MOLLER Spectrometer Update Juliette M Mammei Future Priorities

MOLLER Spectrometer Update Juliette M. Mammei

Future Priorities (from last meeting) • Physicist input to engineering (highest priority) o Magnetic force studies o Sensitivity studies o Design of the water-cooling and electrical services o Radiation doses (brought up by companies) • Optimization of the optics o He bag/central beam pipe o Multiple magnets o No negative bend o Iron in coils • Engineering work (MIT/Bates) o Design of support structure o Vacuum vessel design Lower priority MOLLER Collaboration Meeting May 8, 9 2014 2

• • • Forces with asymmetric coils – http: //ace. phys. virginia. edu/Moller. Spectrometer/297 – http: //ace. phys. virginia. edu/Moller. Spectrometer/298 – http: //ace. phys. virginia. edu/Moller. Spectrometer/299 – http: //ace. phys. virginia. edu/Moller. Spectrometer/300 (Jason) (Juliette) Radiation dose on coils – http: //ace. phys. virginia. edu/Moller. Spectrometer/305 – http: //ace. phys. virginia. edu/Moller. Spectrometer/306 (Tyler) (Seamus) Coil sensitivities – http: //ace. phys. virginia. edu/Moller. Spectrometer/287 – http: //ace. phys. virginia. edu/Moller. Spectrometer/308 – See slides Support Structure – See slides Vacuum vessel – See slides (Sakib, Juliette preliminary) (Tyler) Bids MOLLER Collaboration Meeting May 8, 9 2014 3

Forces Old New Coil off Forces on coil to beam left with adjacent coil off MOLLER Collaboration Meeting May 8, 9 2014 4

Coil off New Old Forces MOLLER Collaboration Meeting May 8, 9 2014 5

Sensitivity Studies • Need to consider the effects of asymmetric coils, misalignments etc. on acceptance • This could affect our manufacturing tolerances and support structure • Have created field maps for a single coil misplaced by five steps in: – -1° < pitch < 1° – -4° < roll < 4° – -1° < yaw < 1° – -2 < r < 2 cm – -10 < z < 10 cm – -5° < φ < 5° MOLLER Collaboration Meeting May 8, 9 2014 Axes in frame of single coil 6

Sensitivity Studies We’ll measure a certain rate R and asymmetry A in each septant. We assume the allowable uncertainty on A to be 0. 1 ppb MOLLER Collaboration Meeting May 8, 9 2014 7

MOLLER Collaboration Meeting May 8, 9 2014 8

Asymmetry vs. position offset

Asymmetry vs. rotation offset

Preliminary Results Z R T Roll Yaw Pitch Mean Asymmetry a (ppb) b 31. 75 -0. 01 ppb/cm 31. 75 0. 34 ppb/cm 31. 74 -0. 01 ppb/degree 31. 72 0. 04 ppb/degree 31. 75 0. 06 ppb/degree 31. 77 -0. 13 ppb/degree -9. 24 cm 2. 94 mm -17. 86° 2. 28° 1. 59° -0. 75° (>10 cm over magnet length) MOLLER Collaboration Meeting May 8, 9 2014 What about physical 11 constraints?

MOLLER Collaboration Meeting May 8, 9 2014 12

Closest approach MOLLER Collaboration Meeting May 8, 9 2014 13

Summary • These results have some simulations with same random seed (statistical uncertainty is not as good as it seems) – Need to re-run those simulations and redo the results – All plots vs. offset treated as linear, though some clearly are not • Very preliminary results show order ~3 mm sensitivities (not sub-mm) • Need to look at the effect of tracking algorithm with incorrect maps • What is the most important parameter – what is it that will determine the sensitivity – A background correction done incorrectly? – The mean asymmetry, as I’ve assumed here? – The mean θlab, which will go into the extraction of sin 2θW? MOLLER Collaboration Meeting May 8, 9 2014 14

Neutron shielding MOLLER Collaboration Meeting May 8, 9 2014 15

Radiation dose MOLLER Collaboration Meeting May 8, 9 2014 16

Support Structure MOLLER Collaboration Meeting May 8, 9 2014 17

Frame Design MOLLER Collaboration Meeting May 8, 9 2014 18

Vacuum Chamber design MOLLER Collaboration Meeting May 8, 9 2014 19

Cut away views MOLLER Collaboration Meeting May 8, 9 2014 20

Stress and deformation analysis MOLLER Collaboration Meeting May 8, 9 2014 21

Bids? MOLLER Collaboration Meeting May 8, 9 2014 22

Extra Slides MOLLER Collaboration Meeting May 8, 9 2014 23

Tracks in GEANT 4 for nominal field Mollers eps (Rate weighted 1 x 1 cm 2 bins) MOLLER Collaboration Meeting May 8, 9 2014 24

MOLLER Collaboration Meeting May 8, 9 2014 25

MOLLER Collaboration Meeting May 8, 9 2014 26

MOLLER Collaboration Meeting May 8, 9 2014 27

Finite Target Effects θhigh, down θlow, down θhigh, up Router θlow, up Assume 5. 5 mrads at upstream end of target, instead of center Rinner ztarg, up ztarg, center zcoll = 590 cm ztarg, up = ztarg, center = ztarg, down = -75 cm 0 cm 75 cm θlow = θhigh = 5. 5 mrad 17 mrad ztarg, down Rinner = 3. 658 cm Router = 11. 306 cm From center: θlow, cen = 6. 200 mrads θhigh, cen = 19. 161 mrads From downstream: θlow, down = 7. 102 mrads θhigh, down = 21. 950 mrads

Looking downstream φ= 14 0°/ +3 60 -36 °/1 4 φ= B Bx By x r In this septant: φ By ~ Bφ y Bx ~ Br MOLLER Collaboration Meeting May 8, 9 2014 29

GEANT 4 • Moved to GDML geometry description • Defined hybrid and upstream toroids • Parameterized in same way as the TOSCA models MOLLER Collaboration Meeting May 8, 9 2014 30

GEANT 4 - Collimators MOLLER Collaboration Meeting May 8, 9 2014 31

GEANT 4 – Acceptance definition MOLLER Collaboration Meeting May 8, 9 2014 32