High-precision laser-assisted absolute determination of x-ray diffraction angles
- Max-Planck-Institute for Nuclear Physics, D-69117 Heidelberg (Germany)
A novel technique for absolute wavelength determination in high-precision crystal x-ray spectroscopy recently introduced has been upgraded reaching unprecedented accuracies. The method combines visible laser beams with the Bond method, where Bragg angles ({theta} and -{theta}) are determined without any x-ray reference lines. Using flat crystals this technique makes absolute x-ray wavelength measurements feasible even at low x-ray fluxes. The upgraded spectrometer has been used in combination with first experiments on the 1s2p {sup 1}P{sub 1}{yields} 1s{sup 2} {sup 1}S{sub 0} w-line in He-like argon. By resolving a minute curvature of the x-ray lines the accuracy reaches there the best ever reported value of 1.5 ppm. The result is sensitive to predicted second-order QED contributions at the level of two-electron screening and two-photon radiative diagrams and will allow for the first time to benchmark predicted binding energies for He-like ions at this level of precision.
- OSTI ID:
- 22063756
- Journal Information:
- Review of Scientific Instruments, Vol. 83, Issue 1; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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