Measurement of 139La(p,x) cross sections from 35–60 MeV by stacked-target activation

Abstract

A stacked-target of natural lanthanum foils (99.9119% 139 La) was irradiated using a 60 MeV proton beam at the LBNL 88-Inch Cyclotron. 139 La(p,x) cross sections are reported between 35-60 MeV for nine product radionuclides. The primary motivation for this measurement was the need to quantify the production of 134 Ce. As a positron-emitting analogue of the promising medical radionuclide 225 Ac, 134 Ce is desirable for in vivo applications of bio-distribution assays for this emerging radio-pharmaceutical. The results of this measurement were compared to the nuclear model codes TALYS, EMPIRE and ALICE (using default parameters), which showed significant deviation from the measured values. arXiv:1907.04431v2 [nucl-ex]

Measurements of $^{160}$Dy($p,γ$) at energies relevant for astrophysical $γ$ process

“…A possible way to improve this is to use the stacked target activation method (e.g. Morrell et al 2020) for measurements of cross sections at energies lower than the provided beam energy. If there are γ activity setups available, simultaneous measurements of cross sections at a series energies would be possible.…”

Resolution of a discrepancy in the γ -ray emission probability from the β decay of Ceg137

“…It may be mentioned that the population branching of the isomeric and ground state, σ m,g /(σ m + σ g ), in 137 Ce m,g was 78(4) and 22(4)%, respectively, with insignificant variation in the incident proton beam energy range of 36-56 MeV, deduced using the cross section data σ from Ref. [42]. In the 139 La(p, 3n) 137 Ce m,g reaction, the high-spin (11/2 − ) isomeric state was preferentially populated compared to the low-spin (3/2 − ) ground state due to higher angular momentum of the compound nucleus carried by the high-energy protons.…”

“…Here we describe the irradiations and measurements in detail relevant to this work, i.e., for relative γ -ray intensities of the parent and daughter radioisotopes in transient equilibrium. Cross section data of the 139 La(p, x) reactions have been published by Morrell et al [42] and data of the 86 Sr(p, x) reactions will be published in upcoming articles.…”

Investigating High-Energy Proton-Induced Reactions on Spherical Nuclei: Implications for the Pre-Equilibrium Exciton Model

“…The continued rise of nuclear medicine to study physiological processes, diagnose, and treat diseases requires improved production routes for existing radionuclides, as well as new production pathways for entirely novel radioisotopes [1]. The implementation of these new methodologies or products in nuclear medicine relies on accurate and precise nuclear reaction cross section data in order to properly inform and optimize large scale creation for clinical use [2][3][4][5][6][7]. A primary component in obtaining these data is a suitable reaction monitor, defined as a long-lived radionuclide with a well-known cross section as a function of incident beam energy, that can accurately describe beam properties during a production irradiation [2,5,[8][9][10].…”

“…In addition to the (p,4n) channel, production cross sections were extracted for 22 additional reaction products. This extensive body of data forms a valuable tool to study nuclear reaction modeling codes and assess the predictive capabilities for proton reactions on spherical nuclei up to 200 MeV [6,[11][12][13][14][15], which have been studied less than neutron-induced reactions [16]. It was demonstrated that default modeling predictions from TALYS, CoH, EMPIRE, and ALICE codes failed to reproduce the measured niobium data and required modifications to improve [17][18][19][20].…”