Abstract
New designs of crystal spectrometers involving multiple Bragg reflections are described. Using synchrotron radiation from the National Institute Northern Accelerator (NINA) as a source, monochromatic X-ray intensities in the region of 1 AA are measured for two such devices made from perfect single crystals of silicon. The output intensity for one of these with an energy resolution of 5.6*10-5 is found to be 107 times greater than that obtained using a conventional 0.8 kV A bremsstrahlung source. Comparisons are made with other sources and applications are discussed.