Package

The devices will be mounted in a compact Peltier cooled package similar to that shown in Fig. 3. Peltier cooler and package will be custom designed and able to cool the CCD sufficiently to meet DC requirements over the full operating frame rates. The estimated power dissipation of the CCD at 1,200 fps (worst case scenario) is shown in Table 2. The Peltier cooler, ceramic chip carrier and CCD will be glued by a thermally conductive epoxy adhesive. The package will be sealed and filled with 0.9 bar of Krypton gas to minimize heat transfer to the outside.

Table 2. Estimated total and on-chip power dissipation of CCD220 at 1,200 fps.

Section

Load

Delta V

Mean f

Wtotal

"Won-chip

Image

4.2 nF

10 V

185 kHz

78 mW

23 mW

Store

3.6 nF

10 V

370 kHz

133 mW

40 mW

Register

1.5 nF

10 V

13.2 MHz

2.0 W

800 mW

HV

0.4 nF

45 V

13.6 MHz

11.0 W

220 mW

Amplifiers

8X50 mW

400 mW

Total

~1.5 W

The CCD220 die will have four fiducial crosses situated with two on either side of the device image area, in the region of the bond pads. These will be clearly visible through the package window for alignment purposes such as when attaching lenslet arrays. An AD590 temperature sensor will be glued to the ceramic chip carrier to provide sensor for temperature regulation. The sapphire entrance window will be of a high optical quality (double path wavefront error of <50 nm rms), good surface quality (defects meet 5/2x0,05 DIN3140), and AR coated with transmission >98% over range 400-950nm.

Figure 3. Photograph of CCD65 Peltier cooling package. The AO CCD220 detector will use a similar Peltier package. Dimensions shown are the requirements on the maximum package size.

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