Flux Monitoring on an X-Ray Refractive Diamond Lens

Synchrotron-based science has had a great scientific impact and will continue to have great impact going forward. For high brightness 3rd and 4th generation light sources, errors are almost completely due to distortion in the front-end optics caused by the high heat loads generated by the broadband radiation from the insertion device. Diamond offers a solution because of its low x-ray absorption and stability under high heat loads. Diamond grown with chemical vapor deposition (CVD) has been found to be an excellent material for detector applications and diamond-based detectors have been made for use with a variety of particles including heavy ions, electrons, neutrons, protons, and photons including UV and x-rays.Combining these thermal and electronic properties of diamond would provide a number of benefits for optical elements in an x-ray beamline. Knowing the beam flux through the optic allows one to place the maximum of the beam at the optic or to move the lens to the maximum. In the case of pulsed sources, the signal from a diamond optic acts as a timing signal for synchronization or provide better pulse-to-pulse normalization. Delaware Diamond Knives has produced a prototype refractive lens from single crystal diamond whose performance approached that of today’s commercially available optics. During Phase I, we prepared diamond refractive lenses, applied platinum electrical contacts to them and measured the signals from the lenses while moving them in the ISR beamline at NSLS-II. We concluded that the signals were sensitive enough to be useful in optimizing the position of the lens within the beam. During Phase II, we will build a prototype automatic lens positioning system, use this system for further testing of lens and system performance, make further improvements in the optical performance of the lens, develop low-Z contacts to reduce absorption, develop a number of other lens types and incorporate what we’ve learned into a final commercial design. The proposed approach has the potential for a significant impact on materials research at synchrotron facilities around the world. It solves an immediate and pressing problem for users of 3rd and 4th generation light sources by non-invasively providing flux and position information during experiments.