Hi Christian, > >We should register the two new parameter sets with the database too. >Please read the DB info avaliable from [1] and in "The Guide". > It turns out to be awkward for me to use the database since I still can only access it by running on the rcas machines--where I have very poor response using editors and such. Once I can access the db on my local machines (all PPC) I work on getting the parameters located properly. I'll probably need you help with this. > >Why do you add 50 to the ADC gap in the Tiles? Why don't you simply >add those 50 to the calibration numbers? > >Remember, hardcoded constants are BAAAD. Calibration paramters in the >database is GOOD. > This was a mistake that I'm very glad you caught. I was checking the sensitivity to the tile gap. My conclusion was that the automatic tile dap search routine that I had been using failed in a large number of cases. I have since switched over to the tile gaps that Hiro found by trying to obtain a smooth distribution at the seam. The factor of 50 has to go. > >>We were already calculating the number of "primary" particles >>hitting each detector element based on HIJING simulations that >>relate these particle multiplicites to the observed energy deposited >>in each si and tile element. I have now added calibrations that >>relate the particle multiplicites to a dNdEta value based on the >>measured vertex position. To obtain the calibrations I position a >>simulated vertex between -46 cm and +46 cm, in 2 cm steps, and at >>each position did a "throw" of HIJING 0-2 fm primary events (no >>CASCADE...). Each particle was checked to see if it hit on the si >>or tile detectors. I also kept track of the total number of >>particles within the pseudorapity range covered by each >>detector. This procedure allows for a simple geometric efficiency >>calculation. >> > >Why the do we need this extra conversion from single element >multiplicity to ring multiplicity? Are the conversion functions not >enough? > The single element multiplicities only give the number of particle hitting each element. The new calculation is intended to develop the dNdeta value taking into account the geometry details. > >I'm not sure I understand this "Hijing-weighted mean >pseudo-rapidity". Could you please explain what that is. And what's >the difference between that, and the one calculated by >BrMultRdoModule::CalibrateEta()? It seems that it's (again) some >parameterisation, but why is that needed? Since you know the z >position of the ring (r_z), the distance of the ring to the beam (d), >and the z-position of the primary vertex, I should think that the eta >would simply be: > The particles are not uniformly distributed over each si/tile element. Therefore, using the geometry of the element we can obtain the eta value associated with the geometric center, but this is different from the average eta value for particles hitting the detector. I'm interested in this latter value. Regards, Steve
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