Experimental demonstration of OSC at IOTA: IOTA Run #3 Report

Optical Stochastic Cooling (OSC) is an optical-bandwidth extension of Stochastic Cooling that could advance the state-of-the-art cooling rate in beam cooling by three to four orders of magnitude [1-3]. The concept of OSC was first suggested in the early 1990s by Zolotorev, Zholents and Mikhailichenko, and replaced the microwave hardware of SC with optical analogs, such as wigglers and optical amplifiers. A number of variations on the original OSC concept have been proposed, and while a variety of proof-of-principle demonstrations and operational uses have been considered, the concept was not experimentally demonstrated up to now [4-9]. An OSC R&D program has been underway at IOTA for the past several years [4]. Run #3 of the IOTA ring, which began in Nov. 2020 and concluded in Aug. 2021, was focused on the worlds first experimental demonstration of OSC. The experimental program was successful in demonstrating and characterizing the OSC physics with the major outcomes including strong cooling in one, two and three dimensions, validation of the theoretical models of OSC and the demonstration of OSC with a single electron. This report briefly describes the activities and major milestones of the OSC program during Run #3. Detailed descriptions of the OSC theory, conceptual design and hardware elements can be found in reference [4].