Electrodeless, Non-Invasive X-Ray Flux Monitor

Flux monitoring is required at modern x-ray light sources for alignment, measurement feedback and calibration. Dedicated x-ray flux monitors occupy space, absorb part of the beam and cannot be easily relocated. At the same time numerous x-ray beamline elements (vacuum windows, monochromators, refractive lenses, zone plates to name a few) inevitably absorb a portion of the x-ray beam which is proportional to incoming flux. At present there are no devices which can measure flux non-invasively without causing any parasitic absorption. Euclid Techlabs LLC proposes a non-invasive, electrodeless method to measure x-ray absorption on the beamline element. This measurement utilizes a microwave resonator placed around the beamline element which is sensitive to photoinduced conductivity resulting from x-ray absorption. Microwave spectroscopy measurements, having an incredible dynamic range of six orders of magnitude are expected to be very sensitive. In Phase I we will produce a high quality factor resonator and perform microwave spectroscopy measurement on various samples exposed to x-ray beam. These samples will include the most popular x-ray beamline materials like diamond, silicon and kapton. The x-ray induced carrier lifetime and density depends on x-ray energy, material properties, dopants and defects. These numbers are not fully tabulated. We will measure a large number of samples to determine practical sensitivity numbers for x-ray flux monitoring. Applications and benefits: The proposed approach is plug and play and can be employed in a large number of x-ray beamlines all over the world. This non-contact flux measurement can potentially eliminate dedicated x-ray flux monitors which occupy space and absorb intensity. This technology will increase the efficiency of x-ray utilization, simplify sample management and help with beam delivery and alignment.