Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses
Dynamical properties of thin epitaxial film of YBa₂Cu₃O₇ HTSC-opening switch models under action of short overcritical current pulses were measured to test this method of control of fast (of nanosecond range) high-power opening switches for accelerator applications.
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| Дата: | 1999 |
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| Автори: | , , , |
| Формат: | Стаття |
| Мова: | English |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
1999
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| Назва видання: | Вопросы атомной науки и техники |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/81499 |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses / A.V. Agafonov, E.G. Krastelev, P.S. Mikhalev, V.S. Voronin // Вопросы атомной науки и техники. — 1999. — № 4. — С. 79-80. — Бібліогр.: 4 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
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irk-123456789-814992015-05-18T03:02:24Z Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses Agafonov, A.V. Krastelev, E.G. Mikhalev, P.S. Voronin, V.S. Dynamical properties of thin epitaxial film of YBa₂Cu₃O₇ HTSC-opening switch models under action of short overcritical current pulses were measured to test this method of control of fast (of nanosecond range) high-power opening switches for accelerator applications. 1999 Article Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses / A.V. Agafonov, E.G. Krastelev, P.S. Mikhalev, V.S. Voronin // Вопросы атомной науки и техники. — 1999. — № 4. — С. 79-80. — Бібліогр.: 4 назв. — англ. 1562-6016 http://dspace.nbuv.gov.ua/handle/123456789/81499 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 |
| description |
Dynamical properties of thin epitaxial film of
YBa₂Cu₃O₇ HTSC-opening switch models under action
of short overcritical current pulses were measured to test
this method of control of fast (of nanosecond range)
high-power opening switches for accelerator
applications. |
| format |
Article |
| author |
Agafonov, A.V. Krastelev, E.G. Mikhalev, P.S. Voronin, V.S. |
| spellingShingle |
Agafonov, A.V. Krastelev, E.G. Mikhalev, P.S. Voronin, V.S. Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses Вопросы атомной науки и техники |
| author_facet |
Agafonov, A.V. Krastelev, E.G. Mikhalev, P.S. Voronin, V.S. |
| author_sort |
Agafonov, A.V. |
| title |
Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses |
| title_short |
Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses |
| title_full |
Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses |
| title_fullStr |
Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses |
| title_full_unstemmed |
Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses |
| title_sort |
dynamic behavior of htsc opening switch models controlled by short over-critical current pulses |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
1999 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/81499 |
| citation_txt |
Dynamic behavior of HTSC opening switch models controlled by short over-critical current pulses / A.V. Agafonov, E.G. Krastelev, P.S. Mikhalev, V.S. Voronin // Вопросы атомной науки и техники. — 1999. — № 4. — С. 79-80. — Бібліогр.: 4 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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AT agafonovav dynamicbehaviorofhtscopeningswitchmodelscontrolledbyshortovercriticalcurrentpulses AT krasteleveg dynamicbehaviorofhtscopeningswitchmodelscontrolledbyshortovercriticalcurrentpulses AT mikhalevps dynamicbehaviorofhtscopeningswitchmodelscontrolledbyshortovercriticalcurrentpulses AT voroninvs dynamicbehaviorofhtscopeningswitchmodelscontrolledbyshortovercriticalcurrentpulses |
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2025-07-06T06:28:19Z |
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2025-07-06T06:28:19Z |
| _version_ |
1836877931712872448 |
| fulltext |
DYNAMIC BEHAVIOR OF HTSC OPENING SWITCH MODELS
CONTROLLED BY SHORT OVER-CRITICAL CURRENT PULSES
A.V.Agafonov, E.G.Krastelev, P.S.Mikhalev, V.S.Voronin
P.N.Lebedev Phisical Institute of RAS
INTRODUCTION
A number of proposals exist for using superconductors
as opening switches for pulsed power generators with
inductive energy storage [1-3]. As far as is known, they
have not actually been used in full-scale pulsed power
systems for many reasons. One of them is connected
with limitations in the material properties of
superconductors available, in particular, high
conductivity in their normal state, necessity to use liquid
helium systems, etc. Recently, however, some changes
have occured in the situation. Developments in
superconducting materials have led to new "high-
temperature" oxide ("ceramic") superconductors which
have critical temperatures greater than 90 K, well above
the temperature of liquid nitrogen (77 K). HTSC can
carry high currents (~1-10 MA/cm2) in their
superconducting state and have moderately high
resistivity in their normal state (~mΩ⋅cm). These
properties open the possibility of making a
superconducting fast opening switch, but many
problems still remain and must be solved before using
the new materials in new applications. There is,
therefore, a need to continue experimental researches to
understand new features of materials, what properties
are relevant and what are the actual limitations.
One of the important questions is the dynamic behavior
of the switches during the opening. It depends on the
method used to quench a superconductor to the normal
state. In this paper we present results of experimental
research of dynamical properties of thin films of
YBa2Cu3O7 HTSC-switch models under action of short
overcritical current pulses to test this method of control
of fast (of nanosecond range) high-power opening
switches for accelerator applications.
EXPERIMENTAL SETUP
The experimental setup consists of a cryogenic system
(dewar) with inserted into liquid nitrogen stainless
cylinder-helium gas filled container of a test sample
assembly, nanosecond pulse generator and a set of
current and voltage monitors connected to a Tektronix
storage scope. Several cable-type generators were used
in the experiments to generate the fast rising (less than 2
ns) current pulses of 15 to 500 ns duration. By
controlling of the charging voltage, the amplitude of the
pulses is varied over a wide range, typically up to
10 ICR, where ICR is the critical current for the HTSC
sample under test.
All HTSC samples used in the experiments are epitaxial
thin films prepared by laser sputtering of the "standard"
HTSC composition YBa2Cu3O7 on the substrate of
SrTiO3. The preparation method and the results of the
detailed research of the film properties are described in
[4]. The critical temperature for the samples used in the
experiments is in the range 89.5-90 K, the critical
current density at T=77 K is about 106 A/cm2, and film
thickness – 200-300 nm.
The simplified sketch of the HTSC opening switch
model is shown in Fig.1.
Fig.1. Flat coax model of HTSC switch
The substrate with the HTSC film is installed between
two metal strips forming together with the sample and
current monitor (not shown in Fig.1) a low-inductance
flat coaxial, connected to the current pulse coaxial
feeder. The dimensions of the substrate with the film
deposited are 10x10 mm2 and 1 mm thickness. To form
the samples with a predicted value of the critical current
ICR and to remove the end effects the working area is
shaped by a laser cutter as a narrow "bridge" between
two wide contact zones. The length of the "bridge" is
about 4-5 mm and the width is in the range 0,6 – 4mm
to keep the ICR close to 2 A for different samples. For
correct measurements of the "bridge" voltage drop, the
contact zones are split into two areas – current part
(wide) and potential. Thin additional cables (not shown
in Fig.1) are connected to the potential ends of the
sample and resistors of the current monitor.
EXPERIMENTAL RESULTS
Dynamic impedance response of the switch models on
the overcritical current pulses was measured using the
single nanosecond pulses as well as trains of several
pulses to distinguish the electrodynamics and thermal
effects.
The typical dependence of the switch voltage versus the
switch current (V-A curve) measured for sample #3 at
the flat top of the pulses is shown in Fig.2.
The second curve in Fig.2 is the resistance dependence
R vs I calculated for data measured. For current levels
below ICR=1.9A the voltage and the resistance are close
to zero level and the sample is in the SC-state. For
currents higher than ICR , the voltage and the resistance
are far enough from zero level and the sample is
switched to a resistive state. This state is nonlinear. The
voltage is not proportional to the current and the
resistance increases with the current level. Most
important for the opening switch application feature of
this state is the relatively low level of resistance. At
currents as high as 5 ICR, it is almost one order of
magnitude less than the normal state resistance
measured near TCR.
For comparison the “cooling” curve is given in Fig.3 –
resistance vs time during the cooling cycle for the same
sample # 3, which has the highest normal state
resistance for all sample tested. The curve shows the
level of the sample resistance at room temperature
(about 45 Ohms) as well as at TCR - just before a fast
jump to zero level, as indicated (about 14 Ohms). Note
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 79-80.
79
that there is no difference in the resistance
measurements done by different methods at strongly
different currents. This means the normal state
resistance is independent of the current level.
Fig.2. Voltage vs. current for 400 ns pulses
Fig.3. Resistance vs time during cooling cycle
The dynamics of the opening of the switch models is
illustrated by Fig.4, showing the scope traces of the
voltage recorded for several currents during the test of
the sample #1 (ICR ≈ 2A, R ≈ 8 Ohm at room
temperature). The traces shown in Fig.4 correspond to
the current pulses with amplitudes 5, 6, 11 and 12 A.
Fig.4. Oscilloscope traces for sample #1
For currents lower than 3-4 ICR, the voltage trace has a
quasi-rectangular shape. It is close to that of the current
pulse except for the inductive spike at the front, well
visible for small overcritical currents when the resistive
component of the voltage V=IR is small compared with
the inductive one V=Ldi/dt. This means that the
resistance is constant during the pulse for a given
current level. Detailed analysis of the initial parts of the
voltage and current pulses showed no time delay
between them at I> ICR within the scope resolution time
of 3 ns – the switching to a resistive state when the ICR is
reached is faster than this resolution. The voltage is not
constant during the pulse for currents higher than 8A for
the sample given. Increasing of the voltage at the end of
the current pulse indicates increasing of resistance. It
may be a thermal effect of the sample, temperature
rising due to power dissipated during the pulse.
To clarify the effect observed, a train of nanosecond
current pulses was used for sample testing. It was
generated by the mismatched cable generator in a mode
when ZLoad<< ZG. The amplitude of the second pulse in
the train was I2≈0,8 I1, where I1 is the amplitude of the
first pulse, of the third - I3≈0,65 I1. The time interval
between the pulses in the train was 30 ns. The
dependences of the resistance of sample #1 measured at
the beginning (t=15 ns) and the end (t=95 ns) of the first
and second pulses (t=100 ns) of the train versus the
current of the first pulse are shown in Fig.5. The
corresponding curves are marked as 1b, 1e, 2b and 2e.
As was mentioned, starting from some current the
curves are split for two branches, indicating that the
sample resistance is not constant during the pulse. It is
possible to see that the splitting takes place for the
second pulse first. By the beginning of the second pulse
in the train, the resistance of the sample is about the
same as at the end of the first pulse. It looks like a
“memory” effect when the sample keeps for some time
the same resistance as measured at the end of the pulse.
The same effects were observed for all samples tested,
but the voltage rising during the pulse took place at
different current levels for different samples, typically at
a higher level for most of the samples.
Fig.5. Resistance value at start (b) and at end (e) of
pulse for the first and second pulses in train
CONCLUSIONS
Dynamical properties of thin epitaxial film of
YBa2Cu3O7 HTSC-opening switch models under action
of short overcritical current pulses were measured to test
this method of control of fast (of nanosecond range)
high-power opening switches for accelerator
applications. It was found that overcritical current
pulses switch HTSC to a resistive state during a short
time small compared with the rise time of the current
pulse. For this state the resistance of samples is a
nonlinear function of the current and is much smaller
than that for the normal state. The effects observed
indicate a complicated picture of processes taking place
under action of short overcritical currents.
REFERENCES
1. D.L Ameen and P.R.Wiederhold, Rev.Sci. Inst., v.35,
p.733, 1964.
2. R.D.Ford and I.Vitkovitsky, IEEE Trans. On Electrical
Insulation, v.EI-20, n.1, p.29, 1985.
3. D.R.Humphreys et al., In Proc. Of the 6-th International
Pulsed Power Conf.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 79-80.
79
4. A.L Vasil’ev et al., Fizika Tverdogo Tela (In Russian),
v.33, n.1, p.25.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 79-80.
79
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