Log entry time 21:25:40 on May 30, 2009

Entry number 277726

This entry is a followup to: 277446

Followups:

• 278240 06/01/09 17:03 Jin Huang EPR Calibration for Longitudinal- Field of Cell Moss; Correct Coils has been ON; BB @ 75Degree

Bad news is last naive calibration constant is wrong

Good News is the naive constant is lower than the real one (discussed below), which means polarization of the day is >60%

============== EPR Log ==================

== Test Condition == Cell: Moss Oven Temperature: 230C Field Direction: Longitudinal - Laser Power: 3x25 COMET Cell Density: 7.962 amg Correction Coil: Small = 0.50A; Large = off

== K == Pumping Direction: Anti-Parallel Data directory: C:\AyeD\EPR\Data\EPR_AFP_20090530_2044 Calibration Constant: 8.74 %/mV Polarization: 56.49% Field: 25.01 G EPR Frequency Shift: 102.77 kHz

======== Discussion on the calibration constant ========

Since 01:49:53 May 30, 2009, we have using a calibration constant of 3.32x2.5 = 8.29%/mV, because pre-amplification was reduced by a factor of 2.5. However, since the correction coil was left on, which was off before, the real calibration constant should be higher, which is shown above = 8.74 %/mV.

By comparing to last long- EPR (Halog 274722), 0.5A current in correction coil dramatically suppressed massing effect. Therefore, polarization loss in this EPR is much smaller than Halog 274722. Since the NMR Polarization of today has reached same level as before, I am going to leave the correction coil on with 0.5A.

======== Recalculated NMR Polarization ========

NMR Time  Posted Pol.   Recalculated Pol.
01:27     53.9%         56.8%
04:11     57.1%         60.2%
08:02     58.5%         61.6%
12:58     59.5%         62.7%
17:19     58.5%         61.6%
20:24     58.7%         61.9%

Figure 1

Figure 2

Figure 3