Crystal spectroscopy and exotic atoms

Recent developments in crystal spectroscopy of X-rays emitted from exotic atoms concentrated on the measurement of the ground state level shift and width in pionic hydrogen. An increase of the pion beam intensity together with a sophisticated stopping technique combined with newly developed reflection spectrometers as well as with large area focal CCD detectors resulted in a gain of luminosity of three orders of magnitude. The potential of these achievements for an improved measurement of the vacuum polarization contribution in exotic atoms is discussed.