%0 Journal Article %J AIP APPLICATION OF ACCELERATORS IN RESEARCH AND INDUSTRY: Twenty-Second International Conference %D 2013 %T Reference free, high-precision measurements of transition energies in few electron argon ions %A Szabo, Csilla I %A Amaro, Pedro %A Guerra, Mauro %A Schlesser, Sophie %A Gumberidze, Alexander %A Santos, Jose Paulo %A Indelicato, Paul %E McDaniel, Floyd D %E Doyle, Barney L %E Glass, Gary A %E Wang, Yongqiang %I AIP %P 68-72 %U http://link.aip.org/link/?APC/1525/68/1 %V 1525 %X The use of a vacuum double crystal spectrometer, coupled to an electron-cyclotron resonance ion source (ECRIS), allows to measure low-energy x-ray transitions energies in highly-charged ions with accuracies of the order of a few parts per million. We have used this installation to measure the 1s2p 1 P1 - 1s2 1 S0 diagram line and the 1s2s 3 S1 - 1s2 1 S0 forbidden M1 transition energies in helium-like argon, the 1s2s2p 2 P j 1s2 2s 2 S1/2 transitions in lithium-like argon and the 1s2s2 2p 1 P1 - 1s2 2s2 1 S0 transition in beryllium-like argon. These transition measurements have accuracies between 2 and 4 ppm depending on the line intensity. Thanks to the excellent agreement between the simulations and the measurements, we were also able to measure the transition width of all the allowed transitions. The results are compared to recent QED and relativistic many-body calculations. %Z journal = {AIP Conference Proceedings}