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I forgot to mention those estimates I quoted also used the target x-offset of +6.7 cm. On Jul 29, 2015, at 16:31, Nathan Baltzell <[log in to unmask]> wrote: > Hi Norman, > > We took a look at this and I think this is due to lack of depth/position correction (since > the one in the reconstruction code is for data with b-field). > > There is an analytic correction that requires only geometry (track and crystal angles) and > shower depth as inputs. And we have a measure of the shower depth for these same crystals > measured from a previous experiment (albeit with photons, average energy around 1.5 GeV). > If we estimate the average geometry from the 2-d plot you showed and remember that target > is 4m upstream from ecal, this gives average expected y-errors of -2.5 mm for top and +2.5 mm > for bottom, and -3 mm for x. This happens to be a good match with the residuals you measure. > > Need to parameterize the crystal angles as function of x/y and then send a correction > for you to try. > > There also is a small x-rotation for top half of ecal from the survey which is not in lcsim. > That could explain the difference in dx for top/bottom. > > -Nathan & Holly > > > On Jul 29, 2015, at 14:40, Graf, Norman A. <[log in to unmask]> wrote: > >> Hello Stepan, >> Yes, the residuals are cluster - track. >> Norman >> >> -----Original Message----- >> From: Stepan Stepanyan [mailto:[log in to unmask]] >> Sent: Wednesday, July 29, 2015 11:38 AM >> To: Graf, Norman A.; hps-software; [log in to unmask] >> Subject: Re: SVT ECal relative alignment >> >> Norman, >> >> On X-axis, is it really cluster_position-track_postion? >> >> Stepan >> >> On 7/29/15 1:13 PM, Graf, Norman A. wrote: >>> Hello All, >>> I've taken the straight tracks from the field-off run 5784 and >>> projected them to the Ecal. The residuals are plotted in the >>> attachment using the z position of the cluster (which was essentially >>> constant at 1393.7). Although the accuracy is quite good (~2.5 to ~3 >>> mm) there are clear systematic shifts in both x and y for both top and >>> bottom. Do these patterns make sense to anyone? I've also attached the >>> cluster x-y positions, showing the fiducial cuts imposed on the clusters. >>> >>> I should note that these events were reconstructed using a >>> non-production steering file. The calorimeter positions were taken >>> from the uncorrected cluster collections pointed to by the >>> ReconstructedParticle objects. The reconstruction did use the >>> >>> HPS-EngRun2015-Nominal-v2 >>> >>> detector which has the SVT survey incorporated. Have the ECal survey >>> numbers been incorporated into this detector? If not, are these shifts >>> commensurate with any of the measured offsets? >>> Thanks, >>> Norman >>> >>> ###################################################################### >>> ## >>> Use REPLY-ALL to reply to list >>> >>> To unsubscribe from the HPS-SOFTWARE list, click the following link: >>> https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1 >> >> >> _______________________________________________ >> Hps-analysis mailing list >> [log in to unmask] >> https://mailman.jlab.org/mailman/listinfo/hps-analysis > > ######################################################################## > Use REPLY-ALL to reply to list > > To unsubscribe from the HPS-SOFTWARE list, click the following link: > https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1 ######################################################################## Use REPLY-ALL to reply to list To unsubscribe from the HPS-SOFTWARE list, click the following link: https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=HPS-SOFTWARE&A=1