Quantifying the Heat Load to Conductors due to Strain Energy Release in CTD-101K Magnet Impregnant

State-of-the-art Nb ₃Sn superconducting accelerator magnets are still prone to lengthy training. This study investigates whether direct heat from fractures in commonly used magnet impregnant is sufficient to cause the instabilities during training. To do so, the strain energy release rate of CTD-101 K epoxy is measured in liquid nitrogen at 77 K, together with the temperature of a nearby copper element representing a Nb ₃Sn strand in the magnet windings. This experiment provides evidence that a large part of the mechanical energy is converted into heat. An analytical model using strain energy release rate data of impregnates at 4.2 K shows that this heat can contribute to the first quenches during magnet training.