Hello, This is a bit of a long shot, but does anyone know any good references for information relating vacuum pressure to thermal conductivity in a Dewar? I am building a small Dewar with a multistage thermoelectric cooler inside and I need to calculate some theoretical values for the heat load at different pressures. I have tried numerous google searches, but basically all I have found is that people genearlly use pressures of 10 millitorr or less Thank you, Glenn _______________________________________________ http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist