User Tools
playground:alphatross
Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
|
playground:alphatross [2020/03/17 16:14] jacobs |
playground:alphatross [2020/06/16 15:52] carter |
||
|---|---|---|---|
| Line 1: | Line 1: | ||
| ==== NEC Alphatross RF Source Instructions ==== | ==== NEC Alphatross RF Source Instructions ==== | ||
| - | THESE ARE DRAFT INSTRUCTIONS WRITTEN REMOTELY. THERE MAY BE OMISSIONS AND INCORRECT NOMENCLATURE, USE YOUR OWN JUDGEMENT... | ||
| - | |||
| ** __START UP__ ** | ** __START UP__ ** | ||
| Line 24: | Line 22: | ||
| - Monitor the Ion Gauge pressure, it should remain less than 4 x 10-6 Torr while setting the Probe. It should settle to around 2 x 10-6 or less when done. | - Monitor the Ion Gauge pressure, it should remain less than 4 x 10-6 Torr while setting the Probe. It should settle to around 2 x 10-6 or less when done. | ||
| - Raise the Probe Voltage to 3 KV as a start, this might be enough to get the plasma going. | - Raise the Probe Voltage to 3 KV as a start, this might be enough to get the plasma going. | ||
| - | - If there is still no plasma try raising the Mass Flow setting to as much as .5 SCCM to inspire ignition and then return to .35 SCCM. | + | - If there is still no plasma try raising the Mass Flow setting to as much as 0.5 SCCM to inspire ignition and then return to 0.35 SCCM. |
| + | - **This is a pause point for source clean up, can run like this for days, should reduce probe current over time** | ||
| - Monitor the Probe Current, maintain 3 mA +/- 1 mA, and continue raising the Probe Voltage until it reaches 6.5 KV. | - Monitor the Probe Current, maintain 3 mA +/- 1 mA, and continue raising the Probe Voltage until it reaches 6.5 KV. | ||
| - Set the Oven Voltage to 87 V, wait ten minutes. After 10 minutes the Oven Temp should be around 150 C. | - Set the Oven Voltage to 87 V, wait ten minutes. After 10 minutes the Oven Temp should be around 150 C. | ||
| - Set the Extractor Voltage to 5.5 KV and the Bias Voltage to a value that gives the desired injection energy less (6.5 + 5.5). Beam yield seems to increase with injection energy above 30 KeV. Suggest trying 41 or 53 KeV settings if pulsing. | - Set the Extractor Voltage to 5.5 KV and the Bias Voltage to a value that gives the desired injection energy less (6.5 + 5.5). Beam yield seems to increase with injection energy above 30 KeV. Suggest trying 41 or 53 KeV settings if pulsing. | ||
| - You may now be able to look at negative beam in the source faraday cup (#7 on the FC meter). Its not clear if this is a useful endeavor. | - You may now be able to look at negative beam in the source faraday cup (#7 on the FC meter). Its not clear if this is a useful endeavor. | ||
| - | - Beam yield will increase as Mass Flow is reduced, expect optimum yield at //around// .2 SCCM. | + | - Beam yield will increase as Mass Flow is reduced, expect optimum yield at //around// 0.2 SCCM. |
| - Optimize negative beam yield by tuning Extractor Voltage, Focus Voltage, and Mass Flow. Adjust Bis Voltage accordingly if an exact injection energy is required for P&B. Expect little or no Focus Voltage. | - Optimize negative beam yield by tuning Extractor Voltage, Focus Voltage, and Mass Flow. Adjust Bis Voltage accordingly if an exact injection energy is required for P&B. Expect little or no Focus Voltage. | ||
| - Use software buttons to take out faraday cup and open gate valve. | - Use software buttons to take out faraday cup and open gate valve. | ||
| - Set Lens A to 10 KV and source Einzel Lens to 15 KV initially and use the inflection magnet to pass beam on to the LE faraday cup. Tune both lenses and magnet for optimum conditions. The BPM may be useful too. | - Set Lens A to 10 KV and source Einzel Lens to 15 KV initially and use the inflection magnet to pass beam on to the LE faraday cup. Tune both lenses and magnet for optimum conditions. The BPM may be useful too. | ||
| - You may need to re-tune with Extractor, Bias, and Focus Voltages and Mass Flow setting. Each voltage tune will affect the inflection magnet. | - You may need to re-tune with Extractor, Bias, and Focus Voltages and Mass Flow setting. Each voltage tune will affect the inflection magnet. | ||
| + | - The maximum Oven Temperature is around 190 C, seems to be around 91 Volts. At this point Rb begins to escape the chamber and the beam becomes twitchy. If the beam is unstable briefly reduce the Oven Voltage until stabile beam and return Oven Voltage to a slightly lesser value. | ||
| + | |||
| + | ** __SHUT DOWN__ ** | ||
| + | |||
| + | - Click the software button "Automatic Shutdown" | ||
| + | - Confirm you wish to quit be answering "y" | ||
| + | - Walk away. | ||
| + | - ** Do not open the source gates until the process is finished ** | ||
| + | - This process puts in the cup, closes the gate valve, and shuts down the source as things cool to proper levels. | ||
| + | - The automated process can be stopped by clicking the "Automatic Shutdown" again. | ||
| + | |||
playground/alphatross.txt · Last modified: 2022/06/08 09:05 by leblanc
Page Tools
Except where otherwise noted, content on this wiki is licensed under the following license: CC Attribution-Noncommercial-Share Alike 3.0 Unported
