Absolute Proton Detection Efficiency Determination in ``Beam'' Experiments

This talk~introduces~a new proposed method to measure proton detector efficiency for use in ``beam'' determinations of the free neutron lifetime.~ There is currently a 4-sigma disagreement between the ``beam'' and ``storage'' methods of measuring the lifetime of the neutron.~ A possible reason for this is a systematic uncertainty that is not properly accounted for in one or both types of experiments. Absolute proton counting is an essential to the ``beam'' experimental approach.~ The absolute detector efficiency is not currently known for existing experiments and could be a source of a hidden systematic error. This proposed calibration technique can also be extended to new, large area particle detectors designed for future experiments.