Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Progress Towards a Precision Measurement of the Neutron Lifetime Using Magnetically Trapped Ultracold Neutrons



P.-N. Seo, Kevin Coakley, J M. Doyle, F H. DuBose, R Golub, E Korobkina, S K. Lamoreaux, Hans Pieter Mumm, C M. O'Shaughnessy, G R. Palmquis, A K. Thompson, Grace L. Yang, L Yang, Paul R. Huffman


As part of an on-going program utilizing magnetically trapped ultracold neutrons (UCNs,) we are developing a technique that offers the possibility of improving the precision of the neutron lifetime by more than an order of magnitude. The experiment works by loading an Ioffe-type superconducting magnetic trap with UCNs through inelastic scattering of 0.89 nm neutrons with phonons in superfluid 4He. Trapped neutrons are detected when they decay; charged decay electrons ionize helium atoms in the superfluid resulting in scintillation light that is recorded in real time using photomultiplier tubes. At present, we are installing a larger and deeper superconducting magnetic trap into our apparatus, implementing techniques to reduce background events, and working to increase the neutron decay detection efficiency. We report the status of the construction of the improved apparatus.
Proceedings Title
Proceedings of "PANIC: Particles and Nucleii International Conference"
Conference Dates
October 24-September 28, 2005
Conference Location
Sante Fe, NM, USA
Conference Title
PANIC: Particles and Nucleii International Conference


magnetic trap, neutron lifetime, scintillation, superfluid helium, superthermal, ultracold


Seo, P. , Coakley, K. , Doyle, J. , DuBose, F. , Golub, R. , Korobkina, E. , Lamoreaux, S. , Mumm, H. , O'Shaughnessy, C. , Palmquis, G. , Thompson, A. , Yang, G. , Yang, L. and Huffman, P. (2006), Progress Towards a Precision Measurement of the Neutron Lifetime Using Magnetically Trapped Ultracold Neutrons, Proceedings of "PANIC: Particles and Nucleii International Conference", Sante Fe, NM, USA (Accessed April 24, 2024)
Created December 31, 2005, Updated October 12, 2021