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Submitted by Anders89 on Tue, 05/04/2010 - 03:23 I wanted to pass along the results of my work with simulating the thermal system for a large CCD camera we are building - this is a dynamic model of the heat flow using cascaded elements, in effect a 1 dimensional slice through the camera assuming it is symmetric about the center (not strictly true, but good enough for the model). Surprisingly, the real data agrees with the model quite well, to ~10% - much better than I'd hoped given the approximations. The differences are probably unmodeled radiative effects in the internal elements - its hard to know the real surface emissivities, and there isn't really a lot of good data on material characteristics at these temperatures. I attach the model and a spreadsheet that contains data and renderings of the camera. The cooling is provided by 2-stage variable-speed helium cryo-pumps, I've put in curves for 2 speeds, might get around to doing an interpolation table to look at controlling the temperature by varying the pump speed but that isn't the operating plan at the moment. Hope this is interesting/useful... Mark F. Waterson Sr. Detector Engineer Mount Stromlo Observatory Research School of Astrophysics and Astronomy Australian National University Cotter Rd Weston, ACT 2611 Australia Skymapper Camera temperature flow.vsm