Accelerator Handbook

Cs Sputter Source Startup Procedure

Last modified on 2009 March 19, 15:20

General Considerations

• Review these illustrations:
  • Cs Sputter Source Cutaway Diagram
  • Cs Sputter Source High Voltage Supplies
• The proper target must be installed. (See Devon.)
• The base pressure of 2 × 10^-6 torr or less.

General Preparations

1. Ensure that desired beam target is loaded.
2. Set buncher tubes to correct configuration for desired beam species.
3. Check vacuum on LE extension, temperature gauge on cryopump should be at minimum value.
4. Open source gate valve by pressing either button on gate valve control at source gate.
5. Remove grounding hook from power supply platform and hang on gate before closing.
6. Close gate to source area. Orange lights on Glassman supplies should come on at gate closing. (If not, check other gate on the other side of the accelerator; both must be secured.)
7. Use long plexi rod to turn on top 2 Glassmans (target and extractor) by pushing green buttons.

Startup and Normal Operation (in control room)

1. Turn on and set the Del main extractor supply to the desired voltage for the particular buncher setting.
2. Slowly turn up the ionizer heater. The ionizer operates at 21 amperes. It should take about 2 minutes to reach 21 A from the standby value of 10 A. Keep in mind that the amperage will fall slightly as the ionizer gets warmer. Keep adjusting the current until the ionizer is stable at 21 A.
3. Turn up the Cs feed tube heater to 0.450 amperes.
4. Set the cesium reservoir heater to 0.285. This should be enough to give ones of microamps beam for p and d. A setting of about 0.290 - 0.300 should produce tens of microamps. Cs vaporization starts at a temperature of ~80° Celsius. The maximum reservoir temperature should not exceed 130° Celsius. The reservoir current should not exceed 0.300
5. Set the Glassman extractor power supply to 12.5 KV. Check to be sure the current is less than about 5 milliamps and the “control milliampres” light is NOT lit. High current indicates that the source needs serviced.
6. Set the Glassman target power supply to 6.5 kV. Check to be sure the current is less than about 5 milliamps and the “control milliampres” light is NOT lit. High current indicates that the source needs serviced.
7. Tune the beam with the inflection magnet, source lens (usually about 1.5 kV), lens A, and 2Y steerer.
8. Monitor the target and extractor currents: target current should be around 2.5 milliamps, and no more than 5 mA.

Out-gassing the source after cleaning

1. The source gate valve should be closed for this operation.
2. Wait for normal vacuum. Normal is when the needle is in the blue mark on the gauge above the TV in the control room.
3. Set ionizer to 10A. This will lead to a rise in the vacuum pressure.
4. Wait for vacuum to fall back to the blue mark on the gauge
5. Raise the ionizer by an additional 2-3 A and wait for the vacuum to fall back into the blue range.
6. Repeat this process until the ionizer is at 21 A and the vacuum is in the blue range, may take 8 hours.
7. Open the source gate valve and carry out the Startup and Normal Operation.

Checklist for Target Pellet Change

• Sputter Source Target Pellet Change

Shut Down Procedure

1. Turn down the reservoir heater power supply. Off is about 0.070 A.
2. Wait for the reservoir temperature to drop below 80° C.
3. Turn down the feed tube power supply.
4. Wait for the feed tube temperature to drop below 80° C.
5. Wait for the Target Supply current to fall to less than 1 milliamp.
6. Turn the ionizer current down to 10 amps. (The ionizer current should be left at 10 amps. This helps avoid the “poisoning” of the ionizer.)
7. Turn down target and extractor voltages to zero.
8. Turn off DEL high voltage supply.
9. Close sputter source vacuum gate valve.

Original Credits
Maintained by:
Thomas N. Massey
Office: Accelerator Lab 217
Telephone: (740)593-0933
E-Mail: massey@ohio.edu
Last modified on 7/30/2010 DKJ