The BL3 Beam Neutron Lifetime Experiment

BL3 is a next generation beam neutron lifetime experiment using the Sussex-ILL-NIST method. BL3 is based on the principles of the existing NIST apparatus but it will employ a larger and more uniform superconducting magnet, a larger and higher flux neutron beam, and a large diameter segmented silicon detector, giving a >100 times increase in proton trapping rate. A number of new features to test and explore systematic effects will be included. The goal of BL3 is twofold: 1) to search for an explanation for the neutron lifetime discrepancy and thoroughly validate systematics in the beam method at the 1 s level; and 2)reduce the ultimate precision in the beam method to <0.3 s. An overview of BL3 and its design will be presented.