492 GHz Receiver Shutdown Procedure:

The most critical part of shutting down the receiver is safely powering down the local oscillator chain.

Here is how to do it:

1. Put on the wrist strap attached to the receiver; static is our enemy!
2. Slowly turn out the LO power attenuator located just before the multiplier. While you turn out the micrometer, slowly turn down the doubler and tripler bias voltages. Try not to let the doubler bias current exceed -.5 mA. Ideally, the current should remain around 0.0 mA. The tripler always reads a small positive current. Leave + 0.2 V on each multiplier.
3. Now turn the Gunn voltage off by flipping down the oscillator supply toggle switch on the Phaselock Box.
4. Turn off the power to the Phaselock Box by flipping the power toggle switch located (inconveniently!)on the back of the box.
5. Now reduce the doubler and tripler bias voltages to zero and rotate the power knob on each front panel counter-clockwise. Note this switch has three positions. Power is not applied to the multipliers except in the most clockwise position. The hard part is over!
6. Next turn down the magnet bias current to 0 mA and shut-off the supply.
7. Turn down the cryo amplifier bias to 0 mA and shut off the supply by rotating the knob on the front panel fully counter clockwise.
8. Turn down the SIS bas voltage to zero and turn the power knob fully counter clockwise to the off position.
9. Turn off the room temperature amplifier supply (located on the left side of the bias box rack mount box).
10. Flip down the total power box power switch located on the lower left hand corner of the front panel.

    You are done!

To power back up the receiver, follow this procedure in reverse order. When you are done, the voltages and currents on each of the bias boxes should resemble the values given in the accompanying table. Remember, power is not applied to the doubler, tripler, SIS junction, and cryo amplifier unless the knobs are in the fully clockwise position!

Feel free to call us if you have questions or problems.

SORAL Lab: 621-3924

Chris' office: 621-8783

cwalker@as.arizona.edu