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Excitation functions for (p,x) reactions of niobium in the energy range of E-p=40-90 MeV
Journal article   Open access   Peer reviewed

Excitation functions for (p,x) reactions of niobium in the energy range of E-p=40-90 MeV

Andrew S. Voyles, Lee A. Bernstein, Eva R. Birnbaum, Jonathan W. Engle, Stephen A. Graves, Toshihiko Kawano, Amanda M. Lewis and Francois M. Nortier
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms, Vol.429, pp.53-74
08/15/2018
DOI: 10.1016/j.nimb.2018.05.028
url
https://doi.org/10.1016/j.nimb.2018.05.028View
Published (Version of record) Open Access

Abstract

A stack of thin Nb foils was irradiated with the 100 MeV proton beam at Los Alamos National Laboratory's Isotope Production Facility, to investigate the Nb-93(p,4n)Mo-90 nuclear reaction as a monitor for intermediate energy proton experiments and to benchmark state-of-the-art reaction model codes. A set of 38 measured cross sections for Nb-nat(p,x) and Cu-nat(p,x) reactions between 40-90 MeV, as well as 5 independent measurements of isomer branching ratios, are reported. These are useful in medical and basic science radionuclide productions at intermediate energies. The Cu-nat(p,x)Co-56, Cu-nat(p,x)Zn-62, and Cu-nat(p,x)Zn-65 reactions were used to determine proton fluence, and all activities were quantified using HPGe spectrometry. Variance minimization techniques were employed to reduce systematic uncertainties in proton energy and fluence, improving the reliability of these measurements. The measured cross sections are shown to be in excellent agreement with literature values, and have been measured with improved precision compared with previous measurements. This work also reports the first measurement of the Nb-nat(p,x)Rb-82m reaction, and of the independent cross sections for Cu-nat(p,x)Mn-52g and Nb-nat(p,x)Y-85g in the 40-90 MeV region. The effects of Si-nat(p,x)Na-22,Na-24 contamination, arising from silicone adhesive in the Kapton tape used to encapsulate the aluminum monitor foils, is also discussed as a cautionary note to future stacked-target cross section measurements. A priori predictions of the reaction modeling codes CoH, EMPIRE, and TALYS are compared with experimentally measured values and used to explore the differences between codes for the Nb-nat(p,x) and Cu-nat(p,x) reactions.
Instruments & Instrumentation Nuclear Science & Technology Physical Sciences Physics Physics, Atomic, Molecular & Chemical Physics, Nuclear Science & Technology Technology

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