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A significant deceleration effect on a stored coasting ion beam by a continuous-wave laser light was observed in the Schottky-noise spectrum during the laser experiments with lithium-like oxygen ion beams stored at a relativistic energy of 275.7 MeV/u at the heavy-ion storage ring CSRe in Lanzhou, China. The observed deceleration range of the laser (Δp/p≈5.7×10−6) is much broader than the expected capture range (Δp/p≈3.6×10−8), as calculated from the natural linewidth of the O5+ ion’s electronic transition (2S1/2 −2 P1/2). In order to explain this huge deviation, a phase space tracking code has been developed to investigate the interaction between the stored coasting ion beam and the laser light. Simulations reveal that the deceleration range of the typically narrow CW laser force is highly enlarged by taking into account the transverse betatron oscillation of the ions with larger emittance and the angular misalignment of the laser light direction. The experimental observation is well described by the systematic simulations. The present work is crucial for forthcoming laser cooling and precision laser spectroscopy experiments and simulations on heavy highly charged ions at the CSRe and the future facility HIAF.

In this work, we present a comprehensive method to measure the gas parameters, such as the effective Townsend coefficient and electron drift velocity in homogeneous high electric fields (up to 100 kV/cm}) at atmospheric pressure and room temperature. A pulsed laser facility with micro-meter spatial accuracy and picosecond pulse duration is used to ignite primary ionizations at specific positions in the gas gap of a Resistive Plate Chamber (RPC) detector prototype. The gas parameters are determined solely by the RPC signals. The main component of the current standard gas for RPC is Tetrafluoroethane (R134a) which has a high Global Warming Potential. Therefore, using Tetrafluoropropene (HFO-1234ze) is under research as an eco-friendly substance. We measure the parameters of these two types of working gases.It is the first direct measurement of the gas parameters of timing RPCs under working conditions. By comparison with existing data from other investigation points, we observe a dependence of gas parameters on the pressure.