Design and Predicted Performance for the ITER Electron Cyclotron Emission Diagnostic System

One of the primary diagnostics for measurement of the electron temperature (T_e) on ITER is based on the detection of electron cyclotron emission (ECE). Here we describe the predicted performance of the newly completed ECE diagnostic design in fulfilling the diverse roles required by ITER. These roles include conventional measurement of T_e, detection of instabilities and MHD modes, and support for runaway measurements. While the primary focus is on operation at the full ITER field of 5.3 T, critical features of the emission spectra during pulse ramp-up and termination are also addressed. ECE will be collected by two nearly identical optical systems: one providing a radial view and the other an oblique view. Both views are used for T_e measurements, while the oblique view additionally enables detection of non-thermal distortions in the electron momentum distribution. An in-vacuum calibration source is integrated into the front end of each view to account for potential degradation of in-vessel optics. The design of the radiometers used for 5.3 T will be described in detail.