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

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:429

Article

Voyles, Andrew S.¹  Bernstein, Lee A.^1,2  Birnbaum, Eva R.³  Engle, Jonathan W.⁴  Graves, Stephen A.⁵  Kawano, Toshihiko⁶  Lewis, Amanda M.¹  Nortier, Francois M.³ 

[1] Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA

[2] Lawrence Berkeley Natl Lab, Nucl Sci Div, Berkeley, CA 94720 USA

[3] Los Alamos Natl Lab, Chem Div, Isotope Prod Facil, Los Alamos, NM 87544 USA

[4] Univ Wisconsin, Dept Med Phys, Madison, WI 53705 USA

[5] Univ Iowa, Dept Radiat Oncol, Iowa City, IA 52242 USA

[6] Los Alamos Natl Lab, Theoret Div, Los Alamos, NM 87544 USA

关键词: Nb plus p;    Cu plus p;    Niobium;    Mo-90;    Nuclear cross sections;    Stacked target activation;    Monitor reactions;    Medical isotope production;    Isomer branching ratios;    MCNP;    LANL;   

DOI  :  10.1016/j.nimb.2018.05.028

来源: Elsevier

【 摘 要 】

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.

【 授权许可】

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