Commissioning and Simulation of the St. Benedict Extraction Beamline*

The University of Notre Dame's Superallowed Transition Beta-Neutrino Decay Ion Coincidence Trap (St. Benedict) is being constructed to investigate electroweak interactions. St. Benedict is designed specifically to measure the beta-neutrino angular correlation parameter for superallowed mixed beta-decay transitions between mirror nuclei. This allows testing of the theoretical corrections in the determination of the Vud element of the Cabibbo-Kobayashi-Maskawa matrix governing quark mixing, acting as a test of the completeness of the SM. There are four components to the St. Benedict project: a gas catcher to thermalize a radioactive ion beam, followed by a differentially pumped chamber with a radio-frequency quadrupole (RFQ) ion guide to extract the cooled ions, an RFQ cooler-buncher to further cool the beam and prepare it for entry into the final element — the Paul trap — used to observe the beta decay with sensors detecting coincident daughter particles and positrons. The work outlined here details the commissioning of the extraction beamline which carries the bunches of ions from the cooler buncher and further prepares them for entry into the Paul trap. A large part of this commissioning consisted of simulations done in SIMION to tune the system specifically for the ion bunches emerging from the cooler buncher.