@article{cooper_hunt_downen_setoodehnia_portillo_marshall_clegg_champagne_longland_2023, title={Correlated characterization of 20Ne-implanted targets using nuclear reaction analysis, Rutherford backscattering spectrometry, and ion transport modeling}, volume={1056}, ISSN={["1872-9576"]}, DOI={10.1016/j.nima.2023.168654}, abstractNote={We present the preparation and characterization of a large sample of implanted noble gas targets for use in precision nuclear astrophysics measurements with intense proton beams. Tantalum and titanium backings were prepared using wet-acid etching, outgassed via resistive heating, and implanted with 20Ne+ beams from differing ion sources. These experimental targets were investigated using both nuclear reaction analysis techniques on the 1169-keV resonance in 20Ne(p, γ)21Na and Rutherford backscattering spectrometry analysis with 2-MeV α-particle beams. Results from these analyses reveal small target-to-target variations in stoichiometry, while exhibiting excellent agreement independent of ion-beam analysis method. We also present a self-consistent validation of the nuclear reaction analysis results using ion transport simulations in TRIM-2013 that rely on input parameters from SIMNRA scattering-yield fits to Rutherford backscattering spectra. In addition to a complete description of the implantation profile, this analysis method provides an alternate solution for characterizing a large sample of implanted targets when no suitable resonances are available for nuclear reaction analysis.}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Cooper, A. L. and Hunt, S. and Downen, L. and Setoodehnia, K. and Portillo, F. and Marshall, C. and Clegg, T. B. and Champagne, A. E. and Longland, R.}, year={2023}, month={Nov} }
 @article{portillo_longland_cooper_hunt_laird_marshall_setoodehnia_2023, title={Spin-parities of subthreshold resonances in the 18F(p, ?)15O reaction}, volume={107}, ISSN={["2469-9993"]}, url={https://doi.org/10.1103/PhysRevC.107.035809}, DOI={10.1103/PhysRevC.107.035809}, abstractNote={The $^{18}$F(p, $\alpha$)$^{15}$O reaction is key to determining the $^{18}$F abundance in classical novae. However, the cross section for this reaction has large uncertainties at low energies largely caused by interference effects. Here, we resolve a longstanding issue with unknown spin-parities of sub-threshold states in $^{19}$Ne that reduces these uncertainties. The $^{20}$Ne($^3$He, $^4$He)$^{19}$Ne neutron pick-up reaction was used to populate $^{19}$Ne excited states, focusing on the energy region of astrophysical interest ($\approx$ 6 - 7 MeV). The experiment was performed at the Triangle Universities Nuclear Laboratory using the high resolution Enge split-pole magnetic spectrograph. Spins and parities were found for states in the astrophysical energy range. In particular, the state at 6.133 MeV (E$_{r}^{\text{c.m.}} = -278$ keV) was found to have spin and parity of $3/2^+$ and we confirm the existence of an unresolved doublet close to 6.288 MeV (E$_{r}^{\text{c.m.}} = -120$ keV) with J$^{\pi}$ = $1/2^+$ and a high-spin state. Using these results, we demonstrate a significant factor of two decrease in the reaction rate uncertainties at nova temperatures.}, number={3}, journal={PHYSICAL REVIEW C}, author={Portillo, F. and Longland, R. and Cooper, A. L. and Hunt, S. and Laird, A. M. and Marshall, C. and Setoodehnia, K.}, year={2023}, month={Mar} }
 @article{marshall_setoodehnia_portillo_kelley_longland_2021, title={New energy for the 133-keV resonance in the Na-23(p, gamma) Mg-24 reaction and its impact on nucleosynthesis in globular clusters}, volume={104}, ISSN={["2469-9993"]}, url={https://doi.org/10.1103/PhysRevC.104.L032801}, DOI={10.1103/PhysRevC.104.L032801}, abstractNote={Globular cluster stars exhibit star-to-star anticorrelations between oxygen and sodium in their atmospheres. An improved description of the sodium-destroying $^{23}\mathrm{Na}+\mathrm{p}$ reaction rates is essential to understanding these observations. We present an energy analysis of $^{24}\mathrm{Mg}$ states based on a new measurement of the $^{23}\mathrm{Na}(^{3}\mathrm{He},\mathrm{d})^{24}\mathrm{Mg}$ reaction. A key resonance in $^{23}\mathrm{Na}(\mathrm{p},\ensuremath{\gamma})^{24}\mathrm{Mg}$ is found to be at ${E}_{r}^{\text{c.m.}}=133(3)$ keV, 5 keV lower than previously adopted. This finding has a dramatic effect on the $^{23}\mathrm{Na}(\mathrm{p},\ensuremath{\gamma})^{24}\mathrm{Mg}$ reaction rate, increasing it by a factor of 2 for the recommended rate. The nucleosynthesis impact of this change is investigated.}, number={3}, journal={PHYSICAL REVIEW C}, author={Marshall, C. and Setoodehnia, K. and Portillo, F. and Kelley, J. H. and Longland, R.}, year={2021}, month={Sep} }
 @article{hamill_woods_kahl_longland_greene_marshall_portillo_setoodehnia_2020, title={Study of the Mg-25(d,p)Mg-26 reaction to constrain the Al-25(p,gamma)Si-26 resonant reaction rates in nova burning conditions}, volume={56}, ISSN={["1434-601X"]}, DOI={10.1140/epja/s10050-020-00052-9}, abstractNote={Abstract}, number={2}, journal={EUROPEAN PHYSICAL JOURNAL A}, author={Hamill, C. B. and Woods, P. J. and Kahl, D. and Longland, R. and Greene, J. P. and Marshall, C. and Portillo, F. and Setoodehnia, K.}, year={2020}, month={Feb} }
 @article{marshall_setoodehnia_kowal_portillo_champagne_hale_dummer_longland_2019, title={The Focal-Plane Detector Package on the TUNL Split-Pole Spectrograph}, volume={68}, ISSN={["1557-9662"]}, DOI={10.1109/TIM.2018.2847938}, abstractNote={A focal-plane detector for the Enge split-pole spectrograph at the Triangle Universities Nuclear Laboratory has been designed. The detector package consists of two position-sensitive gas avalanche counters: a gas proportionality energy loss section and a residual energy scintillator. This setup allows both particle identification and focal-plane reconstruction. In this paper, we will detail the construction of each section along with their accompanying electronics and data acquisition. Effects of energy loss throughout the detector, ray-tracing procedures, and resolution as a function of fill pressure and bias voltage are also investigated. A measurement of the 27Al $(d,p)$  reaction is used to demonstrate a detector performance and to illustrate a Bayesian method of energy calibration.}, number={2}, journal={IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Marshall, Caleb and Setoodehnia, Kiana and Kowal, Katie and Portillo, Federico and Champagne, Arthur E. and Hale, Stephen and Dummer, Andrew and Longland, Richard}, year={2019}, month={Feb}, pages={533–546} }