High spatial resolution X-ray beam position monitor

An ionization chamber with capability to detect the spatio-temporal position of the traversing X-ray beams was developed. This novel detector, based on a quadrupole electrode arrangement, differs from usual parallel plate chambers. The device is used as a position monitor for synchrotron radiation X-ray beams. By combining this position sensitive chamber, that provides a linear range of up to few mm, with suitable current reading and control electronics we could stabilize the X-ray beam by feedback action on an optical element to 100 nm rms precision within the bandwidth of the correcting optics. The resolution of the device is only dependent on the signal to noise ratio at the electronic read out, and for many of our applications the resolution can be pushed below the 100 nm.