Idling Cells

Idle the effusion cells in the order listed below.

Do not turn the cells all the way off until the cryoshroud LN2 has been turned off!

Running cooling water through unheated cells in close proximity to the cryoshroud risks freezing the cooling water and fish tanking the machine. After the LN2 has been turned off, all of the cells (EXCEPT Ga!!) can be further cooled to 10 C.

System Bravo

Valved Cracker Sources

There are recipes that handle cooling for the valved cracker sources. See the recipe run on Bravo 2017-05-09

• Open As, Sb shutters

• Open As, Sb valves to 100 mil to ensure they open completely

• Cool the crackers, in auto mode, to 500 C

• Simultaneously, start cooling the sublimators, in manual mode, by 2.5% every 15 minutes until it reaches 0%

  • Once a particular sublimator reaches 15.0%, start cooling its cracker to 300 C.

  • Once a particular sublimator reaches 5.0%, start cooling its cracker to 150 C.

  • Once a particular sublimator reaches 2.5%, start cooling its cracker to 100 C.

  • We wait to cool the crackers below 500 to 100 C because the sublimator are running nominally between ~450-550 C. Per the cracker/sublimator manuals, the crackers are not supposed to be cooler than their corresponding sublimators.

• Once all sublimators are stable at room temp and the crackers are stable at 100 C:

  • Rehome the As and Sb valves.

  • Close the As and Sb shutters

• The crackers are water cooled, so we should not cool them to room temp until after the LN2 is out of the system

Rare-earths, Bi, Group IIIs, Dopants

You can cool down all of the Rare-earths, Bi, group IIIs, and dopants at the same time

Rare-earths

• Er

  • Ramp rate: 10 C per minute

  • Setpoint: 200 C

Bi

• Bi tip

  • Ramp rate: 10 C per minute

  • Setpoint: 200 C

Group IIIs

• In tip

  • Ramp rate: 10 C per minute

  • Setpoint: 200 C

    • Note, because the In base is set to 200 C it will keep the In top warm (around 250 C)

• In base

  • Set this after setting the In tip, otherwise AMBER will override any base tip temp = tip - 175

  • Ramp rate: 10 C per minute

  • Setpoint: 200 C

• Ga tip

  • Ramp Rate 10 C per minute

  • Setpoint 150 C

    • The output power tends to oscillate too much if the setpoint is below 150C

• Ga base

  • AMBER will complain and not actually adjust the Ga base if the Ga tip temp is set below 200 C. Similar to the discussion above about the In base, set the Ga base after setting the Ga tip

  • Ramp Rate 10 C per minute

  • Setpoint 150 C

• Al must be cooled using a recipe because it freezes

Dopants

• Si

  • Ramp rate: 10 C per minute

  • Setpoint: 100 C

• GaTe

  • Ramp Rate 10 C per minute

  • Setpoint 100 C

• Be

  • Ramp Rate 10 C per minute

  • Setpoint 100 C

• DD Be

  • Ramp Rate 10 C per minute

  • Setpoint 100 C

• DD Si

  • Output power 0

• Leave dopants at 100 C until the cryoshroud LN2 is turned off, this prevents the cooling water from freezing in the dopant cells

Freezing Al

See main page detailing freezing Al: Melting and Freezing Aluminum

System Echo

Valved Cracker Sources

Group IIIs, Dopants, Rare-earths, Bi