Possibilities for the synthesis of superheavy element Z=121 in fusion reactions

Based on the dinuclear system model,the calculated evaporation residue cross sections matched well with the current experimental results.The synthesis of superheavy elements Z=121 was systematically studied through combinations of stable projectiles with Z=21-30 and targets with half-lives exceeding 50 d.The influence of mass asymmetry and isotopic dependence on the projectile and target nuclei was investigated in detail.The reactions^(254)Es(^(46)Ti,3n)^(297)121 and^(252)Es(^(46)Ti,3n)^(295)121 were found to be experimentally feasible for synthesizing superheavy element Z=121,with maximal evaporation residue cross sections of 6.619 and 4.123 fb at 219.9 and 223.9 MeV,respectively.

Positive Q-Value Neutron Transfer Mediated Sub-Barrier Fusion Reactions

Positive Q-value neutron transfer mediated sub-barrier fusion reactions are studied with an empirical coupled channels model, which takes into account neutron rearrangement related only to the dynamical matching condition with no free parameters. Fusion cross sections of collision systems ^32S＋^90,94,96Zr are calculated and analyzed. Logarithmic residual enhancement （LRE） is proposed to evaluate the discrepancy between calculated results and experimental data. The experimental data can be described well with this model for the first time as a whole, while the LRE analysis shows that there are still theoretical systematic deviations.

Prediction of synthesis cross sections of new moscovium isotopes in fusion‑evaporation reactions

In the framework of the dinuclear system model,the synthesis mechanism of the superheavy nuclides with atomic numbers Z=112,114,115 in the reactions of projectiles 40,^(48)Ca bombarding on targets^(238)U,^(242)Pu,and^(243)Am within a wide interval of incident energy has been investigated systematically.Based on the available experimental excitation functions,the dependence of calculated synthesis cross-sections on collision orientations has been studied thoroughly.The total kinetic energy(TKE)of these collisions with fixed collision orientation shows orientation dependence,which can be used to predict the tendency of kinetic energy diffusion.The TKE is dependent on incident energies,as discussed in this paper.We applied the method based on the Coulomb barrier distribution function in our calculations.This allowed us to approximately consider all the collision orientations from tip-tip to side-side.The calculations of excitation functions of^(48)Ca+^(238)U,^(48)Ca+242Pu,and^(48)Ca+^(243)Am are in good agreement with the available experimental data.The isospin effect of projectiles on production cross-sections of moscovium isotopes and the influence of the entrance channel effect on the synthesis cross-sections of superheavy nuclei are also discussed in this paper.The synthesis cross-section of new moscovium isotopes 278−286 Mc was predicted to be as large as hundreds of pb in the fusion-evaporation reactions of^(35,37)Cl+^(248)Cf,^(38,40)Ar+^(247)Bk,^(39,41)K+247 Cm,^(40,42,44,46)Ca+^(243)Am,45 Sc+^(244)Pu,and^(46,48,50)Ti+237Np,51 V+^(238)U at some typical excitation energies.

Effects of entrance channel on fusion probability in hot fusion reactions

Within the framework of the dinuclear system （DNS） model, the fusion reactions leading to the compound nuclei 274Hs＊ and 2S6Cn＊ are investigated. The fusion probability as a function of DNS excitation energy is studied. The calculated results are in good agreement with the available experimental data. The obtained results show that the fusion probabilities are obviously enhanced for the reactions located at high place in potential energy surface, although these reactions may have small values of mass asymmetry. It is found that the enhancement is due to the large potential energy of the initial DNS.

Effects of the entrance channel mass asymmetry in fusion reactions

The symmetric and asymmetric fusion reaction systems forming the same compound nuclei ^26Al, ^30Si, ^38Ar and ^170Hf are investigated with the frame of improved isospin dependent quantum molecular dynamics model. The entrance channel mass asymmetry dependence of compound nucleus formation is found by analyzing the shell correction energies, the Coulomb barriers and the fusion cross sections. The calculated fusion cross sections agree quantitatively with the experimental data. The results indicate that compound nucleus formation is favorable for the systems with larger mass asymmetry because of the smaller Coulomb contribution to the fusion barrier.

Nuclear matter incompressibility effect on the cross-section of fusion reactions with a weakly bound projectile

Fusion reactions with a weakly bound projectile are studied using the double-folding model along with a repulsive interaction modifying term. Using this modified potential, including nuclear matter incompressibility effects, the fusion reaction cross sections and suppression parameters are calculated for 9Be＋209Bi, 208spb, 29Si and 27A1 reactions. The results show that applying these effects at agreement between the calculated and experimental cross sections parameter. energies near the Coulomb barrier improves the and modifies the mean values of the suppression

Double folding model calculation applied to fusion reactions

The interaction potential between a spherical and a deformed nucleus is calculated within the double-folding model for deformed nuclei. We solve the double folding potential numerically by using the truncated multipole expansion method. The shape, separation and orientation dependence of the interaction potential, fusion cross section and barrier distribution of the system ^16O＋^154Sm are investigated by considering the quadrupole and hexadecapole deformations of ^154Sm. It is shown that the height and the position of the barrier depend strongly on the deformation and the orientation angles of the deformed nucleus. These are quite important quantities for heavy-ion fusion reactions, and hence produce great effects on the fusion cross section and barrier distribution.

Study of the dinuclear system for^(296)119 superheavy compound nucleus in fusion reactions

This investigation aims to find an appropriate dinuclear system for the formation of^(296)119 superheavy compound nucleus.By studying the driving potential and measuring the capture cross section of the reactions,the evolution of the dinuclear system can be understood.In this study,we obtained capture,fusion,and evaporation residue cross sections and survival probability at energies near the Coulomb barrier for four reactions,namely ^(45)Sc+^(251)Cf,^(42)Ca+^(254)Es,^(39)K+^(297)Fm,and ^(38)Ar+^(258)Md.Our caleulations show that the reaction 38Ar+258 Md is a suitable choice for the formation of an element with 119 protons among the studied reactions from a the-oretical viewpoint.

Production of super-heavy nuclei in cold fusion reactions

A model for cold-fusion reactions related to the synthesis of super-heavy nuclei in collisions of heavy projectile-nuclei with a ^(208)Pb target nucleus is discussed.In the framework of this model,the production of the com-pound nucleus by two paths,the di-nuclear system path and the fusion path,are taken into account simultaneously.The formation of the compound nucleus in the framework of the di-nuclear system is related to the transfer of nucle-ons from the light nucleus to the heavy one.The fusion path is linked to the sequential evolution of the nuclear shape from the system of contacting nuclei to the compound nucleus.It is shown that the compound nucleus is mainly formed by the fusion path in cold-fusion reactions.The landscape of the potential energy related to the fusion path is discussed in detail.This landscape for very heavy nucleus-nucleus systems has an intermediate state,which is linked to the formation of both the compound nucleus and the quasi-fission fragments.The decay of the intermediate state is taken into account in the calculation of the compound nucleus production cross sections and the quasi-fission cross sections.The values of the cold-fusion cross sections obtained in the model agree well with the experimental data.

Diagnostic technique for measuring fusion reaction rate for inertial confinement fusion experiments at Shen Guang-III prototype laser facility

A study is conducted using a two-dimensional simulation program （Lared-s） with the goal of developing a technique to evaluate the effect of Rayleigh-Taylor growth in a neutron fusion reaction region. Two peaks of fusion reaction rate are simulated by using a two-dimensional simulation program （Lared-s） and confirmed by the experimental results. A neutron temporal diagnostic （NTD） system is developed with a high temporal resolution of - 30 ps at the Shen Guang-Ⅲ （SG-Ⅲ） prototype laser facility in China, to measure the fusion reaction rate history. With the shape of neutron reaction rate curve and the spherical harmonic function in this paper, the degree of Rayleigh-Taylor growth and the main source of the neutron yield in our experiment can be estimated qualitatively. This technique, including the diagnostic system and the simulation program, may provide important information for obtaining a higher neutron yield in implosion experiments of inertial confinement fusion.

Fusion Reaction Rate Coefficient for Different Beam and Target Scenarios

Fusion power output is proportional not only to the fuel particle number densities participating in reaction but also to the fusion reaction rate coefficient （or reactivity）, which is dependent on reactant velocity distribution functions. They are usuMly assumed to be dual Maxwellian distribution functions with the same temperature for thermal nuclear fusion circumstances. However, if high power neutral beam injection and minority ion species ICRF plasma heating, or multi-pinched plasma beam head-on collision, in a converging region are required and investigated in future large scale fusion reactors, then the fractions of the injected energetic fast ion tail resulting from ionization or charge exchange will be large enough and their contribution to the non-Maxwellian distribution functions is not negligible, hence to the fusion reaction rate coefficient or calculation of fusion power. In such cases, beam-target, and beam-beam reaction enhancement effect contributions should play very important roles. In this paper, several useful formulae to calculate the fusion reaction rate coefticient for different beam and target combination scenarios are derived in detail

Investigating the impact of the universal function of the nuclear proximity potential in heavy-ion fusion cross sections

The fusion barriers and cross sections of 15 colliding systems with 320≤Z_(1)Z_(2)≤1512 are investigated in detail to understand the influence of the universal function of proximity potential formalism in the heavy-ion fusion mechanism.To realize this goal,we select three versions of the phenomenological proximity potentials,including Prox.77,Zhang 2013,and Guo 2013,to calculate the nucleus-nucleus potential.The experimental fusion cross sections for the selected reactions are analyzed using the standard coupled-channel calculations,including couplings to the low-lying 2^(+)and 3^(-)states in the target and projectile.The calculated results show that the universal functions of the Guo 2013 and Prox.77 models provide the lowest and highest fusion barriers,respectively.In addition,it is found that the height of the fusion barriers is enhanced by increasing the mass number of the projectile from light to heavy ones.The highest sensitivity to the mass number of the projectile belongs to the results of Prox.77.A discussion is also presented on the influence of the universal function on the radial behavior of the interaction potential in the allowed region for overlapping configurations.Our results reveal that the best fit to the experimental data of the fusion cross sections for the reactions involving light and medium nuclei is obtained using the universal function of the Zhang 2013 model.For the heavier systems,the results of the Guo 2013 model at sub-barrier energies provide a good description of the available data.

Static versus energy-dependent nucleus–nucleus potential for description of sub-barrier fusion dynamics of _8^(16)O+_(50)^(112,116,120)Sn reactions

The static and energy-dependent nucleus–nucleus potentials are simultaneously used along with the Wong formula for exploration of fusion dynamics of 8^16O＋50^112,116,120Sn reactions. The role of internal structure degrees of freedom of colliding pairs, such as inelastic surface vibrations, are examined within the context of coupled channel calculations performed using the code CCFULL. Theoretical calculations based on the static Woods–Saxon potential along with the one-dimensional Wong formula fail to address the fusion data of 8^16O＋50^112,116,120Sn reactions.Such discrepancies can be removed if one uses couplings to internal structure degrees of freedom of colliding nuclei.However, the energy-dependent Woods–Saxon potential model（EDWSP model） accurately describes the sub-barrier fusion enhancement of 8^16O＋50^112,116,120Sn reactions. Therefore, in sub-barrier fusion dynamics, energy dependence in the nucleus–nucleus potential governs barrier modification effects in a closely similar way to that of the coupled channel approach.

Nuclear Astrophysics Experiments in Collaboration with Ruhr University

This paper reports on two nuclear astrophysics experiments performed in collabora- tion with Ruhr University. In a 12C＋2C fusion reaction, the 12C（12C, a）20e and 12C（12C, p）23Na reactions were studied in the energy range of E = 2.10 MeV to 4.75 MeV using -y-ray spectroscopy. The deduced astrophysical S（E）＊ factor exhibited a new, strong resonance at E -= 2.14 MeV, which lay at the high-energy tail of the Gamow peak. The resonance increased the reaction rate of the ^-channel by a factor of five near T = 8 ~ l0s K. The electron screening in d（d, p）t was stud- ied for a series of deuterated metal, insulator and semiconductor targets. Compared with the measurements performed with a gaseous D2 target, a large effect was observed in most metals, while a comparatively small effect was found in the insulators and semiconductors. Subsequently the temperature dependence of the electron screening in the d（d, p）t reaction was studied for the deuterated metals Pt and Co. Enhanced electron screening decreased with increasing tempera- ture. These data represent the first observations of the temperature dependence of a nuclear cross section.

Transfer learning and neural networks in predicting quadrupole deformation

Accurately determining the quadrupole deformation parameters of atomic nuclei is crucial for understanding their structural and dynamic properties.This study introduces an innovative approach that combines transfer learning techniques with neural networks to predict the quadrupole deformation parameters of even-even nuclei.With the application of this innovative technique,the quadrupole deformation parameters of 2331 even-even nuclei are successfully predicted within the nuclear region defined by proton numbers 8≤Z≤134 and neutron numbers N≥8.Additionally,we discuss the impact of nuclear quadrupole deformation parameters on the capture cross-sections in heavy-ion fusion reactions,reconstructing the capture cross-sections for the reactions48Ca+244Pu and48Ca+248Cm.This research offers new insights into the application of neural networks in nuclear physics and highlights the potential of merging advanced machine learning techniques with both theoretical and experimental data,particularly in fields where experimental data are limited.

Region-based fusion of infrared and visible images using nonsubsampled contourlet transform

With the nonsubsampled contourlet transform （NSCT）, a novel region-segmentation-based fusion algorithm for infrared （IR） and visible images is presented. The IR image is segmented according to the physical features of the target. The source images are decomposed by the NSCT, and then, different fusion rules for the target regions and the background regions are employed to merge the NSCT coefficients respectively. Finally, the fused image is obtained by applying the inverse NSCT. Experimental results show that the proposed algorithm outperforms the pixel-based methods, including the traditional wavelet-based method and NSCT-based method.

Integration of GaN thin films with silicon substrates by fusion bonding and laser lift-off

GaN thin films grown on sapphire substrates by metalorganic chemical vapor deposition （MOCVD） are successfully bonded and transferred onto Si receptor substrates using fusion bonding and laser lift-off （LLO） technique. GaN/Al2O3 structures are joined to Si substrates by pressure bonding Ti/Au coated GaN surface onto Ti/Au coated Si receptor substrates at the temperature of 400℃. KrF excimer laser with 400-mJ/cm^2 energy density, 248-nm wavelength, and 30-ns pulse width is used to irradiate the wafer through the transparent sapphire substrates and separate GaN films from sapphire. Cross-section scanning electron microscopy （SEM） combined with energy dispersive X-ray spectrometer （EDS） measurements show that Au/Si solid solution is formed during bonding process. Atomic force microscopy （AFM） and photoluminescence （PL） measurements show that the qualities of GaN films on Si substrates degrade little after substrates transfer.

Role of projectile breakup effects and intrinsic degrees of freedom on fusion dynamics

This article analyzes the fusion dynamics of loosely bound and stable projectiles with Zr-target isotopes within the context of the coupled channel approach and the energy-dependent Woods-Saxon potential model （EDWSP model）. In the case of the 2SSi＋90Zr reaction, the coupling to the inelastic surface excitations results in an adequate description of the observed fusion dynamics while in case of the 2Ssi ＋ 94Zr reaction, the coupling to collective surface vibrational states as well as the neutron （multi-neutron） transfer channel is necessary in the coupled channel calculations to reproduce the below-barrier fusion data. However, the EDWSP model calculation provides an accurate explanation of the fusion data of 2Ssi＋ 90,94Zr reactions in the domain of the Coulomb barrier. In the fusion of the 6Li＋90Zr reaction, the inclusion of the nuclear structure degrees of freedom recovers the observed sub-barrier fusion enhancement but results in suppression of the above barrier fusion data by 34% with respect to the coupled channel calculations. Using EDWSP model calculations, this suppression factor is reduced by 14% and consequently, the above-barrier fusion data of 6Li＋90Zr reaction is suppressed by 20% with reference to the EDWSP model calculations. Such fusion suppression at above-barrier energies can be correlated with the breakupof the projectile （6Li） before reaching the fusion barrier, as a consequence of low binding energy.

Fusion of spherical-octupole pairs of colliding nuclei for compact and elongated configurations

The deformation and associated optimum/uniquely fixed orientations play an important role in the syn-thesis of compound nuclei via cold and hot fusion reactions,respectively,at the lowest and highest barrier energies.The choice of optimum orientation(0_(op))for the'cold or elongated'and hot or cormpact'fusion configurations of quadrupole(β_(2))deformed nuclei depends only on the+/-signs ofβ_(2)-deformation[J.Phys.G:Nucl.Part.Phys.31,631-644(2005)].In our recent study[Phys.Rev.C 101,051601(R)2020],we proposed a new sct of Oopt(iferent from the values reported for quadrupole deformed nuclei)after the inclusion of octupole deformation(up to B3)ef-fects.Using the respective 0op1 of B3-deformed nuclei for cold and hot optimum orientations,we analyzed the im-pact of the soft-and rigid-pear shapes of octupole deformed nuclei on the fusion barrier characterstics(barrier height Vg and barrier position RB).This analysis is applied to approximately 200 spherical-plus B3 deformed nucle-ar partners,that is,^(16)O,^(18)Cat octupole deformed nuclei.Compared with the compact configuration,the elongated fu-sion configuration has a relatively larger impact on the fusion barrier and cross sections ow ing to the inclusion of de-formations up to B3.Its agreement with available experimental data for the^(16)O+^(150)Sm reaction(β_(22)-0.205,β_(32)=0.055)also improves when the optimum orientation degree of freedom is fixed in view of octupole deformations.This reinforces the fact that nuclear structure effects play an important role in the nuclear fusion process.Thus,octu-pole deformed nuclei can be used for the synthesis of heavy and superheavy nuclei.

Molecular detection of EWS-Ets fusion transcripts and their clinicopathologic significance in Ewing’s sarcoma/peripheral primitive neuroectodermal tumor

Background Ewing＇s sarcoma/peripheral primitive neuroectodermal tumor （ES/pPNET） is often difficuh to distinguish from other small round cell tumors. The EWS-Ets gene fusions that result from chromosomal translocations in this tumor provide potential molecular diagnostic markers. To apply these molecular markers to commonly available archival materials, we evaluated the feasibility of detecting EWS-Ets including EWS-Flil and EWS-ERG fusion transcripts in paraffin-embedded tissues and its diagnostic value for detecting ES/pPNET. Methods Thirteen paraffin-embedded samples of ES/pPNETs were retrieved from archives. Thirteen cases of other tumors with small round cell features （including rhabdomyosarcoma, neuroblastoma, lymphoma, small ceil carcinoma, and desmoplastic small round cell tumor ） were used as negative controls. β-actin and β2- microglobulin were used as internal controls. A nested reverse transcriptase-polymerase chain reaction （RT- PCR）-based assay was performed to detect the EWS-Flil and EWS-ERG fusion transcripts. Results β-aetin and β2-mieroglobulin were detected in 10/13 and 13/13 ES/pPNETs, respectively. EWS- Flil fusion transcripts were detected in 11 of 13 （85%） ES/pPNETs. Three chimeric transcripts, all EWS-Flil, were detected in ES/pPNET samples. Among 11 EWS-Flil-positive cases, 7 eases had a type Ⅰ fusion transcript involving fusion of EWS exon 7 with Flil exon 6, 2 eases had a type Ⅱ fusion transcript involving EWS exon 7 with Flil exon 5, and 2 eases expressed fusion transcripts involving EWS exon 7 and Flil exon 8. Type Ⅰ EWS- Flil fusion predominated over other types. Fusion types could not be distinguished in the remaining 2 eases. Thirteen negative controls did not show detectable chimeric messages. There was a significant relationship between EWS-Flil fusion transcripts and CD99 expression. Conclusions Molecular detection of EWS-Flil fusion transcripts in formalin-fixed paraffin-embedded material by nested RT-PCR is feasible and is useful for the diagnosis and differential diagnosis of ES/pPNETs.