共查询到20条相似文献,搜索用时 592 毫秒
1.
M. Okamura R. A. Jameson H. Kashiwagi T. Hattori N. Hayashizaki K. Sakakibara 《辐射效应与固体损伤》2013,168(10-12):445-449
We have developed a new heavy ion production system which uses a combination of an RFQ and a laser ion source. Induced plasma by a laser shot is delivered to the RFQ without an extraction electrode. We named this new idea ‘direct plasma injection scheme (DPIS)’. In 2004, a new RFQ was built for demonstrating the capability of the DPIS. After a few months of commissioning period, we could obtain more than 60 mA of carbon beam from the RFQ. This new scheme could be applied to cancer therapy facilities and high energy nuclear physics accelerator complexes. 相似文献
2.
U. Eisenbarth M. Mudrich B. Eike M. Grieser R. Grimm V. Luger T. Schätz U. Schramm D. Schwalm M. Weidemüller 《Hyperfine Interactions》2000,127(1-4):223-235
We have observed a sudden disappearance of intrabeam scattering in a laser cooled stored 9Be+ beam at the Heidelberg Test Storage Ring. The transition takes place at about 106 ions corresponding to a mean ion distance of ≃50c μm. The disappearance of IBS is accompanied by a decrease of the longitudinal
temperature by more than two orders of magnitude. At the same time, the transverse width of the ion beam shows an increase
which is limited to the diameter of the laser beam. Experimental signatures of this anomalous beam behaviour are described,
and possible interpretations are discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
B. Tordoff J. Billowes P. Campbell B. Cheal D. H. Forest T. Kessler J. Lee I. D. Moore A. Popov G. Tungate J. Äystö 《Hyperfine Interactions》2006,171(1-3):197-201
A new ion beam of 229Th is available at the Jyväsklyä IGISOL facility, produced from the α decay of 233U. A small branching ratio (≈ 2%) is believed to populate the inferred low-lying (5.5 eV) isomeric state in 229Th. A laser ionization scheme is currently being developed to improve the yield of 229Th from the source. The ion source uses a novel electric field configuration for fast and efficient extraction of α-recoils and is able to provide beams of short lived (τ≥ 30 ms) radioactive nuclei. Identification of the isomeric state by collinear laser spectroscopy will reduce the lower lifetime limit of the state and provide the first direct evidence for its existence. 相似文献
4.
A gold target has been irradiated with a Q-switched Nd:Yag laser having 1064?nm wavelength, 9?ns pulse width, 900?mJ maximum pulse energy and a maximum power density of the order of 1010?W/cm2. The laser–target interaction produces a strong gold etching with production of a plasma in front of the target. The plasma contains neutrals and ions having a high charge state. Time-of-flight (TOF) measurements are presented for the analysis of the ion production and ion velocity. A cylindrical electrostatic deflection ion analyzer permits measurement of the yield of the emitted ions, their charge state and their ion energy distribution. Measurements indicate that the ion charge state reaches 6+ and 10+ at a laser fluence of 100?J/cm2 and 160?J/cm2, respectively. The maximum ion energy reaches about 2?keV and 8?keV at these low and high laser fluences, respectively. Experimental ion energy distributions are given as a function of the ion charge state. Obtained results indicate that electrical fields, produced in the plume, along the normal to the plane of the target surface, exist in the unstable plasma. The electrical fields induce ion acceleration away from the target with a final velocity dependent on the ion charge state. The ion velocity distributions follow a “shifted Maxwellian distribution”, which the authors have corrected for the Coulomb interactions occurring inside the plasma. 相似文献
5.
A laser ion source (LIS), which can provide a carbon beam with highly stripped state (C6+) and high intensity (several tens mA), would significantly change the overall design of the hadrontherapy facility. The proposed LIS based hadrontherapy facility has the advantages of short linac length, simple injection scheme, and small synchrotron size. With the experience from the DPIS and HITFiL projects that have been conducted in IMP, a conceptional design of the LIS based hadrontherapy facility will be presented, with special attention given to APF type IH DTL design and simulation. 相似文献
6.
7.
L. Torrisi A.M. Mezzasalma J. Badziak J. Wolowski G. Franco 《Applied Surface Science》2006,252(24):8533-8538
High energy laser plasma-produced Cu ions have been implanted in silicon substrates placed at different distances and angles with respect to the normal to the surface of the ablated target. The implanted samples have been produced using the iodine high power Prague Asterix Laser System (PALS) using 438 nm wavelength irradiating in vacuum a Cu target. The high laser pulse energy (up to 230 J) and the short pulse duration (400 ps) produced a non-equilibrium plasma expanding mainly along the normal to the Cu target surface. Time-of-flight (TOF) technique was employed, through an electrostatic ion energy analyzer (IEA) placed along the target normal, in order to measure the ion energy, the ion charge state, the energy distribution and the charge state distribution. Ions had a Boltzmann energy distributions with an energy increasing with the charge state. At a laser fluence of the order of 6 × 106 J/cm2, the maximum ion energy was about 600 keV and the maximum charge state was about 27+.In order to investigate the implantation processes, Cu depth profiles have been performed with Rutherford backscattering spectrometry (RBS) of 1.5 MeV helium ions, Auger electron spectroscopy (AES) with 3 keV electron beam and 1 keV Ar sputtering ions in combination with scanning electron microscopy (SEM). Surface analysis results indicate that Cu ions are implanted within the first surface layers and that the ion penetration ranges are in agreement with the ion energy measured with IEA analysis. 相似文献
8.
R. Grieser P. Merz G. Huber V. Sebastian P. Seelig M. Grieser R. Grimm I. Lauer V. Luger H.J. Miesner D. Schwalm A. Dax T. Engel M. Gerlach T. Kühl H. Winter 《Hyperfine Interactions》1997,108(1-3):241-250
Heavy ion storage rings allow for tests of the structure of local space time via the Doppler effect. At the TSR/Heidelberg
an experiment with high resolution laser spectroscopy at 7Li+ is performed. To gain the maximum resolution for saturation spectroscopy new methods of relativistic ion beam preparation
and diagnostics have been developed.
The laser cooling of the beam allows for precision determination of the mean velocity of the ions. A novel phase synchronous
detection scheme, ultimately sensitive to single ions, gives insights into the cooling mechanism and dynamics. With an additional
synchronous excitation scheme systematic uncertainties of the test experiment can be drastically reduced. After separation
of the ground state ions from the triplet states of 7Li+ by the combination of laser and electron cooling, a bunched and cooled ensemble of fast moving high precision clocks with
minimized perturbations by space charge effects and intra beam scattering is available.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
I. D. Moore T. Kessler J. Äystö J. Billowes P. Campbell B. Cheal B. Tordoff M. L. Bissel G. Tungate 《Hyperfine Interactions》2006,171(1-3):135-141
A programme of research has commenced at the IGISOL facility, Jyväskylä, combining the technique of resonance ionization spectroscopy with the development of the highly selective laser ion source trap (LIST). The first element of interest is bismuth, which contains three isomers of multi-quasiparticle states in near-spherical nuclei, namely 207Bi (21/2+, 182 μs), 204Bi (10?, 13 ms) and 204Bi (17+, 1.07 ms). A measurement of the optical isomer shift provides a direct comparison of the mean?square charge radii between the isomer and the nuclear ground state. Due to the short isomer lifetimes the spectroscopy will be done either within the ion guide or in a sextupole ion beam guide (SPIG), located after the ion guide and used in the development of the LIST. A mixed dye-Ti:Sapphire laser ionization scheme has been successfully tested for bismuth and first off-line results have been obtained. 相似文献
10.
Electron cyclotron resonance ion sources are now able to attain a beam current as high as some milliamperes, which until a few years ago was obtained only for pulsed laser ion sources with a much higher emittance and energy spread, by keeping also the possibility to produce high charge states close to electron beam ion sources, at much higher intensity. They usually operate at frequencies up to 18 GHz, but now many sources are able to operate or will be able, at 28 GHz frequency or more, with plasma density of the order of 1013 cm?3, much higher than any other source of the previous generation. The state-of-the-art technique will be described along with the major characteristics of the upcoming sources. 相似文献
11.
L. Torrisi 《辐射效应与固体损伤》2013,168(10):689-703
Energetic ions have been obtained irradiating a tungsten target with a Q-switched Nd:Yag laser, 1064?nm wavelength, 9?ns pulse width, 900?mJ maximum pulse energy and power density of the order of 1010?W/cm2. The laser-target interaction induces a strong metal etching with production of plasma in front of the target. The plasma contains neutrals and ions with high charge state. Time-of-flight measurements are presented for qualitative analysis of the ion production. A cylindrical electrostatic ion analyzer permits measuring of the yield of emitted ions, the charge state of detected ions and the ion energy distribution. Measurements indicate that, at a laser fluence of the order of 100?J/cm2, the charge state may reach 9+ and the ion energy reaches about 5?keV. The ion energy distribution is given as a function of the charge state. Experimental results indicate that an electrical field is developed along the normal to the plane of the target surface, which accelerates the ions up to high velocity. The ion velocity distributions follow a “shifted Maxwellian distribution”, which the author has corrected for the Coulomb interactions occurring inside the plasma. 相似文献
12.
A continuous cold atomic beam from a magneto-optical trap 总被引:3,自引:0,他引:3
L. Cacciapuoti A. Castrillo M. de Angelis G.M. Tino 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(2):245-249
We have developed and characterized a new method to produce a continuous beam of cold atoms from a standard vapour-cell magneto-optical
trap (MOT). The experimental apparatus is very simple. Using a single laser beam it is possible to hollow out in the source
MOT a direction of unbalanced radiation pressure along which cold atoms can be accelerated out of the trap. The transverse
cooling process that takes place during the extraction reduces the beam divergence. The atomic beam is used to load a magneto-optical
trap operating in an ultra-high vacuum environment. At a vapour pressure of 10-8mbar in the loading cell, we have produced a continuous flux of 7×107atoms/s at the recapture cell with a mean velocity of 14 m/s. A comparison of this method with a pulsed transfer scheme is
presented.
Received 19 February 2001 相似文献
13.
L. Torrisi 《辐射效应与固体损伤》2015,170(4):355-366
High-intensity sub-nanosecond-pulsed lasers irradiating thin targets in vacuum permit generation of electrons and ion acceleration and high photon yield emission in non-equilibrium plasmas. At intensities higher than 1015?W/cm2 thin foils can be irradiated in the target-normal sheath acceleration regime driving ion acceleration in the forward direction above 1?MeV per charge state. The distributions of emitted ions in terms of energy, charge state and angular emission are controlled by laser parameters, irradiation conditions, target geometry and composition. Advanced targets can be employed to increase the laser absorption in thin foils and to enhance the energy and the yield of the ion acceleration process. Semiconductor detectors, Thomson parabola spectrometer and streak camera can be employed as online plasma diagnostics to monitor the plasma parameters, shot by shot. Some applications in the field of the multiple ion implantation, hadrontherapy and nuclear physics are reported. 相似文献
14.
L. Laska K. Jungwirth J. Krasa M. Pfeifer K. Rohlena J. Ullschmied J. Badziak P. Parys L. Ryc J. Wolowski S. Gammino L. Torrisi F. P. Boody 《Czechoslovak Journal of Physics》2005,55(6):691-699
Generation of various ion groups was studied using lasers of different pulse length and intensities. Up to thirteen ion subgroups have been distinguished when using the PALS iodine laser system in experiments that involve a laser interaction with a preformed plasma. In addition to generally accepted thermal, fast, and slow ion groups, the existence of the second fast (superfast) group was clearly proven. The threshold laser intensity I
L necessary fo appearance of nonlinear effects was confirmed to be × 1014W/cm2 at our experimental conditions. Above this value, there exists an interval of laser focus positions in front of the target in which ions with significantly higher charge states and energies are produced, compared to experiments without pre-plasma interactions, due to nonlinear processes in preformed plasma. 相似文献
15.
A. Zelenski G. Atoian J. Ritter D. Steski F. Podolyako I. Sorokin I. Vizgalov V. Klenov V. Zubets V. Davydenko A. Ivanov A. Kolmogorov 《Physics of Particles and Nuclei》2014,45(1):308-311
The RHIC polarized H? ion source is being upgraded to higher intensity and polarization for use in the RHIC polarization physics program at enhanced luminosity RHIC operation. The higher beam intensity will allow reduction of the longitudinal transverse beam emittance at injection to AGS to reduce polarization losses in AGS. There is also a planned RHIC luminosity upgrade by using the electron beam lens to compensate the beam-beam interaction at collision points. This upgrade is also essential for future BNL plans for a high-luminosity electron-proton (ion) Collider eRHIC. The basic limitations on the high-intensity H? ion beam production in charge-exchange collisions of the neutral atomic hydrogen beam in the Na-vapor jet ionizer cell were experimentally studied. 相似文献
16.
It is suggested to generate cold ion beams by laser collimation and subsequent laser ionization of a primary atomic beam. The primary beam, formed by a standard method, is collimated through transverse cooling by resonance laser radiation. Laser radiation is also used for the multistep ionization of atoms in the collimated beam. Advantages of the proposed method are a low scatter of the initial ion energy (below 10?1 eV) and a high emittance in the region of the virtual source (~10?6 cm rad at a beam current on the level of microamperes). The high monochromaticity of the obtained ion beam allows the chromatic aberration effect to be significantly suppressed, which implies good prospects for using such sources in ion beam lithography. The proposed method also allows the spectrum of elements used in ion beam sources to be expanded, which is an independent technological advantage. 相似文献
17.
A. Lorusso M. V. Siciliano L. Velardi V. Nassisi 《Applied Physics A: Materials Science & Processing》2010,101(1):179-183
We developed an ion accelerator with a double accelerating gap system supplied by two power generators of different polarity.
The ions were generated by laser ion source technique. The laser plasma induced by an excimer KrF laser, freely expanded before
the action of accelerating fields. After the first gap action, the ions were again accelerated by a second gap. The total
acceleration can imprint a maximum ion energy up to 160 keV per charge state. We analysed the extracted charge from a Cu target
as a function of the accelerating voltage at laser energy of 9, 11 and 17 mJ deposited on a spot of 0.005 cm2. The peak of current density was 3.9 and 5.3 mA for the lower and medium laser energy at 60 kV. At the highest laser energy,
the maximum output current was 11.7 mA with an accelerating voltage of 50 kV. The maximum ion dose was estimated to be 1012 ions/cm2. Under the condition of 60 kV accelerating voltage and 5.3 mA output current the normalized emittance of the beam measured
by pepper pot method was 0.22 π mm mrad. 相似文献
18.
U. Schramm M. Bussmann D. Habs M. Steck T. Kühl K. Beckert P. Beller B. Franzke F. Nolden G. Saathoff S. Reinhardt S. Karpuk 《Hyperfine Interactions》2005,162(1-4):181-188
We report on the first laser cooling of a bunched beam of multiply charged ions performed at the ESR (GSI) at a beam energy of GeV. Moderate bunching provided a force counteracting the decelerating laser force of one counterpropagating laser beam.
This versatile type of laser cooling lead to longitudinally space-charge dominated beams with an unprecedented momentum spread
of . Concerning the beam energy and charge state of the ion, the experiment depicts an important intermediate step from the established
field of laser cooling of ion beams at low energies toward the unique laser cooling scheme proposed for relativistic beams
of highly charged heavy ions at SIS 300 (FAIR).
Funded by the German BMBF under contract number 06ML183. 相似文献
19.
用150fs的掺钛蓝宝石激光系统, 在功率密度约为5×1015 W/cm2时 激励氩(Ar)团簇,利用具有空间分辨能力的平场光栅谱仪观察到13—23nm波段Ar的软x射线谱,并观察到Ar的11阶离子谱线.在较宽的激光脉宽和较低的激光功率密度情况下,通过激励Ar团簇,获得 了Ar的高阶电离度的实验结果,且谱线的信噪比明显好于光场感应电离的情况,说明团簇的 形成大幅度地提高了激光能量的吸收效率.
关键词:
Ar团簇
超短强激光
软x射线辐射 相似文献
20.
Kazuhisa NAKAJIMA 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2015,91(6):223-245
To date active research on laser-driven plasma-based accelerators have achieved great progress on production of high-energy, high-quality electron and photon beams in a compact scale. Such laser plasma accelerators have been envisaged bringing a wide range of applications in basic, medical and industrial sciences. Here inheriting the groundbreaker’s review article on “Laser Acceleration and its future” [Toshiki Tajima, (2010)],1) we would like to review recent progress of producing such electron beams due to relativistic laser-plasma interactions followed by laser wakefield acceleration and lead to the scaling formulas that are useful to design laser plasma accelerators with controllability of beam energy and charge. Lastly specific examples of such laser-driven electron/photon beam sources are illustrated. 相似文献