Conceptual design of new polychromator on Thomson scattering system to measure Zeff

To measure the Z(eff) with electron temperature (T-e) and electron density (n(e)) profiles at the same time and the same position in the KSTAR tokamak, we design a new polychromator for Thomson scattering system that has additional function. The additional function is measuring bremsstrahlung intensity to calculate Z(eff) independent of Thomson signals. For this new polychromator, we design and fabricate a collimation lens set, and interference filter that has center wavelength of 523 nm and 2 nm FWHM. Finally, we change the lenses, detector diodes, and add the bremsstrahlung filter on the KSTAR edge Thomson scattering polychromator. Then this new polychromator was tested by Tungsten light and monochromator. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4733737]