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playground:alphatross [2020/06/11 08:41]
jacobs
playground:alphatross [2020/06/16 15:52] (current)
carter
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     - 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**     - **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.   
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   - 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.
playground/alphatross.txt ยท Last modified: 2020/06/16 15:52 by carter