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, 2007 2

Major developments over last year Simulation workshop

in Newport News, Nov. 2006. define CD2 geometry document it implement in XML

GlueX collaboration meeting, Newport News, October 25-27, 2007 3

Major developments, cont. Tracking Review at

Jlab, Mar. 2007. reduce materials quantify effects

GlueX collaboration meeting, Newport News, October 25-27, 2007 4

FDC material reductions

Active region1. CD2 reference design2. reduction 13. reduction 2

Also note CDC1. end plate2. inner cylinder

CDC contribution will get much bigger with additional inner layers – MC study requiredMC study required

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?

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)

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 what about forward

gamma shadowing?gamma shadowing?

MC study needed

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 leastor, at least

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

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?

GlueX collaboration meeting, Newport News, October 25-27, 2007 11

Reference Design for CD3

Now available from David and Simon

GlueX collaboration meeting, Newport News, October 25-27, 2007 12

Reference Design for CD3

Additional layers added to the CDC – tentative?– tentative? Start counter reduced to accomodate new inner

layers in CDC – needs work– needs work Changes to both the FDC annulus and active area

materials – excellent detail– excellent detail Adjust the positions of the FDC packages – good– good Change the shape of the Cerenkov nose from a tube

to a cone + put in correct mirrors, PMTs?+ put in correct mirrors, PMTs? Change magnetic field map from original 1400A to

larger 1500A – requires TOSCA recalculation, – requires TOSCA recalculation, good opportunity to extend coverage of the good opportunity to extend coverage of the mapmap

GlueX collaboration meeting, Newport News, October 25-27, 2007 13

Related developments

Improved detector response models for TOF and BCAL – Matt and Beni– Matt and Beni

Realistic inclusive hadronic event generation using Pythia – Elke and Eugene– Elke and Eugene

CEBAF beam raytracing simulation – CASA– 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

GlueX collaboration meeting, Newport News, October 25-27, 2007 14

Related developments

tagger backgrounds from halo less than 1% of signal with sizeable margin

GlueX collaboration meeting, Newport News, October 25-27, 2007 15

Action items

Implement improved magnetic field – Richard, – Richard, DavidDavid

Release the new reference geometry – Richard – Richard Incremental updates to geom v4 document – David – David Feedback on CDC changes material effects – Mihajlo – Mihajlo Implement mag. field effects in FDC – Simon– Simon Implement mag. field effects in FDC – ?– ? Implement new mirror geometry in hdds – Richard– Richard Implement and test new ideas in calorimetryImplement and test new ideas in calorimetry – –

team team