Development Status of In Situ Insertion Device Field-Measurement System at KEK

We are developing an in situ insertion device field-measurement system for the next-generation light source ring. With our conventional magnetic field-measurement system, measurement is restricted to the development hall, in air, without the vacuum chamber and before installation into the synchrotron. It is necessary to remove these restrictions to prevent brightness degradation of the hard X-ray light of 3-GeV class low-emittance rings. These limitations on the measurement are due to the huge size of our conventional system. The new measurement system under development has both portability and stability by utilizing the rigid metal beam of the undulator frame as part of the system. Based on the results of our test machine, we modified the system design, manufactured the main components for an actual machine and measured their performance. The results indicate a successful first stage of development.