Evaporation Residue Cross Sections Research Articles

Hot fusion reactions with deformed nuclei for synthesis of superheavy nuclei: An extension of the fusion-by-diffusion model

The fusion-by-diffusion model proposed by Swiatecki {\it et al.} [Phys. Rev. C71, 014602 (2005)] has provided a simple and convenient tool to estimate evaporation residue cross sections for superheavy nuclei. I extend this model by taking into account deformation of the target nucleus, and discuss the role of orientation of deformed target in hot fusion reactions at energies around the Coulomb barrier. To this end, I introduce an injection point for the diffusion process over an inner barrier which depends on the orientation angle. I apply this model to the $^{48}$Ca+$^{248}$Cm reaction and show that the maximum of evaporation residue cross section appears at an energy slightly above the height of the capture barrier for the side collision, for which the effective inner barrier is considerably lower than that for the tip collision, thus enhancing the diffusion probability. I also discuss the energy dependence of the injection point, and show that a large part of the energy dependence found in the previous analyses can be attributed to the deformation effect of a target nucleus.

Ca48 -induced reaction on the lanthanide target Gd154 and its decay to ground and metastable states within the dynamical cluster-decay model

The decay mechanism of compound nucleus (CN) $^{202}\mathrm{Po}^{*}$, formed in $^{48}\mathrm{Ca}+^{154}\mathrm{Gd}$ reaction, is studied within the dynamical cluster-decay model (DCM) at various excitation energies ${E}_{\mathrm{CN}}^{*}$, where neutron emission $xn$, $x=3\text{--}5$, are the predominant decay modes. The study is of interest since $^{202}\mathrm{Po}^{*}$ decays to the ground state (g.s.) of $^{198}\mathrm{Po}$ by emission of $4n$ and to metastable states $^{199m}\mathrm{Po}$ and $^{197m}\mathrm{Po}$ via ($3n,5n$) emission, respectively. The DCM is applied here for the first time to the decays of metastable states. Both types of decays are analyzed separately, using neck-length $\mathrm{\ensuremath{\Delta}}R$ (equivalently, barrier-lowering) parameter, the only parameter in the DCM, to best fit the evaporation residue or channel cross section (${\ensuremath{\sigma}}_{xn}$) data and predict the quasifissionlike (qf-like) noncompound (${\ensuremath{\sigma}}_{\mathrm{qf}}$) and fusion-fission (${\ensuremath{\sigma}}_{\mathrm{ff}}$) cross sections. For g.s. to g.s. decay of $^{202}\mathrm{Po}^{*}$, possibly due to involving the deformed rare-earth lanthanide target $^{154}\mathrm{Gd}$, the observed $4n$ decay channel requires the noncompound nucleus (nCN) contribution, treated as the qf-like process. On the other hand, the decay mechanism of $^{202}\mathrm{Po}^{*}$ to metastable states (m.s.) $^{199m}\mathrm{Po}$ and $^{197m}\mathrm{Po}$, is a pure CN decay, i.e., the ${\ensuremath{\sigma}}_{\mathrm{qf}}$ is zero. In this study, we have included the deformation effects up to quadrupole deformations ${\ensuremath{\beta}}_{2i}$ and optimum orientations ${\ensuremath{\theta}}_{i}^{\mathrm{opt}.}$ for coplanar ($\mathrm{\ensuremath{\Phi}}={0}^{0}$) nuclei, using hot-compact configurations, supporting asymmetric fission of CN $^{202}\mathrm{Po}^{*}$. The variation of CN formation probability ${P}_{\mathrm{CN}}$ and survival probability ${P}_{\mathrm{surv}}$ with excitation energy ${E}_{\mathrm{CN}}^{*}$ is in complete agreement with the known systematic of other radioactive CN studied so far, thereby giving credence to the predicted ${\ensuremath{\sigma}}_{\mathrm{qf}}$ in g.s. to g.s. decay and fusion-fission cross section ${\ensuremath{\sigma}}_{\mathrm{ff}}$ of $^{202}\mathrm{Po}^{*}$. Interestingly, both the observed g.s. to g.s. and g.s. to m.s. processes occur at a fixed $\mathrm{\ensuremath{\Delta}}R=2.45\ifmmode\pm\else\textpm\fi{}0.20\phantom{\rule{0.28em}{0ex}}\mathrm{fm}$, which is within the nuclear proximity limit of $\ensuremath{\sim}2.5\phantom{\rule{0.28em}{0ex}}\mathrm{fm}$, and hence useful for making predictions.

Measurement of excitation functions of evaporation residues in the O16+Sn124 reaction and investigation of the dependence of incomplete fusion dynamics on entrance channel parameters

Excitation functions for the 11 evaporation residues populated through complete and/or incomplete fusion in $^{16}\mathrm{O}+^{124}\mathrm{Sn}$ system at low projectile energies $\ensuremath{\approx}3\ensuremath{-}7\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}/\mathrm{nucleon}$ have been measured. Recoil catcher activation technique followed by offline $\ensuremath{\gamma}$-ray spectrometry has been employed. Some of the evaporation residues are found to have contributions from precursor decays. The precursor contributions have been separated out from the measured cumulative cross-sections of evaporation residues. Independent cross-sections are compared with statistical model code PACE-4 predictions. The evaporation residues produced through $xn$ and pxn channels are found to be well reproduced with the PACE-4 predictions after subtraction of precursor decay contributions. A substantial enhancement in the measured excitation functions over their theoretical predictions for the evaporation residues produced in $\ensuremath{\alpha}$-emitting channels has been observed, which is attributed to the presence of incomplete fusion of projectile with target at these low energies. The present study shows that the incomplete fusion and the break-up probability of the incident $^{16}\mathrm{O}$ into $\ensuremath{\alpha}$ clusters (i.e., break-up of $^{16}\mathrm{O}$ into $^{12}\mathrm{C}+\ensuremath{\alpha}$ and/or $^{8}\mathrm{Be}+^{8}\mathrm{Be}$) increases with projectile energy. The present data suggests that the deformation of target is highlighting the important role to affect the ICF reactions independently with different projectiles. The comparison of the present study with literature data also shows that the ICF probability depends on various entrance channel parameters, namely, projectile energy, entrance channel mass-asymmetry, $\ensuremath{\alpha}\text{\ensuremath{-}}Q$ value, Coulomb factor $({Z}_{\mathrm{P}}{Z}_{\mathrm{T}})$, deformation parameter (${\ensuremath{\beta}}_{2}$), and their combinations. Moreover, the combined parameters ${Z}_{\mathrm{P}}{Z}_{\mathrm{T}}\ifmmode\cdot\else\textperiodcentered\fi{}{\ensuremath{\beta}}_{2}$ and ${\ensuremath{\mu}}_{\mathrm{EC}}^{\mathrm{AS}}\ifmmode\cdot\else\textperiodcentered\fi{}{\ensuremath{\beta}}_{2}$ are not found suitable to explain whole ICF characteristics, particularly for spherical and slightly deformed targets. On the other hand, the combined parameter ${Z}_{\mathrm{P}}{Z}_{\mathrm{T}}\ifmmode\cdot\else\textperiodcentered\fi{}{\ensuremath{\mu}}_{\mathrm{EC}}^{\mathrm{AS}}$ has been found to explain more precisely the ICF dynamics as compared to other single and combined entrance channel parameters.

مطالعه سنتز برخی از ایزوتوپهای هسته فلروویوم Fl، واقع در جزیره پایداری و مقایسه پارامترهای سد همجوشی آنها

In the present research, we want to study synthesis of some isotopes of Flerovium ، ، and were produced in the nuclear fusion of 48Ca ions with 239Pu, 240Pu, 241Pu, and 242Pu nuclei. We obtain the parameters of the fusion barriers between48Ca ions with Pu isotopes and compare these parameters with each other. Furthermore, we investigate influence of the direction of target nuclei on the parameters of the fusion barriers. we show that the minimum energies for synthesis of 287Fl, 288Fl, 289Fl and 290Fl nuclei are 184.16 MeV, 183.95 MeV, 183.75 MeV and 183.56 MeV. Finally in the framework of the statistical model, we estimate the evaporation residue cross section for 286Fl, 287Fl nuclei after emission of three and four neutrons from 290Fl nuclei and we will show that the results of calculations for 286Fl nuclei are in good agreement with the experimental data. Although, the results of the calculations of the evaporation residue cross section for 287Fl nuclei lie somewhat below the results of the experimental data.

Investigation to synthesis more isotopes of superheavy nuclei Z = 118

We have studied the α-decay properties of superheavy nuclei Z=118 in the range 275≤A≤325. Most of the predicted, unknown nuclei in the range 291≤A≤301 were found to have α-decay chains. Of these the nuclei 293−301118 were found to have long half-lives and hence could be sufficient to detect them if synthesized in a laboratory. Fusion barries for different projectile-target combinations to synthesis superheavy nuclei Z=118 are studied and are also represented in simple relations. We have also studied the evaporation residue cross section, compound nucleus formation probability (PCN) and survival probability (PSurv) of different projectile-target combinations to synthesis superheavy element Z=118. The selected most probable projectile-target combinations are Ca+Cf, Ti+Cm, Sc+Bk, V+Am, Cr+Pu, Fe+U, Mn+Np, Ni+Th and Kr+Pb. We have formulated simple relations for maximum evaporation residue cross sections and its corresponding energies. This helps to identify the projectile-target combinations quickly. Hence, we have identified the most probable projectile-target combinations to synthesis these superheavy nuclei. We hope that our predictions may be a guide for the future experiments in the synthesis of more isotopes of superheavy nuclei Z=118.

Theoretical studies on the synthesis of SHE 290-302Og (Z=118) using 48Ca, 45Sc, 50Ti, 51V, 54Cr, 55Mn, 58Fe, 59Co and 64Ni induced reactions

Using the phenomenological model for production cross section (PMPC), the production cross sections for the synthesis of isotopes of superheavy element Og (Z = 118) using the fusion reactions 48Ca+249-254Cf $\rightarrow$ 297-302Og, 45Sc+247,249Bk $ \rightarrow$ 292,294Og, 50Ti + 242-248,250Cm $ \rightarrow$ 292-298,300Og, 51V+241,243Am $\rightarrow$ 292,294Og, 54Cr + 238-242,244Pu $ \rightarrow$ 292-296,298Og, 55Mn + 235-237Np $ \rightarrow$ 290-292Og, 58Fe + 232-236, 238U $\rightarrow$ 290-294,296Og, 59Co + 231Pa $\rightarrow$ 290Og, and 64Ni + 228-230,232Cm $\rightarrow$ 292-294,296Og in $x\mathrm{n}$ $(x=3,4,5)$ evaporation channel have been systematically studied at energies near and above the Coulomb barrier. We have predicted most suitable projectile-target combinations for the synthesis of isotopes 290-302Og among these reactions. Our calculated evaporation residue (ER) cross section values for the reaction 48Ca + 249Cf $\rightarrow$ 297Og is in excellent agreement with available experimental values. For the synthesis of Og, among all the reactions mentioned above, the 3n channel cross section (2458 fb) is larger for 48Ca + 251Cf $\rightarrow$ 299Og; 4n channel cross section (212 fb) is larger for 48Ca + 252Cf $ \rightarrow$ 300Og and 5n channel cross section (34 fb) is larger for 48Ca + 253Cf $\rightarrow$ 301Og. The second largest 3n channel cross section (1143 fb) is obtained for the reaction, 50Ti + 245Cm $\rightarrow$ 295Og. Our studies will be useful for the future experiments to synthesize the isotopes of element Og which are not synthesized so far. We have also studied the effect of the use of mass values and shell correction of the Warsaw group which leads to a smaller ER cross section compared to the Moller group.

Mass and angular distributions of the reaction products in heavy ion collisions

The optimal reactions and beam energies leading to synthesize superheavy elements is searched by studying mass and angular distributions of fission-like products in heavy-ion collisions since the evaporation residue cross section consists an ignorable small part of the fusion cross section. The intensity of the yield of fission-like products allows us to estimate the probability of the complete fusion of the interacting nuclei. The overlap of the mass and angular distributions of the fusion-fission and quasifission products causes difficulty at estimation of the correct value of the probability of the compound nucleus formation. A study of the mass and angular distributions of the reaction products is suitable key to understand the interaction mechanism of heavy ion collisions.

The entrance channel effects on the deexcitation ways of the same compound nucleus at a fixed excitation energy

The investigation of various properties of deexcitation of the same 220Th compound nucleus (CN), formed by the different mass (charge) asymmetric 16O+204Pb, 40Ar+180Hf, 82Se+138Ba and 96Zr+124Sn reactions is presented. The effective fission barrier < Bfis > value, as a function of the excitation energy , determined for each intermediate excited nucleus reached along the deexcitation cascade of the CN obtained by the four considered reactions is strongly sensitive to the various orbital angular momentum L=ℓℏ distributions of CN formed with the same excitation energy by the various entrance channels. Therefore, the competition between the fission and evaporation of light particles (neutron, proton, and α-particle) processes along the deexcitation cascade of CN is dependent on the orbital angular momentum distribution of CN. In fact, the ratio between the evaporation residue cross sections obtained when also the charged particles are emitted and the ones obtained after neutron emission only for the same CN with a fixed excitation energy is sensitive to the mass (charge) asymmetry of the entrance channel.

Formation of Superheavy Elements: Study Based on Dynamical Approach

Using multi-dimensional Langevin equations for the probability distribution of the distance between the surfaces of two approaching nuclei, we have studied the formation of superheavy elements via calculation of evaporation and fission cross sections of these elements. Evaporation residue cross sections have been calculated for the 1n, 2n, 3n, 4n, and 5n evaporation channels using one and four dimensional Langevin equations for the 48Ca+226Ra, 232Th, 238U, 237Np, 239,240,242,244Pu, 243Am, 245,248Cm, 249Bk, and 249Cf reactions. Our results show that with increasing dimension of Langevin equations the evaporation residue cross section is increased. Also, obtained results based on fourdimensional Langevin are in better agreement with experimental data in comparison with one-dimensional model.

Distinguishing Features of Radioactive Compound Nucleus Decays within the Dynamical Cluster Decay Model

In this paper, we are interested to study the distinguishing features of the decaying radioactive compound nuclei 246Bk* and 220Th*, using the Dynamical Cluster-decay Model (DCM) with deformation β and non-coplanar degree-of-freedom Φ. 246Bk* and 220Th* have so-far been studied within the DCM, using quadrupole deformations (β2i), “optimum” orientations (θopt) of the two nuclei lying in the same plane (Φ=0o), which shows that there is a non-compound nucleus (nCN) content in the observed data. The first turning point Ra (equivalently, the neck-length ∆R in Ra=R1+R2+∆R), which fixes both the preformation and penetration paths, is used to best fit the measured evaporation residue (ER) and fusion-fission (ff) cross sections, σER, σff, respectively, in 220Th* and 246Bk*, formed via different entrance channels. In this work, we subsequently add higher multipole deformations, the octupole and hexadecupole (β3i, β4i), `compact’ orientations θci and Φ≠00, and look for their effects on the nCN contribution predicted by the DCM calculations referenced above.

Evaporation channel as a tool to study fission dynamics

The dynamics of the fission process is expected to affect the evaporation residue cross section because of the fission hindrance due to the nuclear viscosity. Systems of intermediate fissility constitute a suitable environment for testing such hypothesis since they are characterized by evaporation residue cross sections comparable or larger than the fission ones. Observables related to emitted charged particles, due to their relatively high emission probability, can be used to put stringent constraints on models describing the excited nucleus decay and to recognize the effects of fission dynamics. In this work model simulations are compared with the experimental data collected via the S32+100Mo reaction at Elab=200 MeV. Consequently we pointed out, exploring an extended set of evaporation channel observables, the limits of the statistical model and the large improvement obtained with a dynamical model. Moreover we stress the importance of using an apparatus covering a large fraction of 4π to extract observables. Finally, we discuss the opportunity to measure more sensitive observables by a new detection device in operation at LNL.

Survival-mediated capture and fusion cross sections for heavy-element synthesis

The cross section for producing a heavy evaporation residue ${\ensuremath{\sigma}}_{\mathrm{EVR}}$ in a fusion reaction can be written as a product of three nonseparable factors, i.e., the capture cross section, the fusion probability ${P}_{\mathrm{CN}}$, and the survival probability ${W}_{\text{sur}}$. Each of these factors is dependent on the spin. However, one must remember that the ${W}_{\text{sur}}$ term is zero or very small for higher spin values, thus effectively limiting the capture and fusion terms. For a series of $\ensuremath{\sim}287$ reactions leading to heavy evaporation residues with ${Z}_{\text{CN}}\ensuremath{\le}110$, we point out the implications of this fact for capture cross sections for heavy element formation reactions. From a comparison of calculated and measured evaporation residue cross sections we deduce values of the fusion probability ${P}_{\text{CN}}$ for some of these reactions.

Investigation of Superheavy Element with Z = 120 Production Probability Via Hot Fusion Reaction

Attempt is made in this paper to calculate the synthesis probability of the superheavy nucleus with atomic number 120 and compare our findings to the results obtained by other researchers. Our findings include important parameters such as the survival probability of the residue nucleus and the fission barrier height, leading to determination of the evaporation residue cross section. The fission barrier height of the nucleus with Z = 120 is calculated by a revised relation and then compared to the neutron separation energy. It is shown that the production probability of our superheavy nucleus with Z = 120 and A = 296 is higher as compared to its other isotopes, but the fission barrier height of the superheavy element 120 with mass number 299 is higher than other isotopes. The hot fusion reaction 50Ti + 249–251Cf is suggested for such synthesis.

Statistical and dynamical modeling of heavy-ion fusion–fission reactions

A modified statistical model and a four dimensional dynamical model based on Langevin equations have been used to simulate the fission process of the excited compound nuclei 207At and 216Ra produced in the fusion 19F + 188Os and 19F + 197Au reactions. The evaporation residue cross section, the fission cross section, the pre-scission neutron, proton and alpha multiplicities and the anisotropy of fission fragments angular distribution have been calculated for the excited compound nuclei 207At and 216Ra. In the modified statistical model the effects of spin K about the symmetry axis and temperature have been considered in calculations of the fission widths and the potential energy surfaces. It was shown that the modified statistical model can reproduce the above mentioned experimental data by using appropriate values of the temperature coefficient of the effective potential equal to λ=0.0180±0.0055, 0.0080±0.0030 MeV−2 and the scaling factor of the fission barrier height equal to rs=1.0015±0.0025, 1.0040±0.0020 for the compound nuclei 207At and 216Ra, respectively. Three collective shape coordinates plus the projection of total spin of the compound nucleus on the symmetry axis, K, were considered in the four dimensional dynamical model. In the dynamical calculations, dissipation was generated through the chaos weighted wall and window friction formula. Comparison of the theoretical results with the experimental data showed that two models make it possible to reproduce satisfactorily the above mentioned experimental data for the excited compound nuclei 207At and 216Ra.

Quest for consistent modelling of statistical decay of the compound nucleus

A statistical model description of heavy ion induced fusion–fission reactions is presented where shell effects, collective enhancement of level density, tilting away effect of compound nuclear spin and dissipation are included. It is shown that the inclusion of all these effects provides a consistent picture of fission where fission hindrance is required to explain the experimental values of both pre-scission neutron multiplicities and evaporation residue cross-sections in contrast to some of the earlier works where a fission hindrance is required for pre-scission neutrons but a fission enhancement for evaporation residue cross-sections.

48Ca induced reactions for the synthesis of isotopes 284–292Fl

The production cross sections for the synthesis of superheavy elements 284–292Fl (Z = 114) using the fusion reactions 48Ca+236-244Pu were systematically calculated. Using Coulomb and proximity potentials as the interaction barrier, we calculated the capture cross section, probability of CN formation, survival probability of excited compound nuclei, fusion cross section, and evaporation residue (ER) cross section for these reactions at energies near and above the Coulomb barrier. Our calculated ER cross section values for the reactions 48Ca+240Pu→288Fl, 48Ca+242Pu→290Fl and 48Ca+244Pu→292Fl are in excellent agreement with available experimental values. The predicted maximum value of the ER cross section in 2n, 3n, 4n, and 5n channels for all the reactions 48Ca+236–244Pu→284–292Fl are listed. It was found that the reactions 48Ca +243Pu→291Fl and 48Ca +244Pu→292Fl were more favorable with a maximum ER cross section of 6.924 (3n) and 9.033 pb (4n), respectively. Our studies will be useful for future experiments to synthesize the isotopes of element Fl that have not been synthesized so far.

Studies on the synthesis of isotopes of superheavy element Lv (Z = 116)

The probable projectile-target combinations for the synthesis of superheavy nucleus 296Lv found in the cold valley of 296Lv have been identified by studying the interaction barrier of the colliding nuclei, probability of compound nucleus formation, \(P_{CN}\), and survival probability \(W_{sur}\). At energies near and above the Coulomb barrier, the capture, fusion and evaporation residue (ER) cross sections for the probable combinations for the hot and cold fusion reactions are systematically investigated. By considering intensities of the projectile beams, availabilities of the targets and half lives of the colliding nuclei, the combination 48Ca+248Cm is found to be the most probable projectile-target pair for the synthesis of 296Lv. The calculated maximum value of 2n, 3n, 4n and 5n channel cross section for the reaction 48Ca+248Cm are 0.599 pb, 5.957 pb, 4.805 pb, and 0.065 pb, respectively. Moreover, the production cross sections for the synthesis of isotopes 291-295,298Lv using 48Ca projectile on 243-247,250Cm targets are calculated. Among these reactions, the reactions 48Ca+247Cm \(\rightarrow\) 295Lv and 48Ca+250Cm \(\rightarrow\) 298Lv have maximum production cross section in 3n (10.697 pb) and 4n (12.006 pb) channel, respectively. Our studies on the SHE Lv using the combinations 48Ca+245Cm \( \rightarrow\) 293Lv and 48Ca+248Cm \( \rightarrow\) 296Lv are compared with available experimental data and with other theoretical studies. Our studies are in agreement with experimental data and we hope that these studies will be a guide for the future experiments to synthesize the isotopes of Lv.

Evaporation residue cross-section measurements for Ti48 -induced reactions

Background: A significant research effort is currently aimed at understanding the synthesis of heavy elements. For this purpose, heavy ion induced fusion reactions are used and various experimental observations have indicated the influence of shell and deformation effects in the compound nucleus (CN) formation. There is a need to understand these two effects.Purpose: To investigate the effect of proton shell closure and deformation through the comparison of evaporation residue (ER) cross sections for the systems involving heavy compound nuclei around the ${Z}_{\mathrm{CN}}=82$ region.Methods: A systematic study of ER cross-section measurements was carried out for the $^{48}\mathrm{Ti}+^{142,150}\mathrm{Nd}, ^{144}\mathrm{Sm}$ systems in the energy range of $140--205\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}$. The measurement has been performed using the gas-filled mode of the hybrid recoil mass analyzer present at the Inter University Accelerator Centre (IUAC), New Delhi. Theoretical calculations based on a statistical model were carried out incorporating an adjustable barrier scaling factor to fit the experimental ER cross section. Coupled-channel calculations were also performed using the ccfull code to obtain the spin distribution of the CN, which was used as an input in the calculations.Results: Experimental ER cross sections for $^{48}\mathrm{Ti}+^{142,150}\mathrm{Nd}$ were found to be considerably smaller than the statistical model predictions whereas experimental and statistical model predictions for $^{48}\mathrm{Ti}+^{144}\mathrm{Sm}$ were of comparable magnitudes.Conclusion: Though comparison of experimental ER cross sections with statistical model predictions indicate considerable non-compound-nuclear processes for $^{48}\mathrm{Ti}+^{142,150}\mathrm{Nd}$ reactions, no such evidence is found for the $^{48}\mathrm{Ti}+^{144}\mathrm{Sm}$ system. Further investigations are required to understand the difference in fusion probabilities of $^{48}\mathrm{Ti}+^{142}\mathrm{Nd}$ and $^{48}\mathrm{Ti}+^{144}\mathrm{Sm}$ systems.

Influence of entrance channel on production cross sections of superheavy nuclei

The dependence of the evaporation residue cross section (ERCS) to produce superheavy nuclei (SHN) on the entrance channel of colliding nuclei is analyzed within the dinuclear system concept. The ERCS for the hot fusion reactions are investigated systematically and compared with existing experimental data. The capture cross section depends sensitively on the reaction $Q$ value. The fusion probabilities and surviving probabilities depend sensitively on the neutron numbers of the target and projectile nuclei. In most cases more neutron excess in the system can increase the producing cross section of SHN.

Dynamical Cluster-decay Model (DCM) applied to 9Li+208Pb reaction

The decay mechanism of 217At⁎ formed in Li9+208Pb reaction is studied within the dynamical cluster-decay model (DCM) at various center-of-mass energies. The aim is to see the behavior of a light neutron-rich radioactive beam on a doubly-magic target nucleus for the (total) fusion cross section σfus and the individual decay channel cross sections. Experimentally, only the isotopic yield of heavy mass residues At⁎211–214 [equivalently, the light-particles (LPs) evaporation residue cross sections σxn for x=3–6 neutrons emission] are measured, with the fusion–fission (ff) component σff taken zero. For a fixed neck-length parameter ΔR, the only parameter in the DCM, we are able to fit σfus=∑x=16σxn almost exactly for 9Li on 208Pb at all Ec.m.'s. However, the observed individual decay channels (3n–6n) are very poorly fitted, with unobserved channels (1n, 2n) and σff strongly over-estimated. Different ΔR values, meaning thereby different reaction time scales, are required to fit individually both the observed and unobserved evaporation residue channels (1n–6n) and σff, but then the compound nucleus (CN) contribution σCN is very small (<1%), and the non-compound nucleus (nCN) decay cross section σnCN contributes the most towards total σfus (=σCN+σnCN). Thus, the 9Li induced reaction on doubly-magic 208Pb is more of a quasi-fission-like nCN decay, which is further analyzed in terms of the statistical CN formation probability PCN and CN survival probability Psurv. For the reaction under study, PCN<<1 and Psurv→1, in particular at above barrier energies.