A new type of transmissive pixel detector has been developed for synchrotron radiation diagnostics at Diamond Light Source. A thin single-crystal CVD diamond plate is used as the detector material, and a pulsed-laser technique has been used to write conductive graphitic electrodes inside the diamond plate. Instead of using traditional electrodes formed from a layer of surface metallisation, the graphitic electrodes are buried under the surface of the diamond and result in an all-carbon imaging detector. Within the instrument’s transmissive aperture there are no surface structures that could be damaged by exposure to radiation beams, and no surface metallization that could introduce unwanted absorption edges. The instrument has successfully been used to image the X-ray beam profile and measure the beam position to sub-micron accuracy at 100 Hz at Diamond Light Source. A novel modulation lock-in technique is used to read out all pixels simultaneously. Presented in this work are measurements of the detector’s beam position resolution and intensity resolution. Initial measurements of the instrument’s spread-function are also presented. Numerical simulations are used to identify potential improvements to the electrode geometry to improve the spatial resolution of similar future detectors. The instrument has applications in both synchrotron radiation instrumentation, where real-time monitoring of the beam profile is useful for beam diagnostics and fault-finding, and particle tracking at colliders, where the electrode geometries that buried graphitic tracks can provide increased the charge collection efficiency of the detector
