Determination of the Neutron Lifetime Using Magnetically Trapped Neutrons.
We report progress on an experiment to measure the neutron lifetime using magnetically trapped neutrons. Neutrons are loaded into a 1.1 T deep superconducting Ioffe-type trap by scattering 0.89 nm neutrons in isotopically pure superfluid (4)He. Neutron decays are detected in real time using the scintillation light produced in the helium by the beta-decay electrons. The measured trap lifetime at a helium temperature of 300 mK and with no ameliorative magnetic ramping is substantially shorter than the free neutron lifetime. This is attributed to the presence of neutrons with energies higher than the magnetic potential of the trap. Magnetic field ramping is implemented to eliminate these neutrons, resulting in an [Formula: see text] trap lifetime, consistent with the currently accepted value of the free neutron lifetime.
Harvard University, Cambridge, MA 02138, USA.
S N
SN
Dzhosyuk
Harvard University, Cambridge, MA 02138, USA.
A
A
Copete
Harvard University, Cambridge, MA 02138, USA.
J M
JM
Doyle
Harvard University, Cambridge, MA 02138, USA.
L
L
Yang
National Institute of Standards and Technology, Boulder, CO 80303, USA.
K J
KJ
Coakley
North Carolina State University, Raleigh, NC 27695, USA.
R
R
Golub
Hahn-Meitner-Institut, Berlin, Germany.
E
E
Korobkina
Tulane University, New Orleans, LA 70118, USA.
T
T
Kreft
Los Alamos National Laborataory, Los Alamos, NM 87545, USA.
S K
SK
Lamoreaux
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
A K
AK
Thompson
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
G L
GL
Yang
North Carolina State University, Raleigh, NC 27695, USA.
P R
PR
Huffman
magnetic trapping; neutron lifetime; superthermal neutron production; ultracold neutrons