Open AccessCalibration methods for ITER core LIDAR
Author(s) -
R. Pasqualotto,
L. Giudicotti,
A. Alfier,
Mike Walsh
Publication year - 2010
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/227/1/012044
Subject(s) - optics , calibration , shutter , physics , thomson scattering , laser , diffuser (optics) , wavelength , core (optical fiber) , light source , quantum mechanics
The standard technique for the relative calibration in present Thomson scattering diagnostics, can be used in ITER only if the full collection path is included in the calibration: indeed, the in-vessel optics will be exposed to neutron and gamma irradiation and particle flux, that will likely cause a distortion of the spectral transmission curve. The standard scheme would ask to position a diffuser in front of the first collection mirror, e.g. on the protective shutter, and to illuminate it with a light source nearby. Alternatively, a back illumination scheme could be used, with a more efficient retroreflector array. A completely different approach is based on TS measurements from two lasers with different wavelengths: this self-calibrating method does not require any in-vessel tool and will provide both the electron temperature and the relative sensitivity of spectral channels