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playground:nmr [2012/03/21 10:25]
carter
playground:nmr [2015/05/20 10:05] (current)
carter
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 ===== NMR Setup ===== ===== NMR Setup =====
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-** NMR Fluxmeter ** 
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-{{nmr_panel.jpg}} 
  
    - Depress POWER switch if not illuminated.    - Depress POWER switch if not illuminated.
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    - 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.
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    - The TANDEM window will inform you of how many steps needed to move approximately to the frequency you entered.    - The TANDEM window will inform you of how many steps needed to move approximately to the frequency you entered.
    - When the NMR advances this number of steps it will inform you of the frequency the NMR has moved to at this step position.    - When the NMR advances this number of steps it will inform you of the frequency the NMR has moved to at this step position.
-   - The NMR frequency is read directly on the accelerator console by the Agilent 53131A Universal Counter located directly above the NMR.  The counter that is read by the computer is on the left and is the standard counter to use for the NMR frequency. ​ The NMR may also be connected to the similar counter on the right to allow comparing the frequency readout. ​ The accuracy of the NMR is determined by the accuracy of the counter so if there is disagreement in the counter frequency it needs to be checked. ​ The counters should agree to 7 digits. ​ The counters have 2 inputs and the NMR is connected to inpt #1.  Press the "Freq & Ratio" button until "​Frequency 1" is displayed to read the NMR frequency.+   - The NMR frequency is read directly on the accelerator console by the Agilent 53131A Universal Counter located directly above the NMR.  The counter that is read by the computer is on the left and is the standard counter to use for the NMR frequency. ​ The NMR may also be connected to the similar counter on the right to allow comparing the frequency readout. ​ The accuracy of the NMR is determined by the accuracy of the counter so if there is disagreement in the counter frequency it needs to be checked. ​ The counters should agree to 7 digits. ​ The counters have 2 inputs and the NMR is connected to input #1.  Press the "Freq & Ratio" button until "​Frequency 1" is displayed to read the NMR frequency.
    - If the counter is not updating the frequency readout you need to press the "​Run"​ button on the counter. ​ These counters go into remote mode when read by the computer and need to be manually placed on local mode by pressing the "​Run"​ button.    - If the counter is not updating the frequency readout you need to press the "​Run"​ button on the counter. ​ These counters go into remote mode when read by the computer and need to be manually placed on local mode by pressing the "​Run"​ button.
    - If this frequency is not close enough to the desired frequency, repeat the nmrgoto command and it should get closer. ​ The NMR moves to the entered frequency by estimating the number of steps needed to advance from the current frequency and then moving that number of steps. ​ The closer you are to the desired frequency, the closer the end result will be.    - If this frequency is not close enough to the desired frequency, repeat the nmrgoto command and it should get closer. ​ The NMR moves to the entered frequency by estimating the number of steps needed to advance from the current frequency and then moving that number of steps. ​ The closer you are to the desired frequency, the closer the end result will be.
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    -- 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.
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 +{{HVEC_NMR.pdf|Original HVEC NMR Manual. Main frequency adjustment control and tracking feature now obsolete. ​ See above new procedures.}}
    
-  * {{HVEC_NMR.pdf|Original HVEC NMR Manual. Main frequency adjustment control and tracking feature now obsolete. ​ See above new procedures.}}  +---- 
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 +{{nmr_panel.jpg}} 
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 +//​[[carter@ohio.edu|Don Carter]] 2012/03/21 10:54// 
playground/nmr.1332339908.txt.gz · Last modified: 2012/03/21 10:25 by carter