1. 1 V. Burkert, Drift Chamber Review, 03/6-8/07 Hall B currently houses the CLAS detector. CLAS will be modified and upgraded to CLAS12, which will be worldwide the only large acceptance, multi-purpose detector for fixed target electron scattering experiments. CLAS12 will operate with an upgraded luminosity of >10 35 cm -2 s -1, more than an order of magnitude increase and improved particle identification. With these capabilities CLAS12 will support a broad experimental program in fundamental nuclear physics Hall B Overview

2. 2 V. Burkert, Drift Chamber Review, 03/6-8/07 Drift chambers argon/CO 2 gas, 35,000 cells Electromagnetic calorimeters Lead/scintillator, 1296 PMTs Torus magnet 6 superconducting coils Gas Cherenkov counters e/  separation, 216 PMTs Time-of-flight counters plastic scintillators, 684 PMTs Large angle calorimeters Lead/scintillator, 512 PMTs CEBAF Large Acceptance Spectrometer (CLAS)

3. 3 V. Burkert, Drift Chamber Review, 03/6-8/07  GPD’s and 3D-Imaging of the Nucleon  Deeply Virtual Compton Scattering - DVCS  Deeply Virtual Meson Production at low/high t  Valence Quark Distributions  u- and d-Quark Spin Distributions in Proton and Neutron  Neutron Structure Function F 2n (x,Q 2 ), d/u  TMD Quark Distribution Functions in SIDIS  Form Factors and Resonance Excitations  The Magnetic Structure of the Neutron – G Mn  N* Transition Form Factors at high Q 2 Initial 12 GeV Physics Program in Hall B  Hadrons in the Nuclear Medium  Space-Time Characteristics of Quark Hadronization  Color Transparency  Short Distance Dynamics of Light Nuclei  Hadron Spectroscopy E12-119a, E12-119b E12-108 E12-109 E12-113 E12-112,LOI12-108,LOI-109 LOI12-107 E12-117 E12-106 Program approved by PAC30

4. 4 V. Burkert, Drift Chamber Review, 03/6-8/07 Requirements: Capabilities to measure exclusive processes at 12 GeV – High operating luminosity of >10 35 cm -2 sec -1 – Particle ID to high momentum (e - /π -, π/K/p, γ/π o ) – Good resolution to allow use of missing mass techniques – More complete detection of hadronic final state Complement the forward detection system with central detector – Tracking and magnetic analysis – Particle identification – Operation of polarized target Upgrade the forward detection system – Additional threshold Cherenkov detector p π > 5 GeV/c – Improve time-of-flight resolution to 60 – 80 ps – Increase calorimeter granularity for π o /γ separation Reduce DC occupancies to reach higher luminosities – Reduce DC cell sizes (decrease solid angle and sensitive time) – Improved magnetic shielding for background electrons.. Solution: CLAS12 – Requirements

5. 5 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 in Hall B Faraday cup, Beam monitors Polarimeters Beam monitors, Raster system,..

6. 6 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 Solenoid 5T CTOF SVT Central Detector DC R1, R2, R3 LTCC FTOF 1 FTOF 2 PCAL EC HTCC TORUS Forward Detector Forward carriage

7. 7 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 – Single sector (exploded view) Beamline equipment

8. 8 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 Drift Chambers & Torus R1 R2 R3

9. 9 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 Forward Carriage with Forward Time-of-Flight (FTOF), Preshower Calorimeter (PCAL), Electromagnetic Calorimeter (EC) FTOF PCAL EC

10. 10 V. Burkert, Drift Chamber Review, 03/6-8/07 Re-use existing CLAS detector components – Forward electromagnetic calorimeters – Low threshold gas Cherenkov counters – Time-of-flight scintillators – Drift chamber electronics and gas system – Inner PbW0 4 small-angle calorimeter – DAQ and readout electronics Utilization existing Hall B Equipment Re-use other Hall B components – Cryogenic targets – Møller polarimeter – Raster magnets & power supplies – Faraday cup – Beam diagnostics – Photon energy tagging system – Coherent bremsstrahlung/goniometer – Frozen spin polarized target – Pair spectrometer magnet & power supplies – Utility distribution & space frames

11. 11 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 – Central Detector Central Detector with Solenoid, Time-of-Flight and Central Tracker Solenoid magnet being designed - CEA-Saclay, ITEP & Efremov Inst. CTOF – R&D effort at KNU/Korea Central Tracker – R&D at JLab & Moscow State University (Russia)

12. 12 V. Burkert, Drift Chamber Review, 03/6-8/07 Polarized Target CTOF Light guides CTOF Scintillators CLAS12 – Central Detectors SVT Barrel

13. 13 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 – High Threshold Cerenkov Counter HTCC - R&D and Design ANL, JLab, RPI, UConn

14. 14 V. Burkert, Drift Chamber Review, 03/6-8/07 R1 R2 R3 IC Moller Shield Torus Coils Drift chamber system - R&D and Design effort at JLab, ISU, ODU CLAS12 Forward Drift Chambers

15. 15 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 Forward Carriage LTCC PCAL EC Forward Carriage LTCC – CSU PCAL – JLab, JMU, OU, CEA-Orsay

16. 16 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 Forward TOF FTOF TORUS Cryostat Torus Magnet – Design effort at ITEP/Efremov, JLab. FTOF – R&D at USC

17. 17 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 - Electron/pion separation Estimated  , e - trigger rates L = 10 35 cm -2 sec -1     HTCC LTCC EC

18. 18 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 – FTOF Sensitivity path length = 600 cm Need ~60 psec for 4σ separation of π/p at 6 GeV/c, π/K at 3 GeV/c, and p/K at 5 GeV/c 500 cm

19. 19 V. Burkert, Drift Chamber Review, 03/6-8/07 Kinematics for ep → ep        Needed for measurement of flavor-separated GPDs Forward angle coverage crucial for this program

20. 20 V. Burkert, Drift Chamber Review, 03/6-8/07 Distribution of π +, K + in DIS Kinematics e - p→e - hX, h=π +,K + π+π+ K+K+

21. 21 V. Burkert, Drift Chamber Review, 03/6-8/07 K * (892) K CLAS12 ep → e  (p  - )X Missing Mass Techniques

22. 22 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 – Performance Requirements Forward Central Detector Angular range Tracks 5 0 – 35 0 40 0 – 135 0 Photons 3 0 – 35 0 n.a. Resolution  p/p (%) < 1 @ 5 GeV/c < 5 @ 0.5 GeV/c  (mr)< 1< 15  (mr)< 2< 6 Photon detection Energy (MeV)>150n.a.  (mr)4 @ 1 Gen.a. Neutron detection N eff < 0.7 (EC+PCAL)0.05 (CTOF) Particle ID e/  Full rangen.a.  pFull range< 1.25 GeV/c  /KFull range< 0.65 GeV/c K/p  GeV/c< 1.0 GeV/c    Full rangen.a.  Full rangen.a.

23. 23 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 – Offline Software Short term effort to aid detector R&D and design:  Geant3/4 tools to simulate CLAS12 performance  Simplified event reconstruction software and Fast-MC Longer term:  geant4 – based detector simulations  state-of-the art reconstruction software Offline Software developed by: CUA, ITEP, JLab, MSU, UNH,

24. 24 V. Burkert, Drift Chamber Review, 03/6-8/07 R1 R2 R3 IC Moller Shield Torus Coils Drift chamber system - R&D and Design effort at JLab, ISU, ODU CLAS12 Forward Drift Chambers

25. 25 V. Burkert, Drift Chamber Review, 03/6-8/07 Present-day CLAS

26. 26 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS - Region 1 Assembly

27. 27 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS – Region 2 Fabrication R2 Installation in CLAS R2 Stringing in ODU clean room

28. 28 V. Burkert, Drift Chamber Review, 03/6-8/07 Technical staff assembling Nose-cone R3 prototype CLAS-R3 Prototype/Fabrication/Checkout Steve Christo, head of the R3 drift chamber fabrication team, inspecting the precise locations of the holes in the endplates. Wire stringing operation in Class 10,000 clean room. Elsa Adrian, lead stringer, is checking each wire feed-through for functionality Electronics board Checking wire tensions with magnetically induced oscillations. Michelle Brisiel analyzing wire tension measurements. Technical staff assembling Nose-cone R3 prototype

29. 29 V. Burkert, Drift Chamber Review, 03/6-8/07 Manpower currently on DC Project Engineering/Design staff only since 10/2006 after PED funds approved ManpowerExperience with CLASActivity with CLAS12 DC Hall B - Physicists M. Mestayer L. Elouadrhiri D. Carman Head of DC Group PD Researcher on R1 Co-Leader of DC Group Cost Manager, Simulations DC project, tbd Hall B - Technical Staff D. Kashy S. Christo G. Jacobs K. Wilson R. Getz Operation, maintenance Construction of R3 Construction R2, CLAS DC infrastructure Lead Engineer Hall B Upgrade Coordinator for R1 Design DC Infrastructure Project engineer for R1 R1 designer JLab - Electronics C. Cuevas F. Barbosa W. Gunning Head of JLab FE Group ADB Board DC Electr. maintenance Concept of STB STB design ISU ODU ITEP CUA T. Forest, P. Cole, D. Dale K. Folkman G. Dodge, L. Weinstein (Fac.) S. Bueltman (RS), Tom Hartlove K. Mikhailov, A. Vlassov (RS) F. Klein (Fac.) ODU Group built CLAS R2 Ofline Reconstruction Head of ISU effort R3 design/engineer Co-Leader of DC group R1 Prototype Simulation Offline Reconstruction

30. 30 V. Burkert, Drift Chamber Review, 03/6-8/07 CLAS12 - Drift Chamber Project CLAS12 drift chambers represent a design and construction project of significant size, but it is smaller in scale than the CLAS project.  18 individual chambers with 24,000 sense wires in CLAS12 versus 35,000 sense wires in CLAS  3 different chamber sizes, but flat surfaces in CLAS12 versus curved surfaces in CLAS CLAS12 drift chambers are based on designs and construction techniques that worked well for ten years in all CLAS chambers CLAS12 chambers are smaller in size than the existing CLAS chambers, and have much simpler, triangular geometry CLAS12 chamber design and construction benefit from availability of much of the manpower that has built the CLAS chambers. Prototype of R1 chamber needed for studies of mechanical and electrical details and optimization of operating conditions. Cost estimate based in part on prior experience with CLAS and on vendor information.

31. 31 V. Burkert, Drift Chamber Review, 03/6-8/07 The scope of the Hall B upgrade effort is well defined, and uses well known technology, with overall low technical risk. We have made excellent progress on Conceptual Design and R&D in FY06, and on Project Engineering & Design in FY07.  Advanced the designs on key components Superconducting magnets Drift Chambers High Threshold Č erenkov Counter Silicon Vertex Tracker (SVT) Pre-shower calorimeter Beamline components Event Simulation & reconstruction  Developed collaborative effort with specialists on critical components, especially the magnet design, and the SVT design and construction. CLAS12 collaboration has grown to include more than 30 institutions who have taken on significant projects Solid R&D and PED underway for FY07 and FY08 to support CD-2 and CD-3 approval Hall B - Summary