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--- stm:before_take-off_check_list [2007/06/12 09:11] – galli
+++ stm:before_take-off_check_list [2007/06/12 13:30] (current) – galli
@@ Line 1: / Line 1: @@
+====== Before take-off check list ======
+//Check this EVERY TIME before closing the UHV chamber and bake out and cooling down.//
+Download here PDF version: {{stm:uhv-he3-stm-check-list.pdf}}. Every time a major cool down procedure is started, the operators should print out the check list, and go through it carefully. This is STRICTLY NECESSARY, in order to avoid "expensive" mistakes.\\
+Checklist UHV 300mK STM
+Version 1.7 – modified june 12, 2007
+Date:................................................................................................
+Operator(s):....................................................................................
+Starting position:	Insert with scanner and 1K-shield attached is suspended in cryostat. 				Top flange is closed.
+     I.  Scanner, Insert and Cryostat
+O	Check STM wirings (bias, signal, piezo's, CERNOX thermometer)\\
+O	Check HELIOX wirings (thermometers, heater, see manual)\\
+O	Connect 1K capillary Swagelok. Don't forget capillary fixing screw (“borgschroefje”).\\
+O	Move insert (retract in highest position and extend fully down and retract back). Check for jamming.\\
+O	Mount N2 shield such that it does not touch the capillary and the sides. Check again for insert motion and that the insert won't jam the N2-shield doors.\\
+O	Pump OVC.\\
+Remarks: ....................................................................................................................................
+.....................................................................................................................................................
+     II.	UHV Chamber
+O	Raise cryostat to its highest position on air-pillars and PUT wooden SAFETY BLOCKS in place.\\
+O	Mount water cooling ring and make sure you mount a loop for manual opening of N2 shield doors.\\
+O	Put new CF gasket and move chamber under cryostat. Check for wires being sqeezed.\\
+O	Remove safety blocks. Lower air-pillars, close chamber and mount suspension blocks. \\
+O	Raise again cryostat (air-pillars risen till middle). Remove car.\\
+O	Check pre-pump rotation direction and water cooling for turbo.\\
+O	Start pumping.\\
+Remarks: ....................................................................................................................................
+.....................................................................................................................................................
+    III.	Bakeout
+O	Test vertical motion of insert.\\
+O	Leak-test flanges that have been changed. Leak-test  1K capillary by flushing helium.\\
+O	When pressure is less then 10-4 mbar, open ion pump and all metal valves on sputtering line.\\
+O	Remove Pfeiffer P-gauge and QMS-200. Cover windows with foil.\\
+O	Mount bakeout panels. Connect heaters and thermometers.\\
+O	Degas filaments (RGA, Bayard-Alpert, annealing filament), sublimate Ti and burst ion pump.\\
+O	Cool down slowly, regularly degasing filaments. Remove bakeout panels.\\
+Remarks: ....................................................................................................................................
+.....................................................................................................................................................
+    IV.	Cool-down to 4K
+O	Flush needle-valves (both 1K and sock) with He-gas.\\
+O	Close needle-valves and apply some He pressure (via return line) on 1K and sock pumping lines.\\
+O	Stop pumping on OVC before cooling. \\
+O	Fill both N2 and He-tanks with liquid N2. Use restrictor while magnet is above 77 K.\\
+O	Blow out N2 from He-bath using N2 gas and pump bath to remove the remanent liquid.\\
+O	Flush bath with He-gas and check the flow in the capillaries through the needle-valves. Leave 1K needle-valve open while filling.\\
+O	Fill liquid He. Bath should be at overpressure before inserting transfer tube. \\
+O	When magnet is cold (~4 kOhm) and liquid He level increases, raise transfer tube a bit and increase pressure on He vessel to 400 mbar. \\
+Remarks: ....................................................................................................................................
+.....................................................................................................................................................
+    V.	Cool-down to 300 mK
+O	Start flow through 1K capillary and sock. Adjust needle valves to match prescribed flow rates.\\
+O	When 1K-pot is cold, open 'V1' on he3-dump.\\
+O	When pressure in dump does not drop anymore, close 'V1' and set sorb heater above 50K.\\
+O	When he3-pot temp. matches 1K-pot, turn off the sorb heater. Re-open 'V1' to condense last He3. NOTE: between measurements, turn on sorb heater and keep 'V1' closed.\\
+Remarks: ....................................................................................................................................
+.....................................................................................................................................................