Minutes of the CALCOM meeting, March 13, 1998.
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    Agenda:
          
         G. Heyes - Recent improvements in the CODA performance
                    (no report)
                    
      G. Mutchler - New TOF Scintillator geometries  
                    (will be available as a CLAS note)         
                    
    K. Loukachine - Status of the TOF dE/dx calibration              

         D. Cords - A proposal how to organize disk space
                    (will be distributed separately)
                    
         L. Farhi - Drift chamber alignment using cosmic rays               
                    
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   Individual reports:
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   K.Loukachine: Energy loss calibration in TOF, The SCRC bank.
   ------------
    
   Using time based tracking information the energy loss calibration 
   in TOF counter was done for February'98 e1 run. The values of dE/dx
   calculated as energy deposited in scintilator normalized on path
   length in the counter. The calibration constants are in the map. 
   We suppose it is right way to calibrate and use TOF ADC information 
   since it does not depend on magnetic field and angle of the track.
   It also shows some inprovement in dE/dx particle separation. One 
   can see clearly the interraction effect for pions and protons, and 
   astimate the contents of background during particle identification 
   analysis. The software to get dE/dx values will be soon available
   and implemented in RECSIS and A1. 
   New clastering result bank ( SCRC ) was tested with 4 GeV beam data.
   It works and gives the right effect. SCRC bank contains the complete 
   information set provided by SC package and we incorage people to 
   use it instead of SCR bank.  
   

   
L. Farhi: DRIFT-CHAMBERS ALIGNMENT USING COSMIC RAYS
--------

Starting from a study made in Saclay, it is possible to show that the
position with regards to the 6 degrees of freedom of each drift chambers
(rotation + translation) can be determined using cosmic rays.
Using this method has the advantage to cover the whole CLAS detector and not
to require any field, thus decorelating completely the effects of the
magnetic field from some misalignment of the chambers.
The data would be taken with a trigger on the start-counter and some
selective triggers on time-of-flight in order to catch muons hitting sectors
1 and 4 without hitting the start-counter.
The expected counting rate is more than 200 Hz. The number of counts would
quickly become enough to separate each of the degrees of freedom by selecting
some specific muon tracks, allowing the alignment region to region and sector
to sector.
A program to analyse tracks not coming from the target region has been
written by Nikolai Pivniouk.
2 maintenance days are available on the 7th and 8th of April and should be
used for this purpose. This supposes that the dectector and acquisition would
be ready to work in their standard configuration.
The Saclay group would then take charge of the data analysis.