1/22 MOLLER Juliette M. Mammei

2/22 Working Groups Polarized Source Hydrogen Target Spectrometer Integrating Detectors Tracking Detectors Polarized Beam Instrumentation Polarimetry Electronics/DAQ Simulations Analysis Hall A Collaboration Winter 2012 Meeting Supergroup

3/22 Simulation Hall A Collaboration Winter 2012 Meeting Large group that meets regularly TOSCA and GEANT4 applications Continually improving the usability of the GEANT4 simulation o Adding generators o Improving functionality o Improvements to the radiative effects

4/22 Detector Array Roman Pots (for tracking detectors) Scattering Chamber Target Hybrid Torus Upstream Torus Incoming Beam Collimators Simulation Projects 28 m Hall A Collaboration Winter 2012 Meeting D etector geometry Collimators Target length Backgrounds Spectrometer o Optics o Sensitivity study o Magnetic forces

5/22 Detectors Geometry Define rings Quartz shape, size Quartz housing Light guide shape, size Endcap shape, size Reflector length, angle Optics Refractive index Cerenkov angle TIR critical angle Tolerance to preserve TIR Baseline design from Qweak scanner detector Hall A Collaboration Winter 2012 Meeting

6/22 Detectors Hall A Collaboration Winter 2012 Meeting

7/22 Detectors Hall A Collaboration Winter 2012 Meeting

8/22 Detectors Hall A Collaboration Winter 2012 Meeting

9/22 Detectors Prototypes! Hall A Collaboration Winter 2012 Meeting

10/22 Spectrometer Ongoing simulation and pre-R&D work TOSCA and GEANT4 applications o Conductor size o Optics optimization o 3-coil option o Vacuum vs. air Interfacing with MIT engineers o Jason Bessuille, Ernie Ilhoff, Jim Kelsey, Cathy Moran (designer) o Design (conductor size, electrical and water connections) o Water-cooling o Supports Hall A Collaboration Winter 2012 Meeting Have nominal designs, but choices to make

11/22 Spectrometer 4C4R4L 1AR1AL 1BL1BR 2L 3L 2R 3R Hall A Collaboration Winter 2012 Meeting

12/22 TOSCA → Solidworks Coil Package with single out-of-plane bends Volume comparison of coils. Only the differences are shown. Blue = native SWX model, brown = imported model Note: Imported coils have dual s-bends; Native SWX coils are changed to single s-bends Hall A Collaboration Winter 2012 Meeting

13/22 Cooling Circuits Coolant flow rate A/cm A/cm A/cm 2 Hall A Collaboration Winter 2012 Meeting

14/22 Qweak Coil & Carrier Hall A Collaboration Winter 2012 Meeting

15/22 QWEAK Toroid Assembly QTOR Assembly (with left frame removed for clarity) Hall A Collaboration Winter 2012 Meeting

16/22 MOLLER Toroid Assembly Service feedthru ports (power and cooling) Guide Rails ee and ep tracks In-vacuo coils Standard 3/8 thk 46”diameter 316 Steel Pipe Single module, crane-able assembly, with very limited access during runs Hall A Collaboration Winter 2012 Meeting

17/22 Spectrometer Hall A Collaboration Winter 2012 Meeting 50x deflection scale

18/22 Plan going forward Decide on a conductor type Discuss Hall A infrastructure to develop conceptual system design including pumps, chillers, heat exchangers and power supply Iterate between TOSCA and FEA simulations with the modified coils (single s-bends) and new choice of conductor Involve potential coil vendors at this stage In parallel, review in-vacuum vs. out-of-vacuum options, and 2-coil vs. 3-coil configurations Once a mounting configuration is established, start designing support frame, coil package details, and coil carriers in parallel. Magnet engineering review in spring Hall A Collaboration Winter 2012 Meeting

19/22 Target ρ fluctuations < 26 ppm ½ Qweak 2x power CFD used to model the highly successful Qweak target CFD-FAC under development for R&D o Hall C target o highest power PV suitable target Hall A Collaboration Winter 2012 Meeting

20/22 Polarized Beam Source and Measurement Source work o Pockels vs. Kerr cell o Two cells o Spot size monitoring DAQ –upgrades for > 30 Hz flip rates (>1 MHz!) Polarimetry upgrades o Compton Electron detector Photon detector Improved analysis o Møller Upgraded high field polarimeter Atomic hydrogen Møller (Mainz for P2) 0.4% accuracy or better Polarization Positions, angles, energy, intensity 2 nd order beam properties 0.4% accuracy or better Polarization Positions, angles, energy, intensity 2 nd order beam properties Hall A Collaboration Winter 2012 Meeting

21/22 Auxiliary Detectors Hall A Collaboration Winter 2012 Meeting Tracking – GEMs (Q 2, beam backgrounds, etc.) Luminosity – Quartz (target density and beam fluctuations, electronics noise) Pion Backgrounds – Pb-glass (Pions and other hadron backgrounds)

22/22 Summary Much progress on o Simulation o Spectrometer o Detectors Ramping up o Source o Target o Polarimetry o Auxiliary detectors Hall A Collaboration Winter 2012 Meeting