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Configurational information entropy (CIE) theory was employed to determine the neutron skin thickness of neutron-rich calcium isotopes. The nuclear density distributions and fragment cross-sections in 350 MeV/u $^{40-60}$Ca + $^{9}$Be projectile fragmentation reactions were calculated using a modified statistical abrasion-ablation model. CIE quantities were determined from the nuclear density, isotopic, mass, and charge distributions. The linear correlations between the CIE determined using the isotopic, mass, and charge distributions and the neutron skin thickness of the projectile nucleus show that CIE provides new methods to extract the neutron skin thickness of neutron-rich nuclei., Comment: 7 pages, 5 figures

Two-body correlations of the isotope-resolved light and heavy clusters are measured in $^{86}$Kr+$^{\rm 208}$Pb reactions at 25 MeV/u. The yield and kinetic variables of the $A=3$ isobars, triton and $^3$He, are analyzed in coincidence with the heavy clusters of $7\le A \le 14$ emitted at the earlier chance. While the velocity spectra of both triton and $^3$He exhibit scaling behavior over the type of the heavy clusters, the yield ratios of ${\rm t/^3He}$ correlate reversely to the neutron-to-proton ratio $N/Z$ of the latter, showing the ping-pong modality of the $N/Z$ of emitted clusters. The commonality that the $N/Z$ of the residues keeps the initial system value is extended to the cluster emission in heavy ion reactions. The comparison of transport model calculations to the data is discussed.

The mass dependence of the transverse flow for $Z=1$--5 fragments from the collisions of $^{40}\mathrm{Ar}+^{27}\mathrm{Al}, ^{40}\mathrm{Ar}+^{48}\mathrm{Ti}$, and $^{40}\mathrm{Ar}+^{58}\mathrm{Ni}$ at 47 MeV/nucleon is investigated experimentally in this article. The transverse flow values are determined using the in-plane components of the fragment transverse momenta, where three conventional methods, i.e., the kinetic flow tensor method, the transverse momentum analysis method, and the azimuthal correlation method, are applied to reconstruct the reaction plane in an event-by-event basis. It is demonstrated from the comparison of the present experimental mass dependent flow measurements and the model simulations using an improved antisymmetrized molecular dynamics model that the experimentally observed abnormal $\ensuremath{\alpha}$ transverse flow enhancement is closely related to the reaction plane reconstruction procedure in the flow extraction. We further investigate the physical existence of the abnormal $\ensuremath{\alpha}$ flow behavior using a two-particle azimuthal correlation method, which allows us to provide the relative flow magnitude information with an identification of fragment charge number without the knowledge of the reaction plane differing from the three conventional methods. It is found that the relative flow magnitudes deduced from the two-particle azimuthal correlation functions with an identification of $Z$, with the correction for the recoil effect imposed by the momentum conservation, show a monotonically increasing trend as a function of fragment charge number, with no exception of the $\ensuremath{\alpha}$ flow enhancement. These results, in addition to those from the improved antisymmetrized molecular dynamics model simulations, definitely provide experimental evidences for the inexistence of the abnormal $\ensuremath{\alpha}$ flow behavior in the heavy-ion collisions at the present incident energy region in nature.

The neutron capture cross section of $$^{197}\hbox {Au}$$ was measured using the time-of-flight (TOF) technique at the Back-n facility of the China Spallation Neutron Source (CSNS) in the 1 eV to 100 keV range. Prompt $$\gamma $$ -rays originating from neutron-induced capture events were detected by four C $$_{6}$$ D $$_{6}$$ liquid scintillator detectors. Pulse height weighting technology (PHWT) was used to analyze the data. The results are in good agreement with ENDF/B-VIII.0, CENDL-3.1, and other evaluated libraries in the resonance region, and in agreement with both n $$\_$$ TOF and GELINA experimental data in the 5–100 keV range. Finally, the resonance peaks in the energy range from 1 eV to 1 keV were fitted by the SAMMY R-matrix code.

The experimentally observed abnormal $\ensuremath{\alpha}$ flow behavior from heavy-ion collisions at intermediate energies is investigated using the events of $^{40}\mathrm{Ca}+^{40}\mathrm{Ca}$ at 35 MeV/nucleon simulated with an improved antisymmetrized molecular dynamics model with specific consideration of the Fermi motion in the nucleon-nucleon collision process. Its possible origins in the processes from the fragment formation to the experimental flow extraction, i.e., dynamical process, sequential decay, experimental detection, and data analysis, are closely examined. It is found that the observed abnormal $\ensuremath{\alpha}$ flow behavior originates from the reconstruction of reaction planes in the flow extraction. How the abnormal $\ensuremath{\alpha}$ flow behavior is generated from the reaction plane reconstruction procedure is discussed.

The 74Se is one of 35 p-nuclei, and 82Se is a r-process only nucleus, and their (n, γ) cross sections are vital input parameters for nuclear astrophysics reaction network calculations. The neutron capture cross section in the resonance range of isotopes and even natural selenium samples has not been measured. Prompt γ-rays originating from neutron-induced capture events were detected by four C6D6 liquid scintillator detectors at the Back-n facility of China Spallation Neutron Source (CSNS). The pulse height weighting technique (PHWT) was used to analyze the data in the 1 eV to 100 keV region. The deduced neutron capture cross section was compared with ENDF/B-VIII.0, JEFF-3.2, and JENDL-4.0, and some differences were found. Resonance parameters were extracted by the R-matrix code SAMMY in the 1 eV–1 keV region. All the cross sections of natSe and resonance parameters are given in the datasets. The datasets are openly available at http://www.doi.org/10.11922/sciencedb.j00113.00019.

Machine learning models are constructed to predict fragment production cross sections in projectile fragmentation (PF) reactions using Bayesian neural network (BNN) techniques. The massive learning for BNN models is based on 6393 fragments from 53 measured projectile fragmentation reactions. A direct BNN model and physical guiding BNN via FRACS parametrization (BNN + FRACS) model have been constructed to predict the fragment cross section in projectile fragmentation reactions. It is verified that the BNN and BNN + FRACS models can reproduce a wide range of fragment productions in PF reactions with incident energies from 40 MeV/u to 1 GeV/u, reaction systems with projectile nuclei from 40Ar to 208Pb, and various target nuclei. The high precision of the BNN and BNN + FRACS models makes them applicable for the low production rate of extremely rare isotopes in future PF reactions with large projectile nucleus asymmetry in the new generation of radioactive nuclear beam factories.

The Bayesian neural network (BNN) method is used to construct a predictive model for fragment prediction of proton induced spallation reactions with the guidance of a simplified EPAX formula. Compared to the experimental data, it is found that the BNN + sEPAX model can reasonably extrapolate with less information compared with BNN method. The BNN + sEPAX method provides a new approach to predict the energy-dependent residual cross sections produced in proton-induced spallation reactions from tens of MeV/u up to several GeV/u., Comment: 9 pages, 1 table, and 7 figures

We propose a hybrid approach between the sudden model and the adiabatic model to explain the fusion hindrance in heavy-ion fusion reactions at deep subbarrier energies. Due to the strong Pauli blocking effects at the density overlap region, the $\ensuremath{\alpha}$ particle approaching the target $^{208}\mathrm{Pb}$ becomes enlarged and its density distribution gets changed. By introducing energy dependence into this density variation effect, the potentials at different colliding energies are diverse. With the decrease of colliding energies, the significantly enhanced density variation effects make the nuclear potential more attractive and result in a deeper pocket in the inner part. A reasonable description of the experimental fusion cross sections is achieved for the $\ensuremath{\alpha} + ^{208}\mathrm{Pb}$ reaction. On account of highlighting the influence of density variation effects on the fusion process at deep subbarrier energies, we further investigate the density variation effects in the $^{16}\mathrm{O} + ^{208}\mathrm{Pb}$ fusion reaction based on the $\ensuremath{\alpha}$-cluster structures in $^{16}\mathrm{O}$ nuclei. The fusion hindrance at deep subbarrier energies is described well by considering the density variation effects. In addition, an astrophysical $S$ factor between the sudden model and adiabatic model is predicted at the energies below the experimental data.

Anisotropic flow can offer significant information of evolution dynamics in heavy-ion collisions. A systematic study of the directed flow $v_1$ and elliptic flow $v_2$ of hard photons and free nucleons is performed for $^{40}$Ca+$^{40}$Ca collisions in a framework of isospin dependent quantum molecular dynamics (IQMD) model. The study firstly reveals that thermal photons emitted in intermediate-energy heavy-ion collisions have the behaviors of directed and elliptic flows. The interesting phenomena of incident energy dependence of $v_1$ and $v_2$ for thermal photons in central collisions also confirmed that it can be regarded as a good probe of evolution dynamics. Moreover, the multiplicities of hard photons and free nucleons and their correlation are also investigated. We find that direct photon emission is positively related to free nucleons emission, however, there exists an anti-correlation for thermal photons with free nucleons., 9 pages, 10 figures

Silver indium cadmium (Ag–In–Cd) control rod is widely used in pressurized water reactor nuclear power plants, and it is continuously consumed in a high neutron flux environment. The mass ratio of 107Ag in the Ag–In–Cd control rod is 41.44%. To accurately calculate the consumption value of the control rod, a reliable neutron reaction cross section of the 107Ag is required. Meanwhile, 107Ag is also an important weak r nucleus. Thus, the cross sections for neutron induced interactions with 107Ag are very important both in nuclear energy and nuclear astrophysics. The (n, γ) cross section of 107Ag has been measured in the energy range of 1–60 eV using a back streaming white neutron beam line at China spallation neutron source. The resonance parameters are extracted by an R-matrix code. All the cross section of 107Ag and resonance parameters are given in this paper as datasets. The datasets are openly available at http://www.doi.org/10.11922/sciencedb.j00113.00010.

In this study, the Pauli blocking potential between two colliding nuclei in the density overlapping region is applied to describe the heavy nuclei fusion process. Inspired by the Pauli blocking effect in the -decay of heavy nuclei, the Pauli blocking potential of single nucleon from the surrounding matter is obtained. In fusion reactions with strong density overlap, the Pauli blocking potential between the projectile and target can be constructed using a single folding model. By considering this potential, the double folding model with a new parameter set is employed to analyze the fusion processes of 95 systems. A wider Coulomb barrier and shallower potential pocket are formed in the inner part of the potential between the two colliding nuclei, compared to that calculated using the Akyüz-Winther potential. The fusion hindrance phenomena at deep sub-barrier energies are described well for fusion systems O + Pb and Ni + Ni.

Theoretical prediction shows that about 9000 nuclei could be bounded, of which the properties will be hot topics in the new nuclear physics era opened by the new third generation of radioactive nuclear beam (RNB) facilities. Projectile fragmentation reactions are important to produce rare nuclei with extreme large N / Z asymmetry even to the drip lines. Variety of key questions in nuclear physics, for example, the nuclear Equation of State, the extreme of nuclides at drip lines, the shell evolution, etc, are hoped to be answered. A review is presented on the topic related to projectile fragmentation reactions, including the historical review of RNB facilities, the characteristics of modern RNB facilities, the particle identification techniques for searching rare isotopes in RNB experiments and benchmark projectile fragmentation reactions. Furthermore, the theory reviews for fragment production predictions are also made, which include the empirical formula, transport models, statistical models, machine learning methods, etc. Some important probes to nuclear properties have also been presented, which are the temperature/thermometer, the isoscaling, the isobaric ratio difference scaling, the neutron-skin thickness, etc.

A Compact Spectrometer for Heavy IoN Experiments (CSHINE) has been recently built for the studies of heavy ion reactions at intermediate energies. CSHINE consists of a Si-Si-CsI telescope array and a parallel plate avalanche counter (PPAC) array. Each telescope consists of a thin single-sided silicon strip detector and a thick double-sided silicon strip detector backed by a 3 × 3 CsI(Tl) crystal hodoscope . The thicknesses of the silicon detectors are optimized in order to identify various types of light charged particles in a wide energy range. PPAC is a large-area two-dimensional position-sensitive gas detector, which records fission fragments with the intrinsic efficiency of approximately 100% but filters out light charged particles at properly selected working conditions. In the phase-II run, four Si-Si-CsI telescopes and three PPACs have been installed and operated in the beam experiment with 25 MeV/u Kr+Pb reactions. Particle identification for isotopes from Hydrogen to Boron has been achieved with the Si-Si-CsI telescopes, while excellent timing and position resolution have been achieved with the PPACs.

Fragments productions in spallation reactions are key infrastructure data for various applications. Based on the empirical parameterizations {\sc spacs}, a Bayesian-neural-network (BNN) approach is established to predict the fragment cross sections in the proton induced spallation reactions. A systematic investigation have been performed for the measured proton induced spallation reactions of systems ranging from the intermediate to the heavy nuclei and the incident energy ranging from 168 MeV/u to 1500 MeV/u. By learning the residuals between the experimental measurements and the {\sc spacs} predictions, the BNN predicted results are in good agreement with the measured results. The established method is suggested to benefit the related researches in the nuclear astrophysics, nuclear radioactive beam source, accelerator driven systems, and proton therapy, etc., Comment: 7 figures, accepted by Chinese Physics C

A scaling phenomenon has been found for the cross section of a fragment, which is defined as a “square” cross section (SCS). This phenomenon can unify the cross sections of fragments in projectile fragmentation (PF) reactions. An empirical formula is proposed to calculate SCS for a fragment with parameters determined by an extensive investigation of measured reactions ranging from Fermi energies to relativistic energies. The scaling phenomenon of SCS has been verified using different techniques, showing that the scaling of SCS generally exists in PF reactions. The concept of SCS, which can be assumed as a standard value for a fragment, is shown to accurately predict the cross sections of isotopes in PF reactions with incident energies ranging from tens of A MeV to approximately 1000A MeV.

An isoratio method is proposed to study the chemical potential of neutrons (protons) from the yield ratio of isotopes (isotones) differing in neutron-excess (I = N − Z). The measured fragments in the 140 A MeV 40,48Ca and 58,64Ni + 9Be reactions, as well as those in the simulated 58,64Ni + 9Be reactions by using the antisymmetric molecular dynamics (AMD) model plus the secondary decay model gemini, have been adopted to perform the isoratio analysis. The results of the isoratio method verify that they are similar to that of the well known isoscaling method. The isoratio scaling phenomenon suggested by the isoratio method has also been found in the measured data and the fragments simulated by the AMD + gemini models.

An isoratio method, i.e., the isotopic (isotonic) ratio among three isotopes (isotones), is proposed to study the free energy and temperature effects in the intermediate mass fragments produced in heavy-ion collisions. The parameterizations for the free energy of nucleus at low temperature, which have been proposed in the framework of the density functional theory using the SKM skymre interaction, are adopted to calculate the temperature-dependent free energy of fragment. By analyzing the measured yields of fragments in the 140A MeV 58,64Ni + 9Be reactions, it is verified that the free energy in the isoratio is almost the same for different reactions. A temperature-dependent pairing-energy is introduced into the parameterizations for free energy, which reveals that the weakened pairing energy at the low temperature accounts for the weakened or disappearing odd-even staggering in isoratio.

Complementary metal-oxide-semiconductor (CMOS) sensors can convert X-rays into detectable signals; therefore, they are powerful tools in X-ray detection applications. Herein, we explore the physics behind X-ray detection performed using CMOS sensors. X-ray measurements were obtained using a simulated positioner based on a CMOS sensor, while the X-ray energy was modified by changing the voltage, current, and radiation time. A monitoring control unit collected video data of the detected X-rays. The video images were framed and filtered to detect the effective pixel points (radiation spots). The histograms of the images prove there is a linear relationship between the pixel points and X-ray energy. The relationships between the image pixel points, voltage, and current were quantified, and the resultant correlations were observed to obey some physical laws.

A new method is proposed to determine the binding energy ($B$) of near proton-drip line isotopes from isotopic cross section distribution. To determine $B$ of $Z~=$ 22-28 isotopes (with $T_{z}=-$2 and $-$5/2), the lack of cross sections for proton-rich isotopes in the 345$A$ MeV $^{78}$Kr + $^9$Be is overcome by predicting the proton-rich isotopes from a newly discovered scaling phenomenon found in the proton-rich isotopes measured in the 140$A$ MeV $^{40,~48}$Ca($^{58,~64}$Ni) + $^9$Be reactions. The cross sections for proton-rich isotopes are verified to exponentially depend on the average binding energy per nucleon, based on which $B$ of the $Z~$=22-28 isotopes with $T_{z}=~-$2 and $-$5/2 are determined from cross sections. The determined $B$ of the isotopes are justified from obeying the scaling phenomenon of the difference between the mass of mirror nuclei. The cross sections for the $Z~=$ 22-28 isotopes with $T_{z}=~-$1 and $-$3/2, which in potential can be experimentally studied in mass storage ring, are also predicted.

The production of $\ensuremath{\alpha}$-particle decaying heavy nuclei in reactions of 7.5--6.1 MeV/nucleon $^{238}\mathrm{U}$ +$^{232}\mathrm{Th}$ was explored using an in-beam detection array composed of YAP scintillators and gas ionization chamber-Si telescopes. Comparisons of $\ensuremath{\alpha}$ energies and half-lives for the observed products with those of the previously known isotopes and with theoretically predicted values indicate the observation of a number of previously unreported $\ensuremath{\alpha}$ emitters. $\ensuremath{\alpha}$-particle decay energies reaching as high as 12 MeV are observed. Many of these are expected to be from decay of previously unseen relatively neutron rich products. While the contributions of isomeric states require further exploration and specific isotope identifications need to be made, the production of heavy isotopes with quite high atomic numbers is suggested by the data.

Because the properties of the QCD phase transition and the chiral magnetic effect (CME) depend on the number of quark flavors ($N_{f}$) and quark mass, relativistic heavy-ion collisions provide a natural environment to investigate the flavor features if quark deconfinement occurs. We introduce an initial two-flavor or three-flavor dipole charge separation into a multiphase transport (AMPT) model to investigate the flavor dependence of the CME. By taking advantage of the recent ALICE data of charge azimuthal correlations with identified hadrons, we attempt to disentangle two-flavor and three-flavor CME scenarios in Pb+Pb collisions at 2.76 TeV. We find that the experimental data show a certain potential to distinguish the two scenarios, therefore we further suggest to collect more data to clarify the possible flavor dependence in future experiments., 12 pages, 4 figures; final published version

Neutron-induced reactions on Al-27 and F-19 nuclei are investigated using the optical model implemented in the TALYS 1.4 toolkit. Incident neutron energies in a wide range from 0.1 key to 30 MeV are calculated. The cross sections for the main channels (n, np), (n, p), (n, alpha), (n, 2n), and (n, gamma) and the total reaction cross section (n, tot) of the reactions are obtained. When the default parameters in TALYS 1.4 are adopted, the calculated results agree with the measured results. Based on the calculated results for the n + Al-27 and n + F-19 reactions, the results of the n + Al-27 F-19 reactions are predicted. These results are useful both for the design of thorium-based molten salt reactors and for neutron activation analysis techniques. (C) 2015 Elsevier B.V. All rights reserved.

We propose a system for remote measurement of low-energy radiation, which is implemented using an ARM board and a ZigBee module. The ARM STM32F103 board employs a horizontal and vertical moving CMOS camera for front-end data acquisition. The camera can detect radiation over different coordinates given by latitude and longitude in a determined area. For image processing, we used the subtraction–summation algorithm based on gradient multiplication and edge detection. Compared to algorithms such as the max grayscale value, subtraction–summation, and whole summation, the improved subtraction–summation algorithm filters noise and removes the background grayscale value of the whole image to attain higher accuracy, stronger anti-interference ability, and better consistency to determine the radiation dose. We dedicated one port of the transmission module to send data through the STM32F103 board, whereas another port is connected to the ZigBee module for data reception. By employing this architecture, we achieved low power consumption and fast response in the remote data transmission. Overall, the proposed system performs the remote measurement of low-energy radiation with stability and reliability, which is required for critical scenarios such as the remote detection of nuclear radiation.

A setup based on CMOS sensor and ARM microcontroller is designed to measure the γ-rays. STM32F103 is used as the main platform to control real-time online analysis of the image collected by the OV7670 CAMERACHIP™ and send the image into the LCD at the desired frame rate. Accuracy of sampling interval can be regulated and controlled. The frame number of image is adjusted by STM32F103 to achieve better monitoring. Two methods are adopted to analyze the image data from the CMOS sensor. Although the CMOS sensor is of low efficiency for γ-ray detection, the results show that it is able to discriminate the 60Co γ-rays.

The deformation evolution of giant dipole resonance (GDR), in the chains of Sm and Nd isotopes, are investigated in the framework of an extended quantum molecular dynamics (EQMD) model. The mass number dependence of resonance peak position (Em) in the major and minor axis directions of deformed nuclei as well as the difference Delta E-m between them are described in detail. The correlation between the splitting (Delta E-m/(E) over bar (m)) of the GDR spectra and the deformation (beta(2)) is further studied. The results confirm that Delta Em/(E) over barE(m) is proportional to beta(2). By comparing the calculation with the experimental data on photon absorption cross section sigma(gamma), it shows that the EQMD model can quite well reproduce the shape of GDR spectra from spherical to prolate shape. The GDR shapes in Sm-134, Sm-136, Sm-138, Nd-130, Nd-132, and Nd-134 are also predicted. In addition, the symmetry energy coefficient (E-sym) dependence of GDR spectra of Nd-150 is also discussed. It is found that the calculated GDR spectrum in the EQMD model is perfectly consistent with the experimental results when Esym equals 32 MeV.

The drift of the isospin degree of freedom (IDOF) is experimentally visualized through the wide-range angular distribution and the beam energy dependence of the isospin composition of light charged particles (LCP) produced in heavy ion collisions. It is evidenced that the net isospin transport is presented in the whole process from early dynamic emission to the statistical evaporation lasting to very late stage. Due to the long-time accumulation of the isospin effect, the angular distribution of the relative neutron excess summing over the LCPs is utilized as a sensitive probe to the symmetry energy. With S fixed at 28.3 MeV, a soft density dependence with L=33–61 MeV (0.95 confidential level) at ρ0 is circumstantially deduced using an improved quantum molecular dynamics transport model attached with a statistical emission afterburner.

A symmetrical wedge-to-wedge THz hybrid SPPs waveguide (WWTHSW) with low propagation loss is investigated. The WWTHSW consists of two identical dielectric wedge waveguides symmetrically placed on each side of a micro wedge-patterned thin metal film. The mode characteristics of the WWTHSW, such as the propagation length (Lp), the normalized effective mode area (A) and the figure of merit (FOM) are analyzed by using the finite element method (FEM). Firstly, the influences of the height of Si micro wedge waveguide (H) and the gap between two wedges (g) on Lp and A are studied. For the same g, A first decreases and then increases with the increase of H. A achieves a minimum at an H of ~40 μm. However, Lp monotonically increases as H increases. The change of Lp slows down when H is greater than 40 μm. At a fixed H, Lp slightly increases with the increase of g. But A achieves a minimum when g is ~50 nm. Secondly, the dependencies of the mode characteristics of the WWTHSW on Si wedge tip angle (α) and Ag wedge tip angle (θ) are analyzed. At a fixed α, θ has less effect on Lp and A. As α increases at a fixed θ, Lp increases monotonically but A decreases firstly and then increases. A reaches a minimum when α increases to ~100°. Then, the change of Lp and A with the thicknesses of Ag film (d) and Ag wedge (h) are demonstrated. At a fixed h, both Lp and A slightly decrease as d increases. For the same d, Lp and A decrease with the increase of h. A for h = 0 μm is distinctly larger than those for h = 2 μm and h = 5 μm. According to the above optimizations, the parameters of the WWTHSW are chosen as d = 100 nm, g = 50 nm, h = 2 μm, θ = 80°, α = 100°, H = 40 μm. Under the optimal parameters, Lp of ~51 mm is obtained when Am reaches ~λ2/10280. Compared with the previous hybrid THz plasmonic waveguide, Lp of the WWTHSW increases by 3 times, and A decreases by an order of magnitude. This result reveals that the WWTHSW enables low-loss propagation and ultra-deep-subwavelength mode confinement at THz frequencies. At last, the coupling property of the parallel WWTHSW is investigated. The coupling length of ~8958 μm is achieved without the crosstalk between two parallel waveguides. By comparison, the WWTHSW has more advantages in terms of transmission and coupling characteristics than the previous micro wedge waveguide structure and bow-tie waveguide structure. In summary, due to the excellent transmission and coupling characteristics, the WWTHSW has great potential in the fields of optical force in trapping, biomolecules transporting, and in high-density integrated circuits design.

The Bayesian neural network (BNN) method is proposed to predict the isotopic cross-sections in proton induced spallation reactions. Learning from more than 4000 data sets of isotopic cross-sections from 19 experimental measurements and 5 theoretical predictions with the SPACS parametrization, in which the mass of the spallation system ranges from 36 to 238, and the incident energy from 200 MeV/u to 1500 MeV/u, it is demonstrated that the BNN method can provide good predictions of the residue fragment cross-sections in spallation reactions.

The isoscaling and the isobaric yield ratio difference (IBD) probes, which both are constructed by yield ratio of fragment, provide cancelation of parameters. The information entropy theory is introduced to explain the physical meaning of the isoscaling and IBD probes. The similarity between the isoscaling and IBD results is found, i.e., the information uncertainty determined by the IBD method equals to $\beta-\alpha$ determined by the isoscaling [$\alpha$ ($\beta$) is the parameter fitted from the isotopic (isotonic) yield ratio]., Comment: accepted by Communications in Theoretical Physics

Despite the widespread use of silica nanoparticles (SiO2 NPs) in biological and medical fields, their adverse effects have not been clearly elucidated. In this study, spherical SiO2 NPs with a 50 nm diameter were used to study their interaction with HaCaT cells. SiO2 NPs were found to be readily internalized into HaCaT cells and localized in the cytoplasm, lysosomes and autophagosomes. Decreased cell viability and damaged cell membrane integrity showed the cytotoxicity of SiO2 NPs. Significant glutathione depletion and reactive oxygen species generation, which reduced the cellular antioxidant level, could be the major factor of cytotoxicity induced by SiO2 NPs. Copyright (c) 2013 John Wiley & Sons, Ltd.

Background: The isobaric ratio difference scaling phenomenon, which has been found for the fragments produced in projectile fragmentation reactions, is related to the nuclear density change in reaction systems.Purpose: To verify whether the isobaric ratio difference scaling exists in the fragments produced in the spallation and fission reactions.Methods: The isobaric ratio difference scaling, denoted by ${S}_{\mathrm{\ensuremath{\Delta}}ln{R}_{21}}$, is in theory deduced within the framework of the canonical ensemble theory at the grand-canonical limitation. The fragments measured in a series of projectile fragmentation, spallation, and fission reactions have been analyzed.Results: A good ${S}_{\mathrm{\ensuremath{\Delta}}ln{R}_{21}}$ scaling phenomenon is shown for the fragments produced both in the projectile fragmentation reactions and in the spallation reactions, whereas the ${S}_{\mathrm{\ensuremath{\Delta}}ln{R}_{21}}$ scaling phenomenon for the fragments in the fission reaction is less obvious.Conclusions: The ${S}_{\mathrm{\ensuremath{\Delta}}ln{R}_{21}}$ scaling is used to probe the properties of the equilibrium system at the time of fragment formation. The good scaling of ${S}_{\mathrm{\ensuremath{\Delta}}ln{R}_{21}}$ suggests that the equilibrium state can be achieved in the projectile fragmentation and spallation reactions. Whereas in the fission reaction, the result of ${S}_{\mathrm{\ensuremath{\Delta}}ln{R}_{21}}$ indicates that the equilibrium of the system is hard to achieve.

An improved thermometer (T IB) is proposed for intermediate-mass fragments via the difference between isobaric yield ratios. The residual free energy of three isobars is replaced by that of the binding energy. The measured fragments in the 140A MeV 40, 48Ca + 9Be (181Ta) and 58, 64Ni + 9Be (181Ta) reactions are analyzed to obtain T IB ranging from 0.6 to 3.5 MeV. T IB is suggested to be a direct determination of temperature avoiding the fitting procedure.

The primary fragments in 40Ca + 40Ca reactions at 35, 50, 80, 100, 140, and 300 MeV/u were simulated using the antisymmetrized molecular dynamics model, in the phase space at t = 300 fm/c with a coalescence radius R c = 5 fm. The standard Gogny interactions g0, g0as, and g0ass were adopted in simulating the collisions at an impact parameter of b = 0 fm. It was found, using an isobaric yield ratio method, that temperature of the primary fragment depends on the incident energy and hardness of the interaction potential. The temperature obtained in this work agrees with the results by the self-consistent fitting method.

The pairing energy (${E}_{p}$) of fragments, which is assumed to have a finite temperature in heavy-ion collisions, is obtained using an isobaric yield ratio method in the framework of a modified Fisher model. The fragments in the measured and simulated $140A$ MeV $^{40,48}\mathrm{Ca}+\phantom{\rule{0.16em}{0ex}}^{9}\mathrm{Be}/^{181}\mathrm{Ta}$ and $^{58,64}\mathrm{Ni}+\phantom{\rule{0.16em}{0ex}}^{9}\mathrm{Be}/^{181}\mathrm{Ta}$ reactions have been adopted to perform the analysis. The results show that the ratio of the pairing-energy coefficient to the temperature (${a}_{p}/T$) is not significantly influenced by the reaction system, but depends on the neutron excess $(I=N\ensuremath{-}Z)$ of the fragment. For most fragments, ${a}_{p}/T$ falls in the range of $\ensuremath{-}1.0l{a}_{p}/Tl1.0$. Assuming $T\ensuremath{\approx}2.0$ MeV for the intermediate-mass fragments, ${a}_{p}\ensuremath{\sim}2.0$ MeV is suggested, which is much smaller than the value in the semiclassical mass formula. For a neutron-rich fragment, ${E}_{p}$ may disappear. The results are confirmed by the calculated ${E}_{p}$ of some $A=34$ isobars using the self-consistent finite-temperature relativistic Hartree-Bogoliubov model with the effective interaction PC-PK1 and the Gogny-pairing interaction D1S. The calculated ${E}_{p}$ depends on $T$ in the form of $y=Cexp(\ensuremath{-}a{T}^{4})$ and ${E}_{p}$ goes to zero fast with temperatures at around $T=0.8$ MeV. The results are useful for improving the secondary decay simulation for primary fragments in the heavy-ion collisions.

We have calculated the cross sections of the fragments produced in the projectile fragmentation of the even 36–52 Ca isotopes using the statistical abrasion-ablation model. The isospin effect in the projectile fragmentation are studied by investigating the peak positions and the widths of the fragment isotopic cross section distributions. The peak positions of the fragments isotopic cross section distributions have good linear correlation to the Z of the fragments and the correlations are fitted using the linear function. The correlations between slopes b and the binding energies of the neutron ( S n) of the projectile nuclei, the differences between the binding energies of the neutron and proton( S n- S p) of the projectile nuclei and the neutron-skin thickness (δnp) are studied. It is found that b and δnp has a good linear correlation for the neutron-rich projectile nuclei.

The ratio of pairing-energy coefficient to temperature ($a_{p}/T$) of neutron-rich fragments produced in spallation reactions has been investigated by adopting an isobaric yield ratio method deduced in the framework of a modified Fisher model. A series of spallation reactions, 0.5$A$ and 1$A$ GeV $^{208}$Pb + $p$, 1$A$ GeV $^{238}$U + $p$, 0.5$A$ GeV $^{136}$Xe + $d$, 0.2$A$, 0.5$A$ and 1$A$ GeV $^{136}$Xe + $p$, and $^{56}$Fe + $p$ with incident energy ranging from 0.3$A$ to 1.5$A$ GeV, has been analysed. An obvious odd-even staggering is shown in the fragments with small neutron excess ($I\equiv N - Z$), and in the relatively small-$A$ fragments which have large $I$. The values of $a_{p}/T$ for the fragments, with $I$ from 0 to 36, have been found to be in a range from -4 to 4, and most values of $a_{p}/T$ fall in the range from -1 to 1. It is suggested that a small pairing-energy coefficient should be considered in predicting the cross sections of fragments in spallation reactions. It is also concluded that the method proposed in this article is not good for fragments with $A/A_{s} >$ 85\% (where $A_{s}$ is the mass number of the spallation system)., 8 pages, 6 figures, to appear on Chinese Physics C

\item[Background] Temperature is an important parameter in studying many important questions in heavy-ion collisions. A thermometer based on the isobaric yield ratio (IYR) has been proposed [Ma \textit{et al.}, Phys. Rev. C \textbf{86}, 054611 (2012) and Ma \textit{et al.}, \textit{ibid.}, Phys. Rev. C \textbf{88}, 014609 (2013)]. \item[Purpose] An improved thermometer ($T_{IB}$) is proposed based on the difference between IYRs. $T_{IB}$ obtained from isobars in different reactions will be compared. \item[Methods] The yields of three isobars are employed in $T_{IB}$. The residual free energy of the three isobars are replaced by that of the binding energy. No secondary decay modification for odd $A$ fragment is used in $T_{IB}$. \item[Results] The measured fragment yields in the 140$A$ MeV $^{40, 48}$Ca + $^{9}$Be ($^{181}$Ta) and $^{58, 64}$Ni + $^9$Be ($^{181}$Ta), the 1$A$ GeV $^{124, 136}$Xe + Pb, and the $^{112,124}$Sn + $^{112,124}$Sn reactions have been analyzed to obtain $T_{IB}$ from IMFs. $T_{IB}$ from most of the fragments in the $^{40, 48}$Ca and $^{58, 64}$Ni reactions is in the range of 0.6 MeV $ < T_{IB} < $ 3.5 MeV. $T_{IB}$ from most of the fragments in the $^{124}$Xe and $^{112,124}$Sn reactions is in the range of 0.5 MeV $ < T_{IB} < $ 2.5 MeV, while the range is 0.5 MeV $ < T_{IB}, Comment: 7 pages, 9 figures. To appear on Physical Review C