TibaRay has developed a beam monitor that is capable of resolving the nanosecond-scale bunch structure within individual linear accelerator pulses. This speed makes inter-pulse beam control (on the millisecond time scale) readily achievable, and even creates the possibility of intra-pulse beam control, i.e., measurement and interruption of partial pulses on the microsecond time scale. We have now designed and prototyped the next stage of integration of this concept, by building a beam monitoring RF cavity directly within a 6 MeV FLASH electron linear accelerator structure. The aims of this proposal are to validate the calibration of our integrated RF beam monitor for absolute charge and absolute dose under FLASH irradiation conditions, and to demonstrate a basic closed loop feedback system capable of interrupting the beam between pulses based on the detected signal. With this validation, our approach would represent a general platform for ensuring safe and robust delivery of FLASH RT in the clinic.
