Measurement of the Neutron Lifetime by Counting Trapped Protons

F E Wietfeldt; M S Dewey; D M Gilliam; J S Nico; X Fei; W M Snow; G L Greene; J Pauwels; R Eykens; A Lamberty; J Van Gestel

doi:10.6028/jres.110.048

Measurement of the Neutron Lifetime by Counting Trapped Protons

J Res Natl Inst Stand Technol. 2005 Aug 1;110(4):327-31. doi: 10.6028/jres.110.048. Print 2005 Jul-Aug.

Authors

F E Wietfeldt¹, M S Dewey², D M Gilliam², J S Nico², X Fei³, W M Snow³, G L Greene⁴, J Pauwels⁵, R Eykens⁵, A Lamberty⁵, J Van Gestel⁵

Affiliations

¹ Tulane University, New Orleans, LA 70118.
² National Institute of Standards and Technology, Gaithersburg, MD 20899.
³ Indiana University, Bloomington, IN 47408.
⁴ University of Tennessee/Oak Ridge National Laboratory, Knoxville, TN 37996.
⁵ European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 2440 Geel, Belgium.

Abstract

We measured the neutron decay lifetime by counting in-beam neutron decay recoil protons trapped in a quasi-Penning trap. The absolute neutron beam fluence was measured by capture in a thin (6)LiF foil detector with known efficiency. The combination of these measurements gives the neutron lifetime: τ n = (886.8 ± 1.2 ± 3.2) s, where the first (second) uncertainty is statistical (systematic) in nature. This is the most precise neutron lifetime determination to date using an in-beam method.

Keywords: neutron lifetime; trapped protons.