Novel passive resonant structures for precision assembly of synchrotron X-ray optics

Abstract Many optics at synchrotron and free electron laser facilities need to be cooled to dissipate the heat imparted by the intense photon beams. For indirectly cooled optics, distortion of the surface can occur when excessive or asymmetrical clamping forces are applied during assembly. To address this issue, it is necessary to monitor the effects of assembly and subsequent life cycle of the clamping forces applied to the crystal. We present experimental verification of a non-contact approach to the monitoring of clamping forces applied to the first crystal of a monochromator at Diamond Light Source using additively manufactured passive resonant structures. Laser vibrometery demonstrates the efficacy of this novel approach for assembly of indirectly cooled optics based on feedback from passive resonant structures. Fizeau interferometry of the optical surface reveals greater uniformity and repeatability when compared with a conventional approach to assembly. Furthermore, frequency shifts in the range of 20-60 Hz were observed in the passive structures after cryogenic cooling, indicative of a change in clamping force of up to approximately 25%.