Upgraded calibrations of the Thomson system at DIII-D

The DIII-D Thomson system measures electron density (n(e)) and temperature (T-e) with eight pulsed ND:YAG lasers along three paths through the plasma vessel. The components of the Thomson system are absolutely calibrated so t he measurements can be combined into a single profile from a normalized pla sma radius (rho) of about 0.1 to the edge of the plasma. A monochromator ca libration and opto-electronic calibration measure the detectors' absolute s ensitivity to background and pulsed light. A Rayleigh scattering calibratio n and transmission calibrations measure the transmission of light to the de tectors. The calibration systems are being upgraded to reduce the effect of systematic errors on the temperature and density measurements. The observe d systematic errors can be estimated by comparing fits to averaged profiles to the average profiles. The contributions of the systematic uncertainties relative to the statistical uncertainties of the measurement are discussed through simulations and experimental data. (C) 2001 American Institute of Physics.