовується варіант змінно-фазового фокусування. Прискорююча структура складається із
послідовності комірок з дуже нерегулярною довжиною трубок дрейфу. Описана методика настройки таких
комірок на робочу частоту і процес формування розподілу прискорюючого поля. Роботи виконувались
методом чисельного моделювання, результати перевірялись на експериментальному стенді.
80
НАСТРОЙКА НЕРЕГУЛЯРНОЙ ВСТРЕЧНО-ШТЫРЕВOЙ УСКОРЯЮЩЕЙ СТРУКТУРЫ
С ФОКУСИРОВКОЙ ВЧ-ПОЛЕМ
НАСТРОЙКА НЕРЕГУЛЯРНОЇ ЗУСТРІЧНО-ШТИРЕВOЇ ПРИСКОРЮЮЧОЇ СТРУКТУРИ
З ФОКУСУВАННЯМ ВЧ-ПОЛЕМ
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