RF pulsed measurements at the TNK linear accelerator-injector
Measurements of RF pulse signals in megawatt circuits are an important problem of acceleration technique. Measuring circuits should not degrade WSVR in power transmitting channels or give rise to local electric field overvoltages. An especially developed set of tools including 2.8 GHz detecting un...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2004
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| Цитувати: | RF pulsed measurements at the TNK linear accelerator-injector / L.L. Belova, K.N. Chernov, G.N. Ostreiko, G.V. Serdobintsev, V.V. Tarnetsky // Вопросы атомной науки и техники. — 2004. — № 2. — С. 72-74. — Бібліогр.: 3 назв. — англ. |
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irk-123456789-793342015-04-01T03:02:11Z RF pulsed measurements at the TNK linear accelerator-injector Belova, L.L. Chernov, K.N. Ostreiko, G.N. Serdobintsev, G.V. Tarnetsky, V.V. Элементы ускорителей Measurements of RF pulse signals in megawatt circuits are an important problem of acceleration technique. Measuring circuits should not degrade WSVR in power transmitting channels or give rise to local electric field overvoltages. An especially developed set of tools including 2.8 GHz detecting unit blocks, vacuum directional couplers, phase detectors, and phase shifting lines is described. The set allows one to carry out non-intrusive RF signal measurements in the waveguide channel at up to 20 MW power level with an accuracy of some percents. Вимір високочастотних імпульсних сигналів у пристроях з мегаватними рівнями потужності є важливою задачею прискорювальної техніки. Вимірювальні ланцюги не повинні погіршувати КСВН у трактах передачі потужності і створювати локальні перенапруги електричних полів. Описана спеціально розроблена на частоту 2.8 ГГц елементна база, що складається з блоків детектуючих пристроїв, вакуумних спрямованих відгалужувачів, фазових детекторів, фазозсувних коаксіальних ліній, що забезпечує виміри НВЧ сигналів без збурення у хвилеводному тракті і лінійному прискорювачі з рівнем потужності до 20 МВт із точністю не гірше декількох відсотків. Измерение высокочастотных импульсных сигналов в устройствах с мегаваттными уровнями мощности является важной задачей ускорительной техники. Измерительные цепи не должны ухудшать КСВН в трактах передачи мощности и создавать локальные перенапряжения электрических полей. Описана специально разработанная на частоту 2.8 ГГц элементная база, состоящая из блоков детектирующих устройств, вакуумных направленных ответвителей, фазовых детекторов, фазосдвигающих коаксиальных линий, обеспечивающая не возмущающие измерения СВЧ сигналов в волноводном тракте и линейном ускорителе с уровнем мощности до 20 МВт с точностью не хуже нескольких процентов. 2004 Article RF pulsed measurements at the TNK linear accelerator-injector / L.L. Belova, K.N. Chernov, G.N. Ostreiko, G.V. Serdobintsev, V.V. Tarnetsky // Вопросы атомной науки и техники. — 2004. — № 2. — С. 72-74. — Бібліогр.: 3 назв. — англ. 1562-6016 PACS: 29.17.+w http://dspace.nbuv.gov.ua/handle/123456789/79334 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 |
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DSpace DC |
| language |
English |
| topic |
Элементы ускорителей Элементы ускорителей |
| spellingShingle |
Элементы ускорителей Элементы ускорителей Belova, L.L. Chernov, K.N. Ostreiko, G.N. Serdobintsev, G.V. Tarnetsky, V.V. RF pulsed measurements at the TNK linear accelerator-injector Вопросы атомной науки и техники |
| description |
Measurements of RF pulse signals in megawatt circuits are an important problem of acceleration technique.
Measuring circuits should not degrade WSVR in power transmitting channels or give rise to local electric field
overvoltages. An especially developed set of tools including 2.8 GHz detecting unit blocks, vacuum directional
couplers, phase detectors, and phase shifting lines is described. The set allows one to carry out non-intrusive RF
signal measurements in the waveguide channel at up to 20 MW power level with an accuracy of some percents. |
| format |
Article |
| author |
Belova, L.L. Chernov, K.N. Ostreiko, G.N. Serdobintsev, G.V. Tarnetsky, V.V. |
| author_facet |
Belova, L.L. Chernov, K.N. Ostreiko, G.N. Serdobintsev, G.V. Tarnetsky, V.V. |
| author_sort |
Belova, L.L. |
| title |
RF pulsed measurements at the TNK linear accelerator-injector |
| title_short |
RF pulsed measurements at the TNK linear accelerator-injector |
| title_full |
RF pulsed measurements at the TNK linear accelerator-injector |
| title_fullStr |
RF pulsed measurements at the TNK linear accelerator-injector |
| title_full_unstemmed |
RF pulsed measurements at the TNK linear accelerator-injector |
| title_sort |
rf pulsed measurements at the tnk linear accelerator-injector |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2004 |
| topic_facet |
Элементы ускорителей |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/79334 |
| citation_txt |
RF pulsed measurements at the TNK linear accelerator-injector / L.L. Belova, K.N. Chernov, G.N. Ostreiko, G.V. Serdobintsev, V.V. Tarnetsky // Вопросы атомной науки и техники. — 2004. — № 2. — С. 72-74. — Бібліогр.: 3 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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2025-07-06T03:24:53Z |
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| fulltext |
RF PULSED MEASUREMENTS AT THE TNK LINEAR
ACCELERATOR-INJECTOR
L.L.Belova, K.N. Chernov, G.N. Ostreiko, G.V.Serdobintsev, V.V. Tarnetsky
Budker INP, Novosibirsk, Russia
Measurements of RF pulse signals in megawatt circuits are an important problem of acceleration technique.
Measuring circuits should not degrade WSVR in power transmitting channels or give rise to local electric field
overvoltages. An especially developed set of tools including 2.8 GHz detecting unit blocks, vacuum directional
couplers, phase detectors, and phase shifting lines is described. The set allows one to carry out non-intrusive RF
signal measurements in the waveguide channel at up to 20 MW power level with an accuracy of some percents.
PACS: 29.17.+w
1. INTRODUCTION
The industrial storage facility (TNK, Lukin State
Research Institute for Problems in Physics, Zelenograd)
includes an injector on the base of 80...100 MeV linear
accelerator, and two storage rings: lesser 450 MeV and
main 2.5 GeV. Linac is feed via the waveguide
(90х45 mm) of ~15 meter length from KIU-53A
klystron with an output power up to 20 МW at
2797.8 MHz [1,2]. RF measurement system is an
element of the accelerator facility which controls the
accelerator.
For RF accelerating devices operating in pulsed
mode, the main requirements on measuring RF units
are: measuring within wide dynamic range of signal
amplitudes during facility operating from power-up time
till normal operating regime; possibility to register fast
processes; and constant “twenty-four-hour” device
readiness. At TNK accelerator facility, an assembly of
such RF measuring devices forms an RF control system,
which elements are designed with consideration of the
design of the linac, vacuum and gas waveguide sections
including E- and H- types of turns, in which optical
probes may be installed to register discharges in the
waveguide and ceramic window.
2. RF MEASURING DEVICES
In the course of accelerator facility operating,
measuring devices must be started in the certain order,
specific for each facility.
Figure 1 presents a time chart, which clarifies the
20 MW RF operating system “linac-waveguide-Olivin
klystron station. At RF measurements on linear
accelerators, we prefer propagate RF signals from Rf
source to RF rack via a cable. The rack is located near
the control board. Units for RF pulse amplitudes,
frequency, phase shift, etc. belonged to the same RF
facility located in the protected room and having a
common ground bus with RF rack crate, are located in
the RF rack crate. RF measuring set is made in
“Vishnya” standard with detector probe assemblies
(DPA) for 6 channels and two phase detectors (PDA).
The set also includes the master oscillator and special
frequency 54-times multiplier, from which output
2.8 GHz frequency is applied after pulsed power
amplifier to Olivin klystron station excitation. The
pulsed amplifier power may be also used to test
measuring devices.
RF power level measuring in the waveguide within
the range of 0,1...20 MW and the corresponding field
strength measurements in the linac accelerating cavities
present difficulties in probes for incident and reflected
wave fields creation for level drop by -60...70 dB. At
the same time, it is problematically to avoid a sufficient
error at attenuation constant calibration. Practically, at
RF workbench, where RF power levels of 1...10 W are
available, we can measure with calorimetric microwatt
instruments attenuation rates down to -50 dB with
several percents accuracy. Figure 2 presents the -50 dB
waveguide directional coupler for incident and reflected
waves; it corresponds to 10...200 W per pulse for
derived incident wave power. A “cross” [3] is used to
dump the power in the vacuum waveguide section
90х45 mm. The derived power is transferred through
vacuum-proof waveguide-to-coax junctions and is
applied to radio rack via phase-stable coaxial cable.
Two types of RF detectors are used for RF pulse
amplitude measurements. Photo in Fig.3 shows a broad-
band detector probe assembly for measured power level
up to 1 W together with a special through-pass detector
probe for 16x7 coaxial channel at 6D16D vacuum RF
diode. In this detector, the measured power level
amounts to 100 w at VSWR not worse than 1.05.
Imaginary impedance compensation in the diode
connecting point is realized by the parallel circuit (see
Fig.4), in which Сd=С0, ωLd=2/ωС0, where Cd and Ld are
diode capacitance and its output inductance
respectively.
Detector probe assembly contains three broad-band
detector probes (DP) on the base of D608
semiconductor diodes for pulsed RF signal
measurements and fast (~100...300 ns) processes
registration during RF discharge in the linear accelerator
or waveguide. Broadbandness of the DP is achieved by
use of ~6 dB microstrip attenuator at the detector input
(Wвх=50 Ohms) at VSWR not worse than 1.5 within the
frequency range up to 5.6 GHz and also because of
small (~20 pF) overall reduced capacitance at the video
repeater amplifier input. Frequency bandwidth of the
amplifier is ~100 MHz at input signal of ±4 V,
Rн=50 Ohms.
___________________________________________________________
PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 2.
Series: Nuclear Physics Investigations (43), p.72-74.72
73
Fig.1. Time chart of the “linac-wavaguide-Olivin”RF system operation
S
0
– Start of the charging device for “Olivin”
modulator power source
S
olivin
– Start of the “Olivin” modulator
Uanode – klystron anode pulse amplitude
I
klystron
– cathode current pulse of KIU-53 klystron
S
mod
– Start of radio rack RF amplifier modulator
RF pulse shape of KIU-37A klystron:
“work”- normal mode, “adjustment”- start of the RF
amplifier modulator is delayed relative to “Olivin
modulator start
Uinc and Uref – incident and reflected wave voltages at
linac input. Slot directional coupler -50 dB (cross) is
installed into 90x45 mm waveguide channel.
U
fd
– shape of phase shift between U
inc
and U
linac
.
Ulinac – envelope of field rise in linac structure.
Inductive probe is placed into the central cavity of the
linac structure (regime without beam).
S
beam
– Beam start.
Ulinac – envelope of field rise in linac structure with
beam loading.
Expected shape of voltage on CF-EOC-1 capacitor,
S0
S olivin
mod.S
S beam
Uanode
I klystron
work adjustment
U inc.
U ref.
U linac without beam
U linac with beam
Q i Faraday cup
sec20151050 t
Launching pulse of
modulator "OLIVIN"
launching pulse of
beam
U fd.
Fig. 2. Waveguide directional coupler
Fig.3. Broad-band detector probe assembly with
“special” detector probe for pulsed power up to
100 W
Phase detector assembly (see Fig.5) includes two
phase detectors, either consists of a phase detector itself,
phase shifting line (PSL), RF cables, and pulsed signal
repeater (Rн=50 Ohms). In this variant, phase detector
is assembled on the microstrip board made of Flan-5
with thickness of 1.5 mm on the base of 3 dB bridge.
Bridge RF inputs are made on RF connectors. RF signal
on a certain input pass through the phase shifter. Signals
from bridge outputs are detected by 2A201A RF diodes,
which are connected in circuit with different polarities,
are summarized on the balance resistor and then
transmitted to a broad-band repeater (the signal shape
Ufd is shown in Fig.1). VSWR of inputs is ≤1.25 within
the frequency range 2800 ±50 MHz. The phase shifter is
a phase shift line of telescopic type. The line is set in
motion by the screw with 0.75 mm lead, which results
in 2.57o per turn. Phase shift line VSWRs are not worse
than 1.07. The maximal power at PDA outputs is
~0.6 W. Phase detector sensibility is ~8-10 mV/degr for
optimal linac tune zone, when the reflected wave in the
waveguide Uref is minimal (see Fig.1).
3. CONCLUSIONS
The control system for TNK accelerator-injector has
been created. It includes the set of detecting devices,
directional couplers, phase shifters, and phase detectors,
providing operation of the auto frequency turning and
linac temperature stabilization systems.
REFERENCES
1. V.N. Korchuganov et al.. Status of the Siberia–2
Preinjector // Proc. of EPAC, London. 1994, v.1,
p.739–741.
2. V.I. Beloglazov et al. Klystron-modulator with
1000 porosity – the basic cell of high-current
electron linac RF feeding // VANT, Series
“Tekhnika fizicheskogo experimenta”. 1985,
v.3(24), p.8.
3. A.L. Feldshtein et al. Handbook on waveguide
elements. M.: «Sovetskoe Radio», 1967.
ИЗМЕРЕНИЕ ИМПУЛЬСНЫХ СВЧ СИГНАЛОВ НА ЛИНЕЙНОМ УСКОРИТЕЛЕ ТНК
Л.Л. Белова, Г.Н. Острейко, Г.В. Сердобинцев, В.В. Тарнецкий, К.Н. Чернов
Измерение высокочастотных импульсных сигналов в устройствах с мегаваттными уровнями мощности
является важной задачей ускорительной техники. Измерительные цепи не должны ухудшать КСВН в
трактах передачи мощности и создавать локальные перенапряжения электрических полей. Описана
специально разработанная на частоту 2.8 ГГц элементная база, состоящая из блоков детектирующих
устройств, вакуумных направленных ответвителей, фазовых детекторов, фазосдвигающих коаксиальных
линий, обеспечивающая не возмущающие измерения СВЧ сигналов в волноводном тракте и линейном
ускорителе с уровнем мощности до 20 МВт с точностью не хуже нескольких процентов.
ВИМІР ІМПУЛЬСНИХ НВЧ СИГНАЛІВ НА ЛІНІЙНОМУ ПРИСКОРЮВАЧІ ТНК
74
Fig.5. Phase detector assembly
Fig. 4. Special detector probe circuit
C C0 d
Ld
Uin
Uout
Л.Л. Белова, Г.Н. Острейко, Г.В. Сердобинцев, В.В. Тарнецький, К.Н. Чернов
Вимір високочастотних імпульсних сигналів у пристроях з мегаватними рівнями потужності є важливою
задачею прискорювальної техніки. Вимірювальні ланцюги не повинні погіршувати КСВН у трактах передачі
потужності і створювати локальні перенапруги електричних полів. Описана спеціально розроблена на
частоту 2.8 ГГц елементна база, що складається з блоків детектуючих пристроїв, вакуумних спрямованих
відгалужувачів, фазових детекторів, фазозсувних коаксіальних ліній, що забезпечує виміри НВЧ сигналів
без збурення у хвилеводному тракті і лінійному прискорювачі з рівнем потужності до 20 МВт із точністю не
гірше декількох відсотків.
75
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