Electron-beam size measurement with a beam profile monitor using Fresnel zone plates

We have designed and constructed a non-destructive and real-time beam profile monitor in the KEK-ATF damping ring to measure the extremely small electron-beam size. The monitor has a microscopic structure where two Fresnel zone plates (FZPs) constitute an x-ray imaging optics. In the monitor system, synchrotron radiation from an electron beam is monochromatized by a silicon crystal and the transverse electron-beam image is twenty-times magnified by the two FZP and detected on the x-ray CCD camera With this monitor, we have succeeded in obtaining a clear electron-beam image and measuring the electron-beam size less than 10 μm. The measured magnification of the imaging optics was in good agreement with the design value.