Interestingly, the bipolar output of the amplifier of the CHIO sent (and splitted) to check correlation on the channel 15 of the ADC CHIO (or on channel 29 of the ADC MUST2) provides a much better resolution (about 10%) than the one obtained using the unipolar output that we were looking since then (about 20% resolution).
This can be understood by the fact that the bipolar signal from the spectroscopic amplifier filters the baseline fluctuation by deriving the unipolar signal.
On the attached PID plot, it is easy to see the improvment. On the other hand, the beam spot extends also at lower channels and covers part of the other lines.
Since the bipolar signal has a negative part, it is possible for pile-up signals to arrive on top of this negative part and end up with lower energy.
With NUMEXO, the energies extracted from the digitized signals, this pile-up issue is not visible (see other plots, with less stat).
With Caen digitzer, last plot, and a very basic algorithm.
We have explored all the possible way to extract signal from this detector. We are thinking of writting a Nature on this analysis, if collaborators have any comments on those plot, they are not welcome. |