Research of waveguide accelerating structures with dielectrics
At a choice of slow-wave structure for application in accelerating technique the main attention is given first of all to its two characteristics: 1) opportunity of use of a partial type of structures in the wider range of energies and 2) the transformation efficiency of high-frequency energy, put to...
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| Published in: | Вопросы атомной науки и техники |
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| Date: | 1999 |
| Main Authors: | , , |
| Format: | Article |
| Language: | English |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
1999
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| Online Access: | https://nasplib.isofts.kiev.ua/handle/123456789/81517 |
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| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Research of waveguide accelerating structures with dielectrics / G.A. Brizgalov, V.G. Papkovich, N.A. Khizhnyak // Вопросы атомной науки и техники. — 1999. — № 4. — С. 22-23. — Бібліогр.: 2 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860016637034364928 |
|---|---|
| author | Brizgalov, G.A. Papkovich, V.G. Khizhnyak, N.A. |
| author_facet | Brizgalov, G.A. Papkovich, V.G. Khizhnyak, N.A. |
| citation_txt | Research of waveguide accelerating structures with dielectrics / G.A. Brizgalov, V.G. Papkovich, N.A. Khizhnyak // Вопросы атомной науки и техники. — 1999. — № 4. — С. 22-23. — Бібліогр.: 2 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | At a choice of slow-wave structure for application in accelerating technique the main attention is given first of all to its two characteristics: 1) opportunity of use of a partial type of structures in the wider range of energies and 2) the transformation efficiency of high-frequency energy, put to structure, into a kinetic energy of accelerated particles, that eventually leads to comparison of structures on shunt impedance. From this point of view, the waveguides loaded by dielectric disks have doubtless advantages before other traditionally used structures
|
| first_indexed | 2025-12-07T16:45:27Z |
| format | Article |
| fulltext |
RESEARCH OF WAVEGUIDE ACCELERATING STRUCTURES WITH
DIELECTRICS
G.A.Brizgalov, V.G.Papkovich, N.A.Khizhnyak
NSC KIPT Kharkov
At a choice of slow-wave structure for
application in accelerating technique the main attention
is given first of all to its two characteristics: 1)
opportunity of use of a partial type of structures in the
wider range of energies and 2) the transformation
efficiency of high-frequency energy, put to structure,
into a kinetic energy of accelerated particles, that
eventually leads to comparison of structures on shunt
impedance. From this point of view, the waveguides
loaded by dielectric disks have doubtless advantages
before other traditionally used structures [1]. Really, the
acceleration of particles in waveguide dielectric
structures can be realized in a wide velocity band from
β = 0,1 up to 1,0, that is especially important for
acceleration of heavy charged particles. Here β = v/c -
dimensionless velocity, v - velocity of a particle,
c - velocity of light.
Let us note, that the slow-wave structures of
accelerators with the use of dielectrics were historically
the first offered structures, however, necessity of a
realization of particle acceleration through the vacuum
channel, at which the redistribution of an energy stream
occurs between the channel and dielectric medium, and
absence of natural dielectric materials with necessary
properties have to provide searching for and
development of all-metal slow-wave structures. The use
of artificial anisotropic dielectric mediums in the form
of waveguides loaded by periodically placed dielectric
disks allows more effectively to use energy, put to the
waveguide, and a wide spectrum of different dielectrics.
Thus, now, waveguide dielectric slow-wave structures
are considered as one of perspective directions in
accelerating technique.
The earlier theoretical and experimental
investigations show a fundamental opportunity of
making non-regular waveguide dielectric structures with
a varying phase velocity of a wave along an axes of an
accelerating channel in the π/2- mode of the E01-wave. It
became possible due to use of a condition of a
longitudinal waveguide dielectric resonance (LWDR)
[2], which is observed in the below cutoff waveguide
with a dielectric load, when the single disk resonant
frequency is made equal to the resonant frequency of
disk system in the waveguide
f f c=
+
+
ε
ε ε
2 1
1( )
,
where f is the frequency, fc is the critical frequency of
the empty waveguide of the radius R, ε is the dielectric
permeability of disk material. It is accessible for a
special material of the disk at strictly determinated
dimensions of the waveguide inner diameter and the
disk thickness. The field, exited in every disk, has an
asymmetric pattern with the zero value in the central
cross-section of the disk.
Experimental investigations of such waveguide
dielectric structures were carried out in order to verify
their availability and to estimate their main parameters.
Experimental models of resonance accelerating
structures were made on a basis of comparatively cheap
industrial dielectric materials, in particular, of ceramics
from the dioxide titanium TiO2 (rutile) with ε ≈ 90 and
tgδ ≈ 0,5.10-2. A model consists of a circular copper
waveguide section by the diameter of 81,5 mm, which is
loaded along the axes by 32 dielectric disks having
central hole as a beam aperture. The radius of hole edge
fillets in disks is equal to 1,5 mm. In the present paper
we give the results of investigations of two types of
waveguide dielectric structures: with regular and
biperiodic loading by dielectric disks for two values of
the pass channel diameter. In case of regular structure
(RS) disks were placed at regular intervals along the
waveguide axes with a step proportional to the phase
velocity of a wave βph. In a biperiodic structure (BPS)
disks were placed by pairs, at a 1 mm space between
disks in the pair.
Before installation in the experimental model
each disk of an initial thickness h = 3,0 mm was
attuned by change of thickness to the LWDR resonant
frequency accurate up to ±0,01 MHz. Under grinding
the plane parallel surfaces of a disk were saved within
limits ±0,002 mm. After assembly of an experimental
model its resonant frequency in π/2-mode of oscillations
was equal 2815,70 MHz and did not differ from the
frequency of a single disk more than ±0,025 MHz. In
the main, this frequency difference depends on face
walls of the waveguide and couplers with a measuring
circuit. During adjustment of the disk and measuring the
fields the constant temperature of a product was
supported equal to 24 ±10C. The measuring of a field
distribution was carried out by a small disturbing body
method. The nonuniformity of the electric field
distribution along the axes of the pass channel of
structures did not exceed by 3% the field value of active
gaps BPS measured in points of the maximum value.
The measuring of the electric field distribution
along the radius in active gaps has shown that the field
is concentrated in the neighbouring-to-axis area with a
maximum value on the edge of the hole in the disk.
With increasing of the hole diameter the density of the
electric field in the pass channel area is decreasing and
its shunt impedance drops. It is shown in the figure,
where dependence of shunt impedance Rsh on βph is
given (curve 1 corresponds to the pass channel diameter
of 5 mm, and curve 2 - 7 mm).
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 22-23.
22
0 . 2 5 0 . 5 0 . 7 5 1
0
1 0
4 0
β p h
R
sh
, M
Ω
/m
1
2
3
1
2
3
1
2
3
1
2
3
Fig. 1. Shunt impedance of wave dielectric structure vs
phase velocity of wave.
For biperiodic structure, when the size of a active
gap in comparison with length of a period is extended,
we observed increasing density of an electric field
within the pass channel and, accordingly, increasing of
the shunt impedance (curve 3) in comparison with the
regular structure (curve 2) having the same diameter of
the pass channel (the given curves correspond to the
diameter of the pass channel equal to 7 mm).
The comparison with well-known accelerating
structures such as a circular diaphragmatic waveguide
(CDW) shows that the waveguide dielectric structures
have doubtless advantages in a wide range of values of
accelerated particle velocities 0,1 < β < 1. So, a shunt
impedance of the investigated experimental model of
waveguide dielectric structure even with disks from
industrial ceramics possessing large losses, calculated at
β ~ 0,8, is at a level of 40 MΩ/m, that is comparable to
the shunt impedance of CDW, working at β ~ 1. The
application of dielectric materials with large ε, but with
smaller losses, will rise considerably the efficiency of
such slow-wave structures.
REFERENCES
1. Khizhnyak N.A. The wave-guides loaded by
dielectric disks and working in π/2-wave. // The
theory and calculation of linacs. M. Atomizdat,
1962, p. 203-210. (in Russian).
2. Brizgalov G.A., Papkovich V.G., Khizhnyak N.A. A
longitudinal waveguide dielectric resonance in
systems with an artificial anisotropic loading. ZTF..
1980. Vol. 50. No. 2. p. 409-410. (in Russian).
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 22-23.
22
|
| id | nasplib_isofts_kiev_ua-123456789-81517 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T16:45:27Z |
| publishDate | 1999 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Brizgalov, G.A. Papkovich, V.G. Khizhnyak, N.A. 2015-05-17T16:19:20Z 2015-05-17T16:19:20Z 1999 Research of waveguide accelerating structures with dielectrics / G.A. Brizgalov, V.G. Papkovich, N.A. Khizhnyak // Вопросы атомной науки и техники. — 1999. — № 4. — С. 22-23. — Бібліогр.: 2 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/81517 At a choice of slow-wave structure for application in accelerating technique the main attention is given first of all to its two characteristics: 1) opportunity of use of a partial type of structures in the wider range of energies and 2) the transformation efficiency of high-frequency energy, put to structure, into a kinetic energy of accelerated particles, that eventually leads to comparison of structures on shunt impedance. From this point of view, the waveguides loaded by dielectric disks have doubtless advantages before other traditionally used structures en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Research of waveguide accelerating structures with dielectrics Исследования волноводных ускоряющих структур с диэлектриками Article published earlier |
| spellingShingle | Research of waveguide accelerating structures with dielectrics Brizgalov, G.A. Papkovich, V.G. Khizhnyak, N.A. |
| title | Research of waveguide accelerating structures with dielectrics |
| title_alt | Исследования волноводных ускоряющих структур с диэлектриками |
| title_full | Research of waveguide accelerating structures with dielectrics |
| title_fullStr | Research of waveguide accelerating structures with dielectrics |
| title_full_unstemmed | Research of waveguide accelerating structures with dielectrics |
| title_short | Research of waveguide accelerating structures with dielectrics |
| title_sort | research of waveguide accelerating structures with dielectrics |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/81517 |
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