A method is for closed-loop control of an X-ray pulse chain generated via a linear accelerator system. In an embodiment, the method includes modulating a first electron beam within a first radio-frequency pulse duration, wherein the first multiple amplitude X-ray pulse is produced on modulating the first electron beam; measuring time-resolved actual values of the first multiple amplitude X-ray pulse; adjusting at least one pulse parameter as a function of a comparison of the specified multiple amplitude X-ray pulse profile and the measured time-resolved actual values; and modulating a second electron beam within a second radio-frequency pulse duration as a function of the at least one adjusted pulse parameter for production of the second multiple amplitude X-ray pulse, so the X-ray pulse chain is controlled.