User Tools

Site Tools


playground:nmr

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
playground:nmr [2012/04/18 17:22]
carter
playground:nmr [2021/04/01 11:11] (current)
carter
Line 6: Line 6:
    - You may have to adjust the VERTICAL POSITION control to find the horizontal line.    - You may have to adjust the VERTICAL POSITION control to find the horizontal line.
    - Set the HORIZONTAL SWEEP to 60.    - Set the HORIZONTAL SWEEP to 60.
-   - Recycle the analyzing magnet if needed. ​ This is done using the RECYCLE button on the analyzing magnet control window.+   - Recycle the analyzing magnet if needed. ​ This is done using the RECYCLE button on the analyzing magnet control window(NumLock must be off).
    - Set the analyzing magnet power supply to a current slightly lower than the current predicted for this energy.    - Set the analyzing magnet power supply to a current slightly lower than the current predicted for this energy.
-   - Set the TUNING VERNIER control to about mid range on its 10 turn control. ​ Rotate counterclockwise until stop then 5 turns clockwise.+   - Set the TUNING VERNIER control to about mid range on its 10 turn control. ​ Rotate counterclockwise until it stops then rotate ​5 turns clockwise.
    - Select a frequency about 1% less than the frequency desired for the beam energy.    - Select a frequency about 1% less than the frequency desired for the beam energy.
    - In the light yellow (Tandem) window type the command "​nmrgoto 1234.567"​ where 1234.567 is the frequency calculated in the previous step.    - In the light yellow (Tandem) window type the command "​nmrgoto 1234.567"​ where 1234.567 is the frequency calculated in the previous step.
Line 29: Line 29:
    -- findnmr ; predict the NMR frequency from the analyzing magnet current and move the NMR to that frequency. ​ Usually close enough to find resonance with the browse command.    -- findnmr ; predict the NMR frequency from the analyzing magnet current and move the NMR to that frequency. ​ Usually close enough to find resonance with the browse command.
    -- browse #steps ;  move the NMR down #steps/2 then slowly step up #steps, then down #steps, repeating until enter is pressed. ​ Watch the CRT and when the resonance is seen, press enter. ​ For example, "​findnmr"​ , followed by "​browse 400"​. ​ The arrows on the yellow terminal indicate steps up (>) and down(<), repeating #steps until the enter key is depressed.    -- browse #steps ;  move the NMR down #steps/2 then slowly step up #steps, then down #steps, repeating until enter is pressed. ​ Watch the CRT and when the resonance is seen, press enter. ​ For example, "​findnmr"​ , followed by "​browse 400"​. ​ The arrows on the yellow terminal indicate steps up (>) and down(<), repeating #steps until the enter key is depressed.
 +   - INCREMENTAL ENERGY STEP.  A couple of routines have been written to help tune the switcher magnet and quadrupole magnets to a new energy after a good beam tune has been established at the current energy and you wish to move to a new energy (especially if the energy move is small). This routine scales the magnet currents linearly based on the ratio of the previous energy analyzer current and the new analyzer current. To use this feature (after a good tune at one energy and before attempting to change to a new energy) type the command ​
 +   -- "​base"​ in the blue terminal window. This will establish the base energy from which the new energy is scaled. After tuning the analyzer magnet to the new NMR frequency"​ type the command ​
 +   -- "​retune"​ in the blue terminal window and the switcher magnet and each quadrupole magnet will be set to the new value scaled by the ratio of the base analyzer current and the new analyzer current. ​
  
  
playground/nmr.1334784139.txt.gz ยท Last modified: 2012/04/18 17:22 by carter