Difference between revisions of "Prepare Frig for Polarization"
From Hall A Wiki
(→Prepare Fridge:) |
|||
| (3 intermediate revisions by 2 users not shown) | |||
| Line 1: | Line 1: | ||
| − | |||
| − | |||
===Assumptions:=== | ===Assumptions:=== | ||
*NMR System is tuned | *NMR System is tuned | ||
| Line 10: | Line 8: | ||
*Roughing and Bypass valve open with mechanical pumps on | *Roughing and Bypass valve open with mechanical pumps on | ||
*Beam Permit but no beam on target | *Beam Permit but no beam on target | ||
| − | ===Prepare | + | ===Prepare Frig:=== |
| + | *Ensure Blower 1 interlock light is on | ||
*Close Roughing valve | *Close Roughing valve | ||
*Turn on Blower 1 and wait 2 minutes | *Turn on Blower 1 and wait 2 minutes | ||
| + | *Ensure Blower 2 interlock light is on | ||
*Turn on Blower 2 and wait 2 minutes | *Turn on Blower 2 and wait 2 minutes | ||
| − | * | + | *Ensure Blower 3 interlock light is on |
*Turn on Blower 3 | *Turn on Blower 3 | ||
| + | *Close pump Bypass valve | ||
*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 | ||
| Line 31: | Line 35: | ||
*Log all of your best frequencies when you find them in the Target Operator Microwave Frequency Notebook | *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 | *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. | ||
Latest revision as of 07:26, 17 April 2012
Contents
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.
