Thu·Jan 16, 2025Thursday·January 16, 2025

1. 01*

   Precision Spectroscopy of Antiprotonic Atoms for Investigation of Low-energy Antinucleon-nucleus Interactions

   Takashi Higuchi🇯🇵 · Hiroyuki Fujioka🇯🇵

   We propose a high-precision x-ray spectroscopy experiment of antiprotonic atoms to advance the understanding of low-energy antinucleon-nucleus interactions. The current leading model of antiproton-nucleus interactions is based on an optical potential with parameters derived from a global fit to antiprotonic atom x-ray data across the periodic table. However, the isovector parameter of this potential remains poorly constrained due to uncertainties in nucleon distributions of the nuclei. To address this, we propose to use calcium isotopes with well-studied nucleon distributions to minimize these uncertainties. A superconducting microcalorimeter detector will provide a resolution of 50-70 eV in the energy range of interest, allowing high precision determination of the isotope-dependent strong-interaction shifts and widths. The outcomes of the proposed experiment can be used to refine the model of antinucleon-nucleus interactions and provide critical data for future experiments searching for neutron-antineutron oscillations.

   nucl-exphysics.atom-phPoS(2025)·2 citations
2. 02*

   Stepping into the Sea of Instability: The New Sub-us Superheavy Nucleus 252Rf

   J. Khuyagbaatar · P. Mosat🇷🇴 · J. Ballof🇩🇪 · R. A. Cantemir · Ch. E. Düllmann🇩🇪 · K. Hermainski · F. P. Heßberger🇩🇪 · E. Jäger · B. Kindler🇩🇪 · J. Krier · N. Kurz🇩🇪 · S. Löchner and 5 other authors

   We report the discovery of the new isotope ${}^{252}$Rf. With its extremely short half-life of $60_{-30}^{+90}$~ns, it expands the range of half-lives of the known superheavy nuclei by about two orders of magnitude. This nucleus was synthesized in its high-$K$ isomeric state, for which we measured a half-life of $13_{-3}^{+4}$~$\mu$s. Our results confirm a smooth onset of decreasing ground-state spontaneous fission half-lives in the neutron-deficient Rf isotopes towards the isotopic border of $10^{-14}$~s, which is the time needed to form an atomic shell. Our findings set a new benchmark for further exploration of phenomena associated with high-$K$ states and inverted fission-stability in the heaviest nuclei.

   nucl-exPRL(2025)·15 citations
3. 03*

   In-situ high voltage generation with Cockcroft-Walton multiplier for xenon gas time projection chamber

   Shinichi Akiyama🇯🇵 · Junya Hikida🇯🇵 · Masashi Yoshida🇯🇵 · Kazuhiro Nakamura🇯🇵 · Sei Ban🇯🇵 · Masanori Hirose🇯🇵 · Atsuko K. Ichikawa🇯🇵 · Yoshihisa Iwashita🇯🇵 · Tatsuya Kikawa🇯🇵 · Yasuhiro Nakajima🇯🇵 · Kiseki D. Nakamura🇯🇵 · Tsuyoshi Nakaya🇯🇵 and 8 other authors

   We have newly developed a Cockcroft-Walton (CW) multiplier that can be used in a gas time projection chamber (TPC). A TPC requires a high voltage to form an electric field that drifts ionization electrons. Supplying the high voltage from outside the pressure vessel requires a dedicated high-voltage feedthrough. An alternative approach is to generate the high voltage inside the pressure vessel with a relatively low voltage introduced from outside. A CW multiplier can convert a low AC voltage input to a high DC voltage output, making it suitable for this purpose. We have integrated a CW multiplier into the AXEL (A Xenon ElectroLuminescence detector), a high pressure xenon gas TPC to search for neutrinoless double beta decay of ${}^{136}$Xe. It uses silicon photomultipliers to detect the ionization electrons through elecrtoluminescence, making it strong against electronic noise. Operation of the CW multiplier was successfully demonstrated; the TPC was operated for 40 days at 6.8 bar, and an energy resolution as high as (0.67 $\pm$ 0.08) % (FWHM) at 2615 keV was obtained.

   ↳ physics.ins-dethep-exnucl-exPTEP(2025)·4 citations
4. 04*

   First-Ever Deployment of a SiPM-on-Tile Calorimeter in a Collider: A Parasitic Test with 200 GeV $pp$ Collisions at RHIC

   Weibin Zhang🇺🇸 · Sean Preins🇺🇸 · Jiajun Huang🇺🇸 · Sebouh J. Paul🇺🇸 · Ryan Milton🇺🇸 · Miguel Rodriguez🇺🇸 · Peter Carney🇺🇸 · Ryan Tsiao🇺🇸 · Yousef Abdelkadous🇺🇸 · Miguel Arratia🇺🇸

   We describe the testing of a prototype SiPM-on-tile iron-scintillator calorimeter at the Relativistic Heavy Ion Collider (RHIC) during its 200 GeV $pp$ run in 2024. The prototype, measuring $20\times 20{\text{cm}}^2$ and 24 radiation lengths in depth, was positioned in the STAR experimental hall, approximately 8 m from the interaction point and 65 cm from the beam line, covering a pseudorapidity range of about $3.1<\eta <3.4$. By using the dark current of a reference SiPM as a radiation monitor, we estimate that the prototype was exposed to a fluence of about $10^{10}$ 1-MeV $n_{\mathrm{eq}}$/cm${}^2$. Channel-by-channel calibration was performed in a data-driven way with the signature from minimum-ionizing particles during beam-on conditions. A Geant4 detector simulation, with inputs from the Pythia8 event generator, describes measurements of energy spectra and hit multiplicities reasonably well. These results mark the first deployment, commissioning, calibration, and long-term operation of a SiPM-on-tile calorimeter in a collider environment. This experimental campaign will guide detector designs and operational strategies for the ePIC detector at the future EIC, as well as other applications.

   ↳ physics.ins-dethep-exnucl-exJINST·4 citations
5. 05*

   Background reduction in ${}^{136}$Xe double beta decay experiments through direct barium ion detection

   Álvaro Peralta Conde🇪🇸

   Tagging barium ions in double beta decay experiments involving ${}^{136}$Xe offers a promising pathway to achieving an almost background-free environment, which is essential for addressing key unresolved questions in neutrino physics, such as the nature of neutrinos and their mass hierarchy. In this manuscript, we present a novel detection scheme that relies exclusively on the intrinsic energy levels of the barium ion. This method eliminates the need for additional additives in the xenon vessel, thereby simplifying the experimental setup and enhancing the potential sensitivity of the experiment.

   ↳ physics.atom-phhep-exnucl-exPRA(2025)·1 citation
6. 06*

   First experimental results and optimization study of the portable neutron-gamma imager GN-Vision

   Jorge Lerendegui-Marco🇪🇸 · James Hallam · Gastón Cisterna · Andrea Sanchis-Moltó · Javier Balibrea-Correa · Víctor Babiano · David Calvo · Gabriel de la Fuente🇺🇸 · Bernardo Gameiro🇪🇸 · Ion Ladarescu🇪🇸 · Pablo Torres-Sánchez🇪🇸 · César Domingo-Pardo🇪🇸

   GN-Vision is a compact, dual-modality imaging device designed to simultaneously localize the spatial origin of $\gamma$-ray and slow neutron sources, with potential applications in nuclear safety, security, and hadron therapy. The system utilizes two position-sensitive detection planes, combining Compton imaging techniques for $\gamma$-ray visualization with passive collimation for imaging slow and thermal neutrons (energies below 100 eV). This paper presents the first experimental outcomes from the initial GN-Vision prototype, focused on the development of its neutron imaging capabilities. Following this experimental assessment, we explore the device${}^{\prime }$s performance potential and discuss several Monte Carlo simulation-based optimizations aimed at refining the neutron collimation system. These optimizations seek to improve real-time imaging efficiency and cost-effectiveness, enhancing GN-Vision${}^{\prime }$s applicability for future practical deployments.

   ↳ physics.ins-detnucl-exAppl.Radiat.Isot.(2025)·0 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.