STORI2024: Amorphous Carbon-coated Storage Cell Tests for the Polarized Gas Target at LHCb and Further Results

Abstract As the LHC beams cannot be polarized, introducing a dense polarized gas target at the LHCb experiment at CERN, to be operated concurrently with beam-beam collisions, will facilitate fixed-target interactions to explore a new energy regime of spin physics measurements. Unfortunately, typical surface coatings, such as water, Teflon, or aluminum, commonly used to avoid polarization losses, are prohibited due to restrictions imposed by vacuum and beam policies. Using the former atomic beam source for the polarized target at ANKE@COSY (Forschungszentrum Jülich), an accompanying Lamb-shift polarimeter and a storage cell chamber inside a superconducting magnet, provide a perfect test stand to investigate the properties of a storage cell coated with amorphous carbon. A significant recombination rate, ranging from 93% to 100%, as well as preservation of polarization during recombination surpassing 74%, were observed. We successfully produced H 2 molecules with a nuclear polarization of P ∼ 0.59. In addition, we could produce polarized H 3 + ions for the first time and observed the shift of the axis of rotation within HD molecules.