Difference between revisions of "Prepare Frig for Polarization"

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(New page: ;This procedure has been updated to reflect changes in the target for g2p but has not yet been edited by target coordinator. ===Software=== To aid in the TE calculation, use the "te_get...)
 
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;This procedure has been updated to reflect changes in the target for g2p but has not yet been edited by target coordinator.
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;This procedure has not yet been edited by target coordinator.
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===Software===
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To aid in the TE calculation, use the "te_getter.pl" script in the g2p_te folder on poltarg2p2.  This script reads the last 'x' data entries before unixtime 'y' (default is current time).  It produces a datafile for these points and asks if you'd like to use them in a TE measurement.  Then it performs the TE calculation and returns the results.
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===Assumptions:===
 
===Assumptions:===
 
*NMR System is tuned
 
*NMR System is tuned
 
*Magnet is at full field, persistent mode, leads are ramped down
 
*Magnet is at full field, persistent mode, leads are ramped down
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*Nose is full, run valve in manual mode
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*Nose is over 50%, run valve in PID mode
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*Baseline taken and set
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*TE has been taken and new calibration constant feed into PDP
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*Target in correct position along with NHR Channel setting
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*Roughing and Bypass valve open with mechanical pumps on
 
===Prepare Fridge:===
 
===Prepare Fridge:===
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*Stop RB3, RB2, and RB1 (wait 2 mintues between each), if necessary
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*Close Roughing valve
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*Put Run Valve, EV91120, in Manual Mode
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*Turn on Blower 1 and wait 2 minutes
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*Establish a STEADY Nose level somewhere between 50-65%
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*Turn on Blower 2 and wait 2 minutes
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*Try 0.17 on the run valve.
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*Close Bypass valve
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*If needed only make slight changes to Run Valve for rest of TE (+/- 0.05 each 10 min)
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*Turn on Blower 3
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===Take a Baseline:===
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*Wait a little while
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*Hit "Unlock Magnet Controls" button
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===Begin Polarization:===
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*Type the full-field current in the box labeled "Setpoint" (eg: 60.882)
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*Press "TRANSMIT" on the microwave control panel under Control Unit Status (WARNING: Do not touch the button to the right)
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*Type 3.00 into "Setrate" box, if necessary
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*Press "Take Data" on PDP
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*Hit "To Setpoint" Button
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*Try to maximize polarization by moving the bellows position
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*Wait for leads to reach full current (approx 1 min)
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*Watch the frequency in the top left monitor
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*Hit "Hold"
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*You can try to start out in the frequency range in the plot of frequency vs Dose since last annel
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*Check that leads current and magnet current are equal
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*Generally, you have to search for the "best" frequency When searching, make changes by 5MHz, 10MHz at the most
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*Hit "Heater On" button
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*After making a change, wait about 3 NMR updates to see if it helped/hurt
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*Wait for the 30 second timeout to expire
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*Beam trips will change pol quickly and obscure the effect of your changes especially over 50nA
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*Type the baseline current into the "Setpoint" box (eg: 59.882)
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*If the frequencies display does not work look also at the poltarcama/Jpeg/CamImgs.jpg using Camera Set 0, use F5 to update
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*Hit "To Setpoint" to start the magnet sweeping
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*As radiation damage accumulates, frequency will move if polarizing positively, frequency will move down and if polarizing negatively, frequency will move up
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*Wait for magnet to reach baseline current (approx 6 min)
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*Use the logbook − see what frequencies worked for other people
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*Hit "Hold" button
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*Log all of your best frequencies when you find them in the Target Operator Microwave Frequency Notebook
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*Put NMR into pause mode if necessary
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*Hit the Baseline button
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*Select "Create New Baseline", dialog box should then disappear
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*Change sweeps to 2000 if necessary
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*Double check that all NMR settings are where you want them
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*Hit "One Point" button to take a single nmr measurement
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*Wait for timer to count down
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*Hit Baseline button
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*Select the baseline you just took from the list of timestamps
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*Document the details of the baseline in the logbook:
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**Date Time, #Sweeps, MagCurrent, Top/Bottom, Gain, RFFreq, RFMod
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*Type full-field current into "Setpoint" box (eg: 60.882)
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*Type 3.00 into "Setrate" box, if necessary
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*Hit "To Setpoint" button
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*Wait for magnet to reach full current (approx 6 min)
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*Hit "Hold" button
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*Hit "Heater Off" button
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*Wait for 30 second timeout to expire
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*Hit "To Zero" to ramp the leads down
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*Hit "Lock Magnet Controls" button
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===Take TE measurements:===
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*Make sure ladder is in desired target position
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*Make sure NMR is on desired channel (AND in agreement with target position!)
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*Set sweeps to 2000, if necessary
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*Hit "Take Data" button
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*Wait for timer to count down
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*Make sure you have a STEADY Nose level with roughing and bypass valve closed
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*Use ~0.17 on the run valve (watch the nose temps.)
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*Write the following in the logbook for the next 10 measurements:
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**Time, NMR Area, 4He Press, 4He Temp, 3He Press, 3He Temp, Nose Level
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*Watch data until it flattens out, if in good warm steady state ~1.5K for a while should be less than 30 minutes.
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*calculate the TE calibration constant using poltar@poltarg2p2$ /home/poltar/g2p_te/te_getter.pl 15
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*Type Y to to run te_calc on this data
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*Put new Cal. Const. in under Sweeps in PDP and move on to prepare fridge for polarization
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Revision as of 03:09, 16 March 2012

This procedure has not yet been edited by target coordinator.

Assumptions:

  • NMR System is tuned
  • Magnet is at full field, persistent mode, leads are ramped down
  • Nose is over 50%, run valve in PID mode
  • Baseline taken and set
  • TE has been taken and new calibration constant feed into PDP
  • Target in correct position along with NHR Channel setting
  • Roughing and Bypass valve open with mechanical pumps on

Prepare Fridge:

  • Close Roughing valve
  • Turn on Blower 1 and wait 2 minutes
  • Turn on Blower 2 and wait 2 minutes
  • Close Bypass valve
  • Turn on Blower 3
  • Wait a little while

Begin Polarization:

  • Press "TRANSMIT" on the microwave control panel under Control Unit Status (WARNING: Do not touch the button to the right)
  • Press "Take Data" on PDP
  • Try to maximize polarization by moving the bellows position
  • Watch the frequency in the top left monitor
  • You can try to start out in the frequency range in the plot of frequency vs Dose since last annel
  • Generally, you have to search for the "best" frequency When searching, make changes by 5MHz, 10MHz at the most
  • After making a change, wait about 3 NMR updates to see if it helped/hurt
  • Beam trips will change pol quickly and obscure the effect of your changes especially over 50nA
  • If the frequencies display does not work look also at the poltarcama/Jpeg/CamImgs.jpg using Camera Set 0, use F5 to update
  • As radiation damage accumulates, frequency will move if polarizing positively, frequency will move down and if polarizing negatively, frequency will move up
  • Use the logbook − see what frequencies worked for other people
  • Log all of your best frequencies when you find them in the Target Operator Microwave Frequency Notebook
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