Thu·Sep 7, 2023Thursday·September 7, 2023

1. 01*

   Surprising charge-radius kink in the Sc isotopes at N=20

   Kristian König🇩🇪 · Stephan Fritzsche🇩🇪 · Gaute Hagen🇺🇸 · Jason D. Holt🇨🇦 · Andrew Klose · Jeremy Lantis🇺🇸 · Yuan Liu🇨🇳 · Kei Minamisono🇺🇸 · Takayuki Miyagi🇩🇪 · Witold Nazarewicz🇺🇸 · Thomas Papenbrock🇺🇸 · Skyy V. Pineda🇧🇪 · Robert Powel🇺🇸 · Paul-Gerhard Reinhard🇩🇪

   Charge radii of neutron deficient 40Sc and 41Sc nuclei were determined using collinear laser spectroscopy. With the new data, the chain of Sc charge radii extends below the neutron magic number N=20 and shows a pronounced kink, generally taken as a signature of a shell closure, but one notably absent in the neighboring Ca, K and Ar isotopic chains. Theoretical models that explain the trend at N=20 for the Ca isotopes cannot reproduce this puzzling behavior.

   nucl-exnucl-thPRL(2023)·32 citations
2. 02*

   Searches for baryon number violation in the HIBEAM-NNBAR experiment at the European Spallation Source

   Bernhard Meirose🇸🇪

   The HIBEAM-NNBAR program is a proposed two-stage experiment at the European Spallation Source (ESS) designed to search for baryon number violation, which is - together with C and CP violation - one of the three fundamental Sakharov conditions to explain the observed baryon asymmetry of the Universe. Taking advantage of the ESS' unique capabilities as the future brightest neutron source, the experiment will make high sensitivity searches for neutrons converting into antineutrons and/or sterile neutrons.

   ↳ physics.ins-dethep-exhep-phnucl-exPoS·0 citations
3. 03*

   Effect of Backing on Neutron Spectra for Low Energy Quasi-Mono-energetic p+${}^7$Li Reaction

   H. Kumawat

   $\underline{\text{MO}}$nte-carlo $\underline{\text{N}}$ucleon transport $\underline{\text{C}}$ode (MONC) for nucleon transport is extended for below 20MeV proton transport using ENDF and EXFOR data base. It is used to simulate p+${}^7$Li reaction upto 20MeV proton energies and produced neutron spectra are reported here. The simulated results are compared with calculated values from other available codes like PINO, EPEN, SimLiT and experimental data. The spectra reported here can be used to get the neutron cross-section for the quasi-mono-energetic neutron reaction and will help to subtract the low energy contribution. The neutron spectra also useful as this reaction is used for accelerator based Boron Neutron Capture Therapy. The backing materials are used to fully stop the proton beam hence contribution from the neutrons from backing materials is estimated. It is found that Tantalum is good backing material below $\sim$8 MeV and Carbon is better at higher energies.

   ↳ nucl-thnucl-exNucl.Sci.Eng.(2025)·2 citations
4. 04*

   Measurement of Charge State Distributions using a Scintillation Screen

   C. Marshall🇺🇸 · Z. Meisel🇺🇸 · F. Montes🇺🇸 · L. Wagner🇨🇦 · K. Hermansen🇺🇸 · R. Garg🇮🇳 · K.A. Chipps🇺🇸 · P. Tsintari · N. Dimitrakopoulos · G.P.A. Berg🇺🇸 · C. Brune🇲🇽 · M. Couder🇺🇸 and 3 other authors

   Absolute cross sections measured using electromagnetic devices to separate and detect heavy recoiling ions need to be corrected for charge state fractions. Accurate prediction of charge state distributions using theoretical models is not always a possibility, especially in energy and mass regions where data is sparse. As such, it is often necessary to measure charge state fractions directly. In this paper we present a novel method of using a scintillation screen along with a CMOS camera to image the charge dispersed beam after a set of magnetic dipoles. A measurement of the charge state distribution for 88Sr passing through a natural carbon foil is performed. Using a Bayesian model to extract statistically meaningful uncertainties from these images, we find agreement between the new method and a more traditional method using Faraday cups. Future work is need to better understand systematic uncertainties. Our technique offers a viable method to measure charge state distributions.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2023)·1 citation

* 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.