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

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

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

GlueX collaboration meeting, Newport News, October 25-27, 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

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

GlueX collaboration meeting, Newport News, October 25-27, 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)

GlueX collaboration meeting, Newport News, October 25-27, 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

GlueX collaboration meeting, Newport News, October 25-27, 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

GlueX collaboration meeting, Newport News, October 25-27, 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

GlueX collaboration meeting, Newport News, October 25-27, 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?

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

GlueX collaboration meeting, Newport News, October 25-27, 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

GlueX collaboration meeting, Newport News, October 25-27, 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 < estimate from raytracing: outside core Gaussian ~ 3·10 -5

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

GlueX collaboration meeting, Newport News, October 25-27, 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