Variant of alternating phase focusing with the stepped change of the synchronous phase
In the paper the calculation of the accelerating structure with the stepped change of the synchronous phase is presented. The method is tested for the calculation of the accelerating structure and He⁺ beam with A/q=4 in the energy range from 30 keV/n to 0.975 MeV/n. В роботі запропонований розраху...
Saved in:
| Published in: | Вопросы атомной науки и техники |
|---|---|
| Date: | 2004 |
| Main Authors: | , , , |
| Format: | Article |
| Language: | English |
| Published: |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2004
|
| Subjects: | |
| Online Access: | https://nasplib.isofts.kiev.ua/handle/123456789/79374 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Variant of alternating phase focusing with the stepped change of the synchronous phase / V.A. Bomko, A.P. Kobets, Z.E. Ptukhina, S.S. Tishkin // Вопросы атомной науки и техники. — 2004. — № 2. — С. 153-154. — Бібліогр.: 3 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859957725766615040 |
|---|---|
| author | Bomko, V.A. Kobets, A.P. Ptukhina, Z.E. Tishkin, S.S. |
| author_facet | Bomko, V.A. Kobets, A.P. Ptukhina, Z.E. Tishkin, S.S. |
| citation_txt | Variant of alternating phase focusing with the stepped change of the synchronous phase / V.A. Bomko, A.P. Kobets, Z.E. Ptukhina, S.S. Tishkin // Вопросы атомной науки и техники. — 2004. — № 2. — С. 153-154. — Бібліогр.: 3 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | In the paper the calculation of the accelerating structure with the stepped change of the synchronous phase is presented. The method is tested for the calculation of the accelerating structure and He⁺ beam with A/q=4 in the energy
range from 30 keV/n to 0.975 MeV/n.
В роботі запропонований розрахунок прискорюючої структури із покроковим зміненням синхронної фази. Метод апробовано на розрахунку прискорюючої структури і динаміки пучка іонів Не⁺ з A/q=4 в інтервалі енергій 30 кеВ/н...0.975 МеВ/н.
В работе предлагается расчет ускоряющей структуры с шаговым изменением синхронной фазы. Метод апробирован на расчете ускоряющей структуры и динамики пучка ионов Не⁺ с A/q=4 в диапазоне энергий 30 кэВ/н...0.975 МэВ/н.
|
| first_indexed | 2025-12-07T16:20:37Z |
| format | Article |
| fulltext |
VARIANT OF ALTERNATING PHASE FOCUSING WITH
THE STEPPED CHANGE OF THE SYNCHRONOUS PHASE
V.A.Bomko, A.P.Kobets, Z.E.Ptukhina, S.S.Tishkin
National Science Center “Kharkov Institute of Physics and Technology”, 61108,Kharkov,
Ukraine, bomko@kipt.kharkov.ua
In the paper the calculation of the accelerating structure with the stepped change of the synchronous phase is pre-
sented. The method is tested for the calculation of the accelerating structure and He+ beam with A/q=4 in the energy
range from 30 keV/n to 0.975 MeV/n.
PACS: 29.17.+w
1. INTRODUCTION
The alternating-phase focusing (APF) of ion beams
in linear accelerators since the moment of its discov-
ery [1,2] has passed several stages of improvement until
it has reached characteristics sufficient to its high com-
petitiveness in modern accelerating structures. Howev-
er, the main drawbacks of the traditional APF – the low
acceleration rate, the low limit current of ions being ac-
celerated - are to be improved.
The structure of a focusing period in the method of
stepped change of the synchronous phase (SCP) con-
tains a number of cells where the synchronous phase in
the cells changes in the stepped manner from the nega-
tive values (bunching phase) to the synchronous phase
less in absolute value and ϕs=0, to the region of positive
(focusing) phases and ends in the transition to negative
values. This phase variation in the center of gaps be-
tween cells gives a possibility to ‘capture’ the region of
the strong bunching and focusing, to ensure the high ac-
celeration rate and to provide, together with the increas-
ing field, the high coefficient of beam capture. The cal-
culation of the accelerating and focusing channel was
carried out with taking into account the repulsing
Coulomb forces in the fields created with the actual drift
tube configuration.
2. THE INVESTIGATION OF THE BEAM
DYNAMICS IN THE APF WITH SCP STRUC-
TURE
In the present paper the calculation of electrostatic
fields was carried out with the method of auxiliary
charges [3]. A program for realization of the method
was proposed which allowed us to perform the calcula-
tion in the dialog regime. The accelerating and focusing
period consists of the cells with synchronous phase of –
90o, 75o, 60o, 40o, 0o, -60o. The aperture radius was
changed from 0.75 cm to 1.5 cm, the maximum electric
field strength was changed from 25 kV/cm to 75 kV/cm.
The length of the accelerating structure was 237.7 cm.
The simulation of He+ beam dynamics was carried out
with LINACV2 code by the authors of the present paper
and the results were compared with the results of dy-
namics simulation with the PARMELA code. Coinci-
dence is 98.0%. The number of large particles is 10 000.
In Fig.1 the projection of the input emittance and geo-
metric sizes of He+ beam are shown.
The SCP method allows us to increase the particle
acceleration rate in comparison with the known APF
versions where at both bunching sections and sections
Fig.1. Projections of the input emittance and geometric
sizes of the He+ beam
Fig.2. The amplitude of radial and longitudinal oscilla-
tions and the energy spread of the ion bunch along the
structure
of radial focusing, the synchronous phase is constant
and large in absolute value. This is aided, from one
hand, with the fact that the focusing period contains the
gaps with synchronous phases, which are low by the ab-
solute value, and from the other– comparatively small
___________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 2.
Series: Nuclear Physics Investigations (43), p.153-154. 153
0
0.
0
0
40.0 80.0 120.0
-180.0
-180.0
180.0
180.0
160.0 200.0 240.0
90.0
-90.0
-90.0
90.0
1.50
-1.50
.75
-.75
w-ws (keV) vs. distance
phi-phis vs. distance
x (cm) vs. distance
100
50
-100
-1.5 -.8 .80
0
-5
0
1.5
xp vs. x
100
-100
50
-5
0
0
00
0
0
0
1.5
1.5
1.5
.8
-1.5
-1.
5 -1.5
.8
.8
-.8
-.8
-.8
e-es vs. phi-phisy vs. x
yp vs. y
-500
500
250
-250
-180 18090-9
0
step in changing of ϕs along the focusing period does
not require an insertion βλ in length to change the
bunch center from positive synchronous phases to nega-
tive ones.
Such increasing of the acceleration rate is reached,
from one hand, with the fact that the SCP focusing peri-
od contains the gaps with synchronous phases, which
are low in absolute value. From the other hand the com-
paratively small step in changing of ϕs along the focus-
ing period does not require an insertion βλ in length to
change the bunch center from positive synchronous
phases to negative ones.
The drawback of accelerating structures with APF is
the dependence of the focusing force on the phase of
particle transit to the accelerating and focusing struc-
ture. At the same time, the SCP provides a transverse
and longitudinal stability of the particle bunch as the
value of cosine of the phase advance of the particle radi-
al oscillations with taking into account their phase
movement is in the region of stability. In Fig.3 the out-
put beam parameters are given with the zero injection
current. In the structure calculated by the APF SCP
method, the rise of the transverse emittance of He+ of
96% was observed with the zero injection current and
input phase length of the beam of 150o. This rise in the
emittance is inherent for APF linacs with large capture
angles without the preliminary bunch focusing. The rise
in the emittance of the central part of the bunch (±20o)
was not observed.
The dependence of the output particle current on the
injected current was studied (Fig.4). In the injected
beam a random filling of 4-D transverse phase volume
was supposed.
Fig.3. Output beam parameters with the zero current
Fig.4. Accelerated current as a function of injection
current
In the Table the main parameters of the accelerating
structure are presented.
Operating frequency, MHz 47,2
Injection energy, keV/n 30
Output energy, MeV/n 0,975
Number of accelerating cells 32
Total length, cm 237,7
Electric field at the electrodes, kV/cm 25...75
Maximum electric field, kV/cm 170
Aperture radius, cm 0,75...1,5
Normalized transverse acceptance, π
mm mrad
1,0
Input emittance 90%, π mm mrad 0,59
Rise in normalized emittance with zero
current, %
96
Beam capture coefficient with the injec-
tion current of 0 mА, %
60 mА, %
42
23
Current limit, mА 13,7
REFERENCES
1. J.B. Fainberg // Proc. CERN Symposium on High
Energy Accelerators and Pion Physics. Geneva,
1956, p.91.
2. M.L. Good // Phys. Rev. 1953, v.92, p.538.
3. V.P. Illin. Numerical methods for solving prob-
lems in electrophyscics., Мoscow: Nauka, 1985.
ВАРИАНТ ПЕРЕМЕННО-ФАЗОВОЙ ФОКУСИРОВКИ
С ШАГОВЫМ ИЗМЕНЕНИЕМ СИНХРОННОЙ ФАЗЫ
В.А.Бомко, А.Ф.Кобец, З.Е.Птухина, С.С.Тишкин
В работе предлагается расчет ускоряющей структуры с шаговым изменением синхронной фазы. Метод
апробирован на расчете ускоряющей структуры и динамики пучка ионов Не+ с A/q=4 в диапазоне энергий 30
кэВ/н...0.975 МэВ/н.
ВАРІАНТ ЗМІННО-ФАЗОВОГО ФОКУСУВАННЯ
ІЗ ПОКРОКОВИМ ЗМІНЕННЯМ СИНХРОННОЇ ФАЗИ
154
100100
-100-100
-50 -50
50 50
0 0
0 0
0 0
00
-1.5
-1.5-1.5 1.51.5
1.5-1.5
1.5
-.8
-.8
-.8 -.8
.8
.8
.8 .8500
-500
250
-250
180-180 90-90
e-es vs. phi-phisy vs. x
yp vs. yxp vs. x
0
0
10 20 30 40 50 60
2
4
6
8
10
1
2
14
I
OUT
/m
I
INJ
/mA
В.О.Бомко, А.П.Кобець, З.О.Птухіна, С.С.Тішкін
В роботі запропонований розрахунок прискорюючої структури із покроковим зміненням синхронної
фази. Метод апробовано на розрахунку прискорюючої структури і динаміки пучка іонів Не+ з A/q=4 в
інтервалі енергій 30 кеВ/н...0.975 МеВ/н.
___________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 2.
Series: Nuclear Physics Investigations (43), p.153-154. 155
V.A.Bomko, A.P.Kobets, Z.E.Ptukhina, S.S.Tishkin
REFERENCES
В.А.Бомко, А.Ф.Кобец, З.Е.Птухина, С.С.Тишкин
В.О.Бомко, А.П.Кобець, З.О.Птухіна, С.С.Тішкін
|
| id | nasplib_isofts_kiev_ua-123456789-79374 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T16:20:37Z |
| publishDate | 2004 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Bomko, V.A. Kobets, A.P. Ptukhina, Z.E. Tishkin, S.S. 2015-03-31T15:30:40Z 2015-03-31T15:30:40Z 2004 Variant of alternating phase focusing with the stepped change of the synchronous phase / V.A. Bomko, A.P. Kobets, Z.E. Ptukhina, S.S. Tishkin // Вопросы атомной науки и техники. — 2004. — № 2. — С. 153-154. — Бібліогр.: 3 назв. — англ. 1562-6016 PACS: 29.17.+w https://nasplib.isofts.kiev.ua/handle/123456789/79374 In the paper the calculation of the accelerating structure with the stepped change of the synchronous phase is presented. The method is tested for the calculation of the accelerating structure and He⁺ beam with A/q=4 in the energy range from 30 keV/n to 0.975 MeV/n. В роботі запропонований розрахунок прискорюючої структури із покроковим зміненням синхронної фази. Метод апробовано на розрахунку прискорюючої структури і динаміки пучка іонів Не⁺ з A/q=4 в інтервалі енергій 30 кеВ/н...0.975 МеВ/н. В работе предлагается расчет ускоряющей структуры с шаговым изменением синхронной фазы. Метод апробирован на расчете ускоряющей структуры и динамики пучка ионов Не⁺ с A/q=4 в диапазоне энергий 30 кэВ/н...0.975 МэВ/н. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Динамика пучков Variant of alternating phase focusing with the stepped change of the synchronous phase Варіант змінно-фазового фокусування із покроковим зміненням синхронної фази Вариант переменно-фазовой фокусировки с шаговым изменением синхронной фазы Article published earlier |
| spellingShingle | Variant of alternating phase focusing with the stepped change of the synchronous phase Bomko, V.A. Kobets, A.P. Ptukhina, Z.E. Tishkin, S.S. Динамика пучков |
| title | Variant of alternating phase focusing with the stepped change of the synchronous phase |
| title_alt | Варіант змінно-фазового фокусування із покроковим зміненням синхронної фази Вариант переменно-фазовой фокусировки с шаговым изменением синхронной фазы |
| title_full | Variant of alternating phase focusing with the stepped change of the synchronous phase |
| title_fullStr | Variant of alternating phase focusing with the stepped change of the synchronous phase |
| title_full_unstemmed | Variant of alternating phase focusing with the stepped change of the synchronous phase |
| title_short | Variant of alternating phase focusing with the stepped change of the synchronous phase |
| title_sort | variant of alternating phase focusing with the stepped change of the synchronous phase |
| topic | Динамика пучков |
| topic_facet | Динамика пучков |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/79374 |
| work_keys_str_mv | AT bomkova variantofalternatingphasefocusingwiththesteppedchangeofthesynchronousphase AT kobetsap variantofalternatingphasefocusingwiththesteppedchangeofthesynchronousphase AT ptukhinaze variantofalternatingphasefocusingwiththesteppedchangeofthesynchronousphase AT tishkinss variantofalternatingphasefocusingwiththesteppedchangeofthesynchronousphase AT bomkova varíantzmínnofazovogofokusuvannâízpokrokovimzmínennâmsinhronnoífazi AT kobetsap varíantzmínnofazovogofokusuvannâízpokrokovimzmínennâmsinhronnoífazi AT ptukhinaze varíantzmínnofazovogofokusuvannâízpokrokovimzmínennâmsinhronnoífazi AT tishkinss varíantzmínnofazovogofokusuvannâízpokrokovimzmínennâmsinhronnoífazi AT bomkova variantperemennofazovoifokusirovkisšagovymizmeneniemsinhronnoifazy AT kobetsap variantperemennofazovoifokusirovkisšagovymizmeneniemsinhronnoifazy AT ptukhinaze variantperemennofazovoifokusirovkisšagovymizmeneniemsinhronnoifazy AT tishkinss variantperemennofazovoifokusirovkisšagovymizmeneniemsinhronnoifazy |