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.

中文翻译：

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演示使用来自静电电子冷却器的脉冲束进行电子冷却

强子束的冷却在下一代强子存储环中至关重要，以提供空前的性能。一种这样的应用是目前在美国正在开发的电子离子对撞机。与常规的静电方法相反，期望开发电子冷却器以使其能以比以前获得的能量高得多的能量运行，因此需要使用射频（rf）场进行加速。尽管电子冷却是利用直流束在低能量下的成熟技术，但射频加速要求冷却束成束，从而将参数空间扩展到未探索的领域。通过实验证明用电子束冷却的可行性并进一步研究两束电子束的相对时间结构如何影响冷却性能非常重要。从而，杰斐逊实验室和现代物理研究所（IMP）合作进行了一组四个脉冲束冷却实验。实验已成功地首次证明了使用电子束束在纵向和横向进行冷却。我们已经测量了电子束长度和纵向离子聚焦强度对纵向和横向离子束轮廓的时间演化的影响，并证明了如果可以精确地保持同步，则时间结构的变化不会对动力学产生不利影响。实验已经成功地证明了第一次使用电子束束在纵向和横向进行冷却。我们已经测量了电子束长度和纵向离子聚焦强度对纵向和横向离子束轮廓的时间演化的影响，并证明了如果可以精确地保持同步，则时间结构的变化不会对动力学产生不利影响。实验已经成功地证明了第一次使用电子束束在纵向和横向进行冷却。我们已经测量了电子束长度和纵向离子聚焦强度对纵向和横向离子束轮廓的时间演化的影响，并证明了如果可以精确地保持同步，则时间结构的变化不会对动力学产生不利影响。