Evaluating Performance of Improved SpinQuest/E1039 Trigger Hodoscopes

SpinQuest/E1039 will use the Fermilab 120 GeV Main Injector to measure the antiquark distributions of the nucleon sea using polarized solid NH3 and ND3 targets. This will be the first time such measurements will have been done and will complement the valence polarized antiquark measurements that have been done by COMPASS II at CERN. By using a polarized target and dimuon production via the Drell-Yan process we can increase our knowledge of the contribution of sea-quarks to the spin of the proton. SpinQuest has made multiple improvements of the four hodoscope stations. These include an improved PMT base circuit board, improved clip lines used to reduce the pulse width from 20 to 10 ns without pulse distortion, and adding a horizontal gap in the first station to lower background events. The methods used to evaluate and optimize the new designs, such as testing with a pulsing violet LED to select the best PMTs for the bend plane hodoscopes and stability studies will be discussed. The hodoscope system will be tested using cosmic rays to be prepared for a planned commissioning with beam in June 2019.