Thu·Aug 7, 2025Thursday·August 7, 2025

1. 01*

   Enhanced sensitivity to trace ${}^{238}$U impurity of sapphire via coincidence neutron activation analysis

   D. Chernyak · I.J. Arnquist🇺🇸 · T. Daniels🇺🇸 · S.W. Finch🇺🇸 · L. Hissong · M. Hughes🇺🇸 · R. MacLellan🇺🇸 · A. Piepke🇺🇸 · A. Pocar🇺🇸 · R. Roshong · R. Saldanha🇺🇸 · R.H.M. Tsang🇺🇸

   Sapphire has mechanical and electrical properties that are advantageous for the construction of internal components of radiation detectors such as time projection chambers and bolometers. However, it has proved difficult to assess its ${}^{232}\mathrm{Th}$ and ${}^{238}\mathrm{U}$ content down to the picogram per gram level. This work reports an experimental verification of a computational study that demonstrates $\gamma \gamma$ coincidence counting, coupled with neutron activation analysis (NAA), can reach ppt sensitivities. Combining results from $\gamma \gamma$ coincidence counting with those of earlier single-$\gamma$ counting based NAA shows that a sample of Saint Gobain sapphire has ${}^{232}\mathrm{Th}$ and ${}^{238}\mathrm{U}$ concentrations of $<0.26$ ppt and $<2.3$ ppt, respectively; the best constraints on the radiopurity of sapphire.

   nucl-exphysics.ins-detPRC(2026)·2 citations
2. 02*

   Experimental Study of Bremsstrahlung Gamma Ray Emission and Short-Range Correlations in ${}^{124}$Sn+${}^{124}$Sn Collisions at 25 MeV/u

   Junhuai Xu🇨🇳 · Qinglin Niu🇨🇳 · Yuhao Qin🇨🇳 · Dawei Si🇨🇳 · Yijie Wang🇨🇳 · Sheng Xiao · Baiting Tian🇨🇳 · Zhi Qin🇨🇳 · Haojie Zhang · Boyuan Zhang🇨🇳 · Dong Guo · Minxue Fu🇨🇳 and 24 other authors

   Short-range correlation (SRC) in nuclei refers to nucleons forming temporally correlated pairs in close proximity, giving rise to the high momentum of the nucleons beyond the Fermi surface. It has been reported that bremsstrahlung $\gamma$ production from neutron-proton process in heavy-ion reactions provides a potential probe to the SRC abundance in nuclei. In this paper, we present in detail the precision measurement of bremsstrahlung $\gamma$-rays in ${}^{124}\mathrm{Sn}$+${}^{124}\mathrm{Sn}$ reactions at 25 MeV/u using the Compact Spectrometer for Heavy IoN Experiment (CSHINE). A comprehensive experimental and analysis framework is established to ensure the reliability and robustness of the extracted results. Background contributions are evaluated and subtracted using independent methods, and the consistency of the analysis is systematically validated. By comparing the experimental $\gamma$ spectrum with the Isospin-dependent Boltzmann-Uehling-Uhlenbeck simulations, the high momentum tail (HMT) fraction of $R_{\mathrm{HMT}}=(20\pm 3)\%$ is derived in ${}^{124}$Sn nuclei. This work provides a detailed and validated experimental framework for extracting SRC information from bremsstrahlung $\gamma$-ray emission and demonstrates the feasibility of studying nucleon SRCs with high precision in low-energy heavy-ion collisions.

   nucl-exnucl-thPRC(2026)·7 citations
3. 03*

   Microscopic determination of the interacting boson-fermion model Hamiltonian from the nuclear energy density functional

   M. Homma · K. Nomura

   A microscopic formulation of the interacting boson-fermion model for odd-$A$ nuclei is made using the nuclear energy density functional framework. Strength parameters for the bosonic Hamiltonian and boson-fermion interactions are shown to be determined completely so that energy surfaces and deformed single-particle energies of the Bose-Fermi systems should match the corresponding self-consistent mean-field solutions for fermionic systems. In an illustrative application to axially symmetric odd-$A$ Eu, this procedure is shown to be valid in describing spherical-to-deformed shape phase transitions in odd-$A$ and even-even systems.

   ↳ nucl-thnucl-exPhysics Letters B 869 (2025) 139880
4. 04*

   Neural Networks for 3D Characterisation of AGATA Crystals

   Mojahed Abushawish🇫🇷 · Guillaume Baulieu🇫🇷 · Jérémie Dudouet🇫🇷 · Olivier Stézowski🇫🇷

   Precise localisation of gamma-ray interactions is crucial for the performance of the Advanced GAmma Tracking Array (AGATA). The Pulse Shape Analysis (PSA) method used for the position estimation of gamma-ray interactions relies on a simulated signal database. The Pulse Shape Comparison Scanning (PSCS) method was used to scan AGATA crystals in order to produce an experimental database of signals. This paper presents a novel approach using Long Short-Term Memory (LSTM) neural networks to determine the 3D interaction position of gamma rays within AGATA crystals, trained on data from IPHC Strasbourg, allowing for the construction of an experimental database. A custom masked loss function is introduced to enable training with incomplete position information. The database generated by this new method outperforms the existing simulated database, and the experimental database obtained from the conventional PSCS algorithm.

   ↳ physics.ins-detnucl-exEPJA(2026)·0 citations
5. 05*

   Radiation-tolerant polarized solid target

   K. Tateishi · Y. Saito🇨🇦 · D. Takahashi · K. Sekiguchi🇯🇵 · K. Aradono · K. Hirasawa · Y. Maeda🇯🇵 · Y. Nagao · H. Nishibata · S. Otsuka · H. Sakai🇯🇵 · H. Sugahara and 4 other authors

   Polarized targets evolved into indispensable tools in particle and nuclear physics. However, the polarized solid target is degraded by high-intense beam irradiation, known as radiation damage due to target heating and radical generation. We demonstrated a radiation-tolerant polarized solid target operating at room temperature. An annealing allows the spontaneous repair of the damage by reducing unwanted radicals. Using a single crystal of $p$-terphenyl doped with 0.01 mol\% pentacene-$d$${}_{14}$, Dynamic Nuclear Polarization using photoexcited triplet electrons (Triplet-DNP) was applied to proton spins at room temperature and in 0.39 T. For the proof of concept, a deuteron beam with an energy of 135 MeV/u and the intensities of 10${}^7$-10${}^9$ counts per second (cps) was irradiated. The proton polarization was determined to be 3.0\% $\pm$0.2\%$(stat.)$ $\pm$0.1\%$(sys.)$ from a scattering asymmetry. The polarization was almost not attenuated up to 10${}^9$ cps, but the target crystal was yellowed. The visible-light absorption spectroscopy suggested irreversible radiation damage due to missing protons by the knock-out reaction. The room-temperature polarized solid target allows impractical experiments with the conventional target system, leading to a next-generation spin-dependent accelerator science.

   ↳ physics.ins-detnucl-exPRResearch(2026)·3 citations
6. 06*

   Experimental Scheme for Polarizing the Boron Nuclei

   William R. Milner🇺🇸 · Richard G. Milner🇺🇸

   Unravelling the internal structure of hadrons and nuclei in terms of the quarks and gluons of Quantum Chromodynamics is a central focus of current nuclear physics research. Directly observing gluonic states in the nucleus would be groundbreaking and is an objective of the future Electron-Ion Collider (EIC). Over thirty years ago, Jaffe and Manohar identified a new double-helicity flip structure function, directly sensitive to exotic gluons. They pointed out that this could be measured in inclusive high-energy electron scattering from a transversely polarized nuclear target with spin $I\ge 1$. Here, we identify the spin-3 nucleus boron-10 as a particularly interesting system to search for exotic gluons. Leveraging technical advances in atomic physics over the past decade, we outline an experimental scheme to directly optically pump a beam of stable boron atoms to polarize the nuclear spin. Technical challenges to realize a spin-polarized beam of boron-10 in the EIC are discussed. The proposed scheme will also polarize the ${}^{11}$B nucleus, which could significantly enhance the pB fusion cross section.

   ↳ physics.ins-detnucl-exphysics.atom-phPRC(2025)·2 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.