Drift Chamber Review March 6-8, Overview of Requirements Forward and Central Drift Chambers Elton S. Smith Jefferson Lab Physics goals Overview of Hall D Tracking requirements Simulation

Drift Chamber Review Mar 6-8, Physics goals and key features The physics goal of GlueX is to map the spectrum of hybrid mesons (gluonic excitations) starting with those with the unique signature of exotic quantum numbers. Normal mesons in the quark model cannot have exotic J PC. Identifying J PC requires an amplitude analysis which in turn requires linearly polarized photons detector with excellent acceptance and resolution sensitivity to a wide variety of decay modes In addition, sensitivity to hybrid masses up to 2.5 GeV requires 9 GeV photons which will be produced using coherent bremsstrahlung from 12 GeV electrons. Final states include photons and charged particles and require particle identification. Hermetic detector with large acceptance for charged and neutral particles

Drift Chamber Review Mar 6-8, The GlueX Detector Design has been driven by the need to carry out Amplitude analysis.  p X  n,p Photoproduction  1 → a + 1    → (     )(   ) →         h 0 → b o 1    → (   )  →      Final state particles  ± K ±  p h’ 2 → K + 1 K − →  o K + K − →  +  − K + K −  1  1  ’ 1 b 2 h 2 h’ 2 b 0 h 0 h’ 0 all charged many photons strange particles 1 −+ 2+−2+− 0+−0+− Search for QCD Exotics Mass scale ~ 2 GeV

Drift Chamber Review Mar 6-8, Event Topologies t-channel meson photoproduction Incident 8-9 GeV   t) ~ e -  t photons pions protons ~1GeV/c o ~5 GeV/c <20 o  p→  1 (1800)p

Drift Chamber Review Mar 6-8, Physics Requirements  GlueX is designed to search for J PC exotic particles which are identified in a partial wave analysis of exclusive final states.  The detector must have uniformity of response and hermiticity to minimize false sources of exotic waves (“leakage”).  Leakage can be affected by incomplete knowledge of the detector acceptance and by purity of the event sample.  We have chosen a solenoidal detector configuration (B = 2T) to provide an azimuthally symmetric and well- understood acceptance.  Gluonic excitations are expected to have typical hadronic widths and decay modes with relatively high multiplicities.  Sensitivity to multiple decay modes requires good momentum and angular resolution for both photons and charged particles.

Drift Chamber Review Mar 6-8, GeV CEBAFCHL-2 Upgrade magnets and power supplies 12 Enhance equipment in existing halls add Hall D (and beam line)

Drift Chamber Review Mar 6-8, Overview of Hall D  Hall D is a new experimental hall to be located on the east side of the north linac  The project includes the design, construction and commissioning of the photon beam and experimental equipment in Hall D.  The detector incorporates existing hardware Solenoid magnet used for the LASS experiment at SLAC and the MEGA experiment at LANL Lead glass used in BNL E852  The GlueX physics collaboration (approximately 70 people from 25 institutions) has been active for seven years  The GlueX collaboration is leading the detector R&D and conceptual design efforts in Hall D.

Drift Chamber Review Mar 6-8, Top View 75 m Tagger Area Experimental Hall D Electron beam Coherent Bremsstrahlung photon beam Solenoid- Based detector Collimator Photon Beam dump Photon beam and experimental area East arc North linac Tagger area Hall D Electron Beam dump

Drift Chamber Review Mar 6-8, Hall D Detector Layout Electron Beam from CEBAF Lead Glass Detector Solenoid Coherent Bremsstrahlung Photon Beam Cerenkov Counter Time of Flight Barrel Calorimeter Note that tagger is 80 m upstream of detector Target Central Drift Chambers (CDC) Forward Drift Chambers (FDC)

Drift Chamber Review Mar 6-8, The experiment has sought out expert advice by requesting external reviews Cassel Committee (Dec 1999) David Cassel (chair), Frank Close, John Domingo, William Dunwoodie, Donald Geesaman, David Hitlin, Martin Olsson, Glenn Young GlueX Electronics (Jul 2003) John Domingo, Andy Lankford (chair), Glenn Young GlueX Detector Review (Oct 2004) Mike Albrow, Jim Alexander (chair), William Dunwoodie, Bernhard Mecking Solenoid Assessment (Nov 2004) John Alcorn, Robert Kephart (chair), Claus Rode Review of Tagging Spectrometer and Photon Beamline (Jan 2006) Juergen Ahrens (chair), Bernhard Mecking, Alan Nathan The collaboration has responded to issues raised by these committees and developed the present solid foundation for further design and construction Hall D/GlueX Reviews Note: GlueX has also been reviewed by PAC23 (Jan 2003), PAC27 (Jan 2005), the DOE Science Review (April 2005), and PAC30 (Aug 2006)

Drift Chamber Review Mar 6-8, The GlueX collaboration has designed and optimized the detector to study gluonic excitations. Many university groups have contributed to the R&D and development of major subsystems. Solenoid JLab, IU Cyclotron Facility Detectors Tracking Carnegie Mellon, Ohio, JLab Calorimetry Alberta, Athens, Florida State, Indiana, Regina PID Indiana, Inst for High Energy Physics (Protvino), Oak Ridge, Tennessee, Florida International Computing Carnegie Mellon, Connecticut, Indiana, JLab, Regina Electronics Alberta, Christopher Newport, Guanajuato, Indiana, IU Cyclotron Facility, JLab Beamline Catholic, Connecticut, Glasgow Infrastructure JLab Institutional Responsibilities  Elke Aschenauer took over as Hall D group leader in December, The Hall D group was officially formed in the Physics Division and 12 GeV project in January.

Drift Chamber Review Mar 6-8, CapabilityQuantityRange Charged particlesCoverage 1 o <  < 140 o Momentum Resolution (5 o -140 o )  p /p = 1 − 3% Position resolution  ~  m dE/dx measurements 20 <  < 140 o Time-of-flight measurements  t < 60 ps Cerenkov and  /K separation  < 14 o Barrel time resolution  t < ( /√E) ps Photon detectionEnergy measurements 2 <  < 120 o Veto capability  < 170 o LGD energy resolution (E > 100 MeV)  E /E = ( /√E)% Barrel energy resolution (E > 20 MeV)  E /E = (2 + 5/√E)% LGD position resolution  x,y, ~ 1 cm Barrel position resolution  z ~ 4 cm DAQ/triggerLevel 1200 kHz Level 3 event rate to tape15 kHz Data rate100 MB/s ElectronicsFully pipelinedFlash ADCs, multi-hit TDCs Photon Flux Initial: 10 7  /s rateFinal: 10 8  /s Hall D Scope: Detector Design Parameters

Drift Chamber Review Mar 6-8, Decay Modes  Sensitivity to a variety of decay modes removes dependence on model predictions. For example, for hybrids: favored not-favored Measure many decay modes!  To certify results, checks will be made among different final states for the same decay mode, for example: Should give same results

Drift Chamber Review Mar 6-8, Tracking Requirements For simple kinematics For the narrow  resonance E + 1%  E/E ~ 5%/ √  p/p ~ 2%,  ~ 2 mrad Charged particles Photons  In order to maximize signal to background and at the same time balance the contributions from photons and charged particles, we have set the following goals:  x ~ 5mm/ √ E

Drift Chamber Review Mar 6-8, Illustrative example Perfect tracking Perfect calorimetry nominal Charged tracking resolution is dominated by multiple scattering Charged tracking matched to calorimetry Generate zero-width 

Drift Chamber Review Mar 6-8, Position resolution  Momentum resolution of ~2% requires → Material budget < 5% rad. length → Position uncertainties of  <  m to remain small relative to the multiple scattering contribution. Require  CDC < 150  m Momentum resolution at 90 0  p/p Require  FDC < 200  m

Drift Chamber Review Mar 6-8, Angular coverage in c.m. Require coverage down to 1 o in the laboratory Cos  GJ for X →   lab > 1 o  lab > 2 o Generated    X 

Drift Chamber Review Mar 6-8, Detector Elevation View 125 o 11 o 1o1o 25 o 

Drift Chamber Review Mar 6-8, Forward Region FDC 4 packages of planar drift chambers anode + cathode strip readout six planes per package  xy =200  m active close to the beam line. Central Region CDC cylindrical straw-tube chamber 25 layers from 10cm to 57cm ± 6 o stereo layers  r  =150  m  z = 2mm dE/dx for p < 450 MeV/c Tracking

Drift Chamber Review Mar 6-8, Detector Plan View cryogenic lines electronic racks Central panel 480 AC 3 phase beam solenoid Fcal Cerenkov Staging Area door overhead crane (two levels)  Hall D layout showing approximate location of readout electronics crates, and power distribution.

Drift Chamber Review Mar 6-8, Tools used to evaluate design choices Generated Physics Events “Raw” Monte Carlo Data Model of Detector Reconstruction package Partial Wave Analysis Reconstructed Monte Carlo Data Event Generator GEANT3 Parametric Monte Carlo HDFast Complete model for CD-2 background rates original model Track finding and momentum fitting hardware design Photon reconstruction under development parametric reconstruction PWA studies Under development

Drift Chamber Review Mar 6-8, Simulation and reconstruction Momentum reconstruction applied to full GEANT simulation of event, smeared DC hits, no background. The GEANT simulation event and reconstruction software and are being used to understand detector performance (see next talk).

Drift Chamber Review Mar 6-8, Models of detector performance Parametric Monte Carlo 2004 Momentum Reconstruction 2007

Drift Chamber Review Mar 6-8, Today’s Presentations 6. Reconstruction and prototyping (FDC) Simon Taylor 1. Overview Simulation and reconstruction 4. Central Drift Chamber Curtis Meyer 5. Electronics Fernando Barbosa 3. Forward Drift Chamber Daniel Carman 2. Tracking and simulation David Lawrence On-chamber electronics

Drift Chamber Review Mar 6-8, Summary  Mapping the spectrum of hybrid mesons provides essential experimental data on the physics of the strong interactions in the region of confinement and is one of the main physics motivations for the 12 GeV Project.  This program requires  Momentum resolution of ~ 2%  Angular resolution of ~ 2 mrad  Material thickness < 5% rad. length   (FDC) < 200  m   (CDC) < 150  m  Today you are asked to review the design of the Hall D drift chambers for use in this experimental program.