Fangfang Ruan

Transmission of electrons through a tapered glass capillary

The transmission of high-current electrons through a tapered SiO2 capillary was investigated. The angular distribution and incident energy dependence of transmitted electrons were observed. We found that the transmitted fraction decreases with the incident energy. The transmitted electrons had significant energy loss but could not be focused by the tapered capillary.

Transmission of low-energy electrons through SiO2 tube

The transmission of low-energy (1100eV-1500eV) electrons through SiO2 tube was investigated, the distribution of transmitted beam current was observed. Results indicate that the intensity of transmitted electrons is proportional to the relative incident beam intensity and the angular divergence of the transmitted electrons is reduced when incident energy increased.

Note: a real-time beam current density meter.

We have developed a real-time beam current density meter for charged particle beams. It measures the mean current density by collimating a uniform and large diameter primary beam. The suppression of the secondary electrons and the deflection of the beam were simulated, and it was tested with a 105 keV Ar(7+) ion beam.

Production and decay of K -shell hollow krypton in collisions with 52–197-MeV/u bare xenon ions

X-ray spectra of K-shell hollow krypton atoms produced in single collisions with 52 - 197 MeV/u Xe54+ ions are measured in a heavy-ion storage ring equipped with an internal gas-jet target. Energy shifts of the K{\alpha}_1,2^s, K{\alpha}_1,2^(h,s), and K\b{eta}_1,3^s transitions are obtained. Thus, the average number of the spectator L-vacancies presented during the x-ray emission is deduced. From the relative intensities of the K{\alpha}_1,2^s and K{\alpha}_1,2^(h,s) transitions, the ratio of K-shell hollow krypton to singly K-shell ionized atoms is determined to be 14 - 24%. In the considered collisions, the K-vacancies are mainly created by the direct ionization which cannot be calculated within the perturbation descriptions. The experimental results are compared with a relativistic coupled channel calculation performed within the independent particle approximation.

One-dimension position sensitive MCP detector using a parallel strips readout anode

We have developed a one-dimension position sensitive MCP detector based on a new parallel micro-strips readout anode. The position resolution of the detector is 0.2mm.

Energy spectra of sputtering ions induced by Ar7, 9+ ions on graphite collisions

The Sputtering Ion Energy Spectra (SIES) produced by Ar7, 9+ ions at velocities of 0.9 vBohr, 1.35 vBohr and 1.8 vBohr bombardment at 45o to high oriented graphite target were obtained for the first time.

The Progress of the HIRFL-CSR Project and the Commissioning of the Cluster Target

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.

Single and double electron capture by fast Xe54+ from Kr and Xe

Decay X-ray spectrum of the scattered ions in 52-197 MeV/u Xe54+ collision with Kr and Xe atoms are measured. The transitions form the single capture ion Xe53+* and from the double capture ion Xe52+* are observed, both in a single collision. The single capture is the dominate channel at high energies while the double capture becomes dominate at lower energies.

Guiding effect of 900 keV O6+ through a single glass macro-capillary

We study the guiding effect of 900 keV O6+ through a single macro-capillary with two incident currents of 0.06 nA and 3.00 nA, which is independent on the incident current.

Partial-guiding effects of medium energy O6+ ions through a tapered glass macro-capillary

We measure the transmission of medium energy O6+ ions through a tapered macro-glass capillary with a diameter of 0.2mm at the exit. The results show that the defection angles are smaller than the tilt angles, i.e., the ions propagate the capillary unparalleled to its axis, leading to a partial-guiding effect.