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playground:pulsing
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playground:pulsing [2009/03/04 15:46] 127.0.0.1 external edit |
playground:pulsing [2010/07/19 11:36] 132.235.40.158 Changed buncher plate voltages from keV to kV |
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| === Accelerator Start-Up - Chopping and Bunching === | === Accelerator Start-Up - Chopping and Bunching === | ||
| + | |||
| + | Last modified 2009 April 15, 16:10 | ||
| ** Starting and Tuning Pulsed and Bunched Beam ** | ** Starting and Tuning Pulsed and Bunched Beam ** | ||
| - | 1. Start up source and described in the [[playground:sputter|Sputter Source]] or [[playground:alpha|Duoplasmatron Source]] instructions. | + | - Start up source and described in the [[playground:sputter|Sputter Source]] or [[playground:alpha|Duoplasmatron Source]] instructions. |
| - | 2. With the low energy cup in, tune for maximum current using the inflection magnet, two einzel lenses, and the steerers 2X, and 2Y. | + | - With the low energy cup in, tune for maximum current using the inflection magnet, two einzel lenses, and the steerers 2X, and 2Y. |
| - | 3. Set auxiliary width at maximum. | + | - Set auxiliary width at maximum. |
| - | 4. Turn on oscillator -- beam current will drop. | + | - Turn on oscillator -- beam current will drop. |
| - | 5. Turn 2Y down -- look for peak in pulsed beam (its easier to find the correct peak if the auxiliary width is large). You should normally expect to find the peak somewhere around 4.0 if you start from 5.0 . If you reduce 2Y (after a D.C. tune-up) , the first peak you see is the correct one. | + | - Turn 2Y down -- look for peak in pulsed beam (its easier to find the correct peak if the auxiliary width is large). You should normally expect to find the peak somewhere around 4.0 if you start from 5.0 . If you reduce 2Y (after a D.C. tune-up) , the first peak you see is the correct one. |
| - | 6. Adjust 2X for maximum current for the maximum current. You usually need to adjust both 2Y and 2X together to find the maximum. | + | - Adjust 2X for maximum current for the maximum current. You usually need to adjust both 2Y and 2X together to find the maximum. |
| - | 6. Change to f/2. Adjust the chopper phasing for maximum current. The beam current should drop by a factor of 2 if you are on the proper peak. For best current tune both the 2X and chopper phasing. | + | - Change to f/2. Adjust the chopper phasing for maximum current. The beam current should drop by a factor of 2 if you are on the proper peak. For best current tune both the 2X and chopper phasing. |
| - | 7. Adjust chopper phase for maximum current on the Output Meter. | + | - Return to f/1 |
| - | 8. Turn "chopper power" on. | + | - Adjust chopper phase for maximum beam current. |
| - | 9. Turn buncher on. | + | - Turn "chopper power" on. |
| - | 10. Bring amplifier plate to 1 keV for for deuteron or protons, 0.2-0.4 keV for He-3 and He-4, and 0.5-0.75 keV for Li-7. | + | - Turn buncher on. |
| - | 11. Adjust buncher phase for maximum current. | + | - Bring amplifier plate to 1 kV for for deuteron or protons, 0.2-0.4 kV for He-3 and He-4, and 0.5-0.75 kV for Li-7. |
| - | 12. Peak buncher output current with "buncher output" by cranking the tuning knob. | + | - Adjust buncher phase for maximum current. |
| - | 13. Get high energy end of the accelerator going. | + | - Adjust buncher tuning for peak output current by cranking the tuning knob. |
| - | 14. Adjust low energy steerers to maximize the beam. Try to run the steerers as low as possible and avoid doglegs. | + | - Get high energy end of the accelerator going. |
| - | 15. Adjust the "GRIDDED VOLTAGE TUBE LENS" to maximize the current. Note that this has a slow response time. | + | - Adjust low energy steerers to maximize the beam. Try to run the steerers as low as possible and avoid doglegs. |
| - | 16. Get beam through the analyzing magnet following steps in the Machine Setup steps 11-13 above. | + | - Adjust the "GRIDDED VOLTAGE TUBE LENS" to maximize the current. Note that this has a slow response time. |
| - | 17. Make sure proper doors are closed, and target cooling, etc. are on and take the beam into the target area. | + | - Get beam through the analyzing magnet following steps in the Machine Setup steps 11-13 above. |
| - | 18. Adjust H.E. steering, quads, tweaking magnet, etc. to maximize beam current. | + | - Make sure proper doors are closed, and target cooling, etc. are on and take the beam into the target area. |
| - | 19. Notice beam pick-off repetition rate; if you have adjusted the chopper and buncher properly it should read 500,000 at f/1. | + | - Adjust H.E. steering, quads, tweaking magnet, etc. to maximize beam current. |
| - | 20. Put the cup in, then put gold foil in, then take out cup. Look at TAC output. Adjust chopper phase, buncher phase and amplifier plate to obtain best time tune. | + | - Adjust auxiliary width for beam current; this will affect both beam current and timing and will need to be set when the final timing is set. |
| - | 21. Take out gold foil. Run time-tuned beam. | + | - Examine beam pick-off repetition rate; if you have adjusted the chopper and buncher properly it should read 500,000 at f/1. |
| + | - If you are using a gold foil: | ||
| + | - put the cup in, then | ||
| + | - put gold foil in, then | ||
| + | - take out cup. | ||
| + | - Look at TAC output. | ||
| + | - Adjust chopper phase, buncher phase and amplifier plate to obtain best time tune. | ||
| + | - put the cup in, | ||
| + | - take out gold foil | ||
| + | - take cup out. | ||
| + | - Run time-tuned beam to target | ||
| + | - Make final adjustments as necessary using detector timing if needed | ||
playground/pulsing.txt · Last modified: 2023/01/27 07:11 by carter
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