Simulation For Laser Cooling Of Relativistic¹⁶O⁵⁺ions And Development Of New Photon Detection System At The CSRe

High-quality ion beams with small longitudinal momentum spread and low transverse emission obtained by cooling on the heavy ion storage rings are the basic for conducting precision atomic physics experiments with highly charged ions.Laser cooling has the advantages of fast cooling rate,high efficiency and strong action force compared with the electron cooling and stochastic cooling and is the most promising cooling scheme to achieve phase transition and obtain ordering beam or even crystalline beam on storage rings.The experimental study of precision laser spectroscopy of highly charged ions combined with electron cooling on the basis of laser cooling is expected to achieve a breakthrough in experimental methods and accuracy,thus realizing high-precision tests of fundamental physical theoretical models such as strong field QED effects,electron correlation effects,relativistic effects,and nuclear effects,etc.Recently,we have successfully achieved laser cooling of relativistic Li-like ¹⁶O⁵⁺ion beams at the experimental cooler storage ring CSRe in the Institute of Modern Physics(IMP),Lanzhou.To our knowledge,the ¹⁶O⁵⁺ions are of the highest charge state and at the highest energy that have been ever cooled by laser cooling and the longitudinal momentum spread of the laser cooled ion beams is less than 5×10^-6.In order to interpret the anomalous experimental results,we carried out simulations of the longitudinal Schottky noise spectrum of coasting ion beams and bunched ion beams on the storage ring.The simulations revealed the following:first,the longitudinal Schottky noise spectrum of the coasting ion beams can accurately and rapidly reflect the momentum spread,beam energy,beam current,beam lifetime and many other key parameters of the ion beam.Second,the betatron oscillation of the ions in the storage ring causes a significant broadening of the laser deceleration range,which successfully explains the abnormal laser action range in the laser cooling experiments.Third,the power of the central peak in the Schottky noise spectrum of the bunched ion beams is proportional to the square of the number of ions in the bucket,and the total power of the sideband peak is proportional to the number of ions,which successfully explains the existence of an extremely strong central peak in the Schottky noise spectrum of the laser cooling of bunched ion beams experiments and lays the foundation for the study of the dynamics of the super-cooled ion beams.Furthermore,in order to perform precision laser spectroscopy experiments of lithium-like ¹⁶O⁵⁺ions in the storage ring CSRe,a new photon detection system suitable for UV forward-emitted photon collection and measurements has been designed and installed,and an experiment of precision laser spectroscopy of ¹⁶O⁵⁺ions using a 220 nm laser combined with this new photon detector is planned at the end of 2021.The experimental and simulation of laser cooling relativistic ¹⁶O⁵⁺ion beams and the development of new photon detection system for precision laser spectroscopy of highly charged ions at the storage ring CSRe in this thesis provides a solid foundation for laser cooling and precision laser spectroscopy of ultra-high energy and ultra-high charged ions on the HIAF,the High Intensity heavy-ion Accelerator Facility during the next National Twelfth Five-Year Plan period.