R and D ITPA Activities in Support of Optimizing ITER Diagnostic Performance

Full text: While much progress has been accomplished in the detailed design and integration of the ITER diagnostics, a few generic issues related to ITER environment are still outstanding. ITER diagnostics will experience harsh conditions including but not limited to large radiation flux and fluence, large neutral (atomic) flux, large heat flux at the first wall, reduced access, difficult calibration schemes and long pulses. Addressing these issues and how they can affect diagnostic performance are the focus of the Topical Group's High Priority Items, which are: 1) Development of methods of measuring the energy and density distribution of escaping alpha particles; 2) Assessment of the calibration strategy and calibration source strength needed for the neutron diagnostics; 3) Determination of the life-time of plasma facing mirrors used in optical systems; 4) Assessment of techniques for measurement of dust and erosion; 5) Assessment of impacts of in-vessel wall reflections on optical diagnostics; and 6) Assessment of the measurement requirements for plasma initiation and identification of potential gaps in planned measurement techniques. This paper will describe these issues and present the current status in the development of solutions and accompanied R and D. Other topics, such as protection of diagnostics in presence of large microwave stray power will also be discussed. This work was supported in part by the US Department of Energy under DE-FC02-04ER54698, and in part by the National Research Foundation, Korea. (author)