Difference between revisions of "Cell testing method"

Latest revision as of 16:03, 21 December 2011

1) RTDs:

    - Test the target RTDs and the oven RTD at room temperature against a thermometer. 
    - Record their offsets.
    - Discard RTDs with significant offsets.
    - Place selected RTDs on the cell.

2) Installation of the cell in the oven:

    - Center the pumping chamber with respect to the oven windows.
    - Seal the oven with RTV.
    - Record position of the cell with respect to the pick-up coils for flux calculation purpose.

3) Laser alignment:

    - Check laser alignment (and light loss) at each optical element.
    - Check 1/2 and 1/4 wave plates settings.
    - Check the spectrum analyzer for optimal absorption.

4) Cell testing:

    - Set up the oven at the desired temperature. Wait for the temperature to stabilize.
    - Turn on the lasers. Wait for the temperature to stabilize.
    - Spin up: take NMR measurement every 3 hours.
    - When spin up is done, do the following tests:
             - EPR-NMR calibration: take EPR and NMR measurements 5 minutes apart following this sequence: EPR-NMR-EPR-NMR-EPR
             - temperature test: take NMR measurements with lasers on and off following this sequence: ON-OFF-ON-OFF-ON. Before each measurement, make sure the cell temperature is stable.
             - AFP loss test: take 5 NMR measurements 5 minutes apart.

5) Spin down or test at higher oven temperature

If spin down:

    - Turn off the laser and the oven. Wait for the temperature to stabilize.
    - Take NMR measurement every 3 hours.

If test at higher temperature:

    - Turn off the lasers. Wait for the temperature to stabilize.
    - Go to step 4).