- Here are instructions for cooling the SONIC.
- 1. Attach vacuum valve to pump, start pump. When pressure on-scale
- on gauge, open dewar valve. Wait until pressure is below 5x10^-4;
- below 2x10^-4 is even better.
- 2. Attach helium hoses to cooler if not already done. Note order
- specified on cold head.
- 3. Find a 12 volt power supply, Vac-ion power supply, the 4-pin
- connector with two orange wires coming out, and the bias cable (19
- pin connector on one end, D-15 plus 4-pin plug on the other). If you
- want to monitor temperatures during the cooldown and don't have the
- camera electronics, also find the adaptor with D-15, D-9, and round
- 26-pin socket all wired together.
- 4. Start the compressor. Make sure the water valve is plugged in and
- that cold water is flowing in the compressor. In cold weather, the
- compressor is hard to start. Let it run 10 seconds, then stop for 10
- seconds, then 20 seconds, etc. Soon it should be running continuously.
- 5. Attach the bias cable to the dewar. Plug the 4-pin connector into
- the socket with the orange wires, connect the orange wires to the
- power supply, turn on supply, and set to 12 volts. Check that the
- current is approximately 110 mA.
- 6. To monitor temperature, turn on temperature controller and attach
- to dewar. This can be either via the plug on the camera electronics
- or via the "three-connector adaptor." If using the latter, plug the
- bias cable from the dewar into the D-15 on the adaptor. The round
- plug on the adaptor goes to the dewar, and the D-9 goes to the
- thermometer cable on the DRC-91 temperature controller. Channel A2
- is the detector block, A4 is the cold shield. The temperature of A2
- should never change faster than 1 degree per minute. Following these
- instructions should ensure that.
- 7. When the temperature of A2 has dropped to approximately 150 K, it
- should be possible to plug in the Vac-Ion. This will be 3-5 hours
- after the cooler is started. After another hour or two, when the
- temperature has dropped to 120 K or so, it should be possible to
- close the vacuum valve. The valve will need to be closed and
- reopened a couple of times to clear out air trapped in the valve
- itself. Make sure the Vac-Ion pump stays on-scale with the valve
- closed. When it does, the vacuum pump can be stopped and
- disconnected.
- 8. When temperature A2 is below 100 K, the power supply voltage can
- be reduced to 6 V. After half an hour at 6 V, the power supply can
- be disconnected if desired. Or it can be left at 12 volts as long as
- you like.