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An electron target is proposed for high precision experimental measurement at the SRing (Spectrometry Ring) of HIAF (High Intensity heavy ion Accelerator Facility). It provides low temperature electron beam with a few meV for DR (Dielectronic Recombination) experiments at the energy of 1-��I{80}{keV}. For such a low temperature, the conventional method is adopted by magnetic adiabatic expansion with a factor of 30 after acceleration within 1.2T longitudinal magnetic field at gun section. In this paper, the design optimization of the electron target is introduced., Proceedings of the 13th International Workshop on Beam Cooling and Related Topics, COOL2021, Novosibirsk, Russia

Electron cooling continues to be an invaluable technique to reduce and maintain the emittance in hadron storage rings such as the EIC and EICC where stochastic cooling is inefficient and radiative cooling is negligible. Extending the energy range of electron coolers beyond what is feasible with the conventional, electrostatic approach necessitates the use of RF fields for acceleration and, thus, a bunched electron beam. To experimentally investigate how the relative time structure of the two beams affects the cooling properties, we have set up a pulsed-beam cooling device by adding a synchronized pulsing circuit to the conventional electron source of the CSRm cooler at Institute of Modern Physics. Using both constant and modulated synchronization between electron pulses and ion bunches, we have measured the effects of the electron bunch length and longitudinal ion focusing strength on the temporal evolution of the longitudinal and transverse ion beam profile and demonstrated the detrimental effect of timing jitter as predicted by space-charge theory and simulations. Our experiment suggests a need for further investigations of specific aspects of bunched cooling such as synchro-betatron coupling and phase dithering effects when using short electron bunches to cool longer ion bunches. However, given the comparatively long IBS lifetime of higher-energy proton storage rings like the EIC, slow dithering could potentially provide an option to save cost on the electron cooler linac., Proceedings of the 13th International Workshop on Beam Cooling and Related Topics, COOL2021, Novosibirsk, Russia

The 450 keV electron cooler was proposed to boost the luminosity of high-density internal targets experiment in the spectrometer ring at HIAF. The project is funded since the end of 2019. The cooler is designed based on changes of the 300 keV cooler at IMP, which was made by BINP in 2004. In this paper, experimental testing results of the prototypes of the coils, electron gun and collector are reported. The technical challenges and solutions on the 450-kV high voltage system are discussed., Proceedings of the 13th International Workshop on Beam Cooling and Related Topics, COOL2021, Novosibirsk, Russia

The hadron beam cooling plays an important role in the future e-i collider machines to achieve various physical goals. In EicC, two-stage beam cooling scheme is proposed to maintain the luminosity during the long time collision. First, a traditional electron cooler will be used to pre-cool the low energy proton beam in the BRing. Then, an ERL-based electron cooler will be applied at the pRing to cool the proton beam at high energy. The main purpose of cooling is to counteract the emittance growth due to the IBS. In this paper, we focus on the high energy beam cooling and present some simulation studies on how the cooling rate will be affected by the electron bunch size, magnetic field, and ring parameters in the cooling section, which would be helpful for the cooler design., Proceedings of the 13th International Workshop on Beam Cooling and Related Topics, COOL2021, Novosibirsk, Russia

Cooling of hadron beams is critically important in the next generation of hadron storage rings for delivery of unprecedented performance. One such application is the electron-ion collider presently under development in the US. The desire to develop electron coolers for operation at much higher energies than previously achieved necessitates the use of radio-frequency (RF) fields for acceleration as opposed to the conventional, electrostatic approach. While electron cooling is a mature technology at low energy utilizing a DC beam, RF acceleration requires the cooling beam to be bunched, thus extending the parameter space to an unexplored territory. It is important to experimentally demonstrate the feasibility of cooling with electron bunches and further investigate how the relative time structure of the two beams affects the cooling properties; thus, a set of four pulsed-beam cooling experiments was carried out by a collaboration of Jefferson Lab and Institute of Modern Physics (IMP). The experiments have successfully demonstrated cooling with a beam of electron bunches in both the longitudinal and transverse directions for the first time. We have measured the effect of the electron bunch length and longitudinal ion focusing strength on the temporal evolution of the longitudinal and transverse ion beam profile and demonstrate that if the synchronization can be accurately maintained, the dynamics are not adversely affected by the change in time structure., Comment: 13 pages, 19 figures. Submitted to Physical Review Accelerators and Beams