arXiv subjects

Cathy S. Cutler

Publications and source records attributed to Cathy S. Cutler.

4 recordsLinked to original sources

arXiv2026

Characterizing Secondary Neutrons at BLIP for Isotope Production Applications

Fast secondary neutrons created at the Brookhaven Linac Isotope Producer (BLIP) facility following proton irradiation were characterized by the foil activation technique and compared with FLUKA Monte Carlo simulations. The FLUKA-simulated neutron flux was spectrally adjusted following the maximum entropy formalism using the International Reactor Dosimetry and Fusion File (IRDFF-II), with predictions agreeing with experimental measurements to within 9% following the adjustment procedure. A multitude of degrader configurations were simulated to assess the feasibility of improving the fast (En > 20 MeV) secondary neutron yield at the proposed neutron target position (N-slot). A configuration where the N-slot is closest to the proton degrader produced the highest fast neutron yield, with tungsten degraders achieving the best performance. Assuming the optimized target-degrader configuration proposed in this work, we discuss potential isotope production opportunities with secondary neutrons. In most cases the yields are in the order of several mCi.

physics.app-ph↗

arXiv2025

$\mathrm{^{117m}Sn}$ and $\mathrm{^{119m}Te}$ Production via Proton Bombardment on Natural Antimony and Implications for Modeling Charged Particle Reactions

$\mathrm{^{117m}Sn}$ and $\mathrm{^{119}Sb}$, the latter of which is produced via a $\mathrm{^{119m}Te}$ generator, are promising radionuclides for the targeted treatment of both osteoarthritis and small mass tumors via Auger therapy. Experiments were conducted at Lawrence Berkeley National Laboratory, Los Alamos National Laboratory, and Brookhaven National Laboratory to measure the $\mathrm{^{nat}Sb}$(p,x)$\mathrm{^{117m}Sn}$ and $\mathrm{^{nat}Sb}$(p,x)$\mathrm{^{119m}Te}$ cross sections for incident proton energies up to 200 MeV. Additional measurements for co-produced isotopes are included as well. In addition to this dataset, this paper investigates improvements for proton-induced reaction modeling capabilities through comparison of these experimental dataset against theoretical models in TALYS 1.95. Parameter adjustments affecting level density, optical model potential, and pre-equilibrium emission were explored, with a goodness-of-fit metric established by the largest independent cross section channels and cross-validated with remaining channels.

nucl-ex↗

arXiv2021

Measurement and Modeling of Proton-Induced Reactions on Arsenic from 35 to 200 MeV

$^{72}$As is a promising positron emitter for diagnostic imaging that can be employed locally using a $^{72}$Se generator. However, current reaction pathways to $^{72}$Se have insufficient nuclear data for efficient production using regional 100-200 MeV high-intensity proton accelerators. In order to address this deficiency, stacked-target irradiations were performed at LBNL, LANL, and BNL to measure the production of the $^{72}$Se/$^{72}$As PET generator system via $^{75}$As(p,x) between 35 and 200 MeV. This work provides the most well-characterized excitation function for $^{75}$As(p,4n)$^{72}$Se starting from threshold. Additional focus was given to report the first measurements of $^{75}$As(p,x)$^{68}$Ge and bolster an already robust production capability for the highly valuable $^{68}$Ge/$^{68}$Ga PET generator. Thick target yield comparisons with prior established formation routes to both generators are made. In total, high-energy proton-induced cross sections are reported for 55 measured residual products from $^{75}$As, Cu, and Ti targets, where the latter two materials were present as monitor foils. These results were compared with literature data as well as the default theoretical calculations of the nuclear model codes TALYS, CoH, EMPIRE, and ALICE. Reaction modeling at these energies is typically unsatisfactory due to few prior published data and many interacting physics models. Therefore, a detailed assessment of the TALYS code was performed with simultaneous parameter adjustments applied according to a standardized procedure. Particular attention was paid to the formulation of the two-component exciton model in the transition between the compound and pre-equilibrium regions, with a linked investigation of level density models for nuclei off of stability and their impact on modeling predictive power.

nucl-ex↗

arXiv2021

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

A number of accelerator-based isotope production facilities utilize 100- to 200-MeV proton beams due to the high production rates enabled by high-intensity beam capabilities and the greater diversity of isotope production brought on by the long range of high-energy protons. However, nuclear reaction modeling at these energies can be challenging because of the interplay between different reaction modes and a lack of existing guiding cross section data. A Tri-lab collaboration has been formed among the Lawrence Berkeley, Los Alamos, and Brookhaven National Laboratories to address these complexities by characterizing charged-particle nuclear reactions relevant to the production of established and novel radioisotopes. In the inaugural collaboration experiments, stacked-targets of niobium foils were irradiated at the Brookhaven Linac Isotope Producer (E$_p$=200 MeV) and the Los Alamos Isotope Production Facility (E$_p$=100 MeV) to measure $^{93}$Nb(p,x) cross sections between 50 and 200 MeV. The measured cross-section results were compared with literature data as well as the default calculations of the nuclear model codes TALYS, CoH, EMPIRE, and ALICE. We developed a standardized procedure that determines the reaction model parameters that best reproduce the most prominent reaction channels in a physically justifiable manner. The primary focus of the procedure was to determine the best parametrization for the pre-equilibrium two-component exciton model. This modeling study revealed a trend toward a relative decrease for internal transition rates at intermediate proton energies (E$_p$=20-60 MeV) in the current exciton model as compared to the default values. The results of this work are instrumental for the planning, execution, and analysis essential to isotope production.

nucl-ex↗