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1.
G. Tomassetti A. Ritucci A. Reale L. Palladino L. Reale S. V. Kukhlevsky F. Flora L. Mezi J. Kaiser A. Faenov T. Pikuz 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(1):73-77
A capillary discharge soft X-ray laser operating at 46.9 nm on the transition 3p-3s (J = 0-1) of the Ne-like Ar has been realized by exciting the active medium with a long half-cycle duration current pulse of
140 ns. The current is produced by discharging a 10 nF water dielectric capacitor, initially charged to voltages lower than
200 kV by a six stage Marx generator, through a 15-cm long capillary channels. The laser amplification has been obtained by
properly adjusting all the other experimental parameters. Utilizing a 3-mm in diameter Al2O3 capillary channel initially filled with 0.3 torr of Ar pressure, a laser beam, which has a 4-mrad divergence and a time duration
of 1.3 ns, is characterized by a gain of 0.6±0.1 cm-1. The stability of the plasma compression followed by the laser emission is verified.
Received 13 December 2001 相似文献
2.
S. I. Tkachenko V. M. Romanova A. R. Mingaleev A. E. Ter-Oganesyan T. A. Shelkovenko S. A. Pikuz 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):335-341
Experimental results on electrical explosion of wires in vacuum with current density A/m2, current rise rate (dI/dt) ~ 50 A/ns and current pulse with amplitude ∼10 kA are presented. The structure of the discharge
channels in vacuum has been studied using laser shadow and schlieren imaging with 7 ns frames, UV pinhole images with 5 ns
frames and X pinch X-ray backlighting. The information on the dense core material and the conducting plasma distributions
was obtained in our experiments by analyzing and comparing the results obtained from all diagnostics. 相似文献
3.
A. A. Akunets S. S. Anan’ev Yu. L. Bakshaev P. I. Blinov V. A. Bryzgunov A. S. Chernenko S. A. Dan’ko E. D. Kazakov V. D. Korolev B. R. Meshcherov S. L. Nedoseev V. G. Pimenov E. A. Smirnova G. I. Ustroev V. V. Vikhrev I. V. Volobuyev A. A. Zelenin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):499-502
On the S-300 installation at currents up to 2 MA with rise time 100 ns, the investigation of the formation process of high-temperature
plasma in fast Z-pinch was carried out. The central part of the loads was made from agar-agar and represented a deuterated
polyethylene cylinder with small density 50 and 75 mg/sm3 and 1–2 mm diameter. On the ICT images, obtained in optical and soft X-ray range of a spectrum with 3–5 ns exposition, it
is visible that on the axis of the polyethylene cylinder at the current`s rise time a cord is formed and it is separated into
bright formations. They were observed on a background of a luminous area which occupied the initial neck volume. On time-integrated
pinhole pictures obtained in SXR range (E > 1–4 keV), hot points with minimal size of 50 microns were registered. From the
chronograms results, obtained by means of the optical high-speed-streak camera mount along the neck axis with time resolution
< 1 ns, it follows that luminous formations arise sequentially during the different time moments (in 10–30 ns). Occurrence
of luminous formations was accompanied by X-ray radiation occurrence with energy E > 1 keV with short duration of 2–4 ns.
Simultaneously with X-ray radiation neutrons with the maximal yield of 4.5×109 were registered. The average energy measured in 4 directions under angles with an axis of: 0○ (above the anode), 90○, 180○ (under the cathode) and 270○, were accordingly: 2.4±0.2, 2.5±0.1, 2.5±0.1, 2.5±0.1 MeV. 相似文献
4.
P. Vrba M. Vrbova N. A. Bobrova P. V. Sasorov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):481-486
Pinching discharge in non-ablative and ablative capillaries filled by boron vapors is studied. The aim is to find out conditions
for lasing at Balmer alpha transition of hydrogen-like boron ions B4+ (λ= 26.23 nm). The primary pumping process under consideration is a three-body collisional recombination, which takes place
in non-stationary underheated plasma during the pinch expansion stage. The results of Z-pinch computer modeling including
the plasma kinetics and gain evaluation are compared for two different quarter periods of electrical current passing through
the capillary. 相似文献
5.
L. I. Ivanov A. I. Dedyurin I. V. Borovitskaya O. N. Krokhin V. Y. Nikulin E. N. Peregudova A. V. Oginov A. A. Tikhomirov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):149-152
The work presents the experimental results of investigation of the possibility of the creating of high adhesive compound of
chemically noninteracting metals by means of pulse streams of high temperature dense plasma. The 4 kJ plasma focus installation
was used as a source of pulse streams of plasma. In the experiment assemblies of Cu–W and Pb–Fe samples were used. The deep
penetration of atoms Cu and Pb accordingly in W and Fe was found. The mechanisms of the penetration of chemically neutral
atoms into a material of the target can be connected with the following processes: the energy transfer from plasma pulse to
implanting atoms, the origin and distribution of shock waves in the material of a target, and also the Rayleigh-Taylor instability
of the border of two combining materials. 相似文献
6.
S. Wang H. J. Eichler X. Wang F. Kallmeyer J. Ge T. Riesbeck J. Chen 《Applied physics. B, Lasers and optics》2009,95(4):721-730
Diode lasers with peak powers in the kW range and pulse durations of micro- to milli-seconds have been available since several
years. Pumping solid state lasers with such sources yield high output pulse energies in spiking or Q-switched operation. The
output energy is limited by the thermal lens effects, which are measured and calculated. The time dependent heat conduction
equation in the laser crystal is solved numerically to predict the overall temperature rise and thermal lensing. The thermally
induced optical path difference is approximated by a quadratic distribution to obtain the focal length f of the thermal lens. The thermal lens coefficient K=1/(f⋅P
av), which depends only weakly on the heat transfer coefficient H of the laser crystal to the heat sink, decreases exponentially with increasing pump frequency until the steady state is reached.
Experiments were done with a Nd:YAG crystal at different pump frequencies up to 100 Hz. The thermal lens coefficients obtained
by the power maxima of asymmetric flat-flat resonators agree with our calculations. 相似文献
7.
K. Quinn P. A. Wilson B. Ramakrishna G. Sarri L. Romagnani A. Pipahl O. Willi L. Lancia J. Fuchs D. C. Carroll M. N. Quinn P. Gallegos X. H. Yuan P. McKenna R. J. Clarke D. Neely M. Notley A. Macchi M. Borghesi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(2):293-297
New method of neutron spectrum recovery described in the paper involves accelerated deuterons (that produce neutrons in DD
reaction) and allows getting neutron spectrum in any direction from computed time-velocity characteristics of deuterons. Time of flight signals registered in various distances and directions are used, that makes
information involved in the recovery process (Monte-Carlo simulation) more complete than in a one-directional case, although
additional assumption about axial symmetry of deuterons motion, is required. In the paper recent results of two standard tests
of the proposed method are presented demonstrating its capability to recover neutron spectrum from time-of-flight signals. 相似文献
8.
9.
A. Ulrich J. Wieser R. Pfaffenberger B. Busch W. Krötz H. -J. Körner G. Ribitzki D. E. Murnick 《Zeitschrift für Physik A Hadrons and Nuclei》1991,341(1):111-115
Optical gain on the 476.5 nm Ar II 4p–4s ion laser transition has been observed in argon-gas excited by 2.5 ns pulses of 90 MeV32S ions with a repetition rate of 4883 Hz. The energy per pulse was 23 J. The projectiles were stopped in the target at pressures between 5 and 20 kPa. Gain was determined from a measured transient increase of the intensity of a 476.5 nm probe laser beam sent along the ion beam axis and back reflected by an aluminum foil. The maximum gain observed was (0.4±0.1)×10–3 at a target-gas pressure of 5 kPa. Control experiments using krypton as target-gas were performed and yielded a null result. The optical gain observed in argon is consistent with the result from an analysis of spectroscopic studies of rare-gas targets excited by heavy ion beams.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday. This work has been funded by the German Federal Ministry for Research and Technology (BMFT) under contract No. 06 TM 310 I, Gesellschaft für Schwerionenforschung (GSI), Darmstadt, and the Tandem accelerator laboratory, Munich 相似文献
10.
M. Uebernickel C. Fiebig G. Blume K. Paschke B. Eppich R. Güther G. Erbert 《Applied physics. B, Lasers and optics》2008,93(4):823-827
Continuous wave power of more than 400 mW at 488 nm has been generated by frequency doubling of 2.45 W at 976 nm obtained
from a distributed Bragg reflector tapered diode laser. This results in a wavelength conversion efficiency of 16.5% and an
electrical-to-optical efficiency of more than 4.5%. We used a 50 mm long periodically poled MgO:LiNbO3 bulk crystal in single-pass configuration for the second harmonic generation. This is to the author’s knowledge the highest
output power and the highest wavelength conversion efficiency at 488 nm generated by a monolithic semiconductor laser device
in single pass configuration with a bulk crystal. A deviation from the quadratic dependency of the frequency doubling is explained
by the decrease of the beam quality of the fundamental wave. 相似文献
11.
M. Sharif S. Hussain M. Zakaullah A. Waheed 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(2):337-341
A 1.8 kJ Mather-type plasma focus (PF) for argon and hydrogen
filling is examined. Two anode configurations are used. One is tapered
towards the anode face, and the other is cylindrical but the face is cut at
different angles. At optimum conditions, the system is found to emit Cu–Kα
X-rays of about 1.6±0.1 J/sr in the side-on direction for argon
filling, which
is about 32% of the total X-ray emission. In 4π-geometry, maximum
total X-ray
yield and wall plug efficiency found are 26.4±1.3 J and 1.5±
0.1%
respectively. The modified geometry may help to use the PF as a radiation
source for X-ray diffraction. 相似文献
12.
Z. Q. Huang M. H. Hong T. B. M. Do Q. Y. Lin 《Applied Physics A: Materials Science & Processing》2008,90(1):159-163
TiB2-based cermets are prepared by combustion synthesis followed by a pressing stage in a granulate medium. Products obtained
by combustion synthesis are characterized by a large remaining porosity (typically 50%). To produce dense cermets, a subsequent
densification step is performed after the combustion process and when the reacted material is still hot. To design the process,
numerical simulations are carried out and compared to experimental results. In addition, physical and electrical properties
of the products related to electrical contact applications are evaluated.
PACS 81.20.Ka; 81.05.Mh; 72.80.Tm 相似文献
13.
In the present paper, polyimide surfaces were processed with pulsed KrF laser radiation at fluences near the ablation threshold.
The morphology of the processed surfaces was studied by scanning electron microscopy and chemical analyses performed by electron
dispersive spectroscopy. The formation of conical structures was observed for radiation fluences lower than 0.5 J/cm2. The areal density of cones increases with the number of pulses and decreases with the radiation fluence. At low fluences
(<150 J/cm2), cones are formed due to shadowing by calcium phosphate impurities while for higher fluences the main mechanism of cones
formation is believed to be radiation hardening. 相似文献
14.
B. Cocquelin D. Holleville G. Lucas-Leclin I. Sagnes A. Garnache M. Myara P. Georges 《Applied physics. B, Lasers and optics》2009,95(2):315-321
We report on a diode-pumped vertical external-cavity surface-emitting laser emitting around 852 nm for Cesium atomic clocks
experiments. We have designed a 7-quantum-well semiconductor structure optimized for low laser threshold. An output power
of 330 mW was achieved for 1.1 W of incident pump power. Furthermore, a compact setup was built for low-power single-frequency
emission. We obtained an output power of 17 mW in a single longitudinal mode, exhibiting both broad (9 nm) and continuous
(14 GHz) tunability around the Cesium D2 line. The laser frequency has been stabilized on an atomic transition with residual frequency fluctuations ∼300 kHz. Through
a beatnote experiment the −3 dB laser linewidth has been measured to <500 kHz over 10 ms. 相似文献
15.
L. Cabaret 《Applied physics. B, Lasers and optics》2009,94(1):71-79
An efficient pumping scheme for a quasi-continuous-wave diode-pumped Yb:YAG laser is presented. Single-mode operation and
fine wavelength tuning are assured by the use of a rubidium titanyl phosphate (RTP) Fabry–Perot étalon. When frequency doubled,
the 200–420 μs duration pulses reach a peak power of 70 W at a wavelength of 515 nm. The TEM00 beam is nearly diffraction limited with an M
2 factor of 1.06 at full power. The tuning range spans from 512 to 520 nm and the pulse to pulse frequency stability is on
the order of ±10 MHz.
Laboratoire Aimé Cotton is associated with Université Paris Sud 11. 相似文献
16.
R. Gentner D. Bellm L. Lassen A. Oberstedt A. Giorni A. Lleres J. -B. Viano B. Cheynis B. Chambon D. Drain 《Zeitschrift für Physik A Hadrons and Nuclei》1993,347(2):117-122
The closely associated phenomena of preequilibrium emission and evaporation residue formation in fusion-like reactions were studied in central collisions between40Ar andnatCa at 30 MeV/u. Heavy reaction products were taken in coincidence with neutrons and light charged particles. The preequilibrium neutron data agree very well with predictions of a quantal phase-space model which, in addition to the mean field, takes two-body collisions properly into account. Preequilibrium emission ends in thermally equilibrated hot nuclei with an average excitation energy of about 6 MeV/u. The combined results show a striking interrelation between the missing mass and light-particle multiplicities: the mass difference between the full compound mass and the observed residues can be explained quantitatively by the emission of only neutrons and light charged particles withZ2 during the entire course of energy dissipation.Supported by the German Bundesministerium für Forschung und Technologie (BMFT) under contract 06 HD 983I 相似文献
17.
A. Waxman M. Givon G. Aviv D. Groswasser R. Folman 《Applied physics. B, Lasers and optics》2009,95(2):301-305
The influence of Zn-atom additive on ‘pure’ copper vapor laser output characteristics is studied. The laser pulse width, energy
and power are found to increase under the diffusion of zinc atoms from a zinc-containing reservoir into the discharge of the
copper-vapor laser at temperatures above 500°C. Additional absorption experiments and calculations are consistent with the
conclusion that not only optical resonant pumping by the 213.9-nm Zn I line, but also other processes, should be taken into
account to explain the effects of additive influence. 相似文献
18.
The Lamb dip of CO rovibrational transition is detected by a room temperature extracavity RF optogalvanic cell and employed
to stabilize the frequency of a CO laser. The S/N ratio of optogalvanic signal is about 2000
at optical power < 1 W. The relative depth of Lamb dip is 2.3%. The S/N ratios of first and third harmonic demodulated saturation
signals are about 40
and 10
, respectively. The CO laser is stabilized using the first harmonic demodulated signal, and the frequency stability is better
than 300 kHz.
Concurrently, the influences of operational parameters, which include the coil current, partial pressures of gas mixture,
are investigated. A simple model for the influence of coil current is presented, and further improvements are addressed as
well. 相似文献
19.
An optical clock based on an Er3+ fiber femtosecond laser and a two-mode He–Ne/CH4 optical frequency standard (λ=3.39 μm) is realized. Difference-frequency generation is used to down convert the 1.5-μm frequency comb of the Er3+ femtosecond laser to the 3.4-μm range. The generated infrared comb overlaps with the He–Ne/CH4 laser wavelength and does not depend on the carrier–envelope offset frequency of the 1.5-μm comb. In this way a direct phase-coherent
connection between the optical frequency of the He–Ne/CH4 standard and the radio frequency pulse repetition rate of the fiber laser is established. The stability of the optical clock
is measured against a commercial hydrogen maser. The measured relative instability is 1×10−12 at 1 s and for averaging times less than 50 s it is determined by the microwave standard, while for longer times a drift
of the He–Ne/CH4 optical standard is dominant. 相似文献
20.
M. Hoffmann Y. Barbarin D. J. H. C. Maas M. Golling I. L. Krestnikov S. S. Mikhrin A. R. Kovsh T. Südmeyer U. Keller 《Applied physics. B, Lasers and optics》2008,93(4):733-736
We report the first successful modelocking of a vertical external cavity surface emitting laser (VECSEL) with a quantum dot
(QD) gain region. The VECSEL has a total of 35 QD-layers with an emission wavelength of about 1060 nm. In SESAM modelocked
operation, we obtain an average output power of 27.4 mW with 18-ps pulses at a repetition rate of 2.57 GHz. This QD-VECSEL
is used as-grown on a 450 μm thick substrate, which limits the average output power. 相似文献