gluex simulations status report on cd3 geometry richard jones gluex collaboration meeting, newport...

GlueX Simulations

Status Report on CD3 geometry

Richard Jones

GlueX Collaboration Meeting, Newport News, January 10-12, 2008

GlueX collaboration meeting, Newport News, January 10-12, 2008 2

Detector subsystems

Target - unchanged Start Counter - updated Central Drift Chamber - updated Forward Drift Chamber - updated Barrel Calorimeter - updated Upstream Calorimeter/Veto – removed Gas Cerenkov - updated Time-of-Flight counter - unchanged Forward Calorimeter - unchanged Solenoid / magnetic field – updates in progress


Target- unchanged

liquid hydrogen volume diameter 3 cm length 30 cm kapton walls 150 m thick

vacuum chamber walls 1 cm of high-density (0.11 g/cm3) ROHACELL exterior diameter 8 cm

vacuum entrance, exit windows 70 m of aluminum


Start Counter - updated

layer structure high density ROHACELL r=6.95 - 7.48 cm scintillator 2.15 mm thick low density ROHACELL r=7.69 – 8.68 cm cellulose wrapping tape 0.5 mm thick

forward tapered section first conical section 22.5° taper second conical segment 45° taper all layers constant thickness innermost diameter 4.58 cm


Central Drift Chamber - updated

active length shortened to 150 cm two options for stereo layer sequence

option 11. stereo layers 4-7 and 13-162. sequence -,-,+,+ in each

option 21. stereo layers 4-6, 12-14, 20-222. sequences -,-,- ; +,+,+ ; -,-,-

trade-off issues polar angle resolution track finding / pattern recognition


Forward Drift Chamber - updated

changed package positions compressed in z last package in stronger field region

different dead region in each package 2.3 cm, 3.2 cm, 3.9 cm, 4.6 cm

important reduction in outer radius of active region now r=48.5 cm allows space for HV coupling capacitors

detailed sandwich repeating structure for frames important new materials at r=60cm for cooling

0.5 mm copper cylinder around frame periphery 0.7 mm aluinum cylinder between packages


Barrel Calorimeter - updated

overall dimensions unchanged new readout segmentation scheme

innermost 12 cm covered by 4 (phi) x 6 (depth) 2 x 2 cm2 cells with Winston cones and SiPMs.

outermost 10.48 cm covered by 2 x 25.23 x 5.04 cm2 cells with light collectors, light

pipes readout scheme specifies coupling with Winston

cones of uniform 2 x 2 cm2 collection area large gaps appear in phi at outer layers coverage ranges from 92.6% (layer 1) to 80.4% (layer

6) for inner layers, 96.7% - 90.7% outer layers may affect energy resolution, should be studied only energy in readout cells is seen in simulation


Barrel Calorimeter - updated

total channel count settled 2304 SiPM channels (upstream + downstream 384 outer channels (several per Planacon?)

routing of light pipes not shown, probably doesn’t matter because outside acceptance


Upstream Veto – removed

commented out


Gas Cerenkov

Stand-alone Monte Carlo toy model of Cerenkov optics, Eugene Chudakov

This mirror geometry is now in HDGeant. Optical properties by E. Chudakov


Time-of-Flight counter - unchanged

two layers 2.54 cm thick square area 255 cm on a side square beam hole 12 cm on a side unwrapped in simulation, probably ok


Forward Calorimeter - unchanged

quasi circular, radius 29 x 4 cm beam hole 3 x 3 blocks nothing special for beam-hole region energy deposition response model


Solenoid / magnetic field

uniform field in azimuth map coverage from 4 cm to 254 cm linear extrapolation outside mapped region

probably inaccurate in downstream region update underway to new larger map new map dimensions ?? CD3 studies should use the new map

gluex simulations status report on cd3 geometry richard jones gluex collaboration meeting, newport...

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