Mulyani, E. Flanagan, J.W. JACoW Geneva, Switzerland 978-3-95450-177-9 10.18429/JACoW-IBIC2016-TUPG72 English 525-528 TUPG72 emittance factory detector scattering optics Contribution to a conference proceedings 2017 2017-02 http://dx.doi.org/10.18429/JACoW-IBIC2016-TUPG72 http://jacow.org/ibic2016/papers/tupg72.pdf X-ray monitors (XRM) have been installed in each SuperKEKB ring, the Low Energy Ring (LER) and High Energy Ring (HER), primarily for vertical beam size measurement. Both rings have been commissioned in Phase I of SuperKEKB operation (February-June 2016), and several XRM calibration studies have been carried out. The geometrical scale factors seems to be well understood for both LER and HER. The emittance knob ratio method yielded results consistent with expectations based on the machine model optics (vertical emittance ε_{y} is {§I{≈8}{pm}}). For the HER, the vertical emittance ε_{y} is {§I{≈41}{pm}}, which is 4× greater than the optics model expectation. Analysis of beam size and lifetime measurements suggests unexpectedly large point response functions, particularly in the HER.