Therefore, this afternoon flip interval was increased to 40min. However, the higher polarization of each spin flip pair increased, while the lower one (cooresponding to high energy state -> lower state) stay at same level. Therefore, it's now more likely that there is a massing effect limiting the polarization.
So, as an attempt to increase the massing threshold, mall correction coil is turned on to 1A. As a result extra field gradiant should be introduced so the massing threshold should be higher.
The NMR polarization calibration constant could be shifted a little due
to the extra gradiant. However, if the massing effect is reduced, the
overall signal hight (proportional to online pol.) should increase.
A copy of this log entry has been emailed to: jpchen, yqiang