Toroidal interferometer/polarimeter density measurement system on ITER

In order to measure the line integrated electron density on the International Thermonuclear Experimental Reactor (ITER), a vibration-compensated five-channel CO2 laser interferometer/polarimeter system is being developed. The design of the interferometer/polarimeter has been improved from the previous design, which used a CO2 laser (wavelength, lambda=10.6 mum) and a CO laser (lambda=5.3 mum), on the basis of experience gained with a dual CO2 system (lambda=10.6 and 9.27 mum) on JT-60U. The JT-60U system gives good reliability for both interferometry and polarimetry operation. The performance of the dual CO2 laser is expected to meet the requirements for measurements on ITER (accuracy; 1%, time resolution; 1 ms). (C) 2004 American Institute of Physics.