Changes for new release of E614 GEANT version 1.2

                       D.H. Wright     August 1999


  A. Summary

        The new release of E614 GEANT has several new features:  u and
     v planes have replaced x and y, multiple tracks per event can now be 
     digitized, proportional chambers are digitized in the same manner as
     drift chambers, and drift time calculations are done in the more 
     general daughter coordinate system, allowing one routine to calculate
     the point of closest approach regardless of the cell orientation.

  B. Files changed in new release

     1. chambers.par - increased number of PC planes from 10 to 12

     2. define_data_format.F - increased number of quantities stored 
                      per hit from 20 to 30, track entry and exit 
                      points in daughter coordinates added

     3. digitize_dc.F - combine xpoca and ypoca (point of closest 
                      approach in x and y) into one routine (ypoca.F)
                      which operates in the drift cell coordinate 
                      system (daughter coordinates).  Enable digitization 
                      of multiple tracks.  Remove routine simulate_1877_tdc.F 
 
     4. digitize_pc.F - find point of closest approach in proportional
                      cell (previous version recored only energy loss).
                      Routine is now nearly the same as digitize_dc.F

     5. drift_geom.F - change x, y planes to u, v (+/- 45 degrees)

     6. gtmuon.F - Peter Gumplinger's modification to accommodate 
                      1999 CERN library and still correctly handle 
                      muons with spin

     7. gudigi.F - add 1877 TDC simulation (removed from 
                      digitize_dc.F)

     8. prop_geom.F - change x, y planes to u, v planes

     9. read_tdcmaps.F - add tdc map for proportional chamber digitization 

    10. simulate_1877_tdc.F - digitize PC times as well as DC times

    11. store_track_segments.F - store track entry and exit points in daughter
                      coordinates as well as master coordinates

    12. tdcmap.inc - calculate MAX_PC_CHAN instead of hardwiring it

    13. ypoca.F - calculate point of closest approach in drift or proportional
                      cell coordinates rather than in master coordinates


    14. e614.com - now uses the latest FBTDC map files, fbc1_map.00003, 
                      fbc2_map.00003 and the latest geometry file 
                      dt_geo.00012  

    15. Makefile - xpoca.o removed


  C. Files added:

     1. tdc_times.inc - TDC times from DCs and PCs to be passed to 
                      simulate_1877_tdc.F

         
  D. Files deleted:

     1. xpoca.F - made redundant by new ypoca.F