Experimental Solenoid

Introduction

For ePIC a new solenoid is developed as the experimental magnet with a central field of 1.7T with an operational range Upton 2T. The Magnet has been named MARCO.

Reference material

• Material distribution of MARCO can be found here

Field map

• Description of the field map format pptx
• 1.7 Tesla field map
• 2.0 Tesla field map

Field map used in ECCE proposal studies

Experimental solenoid in the ECCE reference design is based on the Babar super conducting magnet installed in the sPHENIX barrel flux return (double as the barrel outer hadronic calorimeter). This magnet was manufactured by Ansaldo in 1997 and commissioned in 1998. It was transferred to BNL in 2015 for use in the sPHENIX experiment and passed an initial high-field test (up to 1.3~T) in 2018.

Presentations

• 2022.05.23 GDI Magnet meeting

Used in the ECCE proposal study, these field maps assume the central barrel and the backward is using the sPHENIX HCal and backward field return. The forward direction is assuming a magnetic HCal (LFHCAL) to enclose the forward field return as described in the ecce proposal section 2.5.4. The starting surface of the forward and backward magnetic steel is assumed to the at the same location as the sPHENIX field return doors, i.e. magnetically connected with central HCal for flux return.

• 2D simplified field map (from sPHENIX): ECCE prop.7 tagged ROOT ntuple. Note a 1.4/1.5 scaling is applied to this map to account for the intended working point according to [3]
• 3D full field map including the inhomogeneous field return at cut out at chimney (from sPHENIX): distributed via CVMFS at /cvmfs/eic.opensciencegrid.org/ecce/gcc-8.3/release/release_prop/prop.7/share/calibrations//Field/Map/sphenix3dbigmapxyz.root
• Note: the field maps assumed homogeneous material in the barrel field return. Then the field is modified in the hadronic calorimeter to properly reflected the concentrated field in the flux return fins and lower field in the active scintillators: PHG4OuterHcalFieldSetup reference

A notebook provides cross check for the field map readback: [4], and for non-ROOT users, a CSV export is published at EIC S3/eictest/ECCE/MC/prop.7/prop.7.0/FieldMap/ with public read-only username/password = eicS3read

2D field map from [1]

3D field map from [2]