Dzhosyuk S N, Copete A, Doyle J M, Yang L, Coakley K J, Golub R, Korobkina E, Kreft T, Lamoreaux S K, Thompson A K, Yang G L, Huffman P R
Harvard University, Cambridge, MA 02138, USA.
National Institute of Standards and Technology, Boulder, CO 80303, USA.
J Res Natl Inst Stand Technol. 2005 Aug 1;110(4):339-43. doi: 10.6028/jres.110.050. Print 2005 Jul-Aug.
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.
我们报告了一项使用磁阱中子测量中子寿命实验的进展。通过在同位素纯超流⁴He中散射0.89 nm中子，将中子加载到一个1.1 T的深超导伊奥费型陷阱中。利用β衰变电子在氦气中产生的闪烁光实时检测中子衰变。在氦温度为300 mK且无改善磁场斜坡的情况下，测得的陷阱寿命明显短于自由中子寿命。这归因于存在能量高于陷阱磁势的中子。实施磁场斜坡以消除这些中子，从而得到一个与自由中子寿命的当前公认值一致的陷阱寿命。
