Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators
The systems of high-voltage pulses formation in the majority of high-current accelerators with pulse duration from several to hundreds ns are designed on the basis of single or double pulse forming lines. The disadvantage of these systems consists for a number of applications in the relatively low o...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
1999
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| Cite this: | Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators / V.S. Gordeev // Вопросы атомной науки и техники. — 1999. — № 4. — С. 68-70. — Бібліогр.: 12 назв. — англ. |
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| author | Gordeev, V.S. |
| author_facet | Gordeev, V.S. |
| citation_txt | Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators / V.S. Gordeev // Вопросы атомной науки и техники. — 1999. — № 4. — С. 68-70. — Бібліогр.: 12 назв. — англ. |
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| description | The systems of high-voltage pulses formation in the majority of high-current accelerators with pulse duration from several to hundreds ns are designed on the basis of single or double pulse forming lines. The disadvantage of these systems consists for a number of applications in the relatively low output voltage equal in the matched mode for a double forming line to the charging voltage while for a single line – only to a half of this value.
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SCHEMES OF HIGH-VOLTAGE PULSE SHAPERS ON THE BASIS OF
STEPPED TRANSMITION LINES FOR HIGH-CURRENT
ACCELERATORS
V.S. Gordeev
VNIIEF, Sarov, Russia
INTRODUCTION
The systems of high-voltage pulses formation in
the majority of high-current accelerators with pulse
duration from several to hundreds ns are designed on
the basis of single or double pulse forming lines. The
disadvantage of these systems consists for a number of
applications in the relatively low output voltage equal in
the matched mode for a double forming line to the
charging voltage while for a single line – only to a half
of this value.
In the course of creating high current linear
induction accelerators (LIA) there was developed a new
type of multi-cascade high-voltage pulse generators
designed of homogeneous transmission lines of equal
electric length. As in similar devices the impedance
changes stepwise passing from one cascade to another,
they are called step-line (SL) generators and several tens
of schemes are available [1–3]. The energy accumulated
in many lines (cascades) is concentrated as a result of
wave processes at generator output after the switch is
turned on. At specified impedance relation it is possible
to transfer entirely the energy stored to the resistive load
under rectangular pulse formation. Pulse duration does
not depend on the generator full size and is
characterized only by a double electric length of a
separate cascade. A considerable – up to 5-10 fold -
increase of voltage or current is realized depending on
the generator scheme through wave processes. There are
also proposed the schemes capable of providing electric
power increase through the reduction of pulse duration
[3, 4].
As well as all generators on transmission lines
such devices can be subdivided into two types –
generator of capacitive and inductive energy storage
depending on the fact whether the energy is stored in the
form of only electric or only magnetic field. As we
know, recently proposed were, for the first time, the
schemes of generators of a new type. In connection with
the fact that energy is stored in them in the form of
electric and magnetic field such generators are called
inductive-capacitive generators [2]. Basing on
capacitive schemes there are created electron
accelerators: I-3000 (3.5 MeV, 20 kA, 16 ns), STRAUS
(2,3 MeV, 20 kA, 40 ns), STRAUS – 2 (3.3 MeV, 50
kA, 40 ns), LIA-10M (≤25 MeV, ≤50 kA, 25 ns) [3,5-
10]. Below the examples of different-type schemes are
given. The investigations of SL are carried out in the
USA as well [11–13].
CAPACITIVE GENERATOR
The scheme of the capacitive generator formed
by 5≥n homogeneous transmission lines of similar
electric length 0T is presented in Fig. 1a [1, 3]. At
0=t time moment, when maximum charging voltage
0V of four cascades with Z nn ZZ ÷− 3 impedances is
achieved, 1S is turned on. As a result, there appear
electromagnetic waves. Let us consider any place of
different-impedance cascades junction. Let the first
wave comes to it at 1t time moment. The generator
scheme, inpedances and time of load connection are
selected in such a way that by 01 2Tt + time moment
the energy is entirely extracted from all cascades
included between the considered cross-section and 1S
switch. The voltage wave coming at that moment from
the 1S switch and completing energy extraction is
partially reflected from the place of cascades junction.
However, at the same time from the opposite side to the
cross-section in question another voltage wave comes
with such amplitude and polarity that as result of
superposition the amplitude of a wave reflected towards
the switch becomes zero. As a result, the energy is
entirely accumulated near the generator output. Other
generators on SL operate similarly. At the output of the
generator with 1Z impedance and beginning from
0)3( Tnt −= time moment there formed are the
voltage pulses of alternating polarity, their duration
being equal to 02T . The second pulse is the operating
one. The first pulse is cut off from the load by a pre-
pulse switch 2S , that is turned on with 02T delay as
related to the moment of the first wave (from 1S
switch) coming. At the matched load a voltage pulse of
rectangular shape is formed within which the energy is
entirely delivered to the load.
Zn-3
Zn-2Zn-1
Zn Zn-4 Zn-5
t=0 t=(n-1)T0
ZL
S1
V0
S2
Z1
a
3Z
Z
V0 S1
5Z/4
15Z/4
15Z
ZL
S2t=0
t=4T 0
b
Fig. 1. Schemes of generators with capacitive method of
energy storage for an arbitrary number of cascades (a)
and the case of 5=n (b).
To achieve in the ideal case a 100-% efficiency
the impedances of the lines should be selected in accord
with the following formulas: )]1(/[2 1 += iiZZi for
=i 4,.....,2,1 −n , )]2()3(2/[13 −−=− nnZZn ,
=− 2nZ ,3 3−nZ ,31 nn ZZ =− )]2(/[1 −= nnZZn ,
where 1Z is the output generator impedance. The
voltage on the matched load constitutes the value of
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68
0)2( Vn − . The appending of any additional cascade
with the corresponding choice of impedances makes it
possible to increase voltage on the matched load by Vo,
while in the idle mode – by 2Vo. However, the growth
of the number of cascades is accompanied by the
increase of relation between maximum and minimum
impedances of SL which does not exceed (as a rule) 20
for coaxial lines at using in the whole generator of one
and the same type of dielectric.
In Fig. 1b specified is the ratio of impedances for
a five-cascade generator when the output voltage in the
idle mode is 06V , while in the matched mode it is 03V
. On the basis of the scheme under consideration with
5=n , the first accelerator on SL called STRAUS
(stepped transforming accelerator) and a more powerful
accelerator STRAUS–2 are created. Its modification
with 4=n is used as a basis for LIA–10M inductor.
INDUCTIVE GENERATOR
Fig. 2 represents the example of a scheme with
the inductive method of energy storage [2] for an
arbitrary number of cascades (a) and for a case of
3=n (b). In a closed contour formed by the SL
electrodes and opening switch (OS) the 0I current is
generated and the energy is stored in the magnetic field.
At 0=t the time moment OS is turned on and under
the effect of wave processes the energy is concentrated
at the generator output. Under the matched load
)/( 00 ZZZZZ nnL += which is turned on by the S
switch at the moment of the first electromagnetic wave (
0nTt = ) coming to it, a rectangular pulse of 02T
duration is formed.
To achieve ideally 100-% efficiency the
impedances should be selected according to the
following formulas: )]1(/[2 1 += iiZZi for
4,...,2,1 −= ni , =0Z )1/(2 1 +nZ . The current in the
matched load is as high as 2/)1( 0In + . The inclusion
of each additional cascade to the generator as a
component makes it possible to increase current in the
matched load by 05.0 I . In Fig. 2b it is demonstrated that
an optimum ratio of impedances for the case of 3=n
will be with the current equal to 02I .
INDUCTIVE-CAPACITATYIVE GENERATOR
In Fig. 3 an example of an inductive-capacitive
generator is shown. In a closed contour formed by a SL
case and OS the 0I current is generated under the effect
of an external source, and the energy is stored in the
magnetic field in the whole SL volume. At the same
time, the high voltage-electrode is charged from another
source up to 0V voltage and the energy is stored in the
cascades with nn ZZ ÷− 3 impedances in the electric
field. At the moment of energy storage termination the
S switch is turned on and in SL there appear
electromagnetic waves. The generator scheme, the ratio
of impedances as well as of 0I and 0V values are
selected so that all the energy stored is concentrated at
the generator output. At the moment of the first wave
arriving to it the OS interruption takes place and the
energy is transfered to the load on which a 02T
duration pulse of rectangular form is formed.
Z0... Z...iZ1
OS
ZL
t=0
Zn-1 ZnI0
S
Zn-2
a
Z1OS
ZL
t=0 S
I0
Z/31 Z/61 Z/21
t=3T0
I0
I0
b
Fig. 2. Schemes of generators with
inductive method of energy storage for an
arbitrary number of cascades (a) and for a
case of 3=n (b).
To achieve a 100-% efficiency the impedances,
0I and 0V should be selected according to the formulas:
)])(1[(/)]1([1 iiZZi +−++= αααα for 4,.....,2,1 −= ni ,
)]4)(3(2/[)]1([13 −+−++=− nnZZn αααα ,
32 −− = nn ZZ , )]3(2/[)]1([11 −++=− nZZn ααα ,
⋅=⋅= − )/( 1001 ZVIZZ nn )]1(/[)]3(2[ +−+ ααα n . The
voltage on a matched load is found of the formula
=0/VVL αα /)3( −+ n . Here, we introduced the α
coefficient equal to the relation between electric and
magnetic energy stored in the generator. The polarity of
charging voltage should be such that after the S switch
turn-on the current in the line with nZ impedance be
decreased. The supplement of any additional cascade
increases the voltage on a matched load by α2/0V .
The optimum ratio of impedances for a special case (
5=n , 1=α ) when 3/ 0 =VVL is presented in
Fig. 3b. To open OS one can take advantage of the fact
that as a result of the first wave coming to it the current
increases by a factor of ( 1+α ). It is the particular
value for practical realization of synchronous operation
of several generators.
a
Z1t=0
t=2T0
ZL
S
OSI0
V0
Z /61Z /31
Z /31 Z /61
b
Fig. 3. Schemes of generators with inductive-capacitive
method of energy storage for an arbitrary number of
cascades (a) and for the case of 5=n and 1=α (b)
Let us mention that there exists a considerable
difference in the process of energy extraction in
inductive-capacitive generators. After the completion of
the energy storage the strength of electric ( E ) or
magnetic ( H ) field in capacitive and inductive
generators are correspondingly equal to zero. Thus, the
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68
Pounting’s vector is also equal to zero and the energy is
at rest as related to electrodes. In the capacitive
generator a spread takes place at high voltage gap
closure by a switch along the lines of electromagnetic
waves equating the voltage to zero. The electric energy
transforms entirely to the magnetic energy, i.e. after the
first wave passage from the switch the energy stays put,
only its form changes. Thus, for entire extraction of
energy the wave should be returned to the closed switch
and reflected from it with the voltage polarity changed.
The similar process takes place in the inductive
generator on SL (Fig. 2). In this case after the first wave
passage from OS the energy also stays put, while the
magnetic energy transforms entirely to the electric
energy.
For inductive – capacitive generators both E
(near the high-voltage electrode) and H after the
completion of the process of energy storage differ from
zero, as well as, the Pounting’s vector. As a result, the
energy circulates around the high-voltage electrode.
This effect should be necessarily taken into account in a
set of cases to explain the satisfaction of the law of
pulse moment conservation (see, for example, [14]). In
the version of (Fig. 3) being considered the current
direction as well as the polarity of charging voltage
should be chosen in such a way that to realize the mode
of entire energy extraction, the energy must circulate
around a high-voltage electrode anti-clockwise. At high-
voltage gap closure by S switch the way for the energy
flow is cut off at this place. As a result of the ongoing
circulation in a line with nZ impedance, the quantity of
energy will reduce, while in the line with 3−nZ
impedance it will increase. Of most practical interest is
the version of nZVI /00 = , where - after the first wave
passage from the switch - the energy is entirely
extracted from the line with nZ impedance. At the high-
voltage gap closure the voltage in the lines is zero-filled.
At the same time, in the line with nZ impedance there
arises the current equal by value but opposite by
direction to the initial current 0I . As a result of
superposition the current and the magnetic field in this
line turn to zero, what – along with voltage zero-filling
– provides entire extraction of energy from the line. One
can easily check whether the law of energy conservation
is satisfied or not.
PULSE DURATION CONVERTER
In Fig. 3 there is shown an example of a pulse
duration converter. The transmission line with Z
impedance is connected in series with step (
mZZZ .,..., ,21 ) and single ( 0Z ) lines. The SL output is
closed while the load is connected by S switch to the
output of a single line with 02mT time delay as related
to the first wave coming to it. The converter possesses a
100-% efficiency at selecting impedances according to
the following formulas: )1/(0 += mZZ ,
⋅−+= )1( imZZi 2)1/()2( +−+ mim for mi ,....,2,1= .
The energy coming from the external generator in the
form of rectangular pulse of 0)1(2 Tm + duration is
accumulated in the line with 0Z impedance and then –
at S switch turn-on – is entirely transmitted to the
matched load, the rectangular pulse (but of 02T duration)
being formed in it. The output voltage pulse amplitude
is equal to the voltage amplitude of external generator
GV while the current and power increase by a factor of
)1( +m through the corresponding reduction of pulse
duration. In fig. 4b there is demonstrated the optimum
relation of impedances for the case of 3=m when the
current on the matched load and power increase by a
factor of 4.
Z0
Z1
Z Z . . .2
t=2mT0
ZL
S
Zm
VG
a
3Z/4Z
t=6T0
ZL
S
VG
Z/8
Z/4
3Z/8
b
Fig. 4. Scheme of pulse duration converter for an
arbitrary number of cascades (a) and a case of 3=m
(b).
There are also found the schemes of converters
where before the achievement of the external generator
pulse additional energy is accumulated in the form of
electric or magnetic field [4]. Depending on the scheme
there can be insured the increase of voltage and current.
It should be mentioned that by now there have
been determined general regularities and developed
calculation methods that simplify the search of optimum
relations between impedances for SL-based devices.
REFERENCES
1. Bossamykin V.S., Gordeev V.S., Pavlovskii A.I.// IX
Intern. Conf. on High Power Particle Beams "BEAMS 92".
Washington, 1992. V.1. P.511.
2. Gordeev V.S., Bossamykin V.S.// XI Internat. Conf. on
High Power Particle Beams "BEAMS 96". Prague, 1996. V. 2.
P. 938.
Bossamykin V.S., A.I.Gerasimov, V.S.Gordeev. Proc.
VNIIEF, 1997. p. 107-133.
3. Bossamykin V.S., Gordeev V.S.// IX IEEE Intern. Pulsed
Power Conf. Albuquerque, V.2. P. 918.
4. Bossamykin V.S., Gordeev V.S., Pavlovskii A.I. et al. // IX
Intern. Conf. on High Power Particle Beams "BEAMS 92".
Washington, 1992 V.1. P.505.
5. Pavlovskii A.I., Bossamykin V.S., Gordeev V.S.et al.
Relative high frequency electronics. IPF RAn, 1992. N. 7.
p. 81
6. Bossamykin V.S., Gordeev V.S., Pavlovskii A.I. et al. // IX
IEEE Intern. Pulsed Power Conf. Albuquerque, 1993. V. 2.
P. 910.
7. Bossamykin V.S., Gordeev V.S., Myskov G.A.,et al.
VANT, 1997. № 4, 5. p. 120.
8. Bossamykin V.S., Gordeev V.S., Pavlovskii A.I. et al. // IX
IEEE Intern. Pulsed Power Conf. Albuquerque, NM, 1993.
V.2. P.905.
9. Bossamykin V.S., Gordeev V.S., Myskov G.A.,et al. VANT
1997. № 4, 5. p. 117.
10. Eccleshall D., Temperley J.H. // J. Appl. Phys. 1978. V.
49. № 7. P. 3649.
11. Smith I.D. // IEEE Conf. record of 1982 15 Power
modulation simposium. N Y, 1982. P. 223.
12. Eccleshall D. // Nucl. Instr. and Meth. in Phys. Research.
1987. B 24/25. P. 801.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 68-70.
68
|
| id | nasplib_isofts_kiev_ua-123456789-81537 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-11-30T17:24:40Z |
| publishDate | 1999 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Gordeev, V.S. 2015-05-17T16:59:00Z 2015-05-17T16:59:00Z 1999 Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators / V.S. Gordeev // Вопросы атомной науки и техники. — 1999. — № 4. — С. 68-70. — Бібліогр.: 12 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/81537 The systems of high-voltage pulses formation in the majority of high-current accelerators with pulse duration from several to hundreds ns are designed on the basis of single or double pulse forming lines. The disadvantage of these systems consists for a number of applications in the relatively low output voltage equal in the matched mode for a double forming line to the charging voltage while for a single line – only to a half of this value. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators Схемы форм высоковольтных импульсов на основе ступенчатых передаточных линий для сильноточных ускорителей Article published earlier |
| spellingShingle | Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators Gordeev, V.S. |
| title | Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators |
| title_alt | Схемы форм высоковольтных импульсов на основе ступенчатых передаточных линий для сильноточных ускорителей |
| title_full | Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators |
| title_fullStr | Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators |
| title_full_unstemmed | Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators |
| title_short | Schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators |
| title_sort | schemes of high-voltage pulse shapers on the basis of stepped transmition lines for high-current accelerators |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/81537 |
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