Bias scan - done 9-10 june 2025

This is the standard bias voltage scan, intended to put all the MIP peaks at the same location in ADC.

You can find more discussion in last year's bias scan page here, and references therein

Maria took 7 runs at different voltages, but honestly the dark current is so high, especially on the higher bias runs, that I only used four runs, which was enough.  If STAR were going to run even another year, I would have replaced the SiPMs, because the current is high.  But I still think we made the right choice to keep them for one last year.  Anyway, that's what we have.

The big pdf file is attached to the bottom of the page, or click here.

Every year, setting the 744 tile biases involves a little bit of human intervention (10-15 tiles at most).  This year, it was more like 35, due to the current.  It's a pain in the neck.

The new bias voltages are here.  They have been uploaded to daqman and loaded into the GUI.

By the way, I did fix a small bug in the bias code (no effect on functionality) that sometimes caused a crash.  The new code, including some hand-tuning to account for the dark current, is here.