Procedure for Installing SPARO on Viper
Photo of SPARO installed on Viper
A word on timing.
- Steps 2 through 9 must be performed all at one go. This is because
it is not good to have the pumped pot unpumped for a long time (it
could plug) and it is not good to have SPARO unheated outside for
a long time (the snout could leak and/or the preamps could get too
- Step 1 can be performed well ahead of time and steps 10 through
12 can be done at your leisure.
Step 1: Preliminaries (can be done well in advance).
- First, remove the capacitance manometer gage from the
laboratory pump, as follows: Stop pumping on the pumped pot line by
valving off the KF valve that is on the dewar. (This valve is
connected to the red-handled all-metal valve.) Turn off (or valve off)
the pump so that it is possible to remove the capacitance manometer
gage. Remove the capacitance manometer gage and insert a KF-16
blank-off in its place. Pump out the pumping line first and then open
the KF valve that is on the dewar, so that you are again pumping on
the 1.5 K pumped pot.
- You will next install the capacitance manometer gage on the telescope
pump that is inside a box on the telescope: On this pump there is a KF
16 blank off. Momentarily turn off the pump using the power strip
inside the pump box. Remove the blank off and install the gauge using
a KF 16 o-ring and clamp. Connect the DB 9 connector inside the box
to the gauge. Turn the pump back on. Close the KF valve thereby
separating the pump from the 60 feet of stainless steel hose leading
to the dewar mount. Note this action will allow you to later break the
seal as the dewar end without straining the pump.
- Move the capacitance manometer readout to the Viper tower (I think
it goes in the hallway?) and hook it up to the cable coming from the
pump box on the telescope. You should read zero mT, except that the
zero can be off as much as 40 mT, as I recall.
- Check to be sure that the essential cables are ready to be plugged
in and free of snow. The essential cables are the preamp power, the
four SPARO heaters (see below).
- Check that the pumping-line on the telescope has been
located (for pumping on pumped pot - see below).
- Check that the two preamp batteries are charged to plus and minus
12 volts, and that the data system battery is also charged (to +?, +?,
-?). It is not essential to charge the data system batteries at this
point, if this is not convenient. It may be done later, once SPARO
is all installed. (See notes on charging batteries under the maintenance
- You may wait indefinitely before moving to the next step.
Step 2: Inside MAPO
- Disconnect SPARO's Pumped Pot line from the pump by closing the
red conflat valve. Use the torque wrench set to 25 lbs. of torque,
and use countertorque to protect the bellows assembly). .
- Make sure the lab pump is valved off and then disconnect the KF
fixtures so that SPARO's pumped pot is ready to be hooked up to the
telescope pumping line. This connection is made using a KF-25 seal
with a teflon O-ring..
- Remove the JFET heaters and disconnect any monitoring electronics.
- Remove the flow meter assembly from the ring stand.
Step 3: Move SPARO from the Lab to the Telescope
See photos of this process
When lifting SPARO, don't hold on to the foam-covered preamps.
You may hold the external He-3 tanks and the handles below the
preamps, and the telescope mounting frame, and the ring at the top of
SPARO. When gripping SPARO by the extermnal He-3 tanks, try not to
bump the gauges and valves that run alongside these tanks.
Step 4: Install Flow meter Assembly
Using either a C-clamp or bolt, install the flow meter assembly on the
ring stand of SPARO.
- Connect the red rubber hose from the fill tube to
the flow meter assembly.
Step 5: Connect the Five Heaters to their Appropriate
- Snout Heat(on ring stand connector) - use Masterman heating system:
see notes taped to wall in Viper control room.
- Motor Heat(on ring stand connector) - again use Masterman heating system
- Relief Valve heat(on ring stand connector) - again use Masterman heating system
- 2 Preamp heat (one on each preamp) These need to be turned on in the
control room (Turn on both blue power supplies on the bottom of the SPARO rack)
Set voltage to ? Volts - Greg I think this is written in a logbook? I think
the voltage we used in Summer was about 2/3 of the way up from zero to the maximum.
Step 6: Connect Pumped Pot Line
At dewar end, undo the teflon-sealed KF 25 blank off from the pumping line
and attach it to the Pumped Pot port on SPARO using a new teflon
o-ring. Note: teflon loses compression each time it is used and it is
probably best not to reuse them unless absolutely necessary. Tighten the
KF clamp until finger tight. Then using a pliers or vice grips, tighten a few turns
- At the pump, open the KF valve to pump out the line. You can watch
the capacitance manometer gage readout to watch it pump out. When it is
low, move to the next step.
- At the dewar end, open the red handled conflat valve using a torque wrench
(Don't forget to apply a countertorque to preserve the bellows).
Step 7: Power up the preamps.
- Connect 9 pin D connectors (preamp power) to each preamp.
- Turn on each preamp using the little switches
at the top of each preamp.
- Plug in the preamp power cables to the two batteries (in the Viper
- Note that while SPARO is on Viper, the preamps should not be left
off for long periods of time as they also power the JFETs, allowing
them to self heat.
(See notes on charging the batteries under the maintenance
documentation.) If the JFETs are not heated then they will drop to 4
K and it will become impossible to "self-heat" so they must be heated
via special 9-pin "JFET-jumper-cables".
Step 8: Connect Focus Mechanism
Lower the focus as far as it will go. Attach the large bolt through the focus
mechanism and attach into the large cone on SPARO. Note, with SPARO's new mounting
bracket, it may be necessary to use several people to push it up the rails and
hold it while someone installs the bolt. (Recall that the SPARO mounting stage
has never been used. We used the Corona stage in January 1999.)
Step 9: Check a few things and then relax.
- The capillary should not plug as it is now being pumped on, and
the parts of the dewar that need to be heated are being heated
(including the JFETS that are now powered up and self-heating).
Perform the follwing checks and then relax:
- Monitor the AD590's that are in the preamps (see bud box for this
purpose in SPARO control rack). Try to keep preamps between 0 C and
30 C by manually adjusting heater voltage.
- Monitor the temperatures of the three items that are hooked up to
the Masterman heaters. These items should be able cool to -20 C (or
even -40 C?) with no problems.
- Check the pressure on the capacitance manometer gage readout
(in the Viper tower hallway?). In Summer it dropped from about 700 mT
to about 300 mT when we moved it outside. Maybe stopping pumping on
the pumped pot line for a while resulted in a partial plug. You may
experience a similar drop.
- You may wait indefinitely before moving to the next step.
Step 10: Connect miscellaneous cables.
- Signal Cables: Stiff white cables with "D" connectors which attach to
- 3He pressure sensor cables: These are attached to the
Omega pressure gauges near the external 3He tanks on either side
of the cyostat. They have 4 pin small military connectors.
- Cycling cable: 26 pin military connector located on the left side of the
accessory ring facing the plank.
Step 11: Connect the Stepper Motor
- Plug in the Motor Cable to the Motor Cable connector on the L bracket on the
- Turn off power to the data system enclosure.
- Open the data system enclosure and plug in the indexer.
- Turn on power to the data system enclosure.
Step 12: Power up the Data System
Plug the data system power cable into the data system battery (in Viper pump room).
(If the data system battery are not charged yet, charge it before hooking it up.)