Data Analysis and Simulations for the Neutron Electric Dipole Experiment at Spallation Neutron Source (nEDM@SNS)

The experiment conducted at Oak Ridge National Laboratory (ORNL) using their Spallation Neutron Source (SNS) instrument aims to measure the neutron’s electric dipole moment (nEDM), if it exists, and increase the precision of these measurements by a factor of 100. SQUID (superconducting quantum interference device) magnetometers are utilized to measure the precession frequencies of Helium-3 atoms. The magnetic field causes the spins of the UCNs and Helium-3 atoms to precess, the latter of which is then detected in the SQUID detectors [1]. At the University of Kentucky and other institutions, we utilize Monte Carlo simulations that combine SQUID signals with white and pink noise scenarios to help us predict the possible environments in which the nEDM@SNS experiments occur. The same process was done using scintillation functions, whose purpose is to simulate the frequency of capture events between Helium-3 atoms and UCNs, which occur when the spins of the two particles are antiparallel. ROOT is used to analyze these simulated events through histogram fitting and other data analysis methods [2]. With these tools and methods, we aim to formulate code that can be used to gather and process data for us to interpret and analyze. This project successfully analyzed the effect of linearly and quadratically varying magnetic fields on the error estimates of UCNs’ and Helium-3 atoms’ precession frequencies, using the tools mentioned previously.

[1] Oak Ridge National Laboratory. The Experiment. url: https://nedm. ornl.gov/experiment/.

[2] Honor Hare. SQUID Signal Single Charge Point Detection. University of Kentucky. [Research Prospectus]. PHY 395. Aug. 2020.