Imaging Fourier transform spectrometer withphotoconductive detector arrays: an application to theAKARI far-infrared instrument

摘要

We have developed an imaging Fourier transform spectrometer (iFTS) for space-based far-infrared astronomical observations. The iFTS employs newly developed photoconductive detector arrays with a capacitive trans-impedance amplifier, which makes the iFTS a completely unique instrument. The iFTS was installed as a function of the far-infrared instrument (FIS: Far-Infrared Surveyor) on the Japanese astronomical satellite, AKARI, which was launched on February 21, 2006 (UT) from the Uchinoura Space Center. The iFTS had worked properly in the space environment as well as in laboratory for more than one year before liquid helium ran out on August 26, 2007. The iFTS was operated nearly six hundreds of pointed observations. More than one hundred hours of astronomical observations and almost the same amount of time for calibrations have been carried out in the mission life. Meanwhile, it becomes clear that the detector transient effect is a considerable factor for FTSs with photoconductive detectors. In this paper, the instrumentation of the iFTS and interesting phenomena related to FTSs using photoconductive detectors are described, and the calibration strategy of the iFTS is discussed briefly.