Speaker
Description
NanoTerasu, a new 3 GeV synchrotron light source constructed in Sendai, Japan, started user operation in April 2024 and steadily increased its stored beam current. With increasing stored beam current, the ceramic chamber in the storage-ring injection kicker section was found to be heated by Joule heating due to image currents. The chamber temperature was predicted to reach approximately 90°C at the target stored beam current of 400 mA.
The kicker magnet is constructed from laminated silicon steel sheets and insulating layers fastened together with bolts, raising concerns about its performance at elevated temperatures. To suppress the temperature increase, air-cooling fans and cooling units were installed to cool the kicker magnets.
As a result, the target current of 400 mA was successfully achieved in September 2025. The implemented cooling measures successfully maintained the ceramic chamber temperature at approximately 40°C, significantly lower than the previously predicted value of about 90°C at 400 mA. Operation at 400 mA has remained stable through October 2026.
This presentation reports the countermeasures implemented to address the heating issue and presents temperature data obtained under various cooling configurations, together with the results of thermal analysis simulations performed using ANSYS.