  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].
