Let me make a few comments and suggestions up for discussion in this regards. First a clear support for a coordinated effort to calibrations as said by ian . I belive there are some open issues have to be solved to do this taks best. a) BB cal. I belive Hiro has identified some problems in particular in regards to the large BB tube slewing corrections It seems that the detectors have a different response than earlier and we have to deal with this. (I hope hiro can supply some overall info on this). a1) The fact we use specific reference tubes that are NOT slew corrected is a problem in my opinion, should this be done iretatively or via some other detcctor (e.g. ZDC). a2)The tube to tube response have auto-correlations due to overall multiplicity. i.e large result in one tube has a large response in another possible (quite surely) introducing a multiplicity dependence. a3) Please recall that at a number of tubes were replaced (at at least two instances) with better response. e.g in later runs the right tubes 14,17 bad early are good later in the rund- again read e-log. b) tdc timescale. The tdc channels attached to given tubes in tofw was modified during run ; please ensure the tdc-gains calibratuon runs are used before making more calibrations. - at what runs were changes done? Plase consult e-log. c) Are the tof adcgains done using a Landau distr (Gaussians are no good). Do we deal properly with the gains in H2 where significant y dependences of <adc> is present (large attennuation in scint.).? ) I think we ought to use a constant Vscint (as Djam and I have promoted earlier rather than the TPC driftvelocity dependence we used for run 2. )The coding (scripts) should include TFW2. regards Flemming ---------------------------------------------------------------- Flemming Videbaek Physics Department Brookhaven National Laboratory e-mail: videbaek@bnl.gov phone: 631-344-4106 ----- Original Message ----- From: Ian Bearden To: flemming videbaek Cc: hito@bnl.gov ; Eun-Joo Kim ; Ouerdane Djamel ; Catalin Ristea Sent: Tuesday, March 30, 2004 3:20 AM Subject: Re: BB calibration Hi Flemming, others... Djamel is in the process of cleaning up/revising/improving calibration software. We will push through the whole calib chain soon, make the software public and ask for volunteers. I am coordinating, please let me know: 1)if you have done calibrations 2)you have ideas for improving calibrations 3)you want to do calibs. The plan is to do run4 Au-Au first, and do it sequentially from start to finish. We probably want to do the 63GeV run quickly, though. What is the "new tofw cal" you refer to? Is this just that the calibrations have been done, or is there new software? If there is new software, what is the reason for specializing to TOFW? I will try to write a more clear note on the calibration effort after my teaching (for which I am now 5 min. late!)... Cheers, Ian On 29/3-2004, at 23:31, flemming videbaek wrote: Since All of you at one time or another have worked on the BB calibration I think this needs to be coordinated, so no double works gets done. I know catelin have send info what you did to Djamel. I think one of you should coordinate i.e. decide what are the runs to do first (i.e. First Au-Au run for run-4, When tubes are know to have been replaced (a couple of times during the run) and who could do certain other things. the reason for writting on this is t least twofold. a) Cateling has doe a set of runs. b) Are the Large BB really worse than the small. c) Using the default software for recent runs, the BB is certainly not optimal (this may be due to 9930 is the latest committed run) but also that the TOF for both FS and MRS looks rather crummy for MRS there may be 'new tofw cal (eun-joo)? the overall tof shows up as 60 nsec which is no good , but for H1,H2 I know the existing ones worked rather well with default values, which are all tuned to BB vertex? I cannot tell if this is mainly due to Bb or to TOF's though I suspect a combination. Please take this as a note so you all communicate on what is going on, so we can get a consistent analysis. This is clearly just a first step in several. regards Flemming ---------------------------------------------------------------- Flemming Videbaek Physics Department Brookhaven National Laboratory e-mail: videbaek@bnl.gov phone: 631-344-4106 _______________________________________________ Brahms-dev-l mailing list Brahms-dev-l@lists.bnl.gov http://lists.bnl.gov/mailman/listinfo/brahms-dev-lReceived on Tue Mar 30 21:04:50 2004
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