Huiping Liu

A Progress Report of 320 kV Multi-discipline Research Platform for Highly Charged Ions

A dedicated platform for multi-disciplinary research with highly charged ions has been constructed, and an all-permanent magnet ECR ion source was built and installed in the beamline. Five experimental terminals are established for interdisciplinary Research. The high voltage supplied to the platform has reached 320 kV. The commissioning of the platform is successful, different ion beams have been provided for experimental studies, and the current status will be reported.

Preparations for laser cooling of relativistic heavy-ion beams at the CSRe

Laser cooling is one of the most promising techniques to reach high phase-space densities for relativistic heavy-ion beams. Preparations for laser cooling of relativistic lithium-like ions, such as C3+ and N4+, are being made at the experimental cooler storage ring (CSRe) in Lanzhou, China. In December 2011, a new buncher was installed and tested with a 70 MeV u−1 22Ne10+ ion beam by electron cooling at the CSRe. The longitudinal momentum spread of the bunched ion beam was measured by the new resonant Schottky pick-up. As a result, Δp/p ≈ 2 × 10−5 has been reached at ion numbers less than 107. According to this test result, the RF-buncher is suitable for the upcoming experiment of laser cooling at the CSRe. Laser cooling of heavy-ion beams will also be applied at future storage ring facilities, e.g. FAIR in Darmstadt, and HIAF in Lanzhou.

First recombination experiment of fluorine-like nickel ions at the main cooler storage ring

Absolute non-resonant recombination (RR) rate coefficients of Ni19+ ions were measured by employing the electron–ion merged-beams technique at the main cooler storage ring in Lanzhou. Using the electron cooler and energy detuning system, we obtained a narrow momentum spread (Δp/p ~ 2 × 10−4) and tuned precisely relative energies (minimum electron energy detuning step voltage 1 V) between electrons and ions. In addition, we compared the RR rate coefficients with the theoretical ones calculated by the self-consistent-field Dirac–Slater method, and found that they are in good agreement.

A two-dimensional position-sensitive microchannel plate detector realized with two independent one-dimensional resistive anodes

A two-dimensional position-sensitive microchannel plate detector, with a Ø100 mm sensitive area and equipped with four integrated amplifiers, is realized with a new anode scheme. The anode is constructed by two independent one-dimensional resistive anodes, each consisting of an array of parallel copper strips connected by resistors in series on a printed circuit board (PCB). The arrays are perpendicularly aligned to realize two-dimensional position resolution, with the intervals between the adjacent strips on the PCB nearer to the microchannel plate cut out to allow electrons passing through. The detector is tested with an 55Fe x-ray source, and a position resolution of 0.38 mm is achieved.

State-selective single electron capture studied for C4+ ions on H2 at 40 keV

The experiment on state-selective single electron capture process of C4+ ions with molecular hydrogen at 40keV was performed by reaction microscope. The differential cross sections have been obtained by measuring the longitudinal and transverse momentum of recoil ions. The results show that single electron capture into M shell is by far the dominant reaction channel. The results can be qualitatively understood by reaction window of molecular coulomb barrier model.

Recent progresses on atomic physics with highly charged ions in Lanzhou

Storage rings, dedicated small accelerators and experimental setups have been established during past few years in Lanzhou China. The commissioning of the heavy ion Cooler Storage Rings gained great success. These advances give good opportunities for atomic physics researches using highly charged ions. The current status of the accelerators, some experimental setups will be introduced. Examples of some research results will be selected and reported. The future aspects of atomic physics related to ion-matter interactions will be outlined.

Measurement of excitation spectra for highly ionized sulphur

The excitation spectra in the wavelength range of 19—40 nm for highly ionized sulphur ions were measured by using the beam-foil method at the Heavy lon Research Facility in Lanzhou. In this experiment, more than 30 spectral lines were observed, which belonged to the transitions of the excitation energy levels for highly ionized SX—SXV ions, and 5 new lines were determined. The experimental results were compared with those from other experiments and theoretical calculations.