Mulyani, E. Flanagan, J.W. JACoW Geneva, Switzerland 978-3-95450-176-2 10.18429/JACoW-IBIC2015-TUPB025 English 377-380 TUPB025 detector photon optics electron emittance Contribution to a conference proceedings 2016 2016-01 http://dx.doi.org/10.18429/JACoW-IBIC2015-TUPB025 http://accelconf.web.cern.ch/AccelConf/IBIC2015/papers/tupb025.pdf We describe the design of coded aperture optical elements for the SuperKEKB x-ray beam size monitors. X-ray beam profile monitor are being installed in each ring of SuperKEKB (LER and HER) to provide high resolution bunch-by-bunch, turn-by-turn measurement capability for low emittance tuning, collision tuning and instability measurements. We use two types of optical elements, single-slit (pinhole) and multi-slit optical elements (coded apertures, CA). CA imaging offers greater open aperture than a single pinhole, for greater photon throughput and better statistical resolution for single-shot measurements. X-rays produced by a hard-bend magnet pass through a pinhole or CA optical element onto a detector. The resolution is obtained by calculating the differences between the images recorded by the detector for various simulated beam sizes, for a given number of photons. The CA elements that we have designed for use at SuperKEKB are estimated to provide 1.25-2.25 microns resolution for 10-25 microns of vertical beam sizes at 1 mA bunches. We present the design principle and optimizing process used to optimize the resolution at various beam sizes for SuperKEKB.