The science calibration system for the TMT NFIRAOS and client instruments: requirements and design studies

We present the results of the design studies of the science calibration system for the adaptive optics and infrared instruments of the Thirty Meter Telescope. The two major requirements of the science calibration system are to provide pupil-simulated telescope beams to the adaptive optics system for calibration of the telescope pupil and to provide flatfielding and wavelength-calibration illuminations to client instruments of the adaptive optics system. Our current system is composed an integrating sphere with calibration light sources, a retractable pupil-mask system, a lens assembly consisting of a pair of achromatic triplets, and fold mirrors. This system appears to be capable of producing highlyuniform of f/15 beams at the telescope focal plane and pupil simulation at a pupil location within the adaptive optics system. We describe the present design and development of the calibration system along with relevant analyses.