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 MOLLER Collaboration Meeting May 8, Lower priority

Forces with asymmetric coils – (Jason) – – – Radiation dose on coils – – Coil sensitivities – (Sakib, Juliette preliminary) – – See slides Support Structure – See slides Vacuum vessel – See slides MOLLER Collaboration Meeting May 8, Bids

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

Forces MOLLER Collaboration Meeting May 8, Old New Coil off

MOLLER Collaboration Meeting May 8, 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° Axes in frame of single coil

MOLLER Collaboration Meeting May 8, 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 Sensitivity Studies

MOLLER Collaboration Meeting May 8,

Asymmetry vs. position offset

Asymmetry vs. rotation offset

Preliminary Results MOLLER Collaboration Meeting May 8, Mean Asymmetry a (ppb)b Z ppb/cm R ppb/cm T ppb/degree Roll ppb/degree Yaw ppb/degree Pitch ppb/degree -9.24cm 2.94mm ° 2.28° 1.59° -0.75° (>10 cm over magnet length) What about physical constraints?

MOLLER Collaboration Meeting May 8,

Closest approach MOLLER Collaboration Meeting May 8,

Summary MOLLER Collaboration Meeting May 8, 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 θ lab, which will go into the extraction of sin 2 θ W ?

Neutron shielding MOLLER Collaboration Meeting May 8,

Radiation dose MOLLER Collaboration Meeting May 8,

Support Structure MOLLER Collaboration Meeting May 8,

Frame Design MOLLER Collaboration Meeting May 8,

Vacuum Chamber design MOLLER Collaboration Meeting May 8,

Cut away views MOLLER Collaboration Meeting May 8,

Stress and deformation analysis MOLLER Collaboration Meeting May 8,

Bids? MOLLER Collaboration Meeting May 8,

Extra Slides MOLLER Collaboration Meeting May 8,

(Rate weighted 1x1cm 2 bins) Tracks in GEANT4 for nominal field MOLLER Collaboration Meeting May 8, Mollers eps

MOLLER Collaboration Meeting May 8,

MOLLER Collaboration Meeting May 8,

MOLLER Collaboration Meeting May 8,

z coll =590cm z targ,up =-75cm z targ,center =0cm z targ,down =75cm θ low =5.5mrad θ high =17mrad R inner =3.658cm R outer =11.306cm From center:From downstream: θ low,cen =6.200mradsθ low,down =7.102mrads θ high,cen =19.161mradsθ high,down =21.950mrads Finite Target Effects R inner R outer z targ,down z targ,up z targ,center θ low,up θ low,down θ high,up θ high,down Assume 5.5 mrads at upstream end of target, instead of center

Looking downstream x y φ=-360°/14 φ=+360°/14 ͢ B r φ In this septant: B y ~ B φ B x ~ B r ByBy BxBx ByBy BxBx 29 MOLLER Collaboration Meeting May 8,9 2014

GEANT4 MOLLER Collaboration Meeting May 8, Moved to GDML geometry description Defined hybrid and upstream toroids Parameterized in same way as the TOSCA models

GEANT4 - Collimators MOLLER Collaboration Meeting May 8,

GEANT4 – Acceptance definition MOLLER Collaboration Meeting May 8,