1/22

MOLLER

Juliette M. Mammei

Hall A Collaboration Winter 2012 Meeting

2/22

Working Groups

• Polarized Source • Hydrogen Target • Spectrometer• Integrating Detectors• Tracking Detectors• Polarized Beam Instrumentation• Polarimetry• Electronics/DAQ• Simulations• Analysis

Supergroup

Hall A Collaboration Winter 2012 Meeting

3/22

Simulation• Large group that meets regularly• TOSCA and GEANT4 applications• Continually improving the usability of the GEANT4 simulation

o Adding generatorso Improving functionalityo Improvements to the

radiative effects

Hall A Collaboration Winter 2012 Meeting

4/22

Detector Array

Roman Pots

(for tracking detectors)

Scattering Chamber

Target

Hybrid Torus

Upstream Torus

Incoming BeamCollim

ators

Simulation Projects

28 m• Detector geometry• Collimators• Target length• Backgrounds

• Spectrometer o Opticso Sensitivity study o Magnetic forces

Hall A Collaboration Winter 2012 Meeting

5/22

DetectorsGeometry

• 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 sizeo Optics optimizationo 3-coil optiono Vacuum vs. air

• Interfacing with MIT engineerso Jason Bessuille, Ernie Ilhoff, Jim Kelsey, Cathy Moran (designer)o Design (conductor size, electrical and water connections)o Water-coolingo Supports

Have nominal designs, but choices to make

Hall A Collaboration Winter 2012 Meeting

11/22

Spectrometer

4C 4R4L

1AR1AL

1BL 1BR

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 modelNote: Imported coils have dual s-bends; Native SWX coils are changed to single s-bends

Hall A Collaboration Winter 2012 Meeting

13/22

Tmax ΔT8674 8204

Cooling Paths / coil50 35 28 21

60 45 24 17

70 55 23 16

80 65 19 14

Cooling Circuits

35 40 45 50 55 60 650

5

10

15

20

25

306093867483398204Limit

Coolant temperature rise (deg C)

Aver

age

pres

sure

dro

p fo

r 4 tu

rns i

n pa

ralle

l (at

m)

maxT Coolant flow rate

P

8339 - 1550 A/cm2

8674 - 1750 A/cm2

8204 - 2000 A/cm2

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

Preliminary

50x deflection scale

Hall A Collaboration Winter 2012 Meeting

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 δρ/ρ @ 2x power

• CFD used to model the highly successful Qweak target

• CFD-FAC under development for R&Do Hall C targeto highest power PV suitable target

Hall A Collaboration Winter 2012 Meeting

20/22

Polarized Beam Source and Measurement

• Source worko Pockels vs. Kerr cello Two cellso 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 betterPolarization

Positions, angles, energy, intensity2nd order beam properties

Hall A Collaboration Winter 2012 Meeting

21/22

Auxiliary Detectors

Tracking – GEMs(Q2, beam backgrounds, etc.)

Luminosity – Quartz(target density and beam fluctuations, electronics noise)

Pion Backgrounds – Pb-glass (Pions and other hadron backgrounds)

Hall A Collaboration Winter 2012 Meeting

22/22

Summary

• Much progress on o Simulationo Spectrometero Detectors

• Ramping up o Sourceo Targeto Polarimetryo Auxiliary detectors