2016 May: Delivery of the SPIRou calibration module at IRAP/OMP

The SPIRou calibration module was delivered at IRAP/OMP and is currently under integration & tests in our premises.

The calibration module is composed of three sections: (i) the calibration unit itself designed and realized by the Observatoire de Haute-Provence (OHP) in southern France, (ii) the radial velocity (RV) reference unit designed and constructed by Geneva Observatory, and (iii) the calibration fibers manufactured by Le Verre Fluoré (France).  This module is key to calibrating and characterizing the spectrograph response, and to providing the best possible RV precision (1 m/s and 0.25 m/s on long and short timescales respectively), a top level requirement for detecting Earth-like exoplanets.

The calibration unit contains 5 slots for different light sources, including flat-field and hollow cathode lamps. Thanks to these lamps, one can achieve optimal extraction of 1D stellar spectra from the 2D images recorded by the spectrograph, including an accurate determination of how wavelengths project onto detector pixels.  The light from each lamp can be sent to either or both the Cassegrain Unit (feeding the twin stellar fibers) and the Spectrograph (feeding the RV reference fiber) using motorized trolleys. The radial velocity reference unit includes a Fabry-Perot etalon, stabilized in both pressure and temperature, that fibre-feeds the calibration unit.

Integration and tests of the calibration module are ongoing in the P2IS control-command and clean rooms at IRAP, and involve Rico Sottile, François Dolon, Sandrine Perruchot and François Moreau from OHP, with help from the IRAP/OMP team. The full series of tests will allow validating the module performances, and make it ready for the forthcoming tests with the instrument as a whole.