arXiv subjects

I. Hay

Publications and source records attributed to I. Hay.

4 recordsLinked to original sources

arXiv2026

Excited states of $^{148}$Nd studied via the $^{150}$Nd$(p,t){}^{148}$Nd reaction and the observation of possible low-spin two-phonon octupole states at $N=88$

We report new data from a $^{150}$Nd$(p,t){}^{148}$Nd experiment performed at the John D. Fox Accelerator Laboratory of Florida State University. In total, 54 excited states of $^{148}$Nd were observed up to an excitation energy of 3500 keV. In this work, we focus on $0^+$ states and their band members. In contrast to previous work, the $0^+_3$ band is proposed as the candidate for the two-phonon octupole vibrational band. Supporting $spdf$ IBM-1 calculations are presented. To test the robustness of the IBM calculations, several observables were interrogated and are discussed in this publication. In addition, we make the case that neither the $0^+_2$ nor the $0^+_3$ states of the other $N=88$ isotones are likely good candidates for two-phonon octupole states. Based on our new data for $^{148}$Nd, we propose candidates in $^{150}$Sm and $^{152}$Gd. Using available $\gamma$-decay data for states with moderate spins in the yrast sequence and a comparison to IBM calculations, we also show how the staggering of the $B(E1)/B(E2)$ ratios in the yrast sequence can possibly be used to probe the appearance of bands with multiple octupole phonons.

nucl-ex↗

arXiv2026

The ICESPICE demonstrator for particle/$\gamma$-$e^{-}$ coincidence experiments at Florida State University

The Internal Conversion Electron SPectrometer In Coincidence Experiments (ICESPICE) demonstrator has been developed at Florida State University to enable particle/gamma-electron coincidence measurements in low-energy nuclear structure studies. ICESPICE is based on the mini-orange spectrometer concept and features a modular design using commercially available permanent magnets arranged in toroidal configurations to transport internal conversion electrons to room-temperature PIPS detectors while suppressing background from undesired particles. The system was optimized through SolidWorks modeling, COMSOL magnetic field simulations, and Geant4 particle tracking to maximize the magnetic transmission probability for electrons around 1 MeV. Commissioning tests using a calibrated 207Bi source demonstrated the performance of multiple spectrometer-detector configurations. Coincidence measurements between CeBr3 detectors from the CeBrA array and PIPS detectors revealed clear gamma-electron correlations. The first in-beam particle-electron measurements using ICESPICE were performed with the Super-Enge Split-Pole Spectrograph (SE-SPS) in the 208Pb(d,t)207Pb reaction. Prompt coincidences between tritons detected with the SE-SPS and electrons detected with ICESPICE were observed. The presented results show that ICESPICE is a promising ancillary detector system for in-beam internal conversion electron spectroscopy at the FSU SE-SPS.

physics.ins-det↗

arXiv2026

Experimental study of $^{53}$Cr via the $(d,p\gamma)$ reaction

Excited states in $^{53}$Cr were studied via the $^{52}$Cr$(d,p\gamma)$ reaction up to the neutron-separation threshold. Proton-$\gamma$ angular correlations and $\gamma$ decay branching ratios were measured in particle-$\gamma$ coincidences between the Super-Enge Split-Pole Spectrograph (SE-SPS) and CeBr$_3$ Array (CeBrA) demonstrator of the John D. Fox Accelerator Laboratory at Florida State University. Previous spin-parity assignments from a $(d,p)$ singles experiment at the SE-SPS are supported and $\gamma$-ray transitions in $^{53}$Cr reported. We firmly assign higher-lying excited states to $^{53}$Cr because overlapping excited states and contaminants could be identified better due to the complementary $\gamma$-decay information. We also correct some of the previously reported excitation energies and present a reanalysis of previously measured $^{52}$Cr$(d,p){}^{53}${Cr} angular distributions guided by the complementary $\gamma$-ray information. Based on this reanalysis, the fragmentation of the neutron $2p_{3/2}$, $2p_{1/2}$, $1f_{5/2}$, $1g_{9/2}$, and $2d_{5/2}$ single-particle strengths is reassessed for $^{53}$Cr. A comparison to the corresponding strengths in $^{55}$Fe is presented.

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arXiv2023

The CeBrA demonstrator for particle-$\gamma$ coincidence experiments at the FSU Super-Enge Split-Pole Spectrograph

We report on a highly selective experimental setup for particle-$\gamma$ coincidence experiments at the Super-Enge Split-Pole Spectrograph (SE-SPS) of the John D. Fox Superconducting Linear Accelerator Laboratory at Florida State University (FSU) using fast CeBr$_3$ scintillators for $\gamma$-ray detection. Specifically, we report on the results of characterization tests for the first five CeBr$_3$ scintillation detectors of the CeBr$_3$ Array (CeBrA) with respect to energy resolution and timing characteristics. We also present results from the first particle-$\gamma$ coincidence experiments successfully performed with the CeBrA demonstrator and the FSU SE-SPS. We show that with the new setup, $\gamma$-decay branching ratios and particle-$\gamma$ angular correlations can be measured very selectively using narrow excitation energy gates, which are possible thanks to the excellent particle energy resolution of the SE-SPS. In addition, we highlight that nuclear level lifetimes in the nanoseconds regime can be determined by measuring the time difference between particle detection with the SE-SPS focal-plane scintillator and $\gamma$-ray detection with the fast CeBrA detectors. Selective excitation energy gates with the SE-SPS exclude any feeding contributions to these lifetimes.

physics.ins-det↗