Determination of the Neutron Lifetime Using Magnetically Trapped Neutrons

He. Neutron decays aredetected in real time using the scintillationlight produced in the helium by thebeta-decay electrons. The measured traplifetime at a helium temperature of300 mK and with no ameliorativemagnetic ramping is substantially shorterthan the free neutron lifetime. This isattributed to the presence of neutronswith energies higher than the magneticpotential of the trap. Magnetic fieldramping is implemented to eliminatethese neutrons, resulting in an s traplifetime, consistent with the currentlyaccepted value of the free neutron lifetime.