Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam
Laser wakefield acceleration has the possibility to generate an ultrashort electron beam of the order of femtoseconds or less. In applications of these laser accelerated electron beams, stable and controllable electron beams are necessary. A high stability electron bunch is generated by laser wakefi...
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| Цитувати: | Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam / H. Kotaki, M. Mori, Y. Hayashi, M. Kando, I. Daito, Y. Fukuda, A.S. Pirozhkov, J.K. Koga, S.V. Bulanov // Вопросы атомной науки и техники. — 2012. — № 6. — С. 134-138. — Бібліогр.: 32 назв. — англ. |
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irk-123456789-1092272016-11-22T03:03:23Z Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam Kotaki, H. Mori, M. Hayashi, Y. Kando, M. Daito, I. Fukuda, Y. Pirozhkov, A.S. Koga, J.K. Bulanov, S.V. Плазменная электроника Laser wakefield acceleration has the possibility to generate an ultrashort electron beam of the order of femtoseconds or less. In applications of these laser accelerated electron beams, stable and controllable electron beams are necessary. A high stability electron bunch is generated by laser wakefield acceleration with the help of a colliding laser pulse (optical injection). Stable and monoenergetic electron beams have been generated in the self-injection scheme of laser acceleration by using a Nitrogen gas jet target. The electron interaction with the laser field results in transverse oscillations of the electron beam. From the electron oscillation period dependence on the electron energy we find that the electron beam width is equal to 1.7 fs (rms). В процессе ускорения кильватерными волнами возможна генерация сверхкоротких электронных пучков фемтосекундной длительностью. Для приложений требуются электронные пучки с воспроизводимыми и котролируемыми параметрами. Оптическая инжекция, использующая сталкивающиеся лазерные импульсы, обеспечивает высокую воспроизводимость параметров пучков ускоренных электронов. Моноэнергетические пучки электронов с воспроизводимыми параметрами были получены при «самоинжекции» в кильватерную волну в экспериментах, использующих в качестве мишени струю азота. Взаимодействие электронов с излучением лазерного импульса приводит к поперечным осцилляциям электронного пучка. Анализ наблюдаемой в эксперименте зависимости периода осцилляций от энергии электронов позволяет найти длительность электронного пучка, равную 1.7 фс. В процесі прискорення кільватерними хвилями можлива генерація надкоротких електронних пучків фемтосекундної тривалості. Для додатків потрібні електронні пучки з відтворюючими і котролюючими параметрами. Оптична інжекція, що використовує зіштовхуючі лазерні імпульси, забезпечує високу відтворюваність параметрів пучків прискорених електронів. Моноенергетичні пучки електронів з відтворюваними параметрами були отримані при «самоінжекції» в кільватерну хвилю в експериментах, в яких в якості мішені використовувалася струмінь азоту. Взаємодія електронів з випромінюванням лазерного імпульсу призводить до поперечних осциляцій електронного пучка. Аналіз спостерігаючої в експерименті залежності періоду осциляцій від енергії електронів дозволяє знайти тривалість електронного пучка, яка дорівнює 1.7 фс. 2012 Article Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam / H. Kotaki, M. Mori, Y. Hayashi, M. Kando, I. Daito, Y. Fukuda, A.S. Pirozhkov, J.K. Koga, S.V. Bulanov // Вопросы атомной науки и техники. — 2012. — № 6. — С. 134-138. — Бібліогр.: 32 назв. — англ. 1562-6016 PACS: 41.75.Jv, 52.38.-r, 52.38.Kd http://dspace.nbuv.gov.ua/handle/123456789/109227 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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English |
| topic |
Плазменная электроника Плазменная электроника |
| spellingShingle |
Плазменная электроника Плазменная электроника Kotaki, H. Mori, M. Hayashi, Y. Kando, M. Daito, I. Fukuda, Y. Pirozhkov, A.S. Koga, J.K. Bulanov, S.V. Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam Вопросы атомной науки и техники |
| description |
Laser wakefield acceleration has the possibility to generate an ultrashort electron beam of the order of femtoseconds or less. In applications of these laser accelerated electron beams, stable and controllable electron beams are necessary. A high stability electron bunch is generated by laser wakefield acceleration with the help of a colliding laser pulse (optical injection). Stable and monoenergetic electron beams have been generated in the self-injection scheme of laser acceleration by using a Nitrogen gas jet target. The electron interaction with the laser field results in transverse oscillations of the electron beam. From the electron oscillation period dependence on the electron energy we find that the electron beam width is equal to 1.7 fs (rms). |
| format |
Article |
| author |
Kotaki, H. Mori, M. Hayashi, Y. Kando, M. Daito, I. Fukuda, Y. Pirozhkov, A.S. Koga, J.K. Bulanov, S.V. |
| author_facet |
Kotaki, H. Mori, M. Hayashi, Y. Kando, M. Daito, I. Fukuda, Y. Pirozhkov, A.S. Koga, J.K. Bulanov, S.V. |
| author_sort |
Kotaki, H. |
| title |
Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam |
| title_short |
Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam |
| title_full |
Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam |
| title_fullStr |
Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam |
| title_full_unstemmed |
Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam |
| title_sort |
stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2012 |
| topic_facet |
Плазменная электроника |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/109227 |
| citation_txt |
Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam / H. Kotaki, M. Mori, Y. Hayashi, M. Kando, I. Daito, Y. Fukuda, A.S. Pirozhkov, J.K. Koga, S.V. Bulanov // Вопросы атомной науки и техники. — 2012. — № 6. — С. 134-138. — Бібліогр.: 32 назв. — англ. |
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134 ISSN 1562-6016. ВАНТ. 2012. №6(82)
STABILITY IMPROVEMENT OF A LASER-ACCELERATED
ELECTRON BEAM AND THE PULSE WIDTH MEASUREMENT OF THE
ELECTRON BEAM
H. Kotaki1, M. Mori1, Y. Hayashi1, M. Kando1, I. Daito1, Y. Fukuda1,
A.S. Pirozhkov1, J.K. Koga1, and S.V. Bulanov1,2
1Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215, Japan;
2A.M. Prokhorov Institute of General Physics RAS, Moscow, 119991, Russia
E-mail: kotaki.hideyuki@jaea.go.jp
Laser wakefield acceleration has the possibility to generate an ultrashort electron beam of the order of
femtoseconds or less. In applications of these laser accelerated electron beams, stable and controllable electron
beams are necessary. A high stability electron bunch is generated by laser wakefield acceleration with the help of a
colliding laser pulse (optical injection). Stable and monoenergetic electron beams have been generated in the
self-injection scheme of laser acceleration by using a Nitrogen gas jet target. The electron interaction with the laser
field results in transverse oscillations of the electron beam. From the electron oscillation period dependence on the
electron energy we find that the electron beam width is equal to 1.7 fs (rms).
PACS: 41.75.Jv, 52.38.-r, 52.38.Kd
INTRODUCTION
Measurements and manipulation of ultrafast
phenomena open up new science and applications.
Femtosecond (1 fs=10-15 s) pulses can be used to initiate
and control molecular dynamics on a few tens of
femtoseconds timescale, and attosecond (1 as=10-18 s)
pulses can be used to initiate and control quantum
dynamics on attosecond timescales. Generation of
ultrashort pulses is a key to exploring the dynamical
behavior of matter on ever-shorter timescales.
High-order harmonics of femtosecond laser pulses have
been shown to be a source of a sub-femtosecond
extreme-ultraviolet (XUV) pulse [1-4]. However, in
order to observe several phenomena on ultrashort
timescales, an ultrashort x-ray and an electron beam are
necessary. Laser wakefield acceleration (LWFA) [5]
based on the effect of plasma wave excitation in the
wake of an intense laser pulse, has the possibility to
generate an ultrashort electron beam of the order of
femtoseconds or less. In experiments, it has been
demonstrated that LWFA is capable of generating
electron beams with high energy up to 1 GeV [6, 7] and
high quality [8-11]: quasi-monoenergetic, low in
emittance, and a very short duration [12]. In addition,
the electron beam has a current density up to the
kilo-amprere level. It has the possibility to be a source
of a X-ray free-electron laser (XFEL) for a coherent
X-ray source [13].
In order to generate a bunch with high quality,
required for applications, the electrons should be duly
injected into the wakefield and this injection should be
controllable. Several schemes of electron injection were
proposed in order to provide more controllable regimes
including tailored plasma density profiles [14, 15] and
optical injection [16-21]. Experimentally, stable and
controllable electron beams have been generated in the
self-injection [22] and optical injection scheme [19-21].
Within self-injection, a laser pulse excites a wake wave
and injects electrons into the wake. Within optical
injection, the electrons are injected into the wakefield
by an additional laser pulse [16-21]. Optical injection
has an advantage in using a regular pattern wakefield
excited by a driver laser pulse. In applications of the
electron beam, it is necessary to characterize the
electron beam. The important parameters are energy,
energy spread, emittance, and pulse width. Among these
parameters it is difficult, in particular, to measure the
pulse width due to the ultrashort bunch length. 100 fs
electron beams have been measured by using Coherent
Transition Radiation (CTR) [23,24] and an
electro-optical (EO) crystal [25]. An electron generates
radiation at the boundary of materials. The radiation is
called transition radiation. When the pulse width of the
electrons is shorter than the period of the radiation, the
radiation should be coherent. From the boundary in
wavelength between the coherent and incoherent
emission, the pulse width of the electrons can be
calculated. However, the laser-accelerated electrons
have a quasi-monoenergetic part (electron beam) and a
broad-spectrum part (thermal electrons). The pulse
width measured by CTR includes the total width of the
electrons not only the electron beam. In order to observe
the pulse width of the electron beam, the effect of the
thermal electrons should be separated from the electron
beam. In order to measure the pulse width of the laser
accelerated electron beam by using a EO crystal, the
crystal should be placed on the electron and laser axis
near the laser focus point to get on electron beam with
high charge density. The measured pulse width should
be the total width not only the monoenergetic part. The
radiation from the interaction between the crystal and
the laser pulse should be noise. In addition, the crystal
could be damaged by the laser pulse. In order to observe
the pulse width of the electron beam, the effects of the
thermal electrons and the laser pulse should be
separated from the electron beam.
On the other hand, the electron beam oscillates in an
electric field [26-29]. The electric field is caused by the
laser pulse and/or a plasma wave. When the pulse length
of the electron beam is shorter than the plasma
wavelength and the electron beam is in the laser pulse,
the energy spectrum is converted to the pulse width of
the electron beam.
ISSN 1562-6016. ВАНТ. 2012. №6(82) 135
The oscillation by the laser field is a reference for
the conversion. In this paper we present the result of the
optical injection to generate a stable electron beam, and
the pulse width measurement of the laser accelerated
electron beam. The electron beam is in the laser field
and is oscillated by the field. From the oscillation, we
measure the electron pulse width of 1.7 fs (rms).
1. OPTICAL INJECTION
The experiments have been performed with a 3 TW
linearly polarized Ti:sapphire laser [30]. The target is a
supersonic helium gas jet flowing out of a rectangular
nozzle with the size of 1.3 mm x 4 mm. The 70 fs driver
pulse with 0.2 J energy is focused onto the helium gas
jet. The peak irradiance, I0, is 6.8 x 1017 W/cm2
corresponding to a dimensionless amplitude of
a0 = 8.5 x 10-10 λ0 [µm] (I0[W/cm2])1/2 = 0.6, where λ0 is
the laser light wavelength of 800 nm. The 70 fs
injecting pulse with 10 mJ energy is focused onto a
region at the beginning of a channel formed by the
driver pulse at the angle of 135 degrees with respect to
the driver pulse propagation. Its peak irradiance, I1,
is about 2.0 x 1016 W/cm2, corresponding to a
dimensionless amplitude of a1 = 0.1.
The self-injection ceases at lower plasma densities,
when the wake wave becomes more regular. In order to
demonstrate the counter-crossing injection, we must use
plasma with a density below the self-injection threshold.
The threshold parameters are found by changing the
plasma density and measuring accelerated electrons
with the driver pulse alone. When the plasma density
decreases from 4.10 x 1019 cm-3 to ne = 4.00 x 1019 cm-3,
the reproducibility abruptly drops. For our parameters,
the self-injection ceases at the plasma density below the
threshold of 4.00 x 1019 cm-3.
Fig. 1. A typical image of an energy distribution of the
electron bunch obtained by the counter-crossing
injection at ne = 3.95 x 1019 cm-3 (a), and a projection of
the image onto the energy axis (b)
Fig. 1 shows the energy spectrum of the accelerated
electron bunch optically injected with the help of the
injecting pulse for ne = 3.95 x 1019 cm-3. This density is
below the self-injection threshold. The collision of the
two laser pulses produces a quasi-monoenergetic
electron bunch with 15 MeV peak energy, 7.8 %
(1.2 MeV) rms energy spread, 30 pC charge, and
15 mrad divergence.
Fig. 2 compares the stability of the self-injection and
the counter-crossing injection mechanism. The
experiments of the counter-crossing injection were
conducted for ne = 3.95 x 1019 cm-3. The self-injection
has been seen for ne = 4.40 x 1019 cm-3, which is the
optimum density for self-injection to generate
quasi-monoenergetic electron beam. These results show
that the counter-crossing injection has higher stability
than the self-injection. Fig. 2 shows a wide scatter of the
self-injection points, with several at large values, while
the optical-injection points are clustered nearer to the
lower left of each plot.
Fig. 2. The stability of the self-injection and the
countercrossing injection. The stability of the
countercrossing injection is higher than that of the
self-injection
2. PULSEWIDTH MEASUREMENT
A quasi-monoenergetic electron beam is generated
in the self-injection scheme by using a Nitrogen gas
target around the plasma density, ne, of 4.0 x 1019 cm-3
assuming 5 ionizations of N2. The quality of the electron
beam is stable [31], because the laser pulse is guided a
long distance in a channel produced by cascade
a
b
a
b
136 ISSN 1562-6016. ВАНТ. 2012. №6(82)
onization due to the low ionization threshold [22]. By
using the electron beam, a pulse width is measured.
Fig. 3. Typical image of an electron beam in energy
space (a), and a projection of the image onto the energy
axis (b) for the laser pulse of S-polarization at
ne = 4.4 x 1019 cm-3. The electron beam has peak energy
of 17 MeV and a charge of 17.0 pC
Fig. 4. Typical image of an electron beam in energy
space (a), and a projection of the image onto the energy
axis (b) for the laser pulse of P-polarization at
ne = 4.4 x 1019 cm-3. The electron beam has peak
energy of 17 MeV and a charge of 19.3 pC
The experiments have been performed with a Ti:
sapphire laser system at the Japan Atomic Energy
Agency (JAEA) named JLITE-X [30]. The laser pulse,
which is linearly polarized, with 130 mJ energy is
focused onto a 3-mm diameter Nitrogen gas jet by an
off-axis parabolic mirror (OAP) with the focal length of
646 mm (f/22). The pulse width of the laser pulse, τ, is
40 fs. The peak irradiance, I0, is 7.3 x 1017 W/cm2 in
vacuum corresponding to a dimensionless amplitude of
the laser field a0 = 0.6.
The electron beam oscillates in the electric field of
the laser pulse. In phase space, we can see the electron
oscillation by the electric field [32]. The oscillation is a
reference in order to convert the energy spectrum to the
pulse width. Fig. 3 shows the typical image of an energy
distribution at ne = 4.4 x 1019 cm-3 when the laser pulse
has S-polarization (vertical polarization). Using the
sensitivity of the phosphor screen, calibrated with the
help of a conventional electron accelerator, we estimate
that the total charge of the monoenergetic electron beam
is about 17 pC. Electron oscillations are observed in
energy space. The oscillation has an angle of 16 mrad.
The electric field of the laser pulse is parallel to the
direction of the oscillation. The amplitude of the
electron oscillation by the laser field, Ae-laser, is defined
as Ae-laser = a0/γ, where γ is the Lorentz factor of the
electron beam. From the experimental parameters, the
estimated amplitude of the oscillation by the laser pulse
is about 16 mrad. The maximum amplitude of the
experimental data is 16 mrad. The result has good
agreement with the calculated amplitude. When the
laser pulse has P-polarization (horizontal polarization),
no electron oscillation is observed as shown in Fig. 4.
When the laser pulse has P-polarization, the image of
the energy distribution has no oscillation, because the
direction of the oscillation by the laser field is parallel to
the energy axis. The oscillation depends on the laser
polarization. The fact that the electric field of the laser
pulse is parallel to the direction of the oscillation is one
piece of evidence that the electron oscillation is caused
by the laser field. The wave structure of the energy
spectrum depends on the laser frequency. The pulse
width (FWHM) of the electron is 1.5-cycles of the laser
beam at a wavelength of 800 nm. The pulse width is
1.7 fs (rms) (12 % of the period of the plasma wave).
CONCLUSIONS
In order to improve the stability of laser-accelerated
electron beam, optical injection experiments have been
performed. The generated electron beam shows that the
optical injection is one of techniques to generate a stable
electron beam. Stable and monoenergetic electron
beams have been generated in the self-injection scheme
of laser acceleration by using a Nitrogen gas jet target.
In the image of the energy spectrum, the electron
oscillation by the laser field is observed. The energy
spectrum can be converted to the electron pulse width.
The result of the 0.64-cycles oscillations indicates a 1.7
fs (rms) pulse width for the electron beam. The peak
current is 10 kA. The technique of the measurement is
the direct observation of the pulse width of the electron
beam.
a
b
b
a
ISSN 1562-6016. ВАНТ. 2012. №6(82) 137
ACKNOWLEDGEMENTS
We thank T. Homma for his technical support
during the experiment. This work was supported by the
Japan Society for the Promotion of Science under a
Grants-in-Aid for Scientic Research (Contract
# 23600010).
REFERENCES
1. P. M. Paul et al. Observation of a train of attosecond
pulses from high harmonic generation // Science. 2001,
v. 292, p.1689-1692.
2 M. Hentschel et al. Attosecond metrology // Nature.
2001, v. 414, p. 509-513.
3. A. Baltuska, et al. Attosecond control of electronic
processes by intense light fields// Nature. 2003, vol.421,
p.611-615.
4. P. Tzallas et al. Direct observation of attosecond light
bunching // Nature. 2003, v. 426, p. 267-271.
5. T. Tajima and J.M. Dawson. Laser electron
accelerator // Phys. Rev. Lett. 1979, v. 43, p. 267-270.
6. W.P. Leemans et al. GeV electron beams from
a centimeter-scale accelerator // Nature Phys. 2006,
v. 2, p. 696-699.
7. N. Hafz et al. Stable generation of GeV-class electron
beams from self-guided laser-plasma channels // Nature
Photonics. 2008, v. 2, p. 571-577.
8. S.P.D. Mangles et al. Monoenergetic beams of
relativistic electrons from intense laser-plasma
interactions // Nature. 2004, v. 431, p. 535-538.
9. C.G.R. Geddes et al. High-quality electron beams
from a laser wakefield accelerator using plasma-channel
guiding // Nature. 2004, v. 431, p. 538-541.
10. J. Faure et al. A laser-plasma accelerator producing
monoenergetic electron beams // Nature. 2004, v. 431,
p. 541-544.
11. E. Miura et al. Demonstration of quasi-mono-
energetic electron beam generation in laser-driven
plasma acceleration // Appl. Phys. Lett. 2005, v. 86,
p. 251501.
12. O. Lundh et al. Few femtosecond, few kiloampere
electron bunch produced by a laser-plasma accelerator //
Nature Phys. 2011, v. 7, p. 219-222.
13. K. Nakajima. Compact X-ray sources towowards a
table-top free-electron laser // Nature Phys. 2008, v. 4,
p. 92-93.
14. S.V. Bulanov et al. Particle injection into the wave
acceleration phase due to nonlinear wake wave breaking
// Phys. Rev. E. 1998, v. 58, p. R5257-R5260.
15. C.G.R. Geddes et al. Plasma-density-gradient
injection of low absolute-momentum-spread electron
bunches // Phys. Rev. Lett. 2008, v. 100, p. 215004.
16. E. Esarey et al. Electron injection into plasma
wakefields by colliding laser pulses // Phys. Rev. Lett.
1997, v. 79, p. 2682-2685.
17. H. Kotaki et al. Head-on injection of a high quality
electron beam by the interaction of two laser pulses //
Phys. Plasmas. 2004, v. 11, p. 3296-3302.
18. G. Fubiani et al. Beat wave injection of electrons
into plasma waves using two interfering laser pulses //
Phys. Rev. E. 2004, v. 70, p. 016402.
19. J. Faure et al. Controlled injection and acceleration
of electrons in plasma wakefields by colliding laser
pulses // Nature. 2006, v. 444, p. 737-739.
20. H. Kotaki et al. Electron optical injection with
head-on and countercrossing colliding laser pulses //
Phys. Rev. Lett. 2009, v. 103, p. 194803.
21. C. Rechatin et al. Observation of beam loading in a
laser-plasma accelerator // Phys. Rev. Lett. 2009, v. 103,
p. 194804.
22. M. Mori et al. Generation of stable and
low-divergence 10-MeV quasimonoenergetic electron
bunch using argon gas jet // Phys. Rev. ST Accel. Beams.
2009, v. 12, p. 082801.
23. W.P. Leemans et al. Observation of terahertz
emission from a laser-plasma accelerated electron bunch
crossing a plasma-vacuum boundary // Phys. Rev. Lett.
2003, v. 91, p. 074802.
24. U. Happek, A.J. Sievers, and E.B. Blum.
Observation of coherent transition radiation // Phys. Rev.
Lett. 1991, v. 67, p. 2962-2965.
25. I. Wilke et al. Single-shot electron-beam bunch
length measurements // Phys. Rev. Lett. 2002, v. 88,
p. 124801.
26. S.P.D. Mangles, et al. Laser-wakefield acceleration
of monoenergetic electron beams in the first
plasma-wave period// Phys. Rev. Lett. 2006, vol.96,
215001.
27. S. Kiselev et al. X-ray Generation in Strongly
Nonlinear Plasma Waves // Phys. Rev. Lett. 2004, v. 93,
p. 135004.
28. A. Rousse et al. Production of a keV X-Ray Beam
from Synchrotron Radiation in Relativistic
Laser-Plasma Interaction // Phys. Rev. Lett. 2004, v. 93,
p. 135005.
29. Y. Glinec et al. Direct observation of betatron
oscillation in a laser-plasma electron accelerator //
Europhys. Lett. 2008, v. 81, p. 64001.
30. M. Mori et al. Development of beam-pointing
stabilizer on a 10-TW Ti:Al2O3 laser system JLITE-X
for laser-excited ion accelerator research // Laser Phys.
2006, v. 16, p. 1092-1096.
31. M. Mori et al. Stabilization of laser accelerated
electron bunch by the ionization-stage control // Proc. of
the 1st International Particle Accelerator Conference
(IPAC’10), Kyoto, Japan 23-28 May, 2010. Joint
Accelerator Conference Website (JACoW), 2010,
THPEC003.
32. K. Nemeth et al. Laser-driven coherent betatron
oscillation in a laser-wakefield cavity // Phys. Rev. Lett.
2008, v. 100, p. 095002.
Article received 22.09.2012
138 ISSN 1562-6016. ВАНТ. 2012. №6(82)
ПОВЫШЕНИЕ ВОСПРОИЗВОДИМОСТИ ПАРАМЕТРОВ ПУЧКОВ ЭЛЕКТРОНОВ,
УСКОРЯЕМЫХ В ЛАЗЕРНОЙ ПЛАЗМЕ,
И ИЗМЕРЕНИЕ ДЛИТЕЛЬНОСТИ ЭЛЕКТРОННОГО ПУЧКА
Х. Котаки, М. Мори, Ю. Хаяши, М. Кандо, И. Дайто, Ю. Фукуда,
А.С. Пирожков, Д.К. Когa, С.В. Буланов
В процессе ускорения кильватерными волнами возможна генерация сверхкоротких электронных пучков
фемтосекундной длительностью. Для приложений требуются электронные пучки с воспроизводимыми и
котролируемыми параметрами. Оптическая инжекция, использующая сталкивающиеся лазерные импульсы,
обеспечивает высокую воспроизводимость параметров пучков ускоренных электронов. Моноэнергетические
пучки электронов с воспроизводимыми параметрами были получены при «самоинжекции» в кильватерную
волну в экспериментах, использующих в качестве мишени струю азота. Взаимодействие электронов с
излучением лазерного импульса приводит к поперечным осцилляциям электронного пучка. Анализ
наблюдаемой в эксперименте зависимости периода осцилляций от энергии электронов позволяет найти
длительность электронного пучка, равную 1.7 фс.
ПІДВИЩЕННЯ ВІДТВОРЮВАНОСТІ ПАРАМЕТРІВ ПУЧКА ЕЛЕКТРОНІВ,
ЩО УСКОРЮЮТЬСЯ В ЛАЗЕРНІЙ ПЛАЗМІ,
ТА ВИМІРЮВАННЯ ТРИВАЛОСТІ ЕЛЕКТРОННОГО ПУЧКА
Х. Котакі, М. Морі, Ю. Хаяши, М. Кандо, І. Дайто, Ю. Фукуда,
А.С. Пірожков, Д.К. Кога, С.В. Буланов
В процесі прискорення кільватерними хвилями можлива генерація надкоротких електронних пучків
фемтосекундної тривалості. Для додатків потрібні електронні пучки з відтворюючими і котролюючими
параметрами. Оптична інжекція, що використовує зіштовхуючі лазерні імпульси, забезпечує високу
відтворюваність параметрів пучків прискорених електронів. Моноенергетичні пучки електронів з
відтворюваними параметрами були отримані при «самоінжекції» в кільватерну хвилю в експериментах, в
яких в якості мішені використовувалася струмінь азоту. Взаємодія електронів з випромінюванням лазерного
імпульсу призводить до поперечних осциляцій електронного пучка. Аналіз спостерігаючої в експерименті
залежності періоду осциляцій від енергії електронів дозволяє знайти тривалість електронного пучка, яка
дорівнює 1.7 фс.
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