Study of Complete and Incomplete Fusion Reaction in the Interaction of 12 C + 128 Te and 14 N + 128 Te system below 7 MeV / A .

In this paper, an attempt was made to measure the excitation function for the disappearance residues recognized in the interaction of C+Te and 14 N + 128 Te system with the observation to investigating the complete and incomplete fusion reaction dynamics in heavy ion induced reaction. The incentive of this study was break up of 12 C and 14 N in reaction below 7MeV/A and associate the excitation function for C and 14 N with the same target Te prominent different compound system. PACE-4 were used for analysis of the system, and the measured excitation functions for precise decay channel in two case i.e. (C+ 128 Te and 14 N + 128 Te) have been associated and established in Bohr assumption in case of complete fusion channels. The properties of coulomb barrier and other entrance channel parameters were established to be relatively significant in decisive the decay mode of composite system. Additionally the incomplete fusion dynamics were also perceived to be of significant importance in present energy section.


Introduction
Investigating of different reaction mechanism involved in the heavy ion (HI) induced reaction, complete (CF), incomplete fusion (ICF) and direct reaction etc sunil et al [1]. The direct reactions play an important role at higher values of impact parameter, leading to few nucleon transfer processes. However, at smaller values, complete fusion(CF) reaction in which Projectile is completely fused with the target nucleus and highly excited compound nucleus decays by evaporating low-energy nucleons and α particles, incomplete fusion(ICF) in which only a part of the projectile fuses with the target nucleus, leading to the formation of an excited incompletely fused composite system with a mass and/or charge lower than that of the CN, while the remaining part escape sin forward cone with approximately the beam velocity [2 ]. Various dynamical models, such as, Sum rule model [3],break-up fusion (BUF) model [4 ] and promptly emitted particle model [5] have been proposed to explain the mechanism of ICF reactions. However, no theoretical model is available so far fully to explain the gross features of experimental data available below E/A=10 MeV/nucleon. And none of the proposed models is able to reproduce the experimental data obtained at energies as low as ≈ 4-8 MeV/nucleon. Abhishek et al [6 ] studied effect of entrance channel properties in the incomplete fusion of 12 C+ 159 Te at energies≈ 4-7MeV/A. The results indicated that incomplete fusion contribution found to be sensitive to the projectile type, energy and entrance channel mass-asymmetry.
Pushpendra et al [7] studied the dynamics of incomplete fusion by spin distribution of 16 O + 169 Tm system at ≈5.6 MeV/nucleon. The result showed that the measured normalized production yields of fusion-evaporation xn/αxn-channels in good agreement with the predictions of theoretical model code PACE4. Further the study indicated that residues from the complete fusion process are strongly fed over a broad spin range, while residues from incomplete fusion process are found to be less fed and/or the populations of lower spin states are strongly hindered.

Formulations and computer code
There are different computer codes to calculate the theoretical excitation functions. Those are PACE4, CASCADE, ALIC-91 AND COMPLET codes. However, PACE4 predictions were found to be in good agreement for complete fusion channels for the present projectile-target system. And analysis with computer code PACE4 within consideration of Hauser-Feshbach formulation also discussed in this section [8].

PACE4 code
An analysis of experimentally measured excitation functions was also made using the theoretical predictions of the PACE4 code. The code PACE4 is based on Hauser Feshbach theory for CN-decay and uses statistical approach of CN de-excitation by Monte Carlo procedure. The code uses the BASS model for CF cross section calculation. The default optical model parameters for neutrons, protons and α-particles are used. In addition code has been modified to take into account the excitation energy dependence of the level density parameter using the prescription Kataria etal [9]. It should be pointed out that the ICF and PE-emission are not taken into consideration in this code. The process of de-excitation of the excited nuclei was calculated using code PACE4 which follows the correct Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol.81, 2019 2 procedure for angular momentum coupling at each stage of de-excitation. The code PACE4 used as Monte Carlo procedure to determine the decay of sequence of an excited nucleus using Hauser-Feshbach formalism. To compare the measured EF's with theoretical predication obtained from PACE4 for possible residues populated in reaction. Cross-section are deduced using Morgenstern et al [10].
The ICF fraction which tells the contribution of ICF in the total process is calculated To see the correlations between the deduced incomplete fusion fraction and entrance channel properties (normalized projectile energy, mass-asymmetry and projectile structure) Instead of projectile energy (Ep) we used the normalized projectile energy (Ep/VCB) that swallowed the effect coming from different coulomb barrier.
To see the correlation between with normalized projectile velocity (Vrel/c)

Result and Discussion
3.1 System with 12 C projectile C) 12 C + 128 Te systems In this system the values of the level density parameter (K= 8, 10, 12), were diverse to fit to the experimentally restrained EFs for a illustrative of non-α-emitting ( 12 C, 5n) channel, in this channel also there is no probability of ICF reaction arising and consequently, this channel is inhabited only by CF process. As can be perceived from Fig.  1 (a) the PACE4 predication with K=10 in general imitated suitably the experimentally restrained EFs. For all conceivable channels in the reaction 12 C+ 128 Te system all calculations and analysis existed done constantly using K=10. The measured EFs beside with the PACE4 estimate for illustrative residue inhabited through-α-emitting channel is displayed in Fig. 1 Fig.1 (a) non-α-emitted channels for ( 12 C, 5n) and (b) alpha emitted channels for ( 12 C, α5n).

System with 14 N projectile E) 14 N+ 128 Te system
In 14 N+ 128 Te system the values of the level density parameter (K=8, 10, 12) were varied to fit to the experimentally measured EFs for a representative non-α emitting, ( 14 N, 4n) channel. In this channel also there is no prospect of ICF reaction occurring and therefore, this channel is populated only by CF process. As can be seen from this Fig.  2 (a) the PACE-4 predication with K = 12 in general reproduced satisfactorily the experimentally measured EFs. For all possible channels in the interaction 14 N+ 128 Te system all calculations and analysis were done consistently using K = 12. The measured EFs along with the PACE-4 prediction for representative residue populated via αemitting channel is shown in Fig.2 (b). A representative 133 La residue may be populated through CF and/or ICF processes as: i

Incomplete fusion contributions
In this section an attempt has been made to separate out the influences of ICF in all α-emitting channels populated in the interactions of a 12 C, and 14 N projectiles with 128 Te targets. The sum of the ICF cross-section for the respective systems, ICF   , was assigned to the difference between the higher charged isobaric precursor decay Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol.81, 2019 4 corrected measured cross-section for possible α emitting channels, ∑ and the calculated cross-section ∑ for best fitted K value. It is clearly seen in Fig. 3 from (d) to (e) that ICF production cross-section =∑ ∑ increase significantaly with increase in beam energy Fig.3: versus Eproj. It has been mentioned that all the α-emitting channels identified in the present systems are expected to have significant contributions from ICF reactions. Fig. 4 (d) and (e) displayed the sum of contributions coming from all ICF channels andthe sum of all CF channels∑ were plotted along with the total fusion cross-section σTF = +∑ for all α and non-α emitting channels in 12 C + 128 Te systems. As can be observed from these figure the CF components have dominant contribution up to ≈ 72 MeV, and ≈75MeV for 14 N + 128 Te , 12 C + 128 Te systems, respectively, while ICF contribution seems start to influence from these points Fig.4: The total sum of the measured, σTF and the total sum of the CF cross-sections, ∑ along with the total sum of ICF cross-sections, at various energies. Further, except for 14 N + 128 Te system it is clearly seen from these figures that the separation between the plots of and σTF in general decreases significantly from these points onwards with an increase in projectile energy, which indicates that the ICF contribution becomes larger at higher energy points in the respective systems. This may be due to an increase in the probability of projectile break up into α-clusters 14 N ( 10 B+ α) and 12 C ( 8 Be + α → α + α + α) as the projectile energy increases

Conclusion
In present work, the excitation function of several evaporation residue populated through complete and incomplete fusion channels have been measured in the energy range of 3-7 MeV/A. The measured data available were compared with calculation done using the statistical model code PACE4. For illustrative of non-α-emitting channel from the experimental measured excitation functions, after correcting them for possible contributions from higher charger isobaric precursor decays, was in general found to be good agreement with the theoretical predications. However, for α-emitting channels, the measured excitation functions after correcting the HCIP contribution (if any) were significantly higher than the values predicted by PACE4.