College Park, Maryland      June 6 - 10 , 2004

TP42: Measurement of the Neutron Lifetime Using a Proton Trap

F. E. WlETFELDT (Tulane University), M. S. DEWEY, D. M. GILLIAM, J. S. NICO (National Institute of Standards and Technology), X. FEI, W. M. SNOW (Indiana University), G. L. GREENE (University of Tennessee/ORNL), J. PAUWELS, R. EYKENS, A. LAMBERTY, J. Van Gestel (IRMM, Belgium)

We describe a recent measurement of the neutron lifetime by the absolute counting of in-beam neutrons and their decay protons. Protons were confined in a quasi-Penning trap and counted with a silicon detector. The neutron beam fluence was measured by capture in a thin 6LiF foil detector with known absolute efficiency. The combination of these simultaneous measurements gives the neutron lifetime: tn = 886.8 1.2 [stat] 3.2 [sys] s. The systematic uncertainty is dominated by uncertainties in the mass of the 6LiF deposit and the 6Li(n,t) cross section. This is the most precise measurement of the neutron lifetime to date using an in-beam method.

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