Development of a spin tracking simulation for the neutron electric dipole moment at the Spallation Neutron Source

The neutron Electric Dipole Moment experiment at the Spallation Neutron Source (nEDM@SNS) is being commissioned to reach sensitivities of ~ 3 x 10^-28 e•cm. Achieving this sensitivity requires tight control over systematic effects, which will be measured using the Systematics and Observational Studies at the PULSTAR reactor (SOS@PULSTAR) apparatus. SOS@PULSTAR shares many of the same features as nEDM@SNS but is much smaller, cooling and warming on the scale of weeks instead of months. For quickly gaining insights into how operating parameters affect our systematics it is then preferable to turn to simulation. We developed a package for simulating ultracold neutron and ³He spin dynamics using Graphics Processing Units (GPUs). Being able to leverage GPU resources significantly increases compute power, but makes development much more challenging. The entire code was written from scratch to make it as flexible as possible, requiring no external libraries. Shown here are results verifying the physics output of the code versus theory.