Difference between revisions of "Prepare Frig for Polarization"
From Hall A Wiki
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*Wait a little while | *Wait a little while | ||
===Begin Polarization:=== | ===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) | *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 | *Press "Take Data" on PDP | ||
*Try to maximize polarization by moving the bellows position | *Try to maximize polarization by moving the bellows position | ||
Revision as of 17:51, 6 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 Fridge:
- 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
