S800 Documentation

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nmr_probes

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nmr_probes [2013/12/14 11:15]
pereira 		nmr_probes [2013/12/14 11:16]
pereira
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 Two digital oscilloscopes are dedicated to NMR readout – one for the analysis line NMRs and one for the spectrograph NMRs. The scopes are located in data-U6, in upper two shelves on the right electronics rack. They are isolated from clean ground because this signals from the NMR probes are on a dirty ground. Two digital oscilloscopes are dedicated to NMR readout – one for the analysis line NMRs and one for the spectrograph NMRs. The scopes are located in data-U6, in upper two shelves on the right electronics rack. They are isolated from clean ground because this signals from the NMR probes are on a dirty ground.
  
-==== Motivation ====+===== Motivation =====
 Due to the location of the NMR probes in the dipoles of both the S800 analysis line and spectrograph, the NMR signals are usually too small for the NMR module to lock on. This has been a long standing problem which required the users to manually search the resonance, a painful and lengthy process (especially at 3:00 AM!), as well as costly in beam time. The improvement made in 2001 was a remote control panel for the NMR modules that prevented the users from having to enter the vault in order to measure the fields and match the dipoles. Although it greatly shortened the amount of time and energy spent in performing those tasks, it still remained laborious compared to a fully autonomous system like the NMR program running on the A1900 for which the signals are strong enough for the module to lock on.  Due to the location of the NMR probes in the dipoles of both the S800 analysis line and spectrograph, the NMR signals are usually too small for the NMR module to lock on. This has been a long standing problem which required the users to manually search the resonance, a painful and lengthy process (especially at 3:00 AM!), as well as costly in beam time. The improvement made in 2001 was a remote control panel for the NMR modules that prevented the users from having to enter the vault in order to measure the fields and match the dipoles. Although it greatly shortened the amount of time and energy spent in performing those tasks, it still remained laborious compared to a fully autonomous system like the NMR program running on the A1900 for which the signals are strong enough for the module to lock on. 
  
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-==== Description ====+===== Description =====
 The NMR running programs for both the S800 analysis line and spectrograph dipoles can be started by clicking on the icons labeled S800A_NMR and S800S_NMR, located on the desktop of uxpc2. The picture below shows the spectrograph GUI as an example. The top (yellow) panel shows the data relevant to the NMR module, the middle (pink) the digitized signal from the oscilloscope and the bottom (blue) the status and measurements for the dipoles.  The NMR running programs for both the S800 analysis line and spectrograph dipoles can be started by clicking on the icons labeled S800A_NMR and S800S_NMR, located on the desktop of uxpc2. The picture below shows the spectrograph GUI as an example. The top (yellow) panel shows the data relevant to the NMR module, the middle (pink) the digitized signal from the oscilloscope and the bottom (blue) the status and measurements for the dipoles. 
  
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-==== Operation ====+===== Operation =====
 The NMR program constantly checks the status of the various dipoles from the EPICS system and updates the status column. In addition, the program checks the log file at startup for the closest previously measured value. In case no previous measurement can be used the program searches for a signal around the guessed value of the field. This search can take some time if the calibration is off or the hysteresis of the dipole is large.  The NMR program constantly checks the status of the various dipoles from the EPICS system and updates the status column. In addition, the program checks the log file at startup for the closest previously measured value. In case no previous measurement can be used the program searches for a signal around the guessed value of the field. This search can take some time if the calibration is off or the hysteresis of the dipole is large. 
  
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 ===== Matching ===== ===== Matching =====
  
-{{:wiki:matching.png?700|Pannel to match dipoles.}}+{{:wiki:NMR-matching.gif?700|Pannel to match dipoles.}}
 {{:wiki:matching.png?700|Display when running log file.}} {{:wiki:matching.png?700|Display when running log file.}}
  
nmr_probes.txt · Last modified: 2024/06/01 16:35 by swartzj

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