Water-cooled Heat Load Chopper for High-energy Synchrotron Experiments

FIGURE 2. Traditional X-ray scattering experiment setup. Photo Credit: Argonne National Laboratory. In addition to the setup shown in Figure 2, time resolution at BioCARS is provided by precise synchronization of additional beam blocking equipment placed before the sample under test—two rotating disk choppers and a shutter [2]. The X-ray beam is intercepted by a watercooled heat load chopper which reduces the average power of the beam into bursts of pulses but does not attenuate the pulses. The continuously repeating bursts of pulses then travel through a shutter which isolates a single burst of synchrotron pulses. Finally, a high speed chopper is used to extract a single X-ray pulse from the isolated burst of pulses. This paper describes the design and testing of a new water-cooled air bearing heat load chopper with nanosecond-level jitter.