The figures in this directory were produced by Tom Trainor
using the visualization tool DSV ( Data Set Viewer) written by
Duncan Prindle, both of the University of Washington (July 21,
2000).

These figures represent offline reconstruction (DST production
of 100-event file st_physics_1186017_raw_0001.dst.xdf) of a
selection of six Au-Au collision events from the first STAR
data acquisition period in June/July, 2000. The multiplicities
for two events (#15,39) are about 25% of the multiplicities
for four `central' events (#17,32,87,89). Events were chosen
with primary vertex either very close to the TPC midplane
(#15,32,87,89) or far from the midplane (#17,39). 

Track colors are mapped to the solar spectrum according to
transverse momentum: low momentum maps to red, high momentum
maps to magenta. Points on tracks are mapped randomly,
track-by-track, to the same spectrum. Points not on tracks are
mapped to magenta. 

In some figures only points on tracks are shown, while in
others only points not on tracks are shown, to study the
possibility that some tracks are not found properly. Initial
visual inspection indicates that there is little track loss in
these events with the present tracking software. 

Of the points not on tracks, indications are that these are
largely due to anticipated production of electron spirals by
photoconversions, either on TPC gas or on  the TPC readout
chamber structures. Electronic noise seems to be quite low,
resulting in a very clean tracking environment. 

A few figures provide closeup views of tracking `errors.'
These images serve to illustrate the level of detail which
visualization can provide for tracking development. However,
these discrepancies may simply be due to small differences in
tracking and drawing algorithms which occasionally occur
during ongoing development of the tracking and visualization
codes. 

Four files (v0-x) from event 3 show two V0s and one kink among
about 40 tracks. For both V0s the vertex is within the
fiducial volume of the TPC, permitting visual identification.
In image V0-4, points assigned to V0 daughters or kink
segments are mapped to magenta, daughter and segment tracks
themselves are mapped to green. Points belonging on daughters
or segments but not properly assigned are mapped to green. All
extraneous points are mapped to tan.