Make New Entry, Make Followup Entry
User name nmuangma
Log entry time 19:14:04 on March 11, 2011
Entry number 351334
This entry is a followup to: 351272
keyword=BigBite issue: The noise pattern are difference. Might be related to the way coda record data.Comparing the cosmic run from 2/28/2011 to 3/7/2011 & 3/10/2011
The noise pattern on MWDC are difference.
Using the current setting of Analyzer and the BigBiteLib, I replay the cosmic run 2052 (2/28/2011), 2576 (HV OFF-3/7/2011), 2688 (HV OFF-3/10/2011), 2700 (HV ON 3/10/2011)
During 2/28/2011, the cosmics hit pattern is uniformly. During 3/10/2011, the cosmics hit pattern show noise pattern issue. Comparing figure 1 (run 2052) and figure 5 (run 2700), we can see clearly that the hit pattern dramatically change. Focusing on run 2700, plane x1 and x1p, they both have similar noise pattern. This suggest something else rather than the Hardware issues.
I try to track down the problem.
We have other BB cosmic run (2576) on 3/7/2011 but with the HV off. This show the noise in MWDC (see figure 3). None of the noise patterns in any plane are similar.
Another run with HV off is run #2688 on 3/10/2011. This run show that the noise became worse and the patterns in both x1 and x1p are alike. (see figure 4).
Something unphysical happens here. As we plot run 2700 without index and with index[0], we saw the noise pattern disappear when we have the index on. see figure 5 & 6.
A copy of this log entry has been emailed to: doug@jlab.org , eip@tauphy.tau.ac.il , or.chen@mail.huji.ac.il , igor.korover@gmail.com , jwatson@kent.edu , sgilad@mit.edu , vasulk@jlab.org , kelleher@jlab.org , brads@jlab.org , n.muangma@gmail.com
Figure 1: BB cosmics on 2/28/2011
Figure 2: BB cosmics on 2/28/2011 index 0
Figure 3: BB cosmics with MWDC HV OFF 3/7/2011
Figure 4: BB cosmics with MWDC HV OFF 3/10/2011
Figure 5: BB cosmics after power off( then on) all BB components 3/10/2011
Figure 6: BB cosmics on 3/10/2011 index 0
