Provisionally dubbed Cusp, C++ Unified Simulation Package; suggestions welcome on the name!
Reads the full BaBar geometry database (bbgeom.db etc.) using new version of dbio which generates accessor member functions for database parameters that can be inserted in a class
Simple geometry classes for (presently) DCH, EMC, IFR (CuspDchGeom etc.) gain access to geometry through these member functions, and provide member functions to generate the geometry information required to build the Geant4 representation of the detector
- presently, the representation built is crude cylinder envelope volumes for the subsystems
Material definition is complete in the G4 prototype; materials can be defined directly or built from elements and isotopes
Geometry in the prototype is still limited to boxes and cylinders
- Paul Kent, the geometry expert, will probably be leaving the project; a replacement is being sought
- has created a lot of uncertainty right now in the project that they are working hard to resolve
- most important to us in the short term, finishing the Geant3 geometries is proceeding over the summer, which will enable us to migrate our G3 geometry to G4
Particle propagation: choice of
- geometry-only mode, propagating interaction-free pseudo-particles from volume boundary to volume boundary, for benchmarking and fast simulation applications
- real particles fired with particle gun using particle generation apparatus, with interactions and decays
- BUT no field yet
Presently works on HP, using gcc 2.7.2
- 2.6.3 doesn't work
- my version of native compiler doesn't work; others (more recent) do
G4 prototype also runs on Sun, Alpha, IBM, but various problems encountered on these platforms at SLAC

Near term Geant4 concerns relevant to building a BaBar Geant4 prototype:

completion of the Geant3 geometries
addition of magnetic field
secondary stack management, supporting management of secondaries from decays and interactions (already in, I think)
sensitive detector, hits and digitization design: compatibility with BaBar and fast simulation
event management: generator interface
physics development is proceeding rapidly, particularly at CERN and TRIUMF; less immediate relevance to an initially fast simulation directed BaBar prototyping effort

I will be participating in a week long Geant4 workshop, a mix of presentations and working sessions, in Vancouver Aug 3-9, and will push these concerns.

What do do with it?

... over ...