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...)
 
(→‎Prepare Fridge:)
 
(8 intermediate revisions by 3 users not shown)
Line 1: Line 1:
−
;This procedure has been updated to reflect changes in the target for g2p but 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
 +
*Beam Permit but no beam on target
 +
===Prepare Frig:===
 +
*Ensure Blower 1 interlock light is on
 +
*Close Roughing valve
 +
*Turn on Blower 1 and wait 2 minutes
 +
*Ensure Blower 2 interlock light is on
 +
*Turn on Blower 2 and wait 2 minutes
 +
*Ensure Blower 3 interlock light is on
 +
*Turn on Blower 3
 +
*Close pump Bypass valve
 +
*Wait a little while
  
 +
===Begin Polarization:===
 +
*'''new''' Confirm the level in the nose is still around 56%. Set the run valve "man setp" to 0.6 and then the mode to "Man Mode" = YES. Wait for the "Cur Pos" to match the set point of 0.6. (Run valve controls are a pop-up on the cryo-screen, accessed by clicking the button next to "run").
 +
*Press "TRANSMIT" on the microwave control panel under Control Unit Status (WARNING: Do not touch the button to the right)
 +
*'''new''' Change the mode on the run valve to "Man Mode" = NO.
 +
*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 (This shows in Hall bellows position)
 +
*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
 +
*Tell shift leader you are ready for beam
  
−
===Software===
 
  
−
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.
+
===''new'' When it's time to stop polarizing===
 +
When the run plan demands you turn off the microwaves (which will never happen during standard data production), we have found that it is necessary to pre-set the run valve setting to prepare the run valve PID loop for the dramatic change in heat load to the target when the microwaves are switched off.
  
−
===Assumptions:===
+
*'''new''' Set the run valve "man setp" to 0.1 and then the mode to "Man Mode" = YES. (Run valve controls are a pop-up on the cryo-screen, accessed by clicking the button next to "run").
−
*NMR System is tuned
+
*Press "STANDBY" on the microwave control panel under Control Unit Status (WARNING: Do not touch the button to the right on the panel)
−
*Magnet is at full field, persistent mode, leads are ramped down
+
*'''new''' Change the mode on the run valve to "Man Mode" = NO.
−
*Nose is full, run valve in manual mode
+
−
===Prepare Fridge:===
+
−
*Stop RB3, RB2, and RB1 (wait 2 mintues between each), if necessary
+
−
*Put Run Valve, EV91120, in Manual Mode
+
−
*Establish a STEADY Nose level somewhere between 50-65%
+
−
*Try 0.17 on the run valve.
+
−
*If needed only make slight changes to Run Valve for rest of TE (+/- 0.05 each 10 min)
+
−
===Take a Baseline:===
+
−
*Hit "Unlock Magnet Controls" button
+
−
*Type the full-field current in the box labeled "Setpoint" (eg: 60.882)
+
−
*Type 3.00 into "Setrate" box, if necessary
+
−
*Hit "To Setpoint" Button
+
−
*Wait for leads to reach full current (approx 1 min)
+
−
*Hit "Hold"
+
−
*Check that leads current and magnet current are equal
+
−
*Hit "Heater On" button
+
−
*Wait for the 30 second timeout to expire
+
−
*Type the baseline current into the "Setpoint" box (eg: 59.882)
+
−
*Hit "To Setpoint" to start the magnet sweeping
+
−
*Wait for magnet to reach baseline current (approx 6 min)
+
−
*Hit "Hold" button
+
−
*Put NMR into pause mode if necessary
+
−
*Hit the Baseline button
+
−
*Select "Create New Baseline", dialog box should then disappear
+
−
*Change sweeps to 2000 if necessary
+
−
*Double check that all NMR settings are where you want them
+
−
*Hit "One Point" button to take a single nmr measurement
+
−
*Wait for timer to count down
+
−
*Hit Baseline button
+
−
*Select the baseline you just took from the list of timestamps
+
−
*Document the details of the baseline in the logbook:
+
−
**Date Time, #Sweeps, MagCurrent, Top/Bottom, Gain, RFFreq, RFMod
+
−
*Type full-field current into "Setpoint" box (eg: 60.882)
+
−
*Type 3.00 into "Setrate" box, if necessary
+
−
*Hit "To Setpoint" button
+
−
*Wait for magnet to reach full current (approx 6 min)
+
−
*Hit "Hold" button
+
−
*Hit "Heater Off" button
+
−
*Wait for 30 second timeout to expire
+
−
*Hit "To Zero" to ramp the leads down
+
−
*Hit "Lock Magnet Controls" button
+
−
===Take TE measurements:===
+
−
*Make sure ladder is in desired target position
+
−
*Make sure NMR is on desired channel (AND in agreement with target position!)
+
−
*Set sweeps to 2000, if necessary
+
−
*Hit "Take Data" button
+
−
*Wait for timer to count down
+
−
*Make sure you have a STEADY Nose level with roughing and bypass valve closed
+
−
*Use ~0.17 on the run valve (watch the nose temps.)
+
−
*Write the following in the logbook for the next 10 measurements:
+
−
**Time, NMR Area, 4He Press, 4He Temp, 3He Press, 3He Temp, Nose Level
+
−
*Watch data until it flattens out, if in good warm steady state ~1.5K for a while should be less than 30 minutes.
+
−
*calculate the TE calibration constant using poltar@poltarg2p2$ /home/poltar/g2p_te/te_getter.pl 15
+
−
*Type Y to to run te_calc on this data
+
−
*Put new Cal. Const. in under Sweeps in PDP and move on to prepare fridge for polarization
+

Latest revision as of 07:26, 17 April 2012

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
  • Beam Permit but no beam on target

Prepare Frig:

  • Ensure Blower 1 interlock light is on
  • Close Roughing valve
  • Turn on Blower 1 and wait 2 minutes
  • Ensure Blower 2 interlock light is on
  • Turn on Blower 2 and wait 2 minutes
  • Ensure Blower 3 interlock light is on
  • Turn on Blower 3
  • Close pump Bypass valve
  • Wait a little while

Begin Polarization:

  • new Confirm the level in the nose is still around 56%. Set the run valve "man setp" to 0.6 and then the mode to "Man Mode" = YES. Wait for the "Cur Pos" to match the set point of 0.6. (Run valve controls are a pop-up on the cryo-screen, accessed by clicking the button next to "run").
  • Press "TRANSMIT" on the microwave control panel under Control Unit Status (WARNING: Do not touch the button to the right)
  • new Change the mode on the run valve to "Man Mode" = NO.
  • 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 (This shows in Hall bellows position)
  • 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
  • Tell shift leader you are ready for beam


new When it's time to stop polarizing

When the run plan demands you turn off the microwaves (which will never happen during standard data production), we have found that it is necessary to pre-set the run valve setting to prepare the run valve PID loop for the dramatic change in heat load to the target when the microwaves are switched off.

  • new Set the run valve "man setp" to 0.1 and then the mode to "Man Mode" = YES. (Run valve controls are a pop-up on the cryo-screen, accessed by clicking the button next to "run").
  • Press "STANDBY" on the microwave control panel under Control Unit Status (WARNING: Do not touch the button to the right on the panel)
  • new Change the mode on the run valve to "Man Mode" = NO.
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