The STAR experiment

Real Data Productions

Jan's pages are HERE

Updated version.

Abstract:

Motivation:  We see a strange band structure in raw ADC vs. softId plots for the BSMD.  To date these plots have been generated by integrating over all triggers.  The idea here is to restrict to minimum-bias triggers to see if some of these bumps around ADC >~ 500 could be due to trigger turn-on curves.

Results:  At first glance, the trigger doesn't seem to be causing much of the bump.  On the left is a projection of raw ADC for BSMDE strips 1-150 using all triggers from 2005 pp data.  On the right is the same plot for MB-only, rebinned to deal with the limited statistics.  The MB plot was generated from a separate runlist with roughly 3x more statistics than the trigger-integrated plot.

Stats aren't great, but I think one can pick out the three bumps at ~500, ~570, and ~610, plus the ending spikes at ~710.  Looks like it's not the trigger.

References: 
2005 BSMD zero-suppressed ADCs
 

Documents and information for current STAR Software releases

Background:  Ahmed posted some studies of the BSMD in Run 7 indicating that the ADC dynamic range is limited.  Pibero and Willie showed a dramatic band structure of the raw ADCs in the 2006 pp, and people wondered how far back this structure existed.  Here is the data from 2005.

What's being plotted:

• 2005 pp data
• BSMDE
• zero-suppressed at (adc-ped) < 1.5*rms
• NOT pedestal-subtracted
• restricted to status==1
• ~4000 files from throughout Run 5
• strip softId on x-axis -- each plot is another 1000 strips

And finally, here's a projection of strips 1-150:

Clearly, the band structure was there as well.

Update:  Renee mentioned that 4500-4600 look a little cleaner than the rest.  Here are projections for 4500-4590 and 4500-4650.  The band structure doesn't disappear, but the slope of the exponential fall-off is steeper so fewer counts end up in the screwy 500+ regime.  Here are the results of fits to the region 100 - 150:

0001-0150:  slope = -0.0105
4500-4650:  slope = -0.0130
4500-4590:  slope = -0.0150

See also:  2005 BSMD zero-suppressed ADCs (minbias triggers)

See attached version 1 of the Analysis Meeting talk

A new presentation is attached at the bottom.

The pileup_09_14.ppt is with the old algorithm which suffer's statsitcal effect and cause non-flat Z coordinate dependence.