Development of the BL3 Proton Trap Controller

Study of free neutron β-decay provides a rich experimental domain with major implications across fundamental particle physics and cosmology. However, despite decades of effort, a precision measurement of the free neutron lifetime remains elusive. Moreover, a ∼ 4σ (9.5s) disagreement between "beam" and "bottle" measurement techniques and a ∼ 3σ tension with standard model predictions motivate continued efforts toward high precision results. The BL3 experiment, to be conducted at the NIST Center for Neutron Research, will build upon previous beam method experiments to perform a thorough analysis of systematic uncertainties and achieve the highest precision result using this method to date. The neutron decay rate is determined in part by capturing decay protons in a 16-electrode quasi-Penning trap, which is operated by the proton trap controller. The trap controller, which is under development at Drexel University, drives the trap electrodes by performing high voltage switching, generating voltage ramps to flush out captured decay protons, and regulating the overall timing of the proton trapping cycle. Thus the speed, timing accuracy, and robustness of the trap controller directly contribute to the precise determination of the neutron decay rate, the measured neutron lifetime, and the ability to perform a variety of systematic error studies.