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. However, no basic or acidic cleaning solutions are allowed!

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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 packing tool very slightly — just with the weight of the tool.
  
  DO NOT PACK TIGHTLY!
  Powder will spontaneously compress towards the walls during spinning in the next step. Compressing it with a tool downwards 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 packing tool.

3. Close the tube

• If using spacers:  Insert the second spacer.

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• Check depth for the cap with a packing 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 on Auto 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 (stop increasing) in the 1000-1500 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. If stalling occurs in the probe 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.

Once the tube is outside of the probe, it MUST go through benchtop spinner test before you can insert it in the probe again.

You must verify stable spinning of the tube in the benchtop spinner 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 a minimum of 5 minutes at each speed to allow for proper sample packing.

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NOTE 5

If the tube is spinning with fluctuations exceeding 10 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. Prepare the tube
   
   • Use a glove on the left hand to have better grip on the tube and avoid transferring any grease from fingers. Hold the tube by spinning cap. Wipe the sleeve with a kimwipe.

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   • Check the top and bottom caps for gaps (compress)

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   • Do a scratch test.

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8. Insert the tube in the spinner 
   • Hold the tube with your left hand by the spinning cap.
   • With your right hand, tilt the spinner to orient the bore vertically.
   • Rotate the tube such way that the painted portion of the bottom cap will be oriented UPWARD when the spinner is back on the console.
   • Drop the tube into the spinner bore and place the spinner into its box on the console.
   • Close the spinner shield (match arrows).

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

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10. 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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11. 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 5 sec as the recording 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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• Make the sample float  Adjust Bearing pressure to approx. 150 kPa (move slider to the 4th tick). Drive pressure must remain zero. You should see the sample start rotating at a slow speed of a few Hz. Any speed other than 0 Hz is good, this is a signature of the sample floating in the Bearing gas flow.
  
  
  If the sample does not float (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 zero readings?  Click [Stop] to bring Bearing pressure to zero and take the sample out and reinsert making sure that the painted portion of the bottom cap will be facing upwards when it is in the spinner. Try adjusting Bearing pressure again.
    
    
  • Still does not float? Click [Stop] to bring Bearing pressure to zero and take the sample out:
    • Verify that the spinning cap is facing outside;
    • Check that the flutes are not damaged;
    • Check if the spinning and bottom caps are inserted tightly and there is no gap between them and a sleeve;
    • Check the paint on a bottom cap. If it is badly worn, ask NMR staff to repaint the cap.
    • Reinsert the tube in the spinner making sure that the painted portion of the bottom cap will be facing upwards after it is in the spinner.
    • Set the light adjustment knob to the pen mark and try spinning up again.
      
      
  • If your sample is still not floaing, 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 is floating, increase the Drive pressure to 5 kPa (two clicks on the > button).

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• Wait 20 sec for the speed to stabilize (speed will be around 600-700 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.   Note position of the knob.

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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 reflectance of paint on the bottom cap. Your must determine detection range for every time the tube is inserted before you start increasing the drive pressure!

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

• Let the tube spin at the current speed for 5 minutes to allow for the sample powder to compress.

Continue to Automatic mode: