Further measurement of the {beta}-delayed {alpha}-particle emission of {sup 16}N

Journal Article · Fri Jun 15 00:00:00 EDT 2007 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.75.065802· OSTI ID:21003502

France, III, R H; Wilds, E L; McDonald, J E; Gai, M ^[1]

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1. Department of Chemistry and Physics, Campus Box 82, Georgia College and State University, Milledgeville, Georgia 31061 (United States)

We measured the {beta}-delayed {alpha}-particle emission spectrum of {sup 16}N with a sensitivity for {beta}-decay branching ratios of the order of 10{sup -10}. The {sup 16}N nuclei were produced using the d({sup 15}N,{sup 16}N)p reaction with 70 MeV {sup 15}N beams and a deuterium gas target 7.5 cm long at a pressure of 1250 torr. The {sup 16}N nuclei were collected (over 10 s) using a thin aluminum foil with an areal density of 180 {mu}g/cm{sup 2} tilted at 7 deg. with respect to the beam. The activity was transferred to the counting area by means of a stepping motor in less than 3 s with the counting carried out over 8 s. The {beta}-delayed {alpha}-particles were measured using a time-of-flight method to achieve a sufficiently low background. Standard calibration sources ({sup 148}Gd, {sup 241}Am, {sup 208,209}Po, and {sup 227}Ac) as well as {alpha} particles and {sup 7}Li from the {sup 10}B(n,{alpha}){sup 7}Li reaction were used for an accurate energy calibration. The energy resolution of the catcher foil (180-220 keV) was calculated and the time-of-flight resolution (3-10 nsec) was measured using the {beta}-delayed {alpha}-particle emission from {sup 8}Li that was produced using the d({sup 7}Li,{sup 8}Li)p reaction with the same setup. The line shape was corrected to account for the variation in the energy and time resolution and a high statistics spectrum of the {beta}-delayed {alpha}-particle emission of {sup 16}N is reported. However, our data (as well as earlier Mainz data and unpublished Seattle data) do not agree with an earlier measurement of the {beta}-delayed {alpha}-particle emission of {sup 16}N taken at TRIUMF after averaging over the energy resolution of our collection system. This disagreement, among other issues, prohibits accurate inclusion of the f-wave component in the R-matrix analysis.

• OSTI ID: 21003502
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 75, Issue 6; Other Information: DOI: 10.1103/PhysRevC.75.065802; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIUM 227
ALPHA PARTICLES
ALUMINIUM
AMERICIUM 241
BETA DECAY
BORON 10
BRANCHING RATIO
DEUTERIUM
EMISSION SPECTRA
ENERGY RESOLUTION
F WAVES
GADOLINIUM 148
KEV RANGE 100-1000
LITHIUM 7
LITHIUM 8
MEV RANGE 10-100
NITROGEN 15
NITROGEN 16
POLONIUM 209
R MATRIX
TIME RESOLUTION
TIME-OF-FLIGHT METHOD