ELOG CARME

AIDA GELINA BRIKEN nToF CRIB ISOLDE CIRCE nTOFCapture DESPEC DTAS EDI_PSA 179Ta CARME StellarModelling DCF K40

CARME

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Sat Sep 26 09:31:46 2020

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Sat 26 Sep

09:15 Baking started automatic mode

13:30 Baking continues, heating is slower than expected due to high chamber bottom temperatures

00:00 Baking stopped. Temperatures won&#39;t increase due to high temperature of the bottom of the chamber producing thermal gradients that are too high. I believe this is due to heaters being closer to the chamber as tray sits higher up than in previous test (see heaters.png). A shield above the heaters, similar to those we utilised in early tests in Edinburgh, may help to disperse the heat more evenly around the baking volume and not directly at the bottom of the chamber. I can improvise a shield similar to those using pieces of the aluminium outer layer of the baking setup I have spare on Monday and restart baking. This will also allow me to replace the two damaged thermocouples

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Sun 27 Sep

11:50 Baking restarted. Manually set temperature to 50 C. Started automatic mode for additional safety checks. Will check again / increase temperature manually in a few hours

13:45 Found baking had stopped due to automatic mode detecting negative temperature gradient in TC7 Floating (bottom). See plot attached. Restarted baking at 50 C in manual mode

17:30 Found temperatures had stabilised. Increased temperature to 60 C. Issues seems to be that bottom thermocouples run hotter than the reference thermocouples of the RE72. The temperature the RE72 are set to maintain is not the temperature of the chamber. This is the cause of the strong gradients. Swapping the position of the thermocouples may be sufficient. Thermocouples presumed faulty on Friday may be working OK - could just be positioned in hot spot immediately above heaters.

18:00 Baking off to allow cooling down overnight.

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