Development of an Ultraviolet Photon Detection System for Precision Laser Spectroscopy of Li-like ¹⁶O⁵⁺ Ion at the CSRe

Precision measurement of the radiation transition properties of highly charged ions are considered not only provides excellent conditions for precise testing of fundamental theoretical models such as strong field QED effects, relativistic effects, and electron correlation effects, but also contributes to many advanced physics research, including isotope shifts, HCI clock, etc. In order to perform precision laser spectroscopy of lithium-like ¹⁶O⁵⁺ ions to precisely measure the optical transition energy of 2s_1/2→2p_1/2 and 2s_1/2→2p_3/2 at the experimental cooler storage ring CSRe in Heavy Ion Research Facility in Lanzhou(HIRFL), a new non-destructive ultraviolet photon detection system has been developed for efficient detection of the forward-emitted ultraviolet photons. This detection system is mainly consisted of a SiC-made parabolic reflector, a MCP(Microchannel Plate) coated with CsI and a high-speed stepper motor. In the high temperature baking environment and ultra-high vacuum experimental conditions at the CSRe, this new detection system enables high-efficiency detection of the de-excitation ultraviolet photons without affecting the normal operation of the ion beams at the storage ring, and the collection efficiency is improved by more than 50 times as compared to the previously installed Channeltron photomultiplier photons detector. This new detection system will not only provide an efficient real-time detection tool for the precision laser spectroscopy of highly charged ions at the CSRe, but also lays a solid foundation for future research on precision laser spectroscopy of heavy ions with higher energies and higher charge state at High Intensity heavy-ion Accelerator Facility(HIAF).