[show abstract][hide abstract] ABSTRACT: Intense heavy ion beams offer a unique tool for generating samples of high energy density matter with extreme conditions of density and pressure that are believed to exist in the interiors of giant planets. An international accelerator facility named FAIR (Facility for Antiprotons and Ion Research) is being constructed at Darmstadt, which will be completed around the year 2015. It is expected that this accelerator facility will deliver a bunched uranium beam with an intensity of 5×1011 ions per spill with a bunch length of 50-100 ns. An experiment named LAPLAS (Laboratory Planetary Sciences) has been proposed to achieve a low-entropy compression of a sample material like hydrogen or water (which are believed to be abundant in giant planets) that is imploded in a multi-layered target by the ion beam. Detailed numerical simulations have shown that using parameters of the heavy ion beam that will be available at FAIR, one can generate physical conditions that have been predicted to exist in the interior of giant planets. In the present paper, we report simulations of compression of water that show that one can generate a plasma phase as well as a superionic phase of water in the LAPLAS experiments.
New Journal of Physics 01/2010; 12. · 4.06 Impact Factor
[show abstract][hide abstract] ABSTRACT: HIRFL-CSR is a multi-purpose cooler-storage-ring system constructed at the Institute of Modern Physics, Chinese Academy of Sciences in Lanzhou, China. Construction of the HIRFL-CSR storage ring complex has been finished, and passed the government check and acceptance, recently. The first stored beam in the CSRm was obtained in January 2006 using stripping injection. The commissioning got great progress in 2007. In early January 2007 electron cooling in CSRm was successfully done, and the multiple multi-turn injection was successively realized for 12C6+, 36Ar18+ and 129Xe27+ beams, respectively. The 129Xe27+ beams was extracted from the main ring by fast extraction. The 660MeV/u 12C6+ was injected into the experimental ring and reached an intensity of 15mA there. The first two physics experiments were done in December 2007 including the mass measurement in isochronous mode in the experimental ring. The 300MeV/u 12C4+ ions were successfully slow-extracted from the main ring in early 2008. This paper presents the main commissioning results.
Journal of Physics Conference Series 06/2009; 163(1):012113.
[show abstract][hide abstract] ABSTRACT: The highly charged ion 40Ar16+ with the velocity (kinetic energy E
K=150 keV, velocity V=8.5×105 m/s) smaller than Bohr velocity (V
Bohr=2.9×106 m/s) was found to hove impacts on the surfaces of metals Ni, Mo, Au and Al, and the Ar atomic infrared light lines and X-rays
spectra were simultaneously measured. The experimental results show that the highly charged ion that captures electrons is
neutralized, and the multiply-excited hollow atom forms. The hollow atom cascade decay radiates lights from infrared to X-ray
spectrum. The intensity of infrared lights shows that the metallic work functions play an important role in the neutralization
process of highly charged ions during their interaction with metallic surfaces, which verifies the classical over-the-barrier
Science in China Series G Physics Mechanics and Astronomy 01/2009; 52(7):1021-1026. · 1.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: Since the successful completion of the Cooling Storage Ring (CSR) Project at the end of 2007, high qualitative heavy ion beams with energy ranging from keV to GeV/mu have been possible on HIRFL (Heavy Ion Research Facility at Lanzhou). More than 10<sup>9</sup> 1 GeV/mu C<sup>6+</sup> particles or 10<sup>8</sup> 235 MeV/mu Xe<sup>27+</sup> particles can be storied on the CSR main-ring and extracted within hundreds nano-seconds, so that high energy density plasmas (HEDP) derived by intense heavy ion beam could be produced and investigated there. On the other hand, the Superconducting Electron Cyclotron Resonance Ion Source with Advanced design in Lanzhou (SECRAL) can produce intense heavy ion beams with very high charge states, such as 70 emu A for Ca<sup>16+</sup>, 2.2 emuA for Ca<sup>19+</sup> and 38 emuA for Pb<sup>32+</sup>. The ion source is operated at the microwave frequency of 18 GHz which will be extended to 28 GHz in future. This facility provides the possibilities to study magnet confinement plasma and to investigate the intense heavy ion beams with very high charge states. Some significant progress at Lanzhou will be introduced and international collaborations are always welcomed.
[show abstract][hide abstract] ABSTRACT: The total reaction cross section (1724 ± 93 mb) of 17B at the energy of 43.7 A MeV on C target has been measured by using the transmission method at the Radioactive Ion Beam Line
in Lanzhou (RIBLL). Assuming 17B consists of a core 15B plus two halo neutrons, the total cross section of 17B on C target was calculated with the zero-range Glauber model, where double Gaussian density distributions and Gaussian plus
HO density distributions were used. It can fit the experimental data very well. The characteristic of halo structure for 17B was found with a large diffusion of the neutrons density distribution.
Science in China Series G Physics Mechanics and Astronomy 01/2008; 51(7):781-787. · 1.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: Using the slow highly charged ions 129Xe
q+ (q = 25, 26, 27; initial kinetic T
0⩽4.65 keV/a.u.) to impact Au surface, the Au atomic Mα characteristic X-ray spectrum is induced. The result shows that as
long as the charge state of projectile is high enough, the heavy atomic characteristic X-ray can be effectively excited even
though the incident beam is very weak (nA magnitude), and the X-ray yield per ion is in the order of 10−8 and increases with the kinetic energy and potential energy of projectile. By measuring the Au Mα-X-ray spectra, Au atomic
N-level lifetime is estimated at about 1.33×10−18 s based on Heisenberg uncertainty relation.
Science in China Series G Physics Mechanics and Astronomy 12/2007; 51(1):82-89. · 1.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: The X-ray emission induced by highly charged argon and xenon ions impinging on a beryllium surface is investigated. It is found that spectra of the X-ray induced by Ar17,18+ interacting with the surface are very different from those of the X-ray induced by Ar17,18+ interacting with residual gases. The result provides an experimental evidence for the existence of hollow atoms below the surface. Several unexpected X-ray lines are also found in the experiment. Firstly, K X-rays are observed when Ar16+ ions which initially have no K shell holes interact with the surface. Secondly, if there are more than 2 M shell vacancies at the initial time, strong Mαα two-electron-one-photon (TEOP) transitions are found in the collisions of Xe28+,29+,30+ ions with the surface.
Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 05/2007; 258(1):121–124. · 1.27 Impact Factor
[show abstract][hide abstract] ABSTRACT: HIRFL-CSR, a new cooler-storage-ring project, is the post-acceleration system of the Heavy Ion Research Facility in Lanzhou (HIRFL) consisting of a main ring (CSRm) and an experimental ring (CSRe). The construction of the HIRFL-CSR complex is nearing completion. The stored beam in the CSRm has been observed. Recently, the stored beam was accelerated from 7 MeV/u to 30 MeV/u. The cluster target is located in one straight section of the CSRe providing cluster jet targets of inert gases and small molecular gases. The cluster target has been finished and the results of the test running are presented.
Journal of Physics Conference Series 03/2007; 58(1):55.
[show abstract][hide abstract] ABSTRACT: A new storage ring system, HIRFL-CSR, is now in construction in the National Laboratory of Heavy Ion Research Facility of Lanzhou, China. The new facility consists of a main ring (CSRm) and an experimental ring (CSRe). With the flexibility of the production and the investigation of highly charged ions and radioactive ion beams the new HIRFL-CSR facility will make many frontier atomic physics researches possible in the near future. The future physics researches at the HIRFL-CSR are now under consideration. In this paper an overview of the HIRFL-CSR project is given, and the main atomic physics programs to be carried at the HIRFL-CSR are presented.
Physica Scripta 11/2006; 1999(T80B):522. · 1.03 Impact Factor
[show abstract][hide abstract] ABSTRACT: The X-rays induced during interaction of highly charged argon ions with a beryllium surface are reported. It is found that the K shell X-ray yield of single particle during interaction of hydrogen-like argon ions was 3.6 × 10−3, which is five orders more than that of helium-like argon ions. Moreover, due to the screening the 2s electron, no K X-ray was emitted during interaction of lithium-like argon ions with the beryllium surface. It is also found that the X-ray spectrum induced by Ar17+ interacting with residual gases is very different from that induced by Ar17+ interacting with the surfaces, that provided an experimental evidence for the existence of the hollow atoms below the surface.
Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 04/2006; 245(1):72–75. · 1.27 Impact Factor
[show abstract][hide abstract] ABSTRACT: By use of optical spectrum technology, the spectra of X-ray induced by highly charged 40Ar
q+ ions interacting with Au surface have been studied. The results show that the argon Kα X-ray were emitted from the hollow
atoms formed below the surface. There is a process of multi-electron exciting in neutralization of the Ar16+ion, with electronic configuration 1s2 in its ground state below the solid surface. The yield of the projectile Kα X-ray is related to its initial electronic configuration,
and the yield of the target X-ray is related to the projectile kinetic energy.
Science in China Series G Physics Mechanics and Astronomy 03/2006; 49(2):203-212. · 1.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: The brief achievements of HIRFL-CSR commissioning and the achieved parameters of its coolers were presented. With the help of electron cooling code, the cooling time of ion beam were extensive simulated in various parameters of the ion beam in the HIRFL-CSR electron cooling storage rings respectively, such as ion beam energy, initial transverse emittance, and momentum spread. The influence of the machine lattice parameters-betatron function, and dispersion function on the cooling time was investigated. The parameters of electron beam and cooling devices were taken into account, such as effective cooling length, magnetic field strength and its parallelism in cooling section, electron beam size and density. As a result, the lattice parameters of HIRFL-CSR were optimal for electron cooling, and the parameters of electron beam can be optimized according to the parameters of heavy ion beam.
[show abstract][hide abstract] ABSTRACT: HIRFL has been upgraded for basic research on nuclear physics, atomic
physics, irradiative material and biology from beginning of this decade.
So far, the main performances of HIRFL have improved in the beam species
from light ion to uranium and the maximum beam intensities reaching
~10μA from SFC, 1.5 μA from SSC. Therefore, some experiments have
been performed during this period, especially, on new isotope synthesis
and unstable nuclear physics. The new upgrading project Cooling Storage
Ring (CSR) is under commissioning by ~2p μA carbon beam stripping
injection. About 109 C ion have stored inside CSRm, and part
of them have been cooling down by the electron cooler. The acceleration
of CSRm also has been test successful. Some future experiment are under
International Journal of Modern Physics E 01/2006; 15:1941-1956. · 0.63 Impact Factor
[show abstract][hide abstract] ABSTRACT: The HIRFL-CSR internal target can operate in two modes: cluster target mode and polarized target mode. The cluster target may provide the gas target of H2, N2, inert gases and small molecular gases. The test experiments have been done for H2, N2 and Ar gases. The target thicknesses of 6.6×1012, 1.2×1013 and 1.0×1013 atoms/cm2 are obtained for H2, N2 and Ar gases, respectively. In this paper, the structure and the test results of the HIRFL-CSR cluster target system are reported.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/2005; 555:15-19. · 1.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: We report the measured results of the 200 nm—1000 nm characteristic spectral lines of target atoms when highly charged ions40Ar
q+(6≤q≤14) with the same kinetic energy and40Ar6+ with different kinetic energies are incident upon Al, Ti, Ni, Ta and Au surfaces, respectively. The results for129Xe6+,129Xe10+ and129Xe15+ with the same kinetic energy (150 keV) incident upon a Ta surface are also reported. These results show that when the projectile
and target are properly selected (40Ar12+ impinges on Al,129Xe6+ impinges on Ta), the spectral intensity of characteristic spectral lines of the target atom is effectively enhanced, and
is not strongly dependent on the kinetic energy of the incident ions.
Science in China Series G Physics Mechanics and Astronomy 01/2004; 47(6):729-736. · 1.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: A heavy ion cooler-storage ring HIRFL-CSR has being constructed at IMP. It consists of a main ring (CSRm) and an experimental ring (CSRe). Two RF cavities will be employed for CSRm. One is for beam acceleration, and another is for beam RF stacking. The accelerating cavity is designed to accelerate the beam from 10-50 MeV/u to 400-900 MeV/u with harmonic number h=1. The peak RF voltage is 8.0 kV and frequency range is from 0.25 MHz to 1.7 MHz. The RF stacking cavity with maximum voltage amplitude of 20 kV and tunable frequency range 6.0-14.0 MHz is used to capture the injected bunches from injector SSC (or SFC) and to accumulate the beam to high intensity by RF stacking method. In the present paper, the measured RF parameters and the details of hardware for the RF accelerating system are described.
Particle Accelerator Conference, 2003. PAC 2003. Proceedings of the; 06/2003
[show abstract][hide abstract] ABSTRACT: An internal target is to be equipped in the experimental ring CSRe. The
internal target is designed to operate both in the polarized mode and in
the unpolarized mode. The polarized internal target uses the state
selection in multiple magnets to get the polarized atomic beams. The
unpolarized target is a cluster-jet target. A large pumping system is
used to minimize the gas load to the ring to an acceptable level. In
this paper the main parameters, the design philosophy and the structure
of CSRe internal target is described. .
[show abstract][hide abstract] ABSTRACT: The performance of a logarithmic detection system is investigated for the 25 MeV/u 40Ar induced reaction. The detection system consists of four parts: an axial ionization chamber (IC), a position sensitive silicon detector (PSSD), a large area PIN silicon photodiode (SPD) and a 16 element CsI(Tl) scintillator array. The energy resolutions for IC and PSSD tested with 241Am (5.486 MeV) sources were 3 and 2.6% (FWHM), respectively. Fragments with Z values from Z = 2 to Z = 21 were identified in the reaction 40Ar + 115In. A Z resolving power of ZΔZ ∼ 44.5 (FWHM) for Z = 18 has been achieved, and the energy dynamic range for α-particles was about 2–130 MeV. A position resolution of 0.86±0.03 mm (FWHM) for PSSD was obtained for the reaction 40Ar + 27Al with 1 μs amplifier shaping time.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/1996; 368(2):473-478. · 1.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: The performances of a simple timing detector consisting of a thin plastic scintillator foil and an ellipsoidal mirror made of aluminium are investigated in intermediate energy heavy ion time-of-flight research. An intrinsic time resolution of about 140 ps has been measured for 25 MeV/u 40Ar ions passing through 2.06 mg/cm2 NE102A foil. Detection efficiency and light collection have been investigated. The dependence of the time resolution on the fluctuation of light yield has been caculated by a Monte Carlo method.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/1995; 355(2):464-468. · 1.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: Light-charged-particle correlations at small relative momenta are investigated in 46.7 MeV/u 12C-induced reactions. The pp correlation functions are dependent on the target nuclei when the sum energy of the two correlated protons is low. On the other hand, the pp correlation functions are almost independent of the target nuclei when the sum energy of the two correlated protons is high. The populations of several particle-unstable states are also investigated. Nuclear-temperature parameters extracted from relative populations of some particle-unstable states are around 3 MeV.