A late entry for the work I carried out on Thursday.
With the Emco box providing the HV, the pulser peak showed double (or triple) peaks. This was not seen with the SY1527 so I thought this would be better for looking at peak widths.
Same ASIC settings my previous entry, and a HV of 200V with leakage current 3.8uA.
I varied the shaping time in each module using the ASIC4 control page as this also changes the hold time automatically. Slow comparitor threshold of 64.
Checked each module and took sample channels from a couple of ASICs in each but made qualitative comparisons with random channels in all ASICs to make sure the chosen ones were representative of the ASIC/module as a whole.
Tables and graphs are included below for nnaida11 and 13. nnaida13 showed a high level of low E noise on some spectra, but the pulser peaks were always well defined single peaks.
nnaida12 showed noises across the full range of many spectra in all ASICs apart from ASIC4. Patrick suggested this module may possibly be suffering and need replacing. A quick scan through some channels showed:
- average peak width @ shaoing time of 0.5us of ~150-180 ch
- same at shaping times of 2.5 and 4.5us. Noise present over full range throughout
My taxi was arriving so I didn't have chance to go through nnaida14 in depth, but a quick scan showed peak widths within ~10-15ch of those seen in nnaida13. |