UV-Optical CCDs

Mark Clampin,
Space Telescope Science Institute, 3700 San Marhu Drive Baltimore, MD 21218

ABSTRACT

We review the performance of large format CCDscurrently planned for instruments in space science missions to be flown the coming decade. With focal planes of up to a billion pixels, we review technical challenges in transferring this technology from ground-based to space imagers and identify areas for future development to facilitate these missions. The current capabilities of CCDs for UV imaging are also summarized and future directions for the development of CCDs suitable for wide field UV imaging are highlighted.

1. INTRODUCTION

The last decade saw an exponential increase in the size of CCD focal plane arrays for ground-based astronomy as shown in Figure 1 adapted from Luppino et al. 1998. Focal planes at the start of the decade were typically assembled with 2048x2048 CCDs, but the advent of a three-edge buttable 2048x4096 (2kx4k) format in the mid-nineties led to almost universal adoption of this format for the construction of focal plane mosaics. Current plans for the next generation of astronomical instrumentation require focal plane arrays based on 2kx4k CCDs with up to a billion pixels by the middle of this decade. Luppino et al.  (1998) first noted the exponential growth rate in pixel density and predicted that it would flatten out as CCD focal plane arrays fully sampled the working field of view of 8-10 meter telescopes. However, plans for 25 meter (Nelson and Mast 1999) to 100 meter aperture (Gilmozzi 2000) optical telescopes, wide field optimized 8m telescopes (Tyson), and new, high-angular resolution cameras   Kaiser et al. 2000) have provided new impetus to drive for even larger focal plane arrays.

Figure 1.

Plans for space astronomy missions in the new millennium include a number of missions which require large format imaging capabilities in the UV and optical, and are discussed by Morse in these proceedings. In Table 1 I have identified a selection of missions planned by NASA (Morse 2000), ESA and other missions under development by individual groups which are likely to require CCD imaging.

Table 1. A selection of NASA, ESA and University missions, or concepts which are likely to require CCD imagers for UV or visible imaging applications.

Mission	Format		BandPass	Instrument	Reference
Hubble Space Telescope/NASA	1 x	4kx4k	Visible	Wide Field Imager	Ford et al. 1998
Hubble Space Telescope/NASA	1 x	4kx4k	NUV/Visible	Wide Field Imager	Cheng et al. 2000
Fame/USNO	24 x	2kx2k	Visible	Astrometric Imager	Horner et al. 2000
Score/NASA-TBD		TBD	Visible	Coronographic Imager	See Morse 2000
Kepler/JPL	21 x	2kx2k	Visible	Planetary Transit Imager	Koch et al. 1998
GEST/Univ. Notre Dame	60 x	3kx6k	Visible	Micro-lensing/KBO Survey	Bennett, 2000
SNAP/LBL	250 x	2kx2k	Visible	High-Z Supernova Survey	Deustua et al. 2000
Legacy-1/NASA	~16kx16k		UV		See Morse 2000
PBD-8/NASA		TBD	Visible	Earth-like planet detection	See Morse 2000
COROT/ESA-	4	2kx2k	Visible	Planetary transit/astrometer	Weiss et al. 2000