Evaluation of the Texas Instruments' TC215-31 CCD for astronomical imaging

Abstract

The characterization and low light level performance of the TC215-31 CCD is presented. This device has 12 by 12 micron pixels in a 1024 x 1024 format, with an active image area of 1000 x 1018 pixels. The device is evaluated in terms of its linearity, dark current, charge transfer efficiency, and spectral response. The spectral response of this device in the range of 300 nm to 1000 nm is discussed. The structure of the virtual phase pixel is such that half of the area is covered by a clocking electrode, with the uncovered half remaining sensitive to UV light. Thus this device can be useful in the UV provided that special consideration of the sampling is taken into account. Noise characteristics of this device were measured as a function of clock levels, amplifier bias, readout speed, and temperature. The output of this device is unique in that there are two output amplifiers, one for every other pixel. The mean noise of the two output amplifiers is about 20 electrons, with a dark current of 0.016 electrons/sec at -130 C. This device was used as an astronomical imager at the prime focus of a small Schmidt telescope.