Fri·May 28, 2021Friday·May 28, 2021

1. 01*

   Radioactive ion beam production at the Gamma Factory

   Dragos Nichita🇷🇴 · Dimiter Balabanski🇷🇴 · Paul Constantin🇷🇴 · Witold Krasny🇫🇷 · Wieslaw Placzek🇵🇱

   A very intense gamma beam of the Gamma Factory facility proposed at CERN can be used to generate radioactive ion beams (RIBs) with high production yields and study the structure of exotic neutron-rich nuclei. The radioactive nuclides are generated via photo-fission in several actinide targets and thermalized in high-purity cryogenic helium, filling a gas cell which is enclosing the targets. Electric fields are used to extract heavy ions and form RIBs which can be sent to various selection and measurement stations. Estimates for the production and extraction yields of exotic neutron-rich nuclei with such a setup are provided. A study of the impact of space charge, build-up inside the gas cell, on the extraction properties is presented and it is demonstrated that the beam needs to be chopped for achieving optimal extraction yields.

   nucl-exAnnalen Phys.(2022)·13 citations
2. 02*

   Predictions for flow harmonic distributions and flow factorization ratios at RHIC

   Leonardo Barbosa🇧🇷 · Fernando G. Gardim🇧🇷 · Frédérique Grassi🇧🇷 · Pedro Ishida🇧🇷 · Matthew Luzum🇧🇷 · Meera V. Machado🇩🇰 · Jacquelyn Noronha-Hostler🇺🇸

   Data obtained at RHIC can be reproduced with relativistic viscous hydrodynamic simulations by adjusting the viscosity and initial conditions but it is difficult to disentangle these quantities. It is therefore important to find orthogonal observables to constrain the initial conditions separately from the viscosity. New observables have been measured at the LHC and shown to be sensitive to initial conditions and less to medium properties, specifically factorization breaking ratios appears to be promising. Here we consider two initial condition models, NeXus and TRENTO. While both models yield similar results for the scaled flow harmonic distributions both at the LHC and RHIC, they lead to quantitatively much more different patterns for the factorization breaking ratios at RHIC than at LHC, due to the shorter lifetime. Additionally, not only final state interactions but also initial free streaming matter in these ratio predictions and differences between these are enhanced at RHIC compared to LHC. Therefore experimental factorization breaking ratios at RHIC top energy (for transverse momentum) would be interesting to get.

   ↳ nucl-thnucl-ex13 citations
3. 03*

   Optimization of Timepix3-based conventional Compton camera using electron track algorithm

   Jiaxing Wen🇨🇳 · Xutao Zheng · Huaizhong Gao · Ming Zeng🇨🇳 · Yuge Zhang · Minghai Yu · Yuchi Wu🇩🇪 · Jirong Cang🇨🇳 · Ge Ma · Zongqing Zhao🇨🇳

   The hybrid pixel detector Timepix3 allows the measurement of the time and energy deposition of an event simultaneously in each 55 $\mu$m pixel, which makes Timepix3 a promising approach for a compact Compton camera. However, the angular resolution of Compton camera based on this kind of detector with high pixel density is usually degraded in imaging of MeV gamma-ray sources, because the diffusion of energetic Compton electron or photoelectron could trigger many pixels and lead to an inaccurate measurement of interaction position. In this study, an electron track algorithm is used to reconstruct the electron track and determine the interaction point. An demonstrative experiment was carried out, showing that the effect of this algorithm was significant. The angular resolution measures of a single layer Compton camera based on Timepix3 was enhanced to 12 degrees (FWHM) in imaging of a Co-60 gamma source.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2022)·6 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.