Detector system modelling and simulation for pulsed cold neutron beam lifetime experiment

A new experiment proposes a novel technique to measure the beta decay lifetime of free neutrons, in order to resolve the current discrepancy between the results of ‘bottle’ and ‘beam’ type neutron lifetime experiments. A collimated, pulsed beam of cold neutrons will pass through a volume of superfluid helium-4 doped with a known concentration of helium-3. As the neutron pulse traverses the helium, two event types can occur: neutron-³He capture and neutron beta decay, both of which produce charged daughter particles that interact with the superfluid helium to generate 16 eV scintillation photons. Detection of these scintillation signals can be used to quantify and distinguish (although imperfectly) the events that occur as the pulse traverses the helium, thus allowing the neutron lifetime to be extracted. This poster will cover modelling of the proposed detector system and considered variations, the application of machine learning to assess position resolution, as well as possible secondary avenues of investigation.