Abstract Details
| Name: Ravinder K Banyal Affiliation: Indian Institute of Astrophysics Conference ID: ASI2016_709 Title : Development of a Fabry-Perot Wavelength Calibrator for High Precision Doppler Spectroscopy Authors and Co-Authors : Ravinder K Banyal, Tanya Das, B. Ravindra and T. Sivarani Abstract Type : Poster Abstract Category : Instrumentation and Techniques Abstract : There are two major challenges that need to be overcome for doing high precision spectroscopy. First is the spectrograph instability (zero-point drift) largely caused by slow temperature and pressure changes and second is to do with the limitations imposed by traditional calibration methods. The accuracy of the wavelength solution obtained from the emission lamps has serious drawbacks arising from the uneven line spacing, large intensity variations, limited wavelength coverage and spectral contamination from unknown sources. In this paper, we will present our work on proposed wavelength calibrator using Fabry-Perot (FP) interferometer to achieve a 1-10 m/s radial velocity precision. A large number of wide-band (500nm-650 nm) transmission lines of the FP will provide a highly stable and uniform frequency scale for a medium resolution (R~ 40000-60000) astronomy spectrograph. We also describe a frequency locking mechanism that we propose to control and eliminate the long term cavity drift by anchoring the complete transmission spectra of the FP cavity to an intrinsically stable fundamental atomic lines of the Rb-cell. In terms of stability and spectral coverage, FP calibrator is expected to reach a performance level of a laser frequency comb but with a significantly lesser cost and completely off-the-self components. |