Measurement of the neutron lifetime by counting trapped protons in a cold neutron beam

Journal Article · Sun May 01 04:00:00 EDT 2005 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.71.055502· OSTI ID:20698701

Nico, J S; Dewey, M S; Gilliam, D M; Wietfeldt, F E; Fei, X; Snow, W M; Greene, G L; Pauwels, J; Eykens, R; Lamberty, A; Van Gestel, J; Scott, R D ^[1]

---

1. National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

A measurement of the neutron lifetime {tau}{sub n} performed by the absolute counting of in-beam neutrons and their decay protons has been completed. Protons confined in a quasi-Penning trap were accelerated onto a silicon detector held at a high potential and counted with nearly unit efficiency. The neutrons were counted by a device with an efficiency inversely proportional to neutron velocity, which cancels the dwell time of the neutron beam in the trap. The result is {tau}{sub n}=(886.3{+-}1.2[stat]{+-}3.2[sys]) s, which is the most precise measurement of the lifetime using an in-beam method. The systematic uncertainty is dominated by neutron counting, in particular, the mass of the deposit and the {sup 6}Li(n,t) cross section. The measurement technique and apparatus, data analysis, and investigation of systematic uncertainties are discussed in detail.

• OSTI ID: 20698701
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 5 Vol. 71; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ABSOLUTE COUNTING
BETA DECAY
COLD NEUTRONS
CROSS SECTIONS
DATA ANALYSIS
EFFICIENCY
ENERGY LEVELS
LIFETIME
LITHIUM 6 TARGET
NEUTRON BEAMS
NEUTRON REACTIONS
SI SEMICONDUCTOR DETECTORS
TRAPPED PROTONS
TRAPS