Tue·Jan 17, 2023Tuesday·January 17, 2023

1. 01*

   Fundamental limitations of dual energy X-ray scanners for cargo content atomic number discrimination

   Peter Lalor · Areg Danagoulian

   To combat the risk of nuclear smuggling, radiography systems are deployed at ports to scan cargo containers for concealed illicit materials. Dual energy radiography systems enable a rough elemental analysis of cargo containers due to the $Z$-dependence of photon attenuation, allowing for improved material detection. This work studies the capabilities for atomic number discrimination using dual energy MeV systems by considering dual energy $\{6,4\}$ MeV, $\{10,6\}$ MeV, and $\{10,4\}$ MeV bremsstrahlung beams. Results of this analysis show that two different pure materials can sometimes produce identical transparency measurements, leading to a fundamental ambiguity when differentiating between materials of different atomic numbers. Previous literature has observed this property, but the extent of the limitation is poorly understood and the cause of the degeneracy is generally inadequately explained. This non-uniqueness property stems from competition between photoelectric absorption and pair production and is present even in systems with perfect resolution and zero statistical noise. These findings are validated through Monte Carlo transparency simulations. Results of this study show that currently deployed commercial radiographic systems are fundamentally incapable of distinguishing between high-$Z$ nuclear materials and miscellaneous mid-$Z$ cargo contents.

   nucl-exAppl.Radiat.Isot.(2024)·4 citations
2. 02*

   Production of hydrogen isotopes and charged pions in p (3.5 GeV) + Nb reactions

   R. Abou Yassine🇩🇪 · O. Arnold🇩🇪 · M. Becker🇩🇪 · P. Bergmann🇩🇪 · A. Blanco🇵🇹 · C. Blume🇩🇪 · M. Böhmer🇩🇪 · N. Carolino🇵🇹 · L. Chlad🇨🇿 · P. Chudoba🇨🇿 · I. Ciepał🇵🇱 · J. Dreyer🇩🇪 and 76 other authors

   The double differential production cross sections, $d^2\sigma /d\Omega dE$, for hydrogen isotopes and charged pions in the reaction of p + Nb at 3.5 GeV proton beam energy have been measured by the High Acceptance DiElectron Spectrometer (HADES). Thanks to the high acceptance of HADES at forward emission angles and usage of its magnetic field, the measured energy range of hydrogen isotopes could be significantly extended in comparison to the relatively scarce experimental data available in the literature. The data provide information about the development of the intranuclear cascade in the proton-nucleus collisions. They can as well be utilized to study the rate of energy/momentum dissipation in the nuclear systems and the mechanism of elementary and composite particle production in excited nuclear matter at normal density. Data of this type are important also for technological and medical applications. Our results are compared to models developed to describe the processes relevant to nuclear spallation (INCL++) or oriented to probe either the elementary hadronic processes in nuclear matter or the behavior of compressed nuclear matter (GiBUU).

   nucl-exPRC(2023)·2 citations
3. 03*

   Machine learning in nuclear physics at low and intermediate energies

   Wanbing He🇨🇳 · Qingfeng Li🇨🇳 · Yugang Ma🇨🇳 · Zhongming Niu🇨🇳 · Junchen Pei🇨🇳 · Yingxun Zhang🇨🇳

   Machine learning is becoming a new paradigm for scientific research in various research fields due to its exciting and powerful capability of modeling tools used for big-data processing task. In this mini-review, we first briefly introduce different methodologies of the machine learning algorithms and techniques. As a snapshot of many applications by machine learning, some selected applications are presented especially for low and intermediate energy nuclear physics, which include topics on theoretical applications in nuclear structure, nuclear reactions, properties of nuclear matter as well as experimental applications in event identification/reconstruction, complex system control and firmware performance. Finally, we also give a brief summary and outlook on the possible directions of using machine learning in low-intermediate energy nuclear physics and possible improvements in ML algorithms.

   ↳ nucl-thnucl-exSCPMA(2023)·109 citations
4. 04*

   Effective field theory analysis of the Coulomb breakup of the one-neutron halo nucleus 19C

   Pierre Capel🇩🇪 · Daniel R. Phillips🇺🇸 · Andrew Andis🇺🇸 · Mirko Bagnarol🇮🇱 · Behnaz Behzadmoghaddam🇮🇷 · Francesca Bonaiti🇩🇪 · Rishabh Bubna🇩🇪 · Ylenia Capitani🇮🇹 · Pierre-Yves Duerinck🇧🇪 · Victoria Durant🇩🇪 · Niklas Döpper🇩🇪 · Aya El Boustani🇪🇸 and 20 other authors

   We analyse the Coulomb breakup of 19C measured at 67A MeV at RIKEN. We use the Coulomb-Corrected Eikonal (CCE) approximation to model the reaction and describe the one-neutron halo nucleus 19C within Halo Effective Field Theory (EFT). At leading order we obtain a fair reproduction of the measured cross section as a function of energy and angle. The description is insensitive to the choice of optical potential, as long as it accurately represents the size of 18C. It is also insensitive to the interior of the 19C wave function. Comparison between theory and experiment thus enables us to infer asymptotic properties of the ground state of 19C: these data put constraints on the one-neutron separation energy of this nucleus and, for a given binding energy, can be used to extract an asymptotic normalisation coefficient (ANC). These results are confirmed by CCE calculations employing next-to-leading order Halo EFT descriptions of 19C: at this order the results for the Coulomb breakup cross section are completely insensitive to the choice of the regulator. Accordingly, this reaction can be used to constrain the one-neutron separation energy and ANC of 19C.

   ↳ nucl-thnucl-exEPJA(2023)·5 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.