Precision measurement of the neutron-3He spin-dependent scattering length using neutron interferometry

✍ Scribed by M.G. Huber; F.E. Wietfeldt; T.R. Gentile; W.C. Chen; M. Arif; D.A. Hussey; D.A. Pushin; L. Yang; T. Black

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 243 KB
• Volume: 611
• Category: Article
• ISSN: 0168-9002
• DOI: 10.1016/j.nima.2009.07.062

✦ Synopsis

There is strong theoretical interest in the study of few-body nucleon systems. Experimental measurements of neutron scattering lengths are able to perform precise tests of nucleon-nucleon models. Neutron interferometry provides some of the most precise values of spin-independent neutron scattering lengths, b c , including measurements for n-H, n-D, and n-3 He to better than a percent relative uncertainty. The spin-dependent neutron scattering length, b i , of n-3 He has been measured once before by Zimmer et al. using a polarized 3 He target inside a spin echo apparatus. Their result along with measurements of the spin-independent scattering length of n-3 He disagree with current theoretical models. An experiment to measure b i in n-3 He to less than 1% relative uncertainty has been conducted at the Neutron Interferometer and Optics Facility at the National Institute of Standards and Technology using small, flat-windowed 3 He cells. This experiment has different systematics than that of the spin echo measurement, and is the first use of a polarized gas target in a neutron interferometer.