1. GlueX Collaboration Meeting, Newport News, October 25-27, 2007 GlueX Simulations Status Report Richard Jones GlueX Collaboration Meeting, Newport News, October 25-27, 2007

2. GlueX collaboration meeting, Newport News, October 25-27, 2007 2 Major developments over last year  Simulation workshop in Newport News, Nov. 2006.  define CD2 geometry  document it  implement in XML

3. GlueX collaboration meeting, Newport News, October 25-27, 2007 3 Major developments, cont.  Tracking Review at Jlab, Mar. 2007.  reduce materials  quantify effects

4. GlueX collaboration meeting, Newport News, October 25-27, 2007 4 FDC material reductions  Active region 1.CD2 reference design 2.reduction 1 3.reduction 2  Also note CDC 1.end plate 2.inner cylinder MC study required CDC contribution will get much bigger with additional inner layers – MC study required

5. GlueX collaboration meeting, Newport News, October 25-27, 2007 5 Other FDC issues  Singles rates  Forward dead zone is this resolved?  Lorentz angle shifts of FDC hits to be incorporated in HDGeant?

6. GlueX collaboration meeting, Newport News, October 25-27, 2007 6 CDC modifications  Reductions change downstream end plate from aluminum to carbon-epoxy composite reduce thickness from 6mm to 4mm  New inner layers rates are OK inner layers (hypothetical)

7. GlueX collaboration meeting, Newport News, October 25-27, 2007 7 CDC modifications  Reductions change downstream end plate from aluminum to carbon-epoxy composite reduce thickness from 6mm to 4mm  New inner layers rates are OK space is OK, once we shrink the start counter what about forward gamma shadowing? what about forward gamma shadowing?  MC study needed

8. GlueX collaboration meeting, Newport News, October 25-27, 2007 8 Start Counter  existing model based on CLAS design  nice document in docdb describing the existing design  need revised document  specification on how to reduce the existing one or, at least

9. GlueX collaboration meeting, Newport News, October 25-27, 2007 9 Calorimetry  Major insights from simulations shift of UPV coverage to mate with BCAL focus on the BCAL/FCAL overlap region as key to reconstructing important physics channels open question of BCAL energy threshold radiation damage around forward beam hole  Geometry models BCAL and FCAL models are stable UPV model is in flux New development in forward region, hopefully

10. GlueX collaboration meeting, Newport News, October 25-27, 2007 10 Gas Cerenkov Stand-alone Monte Carlo toy model of Cerenkov optics, Eugene Chudakov This mirror geometry can go into HDGeant. Is it ready for prime time?

11. GlueX collaboration meeting, Newport News, October 25-27, 2007 11 Reference Design for CD3  Now available from David and Simon

12. GlueX collaboration meeting, Newport News, October 25-27, 2007 12 Reference Design for CD3 – tentative?  Additional layers added to the CDC – tentative? – needs work  Start counter reduced to accomodate new inner layers in CDC – needs work – excellent detail  Changes to both the FDC annulus and active area materials – excellent detail – good  Adjust the positions of the FDC packages – good + put in correct mirrors, PMTs?  Change the shape of the Cerenkov nose from a tube to a cone + put in correct mirrors, PMTs? – requires TOSCA recalculation, good opportunity to extend coverage of the map  Change magnetic field map from original 1400A to larger 1500A – requires TOSCA recalculation, good opportunity to extend coverage of the map

13. GlueX collaboration meeting, Newport News, October 25-27, 2007 13 Related developments – Matt and Beni  Improved detector response models for TOF and BCAL – Matt and Beni – Elke and Eugene  Realistic inclusive hadronic event generation using Pythia – Elke and Eugene – CASA  CEBAF beam raytracing simulation – CASA realistic halo model for tagger simulation currently limited by CASA sim statistics used to justify an updated halo spec for Hall D preliminary spec: fraction outside core Gaussian < 10 -5 estimate from raytracing: outside core Gaussian ~ 3·10 -5

14. GlueX collaboration meeting, Newport News, October 25-27, 2007 14 Related developments tagger backgrounds from halo less than 1% of signal with sizeable margin

15. GlueX collaboration meeting, Newport News, October 25-27, 2007 15 Action items – Richard, David  Implement improved magnetic field – Richard, David – Richard  Release the new reference geometry – Richard – David  Incremental updates to geom v4 document – David – Mihajlo  Feedback on CDC changes material effects – Mihajlo – Simon  Implement mag. field effects in FDC – Simon – ?  Implement mag. field effects in FDC – ? – Richard  Implement new mirror geometry in hdds – Richard  Implement and test new ideas in calorimetry – team