====== Bolometer Cycle ======

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SUMMARY OF INSTRUCTIONS FOR BOLOMETER INITIAL COOL DOWN

1)Pump on the bolometer with the turbo pump until a pressure of 10 -5 is
  achieved.  Secure bolometer from turbo pump.
2)Open(CCW) green Nupro Valve on the bolometer.  Close(CCW) "Pump" and "He3"
  switches approximately 30 turns.  Retract shafts and secure with vinyl tubing.
  Tubing is labeled for each shaft.
3)Pre-cool with liquid nitrogen for 1-3 hours, longer is better.  Fill LN2
  reservoir(outer) first.  After it is full, fill the LHe reservoir(inner).
  The 3He pressure gauge reads 40 PSI and "Pump Tem" BNC on pre-amp reads
  >1.35K ohms when the bolometer is at equilibrium temperature.
4)Ensure all 3 pre amp power switches are off.  Replace all 3 batteries in the
  pre-amp.  Turn on "Power", "Bias" and "Input" switches on the pre amp.
5)Invert the bolometer to dump out the LN2.  Blow helium gas into the helium
  reservoir to make sure it is empty.
6)Refill the LN2 reservoir(outer) with LN2.  Slowly transfer liquid helium into
  the helium reservoir(inner).
7)Allow the bolometer to sit at least 4 hours.  The "Pump Temp" BNC on the pre-
  amp reads approximately 19K ohms.  The "3He Temp" BNC reads about .026V.
  Close(CW) the green Nupro valve and open(CW) the "Pump" switch.

START HERE IF THE BOLOMETER IS ALREADY AT LIQUID HELIUM TEMPERATURE.

8)Check liquid helium level.  Retransfer if there is <3 inches left.
9)Besure the pump is on.  Screw the dewar pumping fixture to the liquid helium
  fill port.
NOTE:  You will be performing steps 10 and 11 simultaneously.  During pump down
       and heating, the 3He gauge should go up to 5-15 in/Hg then go back down
       slowly to about 18 in/Hg.  For the initial cycle, it may go slightly 
       higher, but should not get over 0.  If it does, you are out of liquid
       helium of the switches are not in the correct positions.
10)Slightly open the large vacuum valve until you hear a hiss.  You are pumping
   too fast if it frosts more than a foot beyond the hose coupling.  Observe
   the vacuum gauge.  It should take >20 minutes to reach 100 torr.  When it 
   reaches 100 torr, open the valve slightly more to reach 33 torr in 10-15 
   minutes.  Open/close valve to maintain this rate.  When the gauge reads 33
   torr, open the large valve all the way.
11)The "Pump Temp" BNC on the pre amp reads 3.83K ohms.  Immediately after 
   startind the pump down, apply 2.5V to the "Heater" BNC on the pre amp.
   "Pump Temp" resistance should reach 2.5K ohms at the same time that the 
   vacuum gauge reaches 3-6 torr.  Adjust the heater voltage to regulate this.
   Voltages up to 5V are ok.
12)When the vacuum gauge reaches 3-6 torr and the "Pump Temp" resistance equals
   2.5K ohms, disconnect the heater voltage and closed the large vacuum valve.
13)Open(CW) the 3He switch and close the Pump switch in that order.
14)Connect helium gas cylinder to nipple on vacuum system.  Open small vacuum
   valve and slowly fill vacuum with helium gas until pressure on the large 
   gauge reaches 450 torr.  Close small valve, and put helium gas cylinder away.
15)Remove the pumping fixture from the liquid helium fill port.  Top off both
   the LHe and LN2 reservoirs and light stuff kim wipes into the openings.
16)Mount dewar on telescope.  Dewar is at operating temperature when the 
   following conditions are met:
                               3He Temp is approximately .055V
                               Pump Temp resistance is approximately 17.99K ohms
                               Vs BNC reads .4-.5V with "Bias" off
                                            .6-.7V with "Bias" on

THE MORNING AFTER OBSERVING

If the bolometer is going to be cycled later in the day by the daycrew or 
yourself, top off the LHe reservoir(inner) and LN2 reservoir(outer).  Leave
the "Pump" heat switch closed and the "3He" heat switch opened.  Proceed to 
"CONTINUED 3He OPERATION" when you are ready to cycle the bolometer.

CONTINUED 3He OPERATION

1)Turn off pre-amp power.  Replace 2 batteries on the bottom of the pre-amp.
  Turn on the pre-amp power.
2)Open(CW) the "Pump" heat switch and close(CCW) the "3He" heat switch.
3)Refill the LN2 reservoir.
4)Go to step 8 of "SUMMARY OF INSTRUCTIONS FOR BOLOMETER INITAIAL COOL DOWN".
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Summary by Ed Bufil