Investigation of STRAUS-2 pulsed electron accelerator characteristics
Last years a successful development of highvoltage pulse forming techniques based on stepped transmission lines led to creation of a set of powerful and compact electrophysics facilities including a highcurrent pulsed electron accelerator STRAUS-2 [1, 2]. The first sample of this accelerator was sta...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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| Дата: | 1999 |
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| Формат: | Стаття |
| Мова: | Англійська |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
1999
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Investigation of STRAUS-2 pulsed electron accelerator characteristics / V.S. Gordeev, G.A. Myskov, V.O. Filippov, V.Ya. Averchenkov // Вопросы атомной науки и техники. — 1999. — № 4. — С. 71-73. — Бібліогр.: 7 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860002055354056704 |
|---|---|
| author | Gordeev, V.S. Myskov, G.A. Filippov, V.O. Averchenkov, V.Ya. |
| author_facet | Gordeev, V.S. Myskov, G.A. Filippov, V.O. Averchenkov, V.Ya. |
| citation_txt | Investigation of STRAUS-2 pulsed electron accelerator characteristics / V.S. Gordeev, G.A. Myskov, V.O. Filippov, V.Ya. Averchenkov // Вопросы атомной науки и техники. — 1999. — № 4. — С. 71-73. — Бібліогр.: 7 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | Last years a successful development of highvoltage pulse forming techniques based on stepped transmission lines led to creation of a set of powerful and compact electrophysics facilities including a highcurrent pulsed electron accelerator STRAUS-2 [1, 2]. The first sample of this accelerator was started up into exploitation in 1989. At present, three facilities of the same type exist in VNIIEF, one of them is used as an injector for a linear induction accelerator LIA-10M [2-5]. Two others are autonomous and applied for research in radiation physics.
|
| first_indexed | 2025-12-07T16:36:20Z |
| format | Article |
| fulltext |
INVESTIGATION OF STRAUS-2 PULSED ELECTRON ACCELERATOR
CHARACTERISTICS
V.S. Gordeev, G.A. Myskov, V.O. Filippov, V.Ya. Averchenkov
VNIIEF, Sarov, Russia
Last years a successful development of high-
voltage pulse forming techniques based on stepped
transmission lines led to creation of a set of powerful
and compact electrophysics facilities including a high-
current pulsed electron accelerator STRAUS-2 [1, 2].
The first sample of this accelerator was started up into
exploitation in 1989. At present, three facilities of the
same type exist in VNIIEF, one of them is used as an
injector for a linear induction accelerator LIA-10M [2-
5]. Two others are autonomous and applied for research
in radiation physics.
STRAUS-2 accelerator (Fig. 1a) is designed by a
scheme of five-cascade double stepped forming line –
DSFL (Fig. 1b), that allows to realize a high voltage
transformation factor: when charging the accelerator’s
DSFL up to 0.63 MV the idle voltage pulse amplitude
reaches 4.1 MV on its output.
1.
2
m
WATER
OIL
VACUUM
2.7 m
12 3 5 467 8 9 10 11
Z4
Z3 Z5
Z2
Z1
1 – DSFL; 2 – multichannel switch; 3 – pre-pulse
switch; 4 – sectioned isolator; 5 – polyethylene tube;
6 - electrolyte layer; 7 – water–oil separating
diaphragm; 8 – shielding electrode; 9 – cathode holder
with a cathode; 10 – output vacuum chamber;
11 - anode flange with a target unit.
a)
Z4
Т0 Т0 Т0
Z3
Z5
V0 V
V
idle
ML
= 7.2V
= 3.6V
0
0V0
Z
(Z )
(Z )
=
= ZL
L
L 5Z2
Z1
S 2 0(t = 4T )
S 1 (t = 0)
∞
Z1=0.8 Ohm; Z2=1.9 Ohm; Z3=3.2 Ohm; Z4=0.9 Ohm;
Z5=18 Ohm;
Т0≈20 ns.
b)
Fig. 1. Sketch of STRAUS-2 accelerator (a) and an
electric circuit of its DSFL (b).
The output voltage, current and pulse duration
can be varied, but most often the follow operating mode
is realized: V∼3 МV, I∼50 kA, τp∼20÷40 ns (FWHM),
that corresponds to maximum dose parameters at
accelerator operating in the X-ray generation mode. In
this case the diode configuration is used as follows:
graphite cathode ∅30÷40 mm having two coaxial ring
edges, accelerating gap – ∆A-C∼50 mm, target unit – 0.5
mm of tantalum and 10 mm of aluminum (as a filter).
The target is chosen some thicker than optimal for
enlarging its operation resource (100÷150 pulses).
Below the characteristics are given for X-ray radiation
produced by the STRAUS-2 accelerator [1, 5].
Dose (Si): at the output flange 100 Gy
at 1 m from the target 0.2 Gy
Dose power: at the output flange 5⋅109 Gy/s
at 1 m from the target 1⋅107 Gy/s
X-ray radiation pulse width: 15÷25 ns
Irradiation spot diameter
(Dmax/Dmin=2): at the output flange 8 сm
at 1 m from the target 80 сm
The dose remains practically unchangeable
within the X-ray pulse duration 15÷25 ns (FWHM), but
the dose power has a maximum at τp∼15 ns. The dose
constancy is provided for account of some growth (∼10
÷15 %) of the diode current and voltage, observed at
pulse width reduction. Out of the above-mentioned
range the dose falls because of the diode voltage and
current decrease. In case of τp>25ns it occurs due to
arrival time mismatching of partial electromagnetic
waves, forming the output pulse, to the diode load. At τ
p<15 ns the X-ray radiation pulse is formed at the falling
part of the accelerating pulse. Notice, that the dose
parameters can be risen by ∼1.5 times through
increasing the DSFL charging voltage up to the
maximum value 0.7 MV along with decreasing the
target thickness up to 0.25÷0.3 mm. At that, however,
resource characteristics of the accelerator will be some
below.
In Fig. 2 the X-ray radiation pulse shape and the
energy spectrum of photons generated by the
STRAUS-2 accelerator are shown. The spectrum was
calculated, being based on the experimentally measured
curve of the photon flux attenuation in plumbum, with a
method of minimization of directed divergence. The
measured photon fluence near the accelerator axis at
2.5 m from the target is about 6.1⋅109 сm-2. At the
photon boundary energy 2.8 MeV a maximum of the
spectrum distribution lies near 0.55 MeV, and the mean
energy of quanta is about 0.73 MeV. The RMS error of
the calculations does not exceed ±6% overall the
spectrum besides its lower boundary, where it reaches ±
15%. In the field <0.1 MeV the spectrum was not
specified, because this energy range lay under the
sensitivity threshold of the radiation detectors
(SCD1-01) used for the measurements.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 71-73.
71
Time label frequency - 25 МHz
а)
0.0E+00
2.0E+08
4.0E+08
6.0E+08
8.0E+08
1.0E+09
1.2E+09
1.4E+09
0 0.5 1 1.5 2 2.5 3
Energy, MeV
Ph
ot
on
fl
ue
nc
e,
1
/(с
m
*с
m
)
b)
Fig. 2. X-ray radiation pulse shape (а) and the photon
energy spectrum (b) of STRAUS-2 accelerator.
For output of the electron beam (jе≤10 kА/сm2)
into atmosphere a window ∅180 mm is used, that
consist of two 0.1 mm thickness titanium foils placed at
15 mm distance each from other. Only the external foil
is hermetic, while the internal one provides the
constancy of diode geometry, as it is not deformed at
vacuum pumping. In such configuration the energy and
current losses are less than 10%. Leaving the diode
electrons undergo strong deceleration in the electric
field of the self beam space charge, that is illustrated by
Fig. 3, where, for comparison, the relative dose
distributions of electron beam in aluminum and in air
are given. In aluminum, where the space charge is
compensated, at the boundary electron energy ∼3 MeV
their radiation length is ∼1.5 g/сm2. In air this value is ≤
0.2 g/сm2. The cross section dimensions of the beam
grow significantly, too. For example, at 1 m distance
from the output window the beam increases its diameter
from 4 cm to ∼30 сm.
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
R, g/(сm*сm)
D
os
e,
re
l.
un
its
aluminum air
Fig. 3. Relative dose distributions in aluminum and in
air for the electron beam of STRAUS-2 accelerator.
For some applications electron beam focusing
mode are of interest to form a spot of a small diameter
at the target, what allows using the STRAUS-2
accelerator as a near-point X-ray source. In this case a
focusing unit on the base of vacuum conic transmission
line with a self-magnetic insulation (MITL) is joined to
the accelerator output (Fig. 4). The length of this line is
about 25 cm, and its wave impedance is approximately
90 Ohm. As a prototype it was used a scheme realized
in a PULSERAD-1480 accelerator [6]. The focusing
unit configuration was optimized on results of numeric
calculations for electron flow in the MITL and in the
diode with the electromagnetic code KARAT [7]. The
inner electrode of the MITL is a cone with a half-angle
∼10° and it is a constructive prolongation of the
accelerator cathode holder. A half-angle of the outer
conic electrode of the MITL is about 45°. The cathode
is made of Wo-Ni-Fe alloy. It is also cone with a flat or
annular face edge of 4÷15 mm diameter. The anode is
flat with a diameter ∼100 mm. The target is a tantalum
disk ∅30 mm (working part of 20 mm diameter) and of
0.3 mm thickness. Behind the target an aluminum filter
of 15 mm thickness is placed. The accelerating gap can
be varied within 5÷20 mm by choice of a cathode of
corresponding length.
1 2 3 4 5 6 7
∅
6
80
m
m
600 mm
250 mm
Fig. 4. Sketch of the focusing unit: 1 – vacuum
chamber; 2 – cathode holder; 3 – inner MITL electrode;
4 – focusing unit case; 5 – outer MITL electrode;
6 - cathode; 7 – anode flange with a target unit.
During a pulse the target suffered a significant
thermomechanic effect of the beam and plasma being
formed in the diode, because of that its working part
was entirely destroyed (Fig. 5a). There was also
observed melting the central part of aluminum filter up
to 5÷6 mm depth. The quality of beam focusing was
evaluated on its X-ray images obtained with an obscure
chamber (Fig. 5b). With the same purpose in a number
of pulses it was used a target of 1 mm thickness instead
of 0.3 mm one, affecting an electron beam on that did
not cause its entire destruction but only perforation its
central part (Fig. 5b). At that, the diameter of the
formed hole corresponded rather well to the mean beam
diameter on the target. However, in this case the X-ray
generation efficiency was lowered by ∼30÷50%
depending on the accelerating gap.
tt=0.3 mm tt=1mm
а)
∆А-C=5 mm ∆А-C=15 mm ∆А-C=20 mm
b)
Fig. 5. Target fotos (а, scale 1:2) and X-ray images of
the beam (b, scale 1:1).
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 71-73.
71
Beam focusing was provided at ∆А-C ≤ 20 mm,
and the best results were achieved at the current pulse
duration τ0,5=45 ns being maximal for the STRAUS-2
accelerator. At ∆А-C>20 mm beam focusing was
disturbed due to the change of MITL operation mode, as
the diode impedance became higher than the effective
MITL impedance. In this case the MITL voltage and
current practically did not change with the accelerating
gap growth (fig. 6) and became equal to 2.85 MV and
42 kA corresponding to the self-consistent operation
mode of the MITL (line-dominated mode). At that, the
electron flow was absent on the target but was closed on
the MITL outer (anode) electrode surface.
0
20
40
60
80
100
120
0 5 10 15 20 25 30 35 40
Anode-cathode gap, mm
C
ur
re
nt
, k
A
0
0.5
1
1.5
2
2.5
3
V
ol
ta
ge
, M
V
current voltage
Fig. 6. Diode voltage and current versus the anode-
cathode gap.
In Fig. 7 there are shown X-ray intensity
distributions in the focused spot on the target at
different anode-cathode gap. At growth of the gap ∆А-C
from 5 to 20 mm the average spot diameter weakly
increases from 4.5 to 6 mm. Simultaneously a
redistribution of radiation intensity occurs in the spot
from its center to periphery. The radiation dose grows
and reaches the maximum at ∆А-C=15 mm: ∼0,12 Gy
(Si) at 1 m distance from the target. At that, the focused
spot has the diameter about 5 mm. Beam pinching on
the target under the influence of the self-magnetic field
(∼5÷8 Т) lead to some deterioration of its angular
characteristics. This is most noticeable at ∆А-C ≤ 10 mm
and it is revealed as the characteristic dose drop near
r=0 on the curve of transverse dose distribution at 1 m
from the target (Fig. 8). It is interesting to note that in
this mode the dose inhomogeneity in the irradiation spot
of ∼0,6 m diameter (at 1 m from the target) is ≤±15%,
that is twice less than in a usual irradiating mode.
0
0.2
0.4
0.6
0.8
1
0 1 2 3 4 5 6 7
Radius, mm
In
te
ns
ity
, r
el
. u
ni
ts
5 mm 15 mm 20 mm
Fig. 7. Relative distributions of X-ray radiation intensity
in the focused spot at different accelerating gap.
0
0.01
0.02
0.03
0.04
0.05
0.06
-50 -40 -30 -20 -10 0 10 20 30 40 50
Radius, cm
D
os
e
(S
i),
G
y
Fig. 8. Transverse dose distribution of X-ray radiation at
1 m from the target (∆А-C=10 mm, tt=1 mm).
At present time a lot of experimental data was
obtained at the STRAUS-2 accelerator, being of
practical interest in view of its application for research
in radiation physics, pulsed radiography and other
spheres. Furthermore, this data were used for verifying
and testing of simulation methods, algorithms and codes
applied for calculations in a designing process of similar
type facilities as the STRAUS-2 accelerator.
REFERENCES
1. V.S. Bossamykin, V.S. Gordeev, A.I. Pavlovskii et
al. STRAUS-2 Electron Pulsed Accelerator. Proc.
9th Int. Pulsed Power Conf., Albuquerque, NM,
1993, pp. 910-912.
2. V.S. Bossamykin, V.S. Gordeev, A.I. Pavlovskii et
al. Pulsed Power Electron Accelerators with the
Forming Systems Based on Stepped Transmission
Lines. Proc. 9th Int. Conf. on High Power Particle
Beams (BEAMS-92), Washington, DC, 1992, vol.
1, pp. 505-510.
3. V.S. Gordeev, V.S. Bossamykin, A.I. Pavlovskii et
al. Linear Induction Accelerator LIA-10M. Proc.
9th Int. Pulsed Power Conf., Albuquerque, NM,
1993, pp. 905-907.
4. V.S. Bossamykin, V.S. Gordeev V.F.Basmanov et
al. VANT, 1997, N. 4-5 (31-32), p 117 - 119.
5. V.S. Bossamykin, V.S. Gordeev V.F.Basmanov et
al. VANT, 1997, N. 4-5 (31-32), p 120 – 122.
6. V.P. Tarakanov. User Manual for Code KARAT.
BRA Inc., USA, 1992.
7. P. Champney, P. Spence. PULSERAD 1480 – a 9
MV Pulsed Electron Accelerator with an Intensely
Focused Beam. IEEE Trans. Nucl. Sc., Vol. NS-
22, No. 3, June 1975.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 71-73.
71
|
| id | nasplib_isofts_kiev_ua-123456789-81496 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T16:36:20Z |
| publishDate | 1999 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Gordeev, V.S. Myskov, G.A. Filippov, V.O. Averchenkov, V.Ya. 2015-05-17T15:19:54Z 2015-05-17T15:19:54Z 1999 Investigation of STRAUS-2 pulsed electron accelerator characteristics / V.S. Gordeev, G.A. Myskov, V.O. Filippov, V.Ya. Averchenkov // Вопросы атомной науки и техники. — 1999. — № 4. — С. 71-73. — Бібліогр.: 7 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/81496 Last years a successful development of highvoltage pulse forming techniques based on stepped transmission lines led to creation of a set of powerful and compact electrophysics facilities including a highcurrent pulsed electron accelerator STRAUS-2 [1, 2]. The first sample of this accelerator was started up into exploitation in 1989. At present, three facilities of the same type exist in VNIIEF, one of them is used as an injector for a linear induction accelerator LIA-10M [2-5]. Two others are autonomous and applied for research in radiation physics. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Investigation of STRAUS-2 pulsed electron accelerator characteristics Исследование характеристик импульсного электронного ускорителя СТРАУС-2 Article published earlier |
| spellingShingle | Investigation of STRAUS-2 pulsed electron accelerator characteristics Gordeev, V.S. Myskov, G.A. Filippov, V.O. Averchenkov, V.Ya. |
| title | Investigation of STRAUS-2 pulsed electron accelerator characteristics |
| title_alt | Исследование характеристик импульсного электронного ускорителя СТРАУС-2 |
| title_full | Investigation of STRAUS-2 pulsed electron accelerator characteristics |
| title_fullStr | Investigation of STRAUS-2 pulsed electron accelerator characteristics |
| title_full_unstemmed | Investigation of STRAUS-2 pulsed electron accelerator characteristics |
| title_short | Investigation of STRAUS-2 pulsed electron accelerator characteristics |
| title_sort | investigation of straus-2 pulsed electron accelerator characteristics |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/81496 |
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