- Can GCRcalib help to calibrate ACD HI charge scale? (Fred)
Following the presentation of last week, I analysed 50 runs of opssim2 data. The collection time is 70h (effective duration of 60h).
For each event where GCRCalib found an even value for the atomic number in the range 6-14 (i.e. C, O, Ne, Mg, Si), I loop on the AcdTrkHitPoca list in ACD recon. For those hits which have a suitable DOCA to Tkr1 track (doca>-50mm, i.e. Tkr1 track within 50mm of the tile), I get the number of MIPs from the AcdHit collection. This is a very slow analysis (8h30 to analyse 50 runs!). The following plot show the obtained MIP spectrum: the vertical lines
I modified the code I used to analyse the GCR events in opssim2 data, and added the reading of digi events (now it reads merit, gcr and digi files). I obtained the spectrum of each PM of each tile when GCRcalib is able to infer a value for the atomic number Z. The plots below show the low-range and high-range spectrum (top and medium plots, resp.) for all species, and the high-range spectrum for events tagged as carbons (bottom plots). This is for the PMT A of the central tile at the top of the ACD (left panel) and of the central tile (2nd row, 3rd column) of an ACD side (right panel).
The spectra do not exhibit any clear signature of heavy ions, probably due to all the "stuff where a bunch of particles leave the side of the ACD and cause a pile up of charge" (E. charles), especially in high-energy events. So the next step will be to correlate these results with AcdTrkHitPoca in ACD recon, in order to only keep the hits which have a suitable DOCA to Tkr1 track.