The phenomena of electron charge ejection during the hot electron beam transportation
The transportation of hot electron beam through the drift chamber along the magnetic field was experimentally studied. The main attention was paid to the phenomena of electron charge ejection on the drift chamber wall. Experimental results shows that self-consistent Penning-Malmberg trap occurs af...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2006
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| Цитувати: | The phenomena of electron charge ejection during the hot electron beam transportation / I.K. Tarasov, D.A. Sytnykov, M.I. Tarasov // Вопросы атомной науки и техники. — 2006. — № 6. — С. 124-126. — Бібліогр.: 2 назв. — англ. |
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Tarasov, I.K. Sytnykov, D.A. Tarasov, M.I. 2015-05-20T17:22:27Z 2015-05-20T17:22:27Z 2006 The phenomena of electron charge ejection during the hot electron beam transportation / I.K. Tarasov, D.A. Sytnykov, M.I. Tarasov // Вопросы атомной науки и техники. — 2006. — № 6. — С. 124-126. — Бібліогр.: 2 назв. — англ. 1562-6016 PACS: 52.27.Jt https://nasplib.isofts.kiev.ua/handle/123456789/81799 The transportation of hot electron beam through the drift chamber along the magnetic field was experimentally studied. The main attention was paid to the phenomena of electron charge ejection on the drift chamber wall. Experimental results shows that self-consistent Penning-Malmberg trap occurs after the stage of non-stationary virtual cathode with the limiting of electrons current in axial direction and radial ejection of electrons on the chamber wall. Произведено экспериментальное исследование транспорта горячего пучка электронов в камере дрейфа в продольном магнитном поле. Основное внимание уделялось явлению сброса электронного заряда на стенку камеры дрейфа. Результаты экспериментов показывают, что формирование самосогласованной ловушки Пеннинга-Малмберга наблюдается после стадии формирования виртуального катода с сопутствующим ограничением аксиального тока электронов и выбросом их на стенку камеры. Проведено експериментальне дослідження транспорту гарячого пучка електронів крізь камеру дрейфу у повздовжньому магнітному полі. Багато уваги приділено явищу скиду електронного заряду на стінку камери дрейфу. Результати експериментів показують, що формування самоузгодженої пастки Пеннінга-Малмберга спостерігається після стадії формування віртуального катоду з супутнім обмеженням аксіального току електронів та викидом їх на стінку камери. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Basic plasma physics The phenomena of electron charge ejection during the hot electron beam transportation Явление сброса электронного заряда при транспортировке горячего пучка электронов Явище скиду електронного заряду при транспортуванні гарячого пучка електронів Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
The phenomena of electron charge ejection during the hot electron beam transportation |
| spellingShingle |
The phenomena of electron charge ejection during the hot electron beam transportation Tarasov, I.K. Sytnykov, D.A. Tarasov, M.I. Basic plasma physics |
| title_short |
The phenomena of electron charge ejection during the hot electron beam transportation |
| title_full |
The phenomena of electron charge ejection during the hot electron beam transportation |
| title_fullStr |
The phenomena of electron charge ejection during the hot electron beam transportation |
| title_full_unstemmed |
The phenomena of electron charge ejection during the hot electron beam transportation |
| title_sort |
phenomena of electron charge ejection during the hot electron beam transportation |
| author |
Tarasov, I.K. Sytnykov, D.A. Tarasov, M.I. |
| author_facet |
Tarasov, I.K. Sytnykov, D.A. Tarasov, M.I. |
| topic |
Basic plasma physics |
| topic_facet |
Basic plasma physics |
| publishDate |
2006 |
| language |
English |
| container_title |
Вопросы атомной науки и техники |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Явление сброса электронного заряда при транспортировке горячего пучка электронов Явище скиду електронного заряду при транспортуванні гарячого пучка електронів |
| description |
The transportation of hot electron beam through the drift chamber along the magnetic field was experimentally
studied. The main attention was paid to the phenomena of electron charge ejection on the drift chamber wall.
Experimental results shows that self-consistent Penning-Malmberg trap occurs after the stage of non-stationary virtual
cathode with the limiting of electrons current in axial direction and radial ejection of electrons on the chamber wall.
Произведено экспериментальное исследование транспорта горячего пучка электронов в камере дрейфа в
продольном магнитном поле. Основное внимание уделялось явлению сброса электронного заряда на стенку
камеры дрейфа. Результаты экспериментов показывают, что формирование самосогласованной ловушки
Пеннинга-Малмберга наблюдается после стадии формирования виртуального катода с сопутствующим
ограничением аксиального тока электронов и выбросом их на стенку камеры.
Проведено експериментальне дослідження транспорту гарячого пучка електронів крізь камеру дрейфу у
повздовжньому магнітному полі. Багато уваги приділено явищу скиду електронного заряду на стінку камери
дрейфу. Результати експериментів показують, що формування самоузгодженої пастки Пеннінга-Малмберга
спостерігається після стадії формування віртуального катоду з супутнім обмеженням аксіального току
електронів та викидом їх на стінку камери.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/81799 |
| citation_txt |
The phenomena of electron charge ejection during the hot electron beam transportation / I.K. Tarasov, D.A. Sytnykov, M.I. Tarasov // Вопросы атомной науки и техники. — 2006. — № 6. — С. 124-126. — Бібліогр.: 2 назв. — англ. |
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2025-11-27T04:09:03Z |
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THE PHENOMENA OF ELECTRON CHARGE EJECTION DURING THE
HOT ELECTRON BEAM TRANSPORTATION
I.K. Tarasov, D.A. Sytnykov, M.I. Tarasov1
NSC Kharkov Institute of Physics and Technology, Kharkov, Ukraine,
e-mail: itarasov@ipp.kharkov.ua;
1V.N. Karazin Kharkov National University, Kharkov, Ukraine
The transportation of hot electron beam through the drift chamber along the magnetic field was experimentally
studied. The main attention was paid to the phenomena of electron charge ejection on the drift chamber wall.
Experimental results shows that self-consistent Penning-Malmberg trap occurs after the stage of non-stationary virtual
cathode with the limiting of electrons current in axial direction and radial ejection of electrons on the chamber wall.
PACS: 52.27.Jt
1. INTRODUCTION
Theoretical consideration of electron charge ejection
phenomena was made in [1]. The results of this
consideration were experimentally confirmed by V.
Fedorchenko [2]. Both considered a simple diode
configuration without a magnetic field.
In this work the transportation of hot electron beam
through the drift chamber along the magnetic field was
experimentally studied. The main attention was paid to
the phenomena of electron charge ejection on the drift
chamber wall.
The experimental results of charged particles
ejection dynamics for a various charge density
increasing rates in the space of drift are submitted.
The main differences between phenomenon described
in this work and charge ejection studied in [1, 2] are:
- the presence of a longitudinal magnetic field;
- the ejection of a charge occurs in a radial direction;
- the ejection of a charge occurs at the moment of a
beam current break-down.
2. EXPERIMENTAL SETUP
The scheme of experimental setup is shown on Fig.1.
The main beam was generated by the electron gun. Such
gun consists from indirectly heated cathode and anode
metal grid. The injection of electron beam was provided
by applying of positive voltage pulse (injection pulse) to
the anode grid. The form of anode grid was chosen
specially for obtaining the required form of electron beam
(hollow cylinder). The main beam was injected into the
drift space (a brass tube of length L = 150 cm. and
diameter D = 4 cm.) at whose entrance and exit were flat
metal grids. The tube was cut parallel to the generatrix
into two equal halves and was made up of two sectors of
angular extent 180º (π - electrodes). Both sectors were
attached to the leads and used for diagnostic purposes.
The thickness of injected beam was Δ = 1…2 mm. and its
diameter was d = 2 cm. The beam energy was 20…80 eV.
The constant longitudinal magnetic field had a strength of
H = 100…2000 Oe. The magnetic field varied over the
length of the drift tube by less than 5% so we assumed it
to be uniform inside the drift tube. It is also necessary to
note that injector is located near the entrance to the drift
tube at the area of non-uniform magnetic field. The range
of working pressures was 10-4…10-7 Torr.
Diagnostic measurements of axial distribution of
electrostatic potential were made by high-frequency
Langmuir probe. The probe was placed on the mobile
carriage together with a multigrid electrostatic analyzer.
The occurrence and evolution of diocotron oscillations
was detected by π – electrodes. In this experiments we
generated diocotron modes with the azimuthal wave
number l = 1. In this case the oscillations of current
induced on each of the π – electrodes are in opposite
phases. The flat grids located at the entrance and exit of
the drift tube were used for measuring of current input
and output.
Fig.1. Schematic of the experimental setup:
1) electron beam; 2) drift tube; 3) vacuum chamber;
4) electron gun; 5) entrance grid; 6) exit grid; 7) collector;
8) carriage; 9) high-frequency Langmuir probe;
10) electrostatic analyzer
3. EXPERIMENTAL RESULTS
3.1. DYNAMICS OF PARTICLES EJECTION
DEVELOPMENT
The Ejection charged particles across the magnetic
field was observed during the transportation of cylindrical
electron beam through the space of drift. Such beam had a
strong dispersion in velocities.
The space of drift was limited axially by two π-
electrodes and radially by two measuring grids. Fig.2.
represents the oscillograms of signals obtained from π-
electrodes. This oscillograms displays the dynamics of
particles ejection process and diocoron instability absence
thereof instability. Asymmetrical pulses were
development. Fig.2(1) displays the signals obtained in the
124 Problems of Atomic Science and Technology. 2006, № 6. Series: Plasma Physics (12), p. 124-126
drift chamber. The occurrence of diocotron oscillations
was always preceded by the ejection process. Such
process arises initially at the end of the injection pulse as
a small pulse of voltage. In case of beam current
increasing the ejection pulse moves towards the first front
injection pulse. During such movement the pulse of
ejection becomes shortened (Fig.2(2)-2(6)).
Fig.2. Oscillograms of signals from π-electrodes.
Sensitivity - 0.05 V/div; broach - 0.2 ms/div; H=1 кOe.
Amplitudes of injection impulses: U1=20 V, U2=21 V,
U3=23.5 V, U4=25 V, U5=27.5 V, U6=30 V, U7=32.5 V,
U8=35 V
It is also necessary to note that the diocotron oscillations
were not only observed during the pulse of injection. So
called “tails” of damped diocotron oscillations were
formed after the pulse of injection (Fig.2(2)). In case of
beam current or energy increasing the duration of such
tails grows together with the injection pulse amplitude.
Finally "tail" duration may exceed the length injection
pulse. Further growth of the injection pulse amplitude
reduces to transition of the diocotron oscillations into a
noise mode (Fig.2(7)-2(8)).
3.2. THE DYNAMICS OF LONGITUDINAL
AND CROSS CURRENTS
There is a strong connection between variations of
longitudinal and cross currents during the injection pulse
energy changing. The oscillograms of such currents are
presented on Fig.3. Here the top traces represent the signal
from π-electrodes while the bottom traces represent the
signal from the measuring grid. It is easy to notice from
given oscillograms (Fig. 3(1)) that the ejection pulse is
followed by the stage of longitudinal output current growth.
Fig.3(2), 3(3) displays the time shortening of signals
observed on π-electrodes. From Fig.3(4) one can conclude
that the longitudinal output current growth stage is followed
by satiation stage. After the electrons cross-ejection the
amplitude of π-electrode signal is also established on the
certain level which does not change during the pulse of
injection. Fig.3. gives a rough idea about dynamics of
longitudinal and cross currents in considered system.
Fig.3. Signals obtained from π-electrode and measuring
grid. Sensitivity of the top trace - 0.5 V/div; sensitivity of
the bottom trace - 2 V/div; broach - 0.1 ms/div;
Н = 1 кOe
3.3. THE CASE OF SINUSOIDAL INJECTION
PULSE
The experimental study of charged particles cross
ejection was also provided for various durations of the
injection pulse fronts. With this purpose we applied a
sinusoidal injection pulse on the anode grid of the electron
gun. Different durations of the injection pulse were obtained
by varying the frequency of applied sinusoidal voltage.
Fig.4(1) represents the oscillograms of input and output
longitudinal currents obtained from entrance and exit grids
respectively. The top trace displays a signal from the exit
measuring grid and the bottom with the entrance. The exit
grid oscillogram observed two jumps of longitudinal current.
First of them is caused by the virtual cathode formation
process that takes place in the chamber of drift. Second jump
corresponds to a longitudinal ejection of electrons. Fig.4(2)
displays the oscillogram of signal obtained from π-electrode.
The formation of virtual cathode is followed by the particles
cross ejection. After such ejection the occurrence of
diocotron oscillations was observed. It is also necessary to
note that after the second jump of longitudinal current (the
restoration of longitudinal current) the “tail” of damping
diocotron oscillations was observed.
Fig.4. The excitation of diocotron oscillations during and
after the sinusoidal injection pulse.
1- Sensitivity of the top trace -0.1 V/div; sensitivity of the
bottom trace–5V/div; broach-0.1ms/div;Н = 2кOe;
2- Sensitivity – 0.05 V/div, broach – 0.05 ms/div
3.4. HYSTERETIC DEPENDENCES OF
LONGITUDINAL CURRENT
The dependences of output longitudinal current on its
input value are expressed graphically on Fig.5. This
dependence has a hysteretic character. By comparison
125
with Fig.4. one can conclude that during the reverse
motion by the hysteresis curve there is a current after the
moment of virtual cathode disappearance. This jump of
longitudinal current can be explained as result of charged
particles longitudinal ejection. Such ejection was
described by V.Rutkevich and A. Paschenko [2].
Fig.5. The dependences of output longitudinal current on
its input value. Н1=1 кOe; Н2=2 кOe
4. CONCLUSIONS
In the presented work the phenomenon of charged
particles (electrons) ejection across the magnetic field is
considered. Such phenomenon arises during the
injection of cylindrical electron beam with a strong
dispersion in velocities into the drift tube placed in
longitudinal magnetic field.
Such ejection is followed by the process of non-
stationary virtual cathode formation. This formation
occurs as result of longitudinal current limiting
provided by the spatial charge of injected beam.
It was noticed, that studied phenomenon always
precedes the formation of potential double sagging
followed by the coherent diocotron oscillations
excitation in the space of drift.
Also it is shown, that diocotron instability arises not
only in tubular beams, but also in the continuous beams
of electrons strongly washed away on the speeds.
REFERENCES
1. A.V. Paschenko, B.N. Rutkevich // Radiotechnics and
Electronics. 1979, v. 24, p.152 (in Russian).
2. A.V. Paschenko, B.N. Rutkevich, V.D. Fedorchenko,
Y.P. Mazalov // Jornal of Technical Physics. 1983,
v.53, N1 (in Russian).
ЯВЛЕНИЕ СБРОСА ЭЛЕКТРОННОГО ЗАРЯДА ПРИ ТРАНСПОРТИРОВКЕ ГОРЯЧЕГО ПУЧКА
ЭЛЕКТРОНОВ
И.К.Тарасов, Д.А. Ситников, М.И. Тарасов
Произведено экспериментальное исследование транспорта горячего пучка электронов в камере дрейфа в
продольном магнитном поле. Основное внимание уделялось явлению сброса электронного заряда на стенку
камеры дрейфа. Результаты экспериментов показывают, что формирование самосогласованной ловушки
Пеннинга-Малмберга наблюдается после стадии формирования виртуального катода с сопутствующим
ограничением аксиального тока электронов и выбросом их на стенку камеры.
ЯВИЩЕ СКИДУ ЕЛЕКТРОННОГО ЗАРЯДУ ПРИ ТРАНСПОРТУВАННІ ГАРЯЧОГО ПУЧКА
ЕЛЕКТРОНІВ
І.К. Тарасов, Д.А. Ситников, М.І. Тарасов
Проведено експериментальне дослідження транспорту гарячого пучка електронів крізь камеру дрейфу у
повздовжньому магнітному полі. Багато уваги приділено явищу скиду електронного заряду на стінку камери
дрейфу. Результати експериментів показують, що формування самоузгодженої пастки Пеннінга-Малмберга
спостерігається після стадії формування віртуального катоду з супутнім обмеженням аксіального току
електронів та викидом їх на стінку камери.
126
References
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