Load the sample tube and pack the sample on the benchtop spinner

1. Clean the sample tube

1. Perform a scratch test of the tube.
   
   
   IF YOU FEEL ANY SCRATCHES, THE TUBE MUST BE REMOVED FROM USE!
   
   If you continue using a scratched tube, it may explode in the probe destroying the probehead and leading to a repair cost in excess of $30,000!

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2. Disassemble the sample tube completely.

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3. Scratch out the old sample with the blue scraper tool

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4. Soak all parts in water or water-alcohol mixture.
   The sleeve may be soaked in other organic solvents to dissolve the solid sample particles, if needed.

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5. Clean the sleeve inside with a soft wire brush to make sure no particles are stuck to the inner surface.

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6. Check inside of the sleeve with a packing tool that the surface is smooth and was thoroughly cleaned up.

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7. Check inside of the inserts, top, and bottom caps for stuck particles.

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8. Rinse all parts in alcohol and allow them air-dry.

2. Load the sample powder

NOTE: Sample must be completely dry as the sample tubes are NOT leak-proof.

• Clean black funnel with the wire brush

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• Insert the bottom plug into a clean sleeve. The side does not matter. Press to eliminate the gap between the bottom end and a sleeve.

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• If you intend to use spacers: place one spacer inside.

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• Drop the tube down the funnel.

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• Add sample powder in small portions.

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• Tap with the funnel to help direct the powder down .

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• Compress the powder with the blue tool very slightly — just with the weight of the tool.
  
  DO NOT PACK TIGHTLY!
  Powder will spontaneously compress towards the walls during spinning. Compressing it with a tool from top may lead to an unbalanced tube!

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• Use just enough powder to have
  
  
• if using spacers: the metallic strip fully inside the tube - the tube top should meet the colored portion.
  
  
• if not using spacers: the blue strip inside, metallic strip fully outside the tube

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• If you loaded too much sample, DO NOT COMPACT POWDER to make space for the top cap! Instead, scratch out the excess powder with a scraper end of the blue tool.

3. Close the tube

• If using spacers:  Insert the second spacer.

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• Check depth for the cap with a blue tool.
  
  NOTE: you should see entire metallic band of the tool outside of the tube!

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• Insert the spinning cap: push down with your fingers to fully insert.
  
  If there is a gap between the cap and a sleeve, this means that you put in too much sample. You must take out the spinning cap and remove some powder!

4. Check the bottom cap

The paint for spinning speed detection should be black and coloring 1/2 of the circumference of the cap. If it is not good, you may

• wash it off with ethanol

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• repaint with a black marker

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• You MUST give it a minimum of 15 min to dry up before inserting your sample tube in the benchtop spinner .

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If in doubt, ask NMR staff to paint the bottom cap for you.

2.1 Read Important Notes

NOTE 1

We spin the tube in multiple steps with a gradually increasing the spining speed to pack the sample powder along the walls of the tube. You must spin at required speeds and for required time periods to correctly pack the sample. If the sample was not packed well, the tube will be unbalanced and may explode at a high spinning speed damaging the probe!

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NOTE 2

Never turn on spinning and walk away!

Stand by while watching the system to attain the expected Drive Pressure with every new speed (see table below).

If you observe that the system increases Drive Pressure more than 10 kPa over the expected value: hit STOP! The rotor is unbalanced and must be repacked.

When the system reached the expected pressure: stand by to witness the speed to slightly overshoot the target and then begin drifting back. Wait for the speed to settle and verify that fluctuations do not exceed 3-5 Hz.

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NOTE 3

If you see the speed to stall in the 1000-1200 Hz speed range, YOUR MUST STOP SPINNING IMMEDIATELY. The tube is unbalanced and continuous spinning will lead to the tube and probe damage!

Important: The MASCONT software misinterprets the stall condition and overreacts by indiscriminately increasing Drive pressure until a speed increase is detected. This results in significant pressure overshoot, pushing the probe's spinning speed beyond safe operating range for the tube.

If the speed stalls: the tube is unbalanced and must be repacked even if it span correctly in the benchtop spinner. If stalling occurs again after repacking and a successful test on a benchtop spinner, contact NMR staff to deal with this problem!

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NOTE 4

The sample tube must be always tested in the benchtop spinner before inserting it in the probe even if the sample was measured before. This is required because handling of the tube might have disturbed its internal packing.

You must verify stable spinning of the tube at the range of speeds up to the maximum speed exceeding the speed you intend to use in the probe by 2 kHz. For example, if you need to spin at 10 kHz in a probe, you must spin up to 12 kHz on a benchtop.

Freshly loaded sample must be spun for additional 5 minutes at each speed.

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NOTE 5

If the tube is spinning with fluctuations exceeding 5 Hz, it is unbalanced and will get scratched, and may explode at high speeds damaging the probe.

You MUST stop spinning and repack the sample.

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NOTE 6:

Light adjustment is mandatory every time after you inserted a sample in either probe or benchtop spinner.

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2.2 Check JEOL spectrometer system 

1. Open N2 gas valve on a wall

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2. Spectrometer is always ON

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3. MAS controller must be ON

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4. Start MASCONT on the computer

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If you found MAS controller powered off:

1. Turn the unit on.

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2. Re-launch the MASCONT software.

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3. Click the Disconnect/Connect button.

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2.3 Load the benchtop spinner

1. Take the probe out of the magnet.

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2. Disconnect spinning and bearing gas lines from the probe.

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3. Attach gas lines to the benchtop spinner (according to color).

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4. Check if they are attached well by pulling on each line.

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5. Disconnect SPIN cable from the probe and attach to a spinner.

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6. Open the spinner shield.

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7. Wipe the sample tube with a kimwipe.

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8. Check the top and bottom caps for gaps.

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9. Do a scratch test.

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10. Put the tube into the spinner with the spinning cap (brown) facing outside.

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11. Knock gently on the benchtop spinner body to help the tube settle to the bottom of the bore.

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12. Close the spinner shield.

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13. Set the light adjustment knob to the pen mark.

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14. In the MASCONT window, check that you see the correct tube material shown in the "Sleeve" window (ZrO2 for our tubes).

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15. Start logging the speed:

    1. Enter the File Name in the "Log" section as [Your initials]_[experiment ID]_benchtop

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    2. Enter 20 sec as logging interval

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    3. Click "Start" to begin recording the spinning speed.

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2.4 Adjust Light Intensity for the Speed Measurement

• Make sure the MASCONT software is in the Manual mode (default mode when stopped). Click Manual button to switch.

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• Set the light adjustment knob to the pen mark.

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• Adjust Bearing pressure to approx. 150 kPa (move slider to the 4th tick). You should see the sample start spinning at a slow speed of a few Hz. Any speed other than 0 Hz is good.
  
  
  If the sample does not spin (readings remain at zero)

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  • Rotate the light adjustment knob slowly from one limit to another watching the readings. If it starts reading, proceed with light intensity adjustment.
    
    
  • Still does not spin? Click [Stop] to bring Bearing pressure to zero and take the sample out:
    • Verify that the flute (turbine) is facing outside;
    • Check that the flute is not damaged;
    • Check if the flute and end cap are inserted tightly and there is no gap between them and a sleeve;
    • Check the paint on a bottom cap. If it is worn, ask NMR staff to repaint the cap.
    • Set the light adjustment knob to the pen mark and try spinning up again.
      
      
  • If you still cannot start spinning, insert the standard AGK sample.
    • If it does not spin either: the spinner stator needs cleaning, contact NMR staff.
    • If AGK tube spins well, clean your tube from the outside with alcohol and try again. If still does not work - contact NMR staff.
  
  
• If your tube successfully started spinning, increase the Drive pressure to 4 kPa (two clicks on the > button).

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• Wait 20 sec for the speed to stabilize (speed will be around 500 Hz).

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• Slowly rotate the light adjustment knob to find one end of the detection region: once the readings drop, rotate back slightly to restore the readings. This is the one end of the detection region.

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• Rotate the knob in the opposite direction and look for the other end of the detection region. This is the second end of the detection region.

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• Set the knob to the middle between the two ends of the detection region.
  
  
  NOTE: The detection region will be different for different tubes due to variable quality of paint on the bottom cap. Your must determine detection range every time the tube is inserted in the benchtop spinner.

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2.5 Spin Up to Test for the Working Speed of 10 kHz

NOTE: If you see fluctuations in the 50-100Hz range - STOP IMMEDIATELY. Tube is unbalanced and must be repacked if you need to continue with this speed!

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• Click once on the > button to increase Drive pressure to 5 kPa. Wait for the spinning speed to stabilize. You should reach around 740 Hz with fluctuations not exceeding 5 Hz

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  Wait 5 minutes to allow for the sample powder to compress.

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Important: The next step decides whether the tube may be span at higher speeds. 

The speed must increase to 1600-1700 without any hesitation around 1100-1300 Hz.

 If the speed stalls in this range - hit STOP immediately. 
Listen for the noise the tube makes: oscillating buzzing noise means that the tube touches the walls!


 Stalling means that the tube touches the stator walls and slows down despite the high Drive pressure. Both the spinner stator and the tube will be damaged by continued spinning. Report the issue to NMR staff.



• Click four times on the > button to increase Drive pressure to 9 kPa.
  
  
  Did the speed stall around 1100-1200? STOP immediately!

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  If the tube smoothly reached the speed around 1600 Hz with fluctuations no more than 5 Hz:
  • Type 1600 in Target Speed window
  • Click Auto

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  Wait 5 minutes to allow for the sample powder to compress.
  
  

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• Look up the next speed from Target Speed column in the table below and notice the expected value of the Drive Pressure.


• Type next speed in Target Speed window and hit Enter on the keyboard.
  
  
  NOTE 1: Watch for Drive pressure NOT to exceed what is expected in the spinning rate table by more than a few kPa.
  
  NOTE 2: Watch for fluctuations to remain in the "permitted" range.
  
  
  
Wait 5 minutes to allow for the sample powder to compress after your tube stabilized at each new speed!

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Target Speed, Hz	Permitted Fluctuations, Hz	Expected Drive Pressure, kPa	Expected Bearing Pressure, kPa
Auto: 3,000	+/- 5 Hz	26-28	150
Auto: 6,000	+/- 3 Hz	74-76	200
Auto: 9,000	+/- 3 Hz	121	200
Auto: 12,000	+/- 3 Hz	167	300

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Did your tube spin stably at 12 kHz?  You may proceed with using it in the probe.