Thu·Jun 23, 2022Thursday·June 23, 2022

1. 01*

   alpha-cluster structure of 18Ne

   M. Barbui🇺🇸 · A. Volya🇺🇸 · E. Aboud🇺🇸 · S. Ahn🇺🇸 · J. Bishop🇺🇸 · V.Z. Goldberg🇺🇸 · J. Hooker🇺🇸 · C.H. Hunt🇺🇸 · H. Jayatissa🇺🇸 · Tz. Kokalova🇬🇧 · E. Koshchiy🇺🇸 · S. Pirrie🇬🇧 and 6 other authors

   In this work we study alpha-clustering in 18Ne and compare it with what is known about clustering in the mirror nucleus 18O. The excitation function of 18Ne was measured in inverse kinematics from the resonant elastic scattering reaction of 14O on 4He in the excitation energy range from 8 to 17 MeV, using the active target TexAT. The analysis was performed using a multi-channel R-matrix approach. Detailed spectroscopic information is obtained from the R-matrix analysis: excitation energy of the states, spin and parity as well as partial alpha and total widths. This information is compared with theoretical models and previous data. Clustering structures appear to be robust and mostly isospin symmetric. A good correspondence was found between the levels in 18O and 18Ne. We carried out an extensive shell model analysis of the experimental data. This comparison suggests that strongly clustered states remain organized in relation to the corresponding reaction channel identified by the number of nodes in the relative alpha plus core wave function. The agreement between theory and experiment is very good and especially useful when it comes to understanding the clustering strength distribution. The comparison of the experimental data with theory shows that certain states, especially at high excitation energies, are significantly more clustered than predicted. This indicates that the structure of these states is collective and is aligned towards the corresponding alpha reaction channel.

   nucl-exnucl-thPRC(2022)·8 citations
2. 02*

   The `n2EDM MSR' -- a very large magnetically shielded room with an exceptional performance for fundamental physics measurements

   N.J. Ayres🇨🇭 · G. Ban🇫🇷 · G. Bison🇨🇭 · K. Bodek🇵🇱 · V. Bondar🇨🇭 · T. Bouillaud🇫🇷 · B. Clement🇫🇷 · E. Chanel🇨🇭 · P.-J. Chiu🇨🇭 · C. B. Crawford🇺🇸 · M. Daum🇨🇭 · C. B. Doorenbos and 32 other authors

   We present the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute which features an interior cubic volume with each side of length 2.92m, thus providing an accessible space of 25m3. The MSR has 87 openings up to 220mm diameter to operate the experimental apparatus inside, and an intermediate space between the layers for sensitive signal processing electronics. The characterization measurements show a remanent magnetic field in the central 1m3 below 100pT, and a field below 600pT in the entire inner volume, up to 4\,cm to the walls. The quasi-static shielding factor at 0.01\,Hz measured with a sinusoidal 2muT peak-to-peak signal is about 100,000 in all three spatial directions and rises fast with frequency to reach 10^8 above 1Hz.

   ↳ physics.ins-dethep-exnucl-exRev.Sci.Instrum.(2022)·18 citations
3. 03*

   Probing high-density nuclear symmetry energy with ${\Xi }^{-}/{\Xi }^0$ ratio in heavy-ion collisions at $\sqrt{s_{NN}}\sim 3$ GeV

   Gao-Chan Yong🇨🇳 · Bao-An Li🇺🇸 · Zhi-Gang Xiao🇨🇳 · Zi-Wei Lin🇺🇸

   Recent beam energy scan (BES) experiments at RHIC by the STAR Collaboration (PLB {\bf 827},137003 (2022) and PRL {\bf 128}, 202303 (2022)) found that hadronic interactions dominate the collective flow and the proton cumulant ratios are driven by baryon number conservation in a region of high baryon density in $\sqrt{s_{NN}}$ = 3 GeV Au+Au reactions, indicating the dense medium formed in such collisions is likely hadronic matter. Within an updated ART (A Relativistic Transport) model with momentum dependent isoscalar and isovector single-nucleon mean-field potentials corresponding to different symmetry energies at suprasaturation densities, the $n/p$, ${\pi }^{-}/{\pi }^{+}$, $K_s^0/K^{+}$, ${\Sigma }^{-}/{\Sigma }^{+}$ and ${\Xi }^{-}/{\Xi }^0$ ratios are studied for central Au+Au collisions at $\sqrt{s_{NN}}$ = 3 GeV where the maximum central density reaches about $(3.6\sim 4.0){\rho }_0$. The doubly strange ${\Xi }^{-}/{\Xi }^0$ ratio is found to have the strongest sensitivity to the variation of high-density nuclear symmetry energy. Thus, the ${\Xi }^{-}/{\Xi }^0$ ratio in relativistic heavy-ion reactions at $\sqrt{s_{NN}}\sim 3$ GeV may help probe sensitively the poorly known symmetry energy of dense neutron-rich matter critically important for understanding various properties of neutron stars.

   ↳ nucl-thastro-ph.HEnucl-exPRC(2022)·31 citations
4. 04*

   Effect of charging-up on the uniformity of a single mask triple GEM detector

   S. Chatterjee🇮🇳 · A. Sen🇮🇳 · S. Das🇮🇳 · S. Biswas🇮🇳

   The Gas Electron Multiplier (GEM) detector is one of the advanced members of the Micro Pattern Gas Detector (MPGD) family, used in High Energy Physics (HEP) experiments as a tracking device due to its high rate handling capability and good spatial resolution. The uniformity in the performance of the detector is an essential criterion for any tracking device. The presence of the dielectric medium (Kapton) inside the active volume of the GEM chamber changes its behaviour when exposed to external irradiation. This phenomenon is known as the charging-up effect. In this article, the uniformity in terms of gain, energy resolution and count rate of a Single Mask (SM) triple GEM chamber of dimension 10 cm $\times$ 10 cm are reported for both the charged-up and uncharged GEM foils.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2023)·8 citations
5. 05*

   Theoretical and experimental study on Noise Equivalent Power of X-ray semiconductor ultra-fast response material based on the rad-optic effect

   Xin Yan · Tao Wang🇨🇳 · Gang Wang🇺🇸 · Dong Yao · Yiheng Liu · Guilong Gao · Liwei Xin · Fei Yin🇨🇳 · Jinshou Tian · Xinlong Chang · Kai He

   Semiconductor material based on the rad-optic effect enables ultra-fast detection of X-rays and plays an important role in fusion diagnostics. Obtaining the accurate noise equivalent power (NEP) of the semiconductor ultrafast response material is the key to detecting X-rays. In this paper, the refractive index change mechanism of the semiconductor under X-ray irradiation was analyzed, and the quantitative relationship between the diffraction efficiency and the X-ray photon energy was established through the LT-AlGaAs diffraction imaging experiments. The impulse responses of LT-AlGaAs under 1 KeV-10 KeV X-ray radiation were calculated, revealing the variation of NEP density with radiated photon energy. In the case of bombarding the Al target to generate 1.5 KeV X-rays, the imaging experiments of LT-AlGaAs were performed. The diffraction image of LT-AlGaAs has a linear relationship with the radiation intensity, and the NEP density of LT-AlGaAs reaches 4.80*105W/cm2. This study has reference significance for the development of ultra-fast X-ray imaging systems based on the rad-optic effect.

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