Active interlock for storage ring insertion devices

The insertion devices in the NSLS (National Synchrotron Light Source) X-ray ring produce such intense photon beams that passive measures alone are not adequate to protect the vacuum chamber. An active interlock is used to prevent thermal damage from improperly steered electron beams. The interlock system measures the position of the electron beam on both sides of the insertion devices using pickup electrodes and interrupts the RF if the beam moves outside a safe window. The interlock features redundant circuitry as well as an automatic testing procedure