In the ITER Core Plasma Thomson Scattering, the scattered light collection optics system is installed both inside and outside the diagnostic port under vacuum. The length of the optical path (∼6 m) and the need to shield the neutron and γ radiation increased the complexity of the system with the inclusion of multiple dog-legs, forcing the use of many elements with optical power. Multiple rounds of design have been required in order to satisfy iteratively the system requirements in terms of resolution, aberration, and shielding. The adoption of quasi-free-form reflective surfaces for several mirrors eventually allowed the correct compromise between all conflicting requirements.
M. Bassan1,2 R. Huxford3, B. Crowther4, R. Scannell5, G. Vayakis2, and M. Walsh2
- 1ITRE srl, Campodarsego PD 35011, Italy
- 2ITER Organization, CS 90 046, F-13067 Saint Paul Lez Durance Cedex, France
- 3RBH Optics, Burgess Hill RH15 8HL, United Kingdom
- 4Synopsis, Inc., Mountain View, California 94043, USA
- 5UK Atomic Energy Authority, Culham Science Center, Abingdon OX14 3DB, United Kingdom