Radio Frequency Knock Out (RF-KO) resonant slow extraction is commissioned at the Cooler Synchrotron (COSY) Jülich for the first time to extract the stored beam and deliver spills with constant particle rates to the experiments. Therefore, transverse RF excitation generated with a software-defined radio is applied to control the extraction rate. A built-in feedback system adjusts the excitation amplitude to maintain the desired extraction rate. To suppress fluctuations of the particle rate on timescales of milliseconds and below, an optimization algorithm is used to tune the RF excitation signals. The method was used extensively during the final run of COSY in 2023, reliably delivering stable beams to various users.

The operation of the COler SYnchrotron COSY and its further development ended in October 2023. We briefly review the operation of the accelerator facility and continuous development of its sub-systems. Additionally, this work is put in context of the transformation process that COSY operation and the Institute of Nuclear Physics (IKP) of the Research Center Jülich went through starting 2015. Furthermore, the decommissioning strategy along with the possible further use of COSY components are discussed.

Radio Frequency Knock Out (RF-KO) resonant slow extraction is commissioned at the Cooler Synchrotron (COSY) Jülich for the first time to extract the stored beam and deliver spills with constant particle rates to the experiments. Therefore, transverse RF excitation generated with a software-defined radio is applied to control the extraction rate. A built-in feedback system adjusts the excitation amplitude to maintain the desired extraction rate. To suppress fluctuations of the particle rate on timescales of milliseconds and below, an optimization algorithm is used to tune the RF excitation signals. The method was used extensively during the final run of COSY in 2023, reliably delivering stable beams to various users.