MOA01
IMP/CAS, Lanzhou, People’s Republic of China
USTRAT/SUPA, Glasgow, United Kingdom
Fudan University, Shanghai, People’s Republic of China
USTC, Hefei, Anhui, People’s Republic of China
University of Leicester, Department of Physics and Astronomy, Leicester, United Kingdom
Based on the successful DR measurement of Be-like Ar14+* and Ca16+** at the cooler storage ring CSRm, the absolute electron-ion recombination rate coefficients for Na-like Kr25+ ions have been determined at the cooler storage ring CSRm at the Institute of Modern Physics in Lanzhou, China. In the electron-ion collision energy range 0-70 eV resonances due to 3s-3p,3d (DeltaN = 0) and 3s-4l (DeltaN = 1) core excitation were detected. The resonant energies and strengths were obtained by fitting to the spectrum with a anisotropic electron-energy distribution and compared to the calculated ones by using a relativistic configuration interaction flaxcible atomic code (FAC) and the distorted-wave collision package AUTOSTRUCTURE. The merged-beams recombination rate coefficients are then convolved with a Maxwellian-boltzmann distribution to obtain the temperature dependent plasma recombination rate coefficient (PRRC) within the temperature range 103-108 K.
*Z.K. Huang, W.Q. Wen, X. Xu, et al., Astrophys J Suppl S, 2018; 235, 2.
**S.X. Wang, X. Xu, Z.K. Huang, et al., The Astrophysical Journal, 2018; 862, 134.
TUPS16
IMP/CAS, Lanzhou, People’s Republic of China
HZDR, Dresden, Germany
Xidian University, Xi’an, People’s Republic of China
TU Darmstadt, Darmstadt, Germany
GSI, Darmstadt, Germany
Laser cooling of Li-like O5+ ion beams with an relativistic energy of 275.7 MeV/u was achieved for the first time at the heavy-ion storage ring CSRe in Lanzhou, China [*,**]. In the experiment, a CW la-ser system with a wavelength of 220 nm was used to interact with the closed 2s1/2-2p1/2 optical transi-tion of O5+ ions. In order to cool the relativistic ion beams with only one counter-propagating CW laser, the ion beams were bunched by applying a sinusoidal voltage to the RF-buncher system. The relative longitudinal momentum spread dp/p of laser-cooled ion beams reached 1×10-6. The O5+ ions are of the highest charge state and highest beam energy that have ever been cooled by laser cooling method. We will present the very recent experimental results on this COOL 2019 workshop. Based on this successful laser cooling experiment, the precision laser spectroscopy experiment of O5+ ions is in preparation at the CSRe. A new optical detector is under design and will be installed at the CSRe to measure the forward-emitted fluorescence by the laser-excited O5+ ions [***,****]. The high voltage of the electron cooler will be precisely calibrated to determine the beam energy. Precision laser spectroscopy of O5+ ions to measure the transition energy of 2s1/2-2p1/2 and 2s1/2-2p3/2 is foreseen, and the relative accuracy could reach 1×10-5.
*Wang H B, et al., in preparation
**Wen W Q, et al, 2019 Hyperfine Interact. 240 45
***Hannen V, et al., 2013 JINST 8 09018
****Winters D, et al., 2013 Phys. Scr. T156 014089