Spin distribution of evaporation residues formed in complete and incomplete fusion in 16 O+ 154 Sm system

The spin-distributions of different reaction products populated via x n and α/2αx n channels in C 12 + Tm 169 system have been measured at E lab ≈ 6, 7 and 7.5 MeV A−1 to disentangle complete and incomplete fusion events. Particle (p, α)-γ-coincidences were recorded to identify evaporation residues channel-by-channel. The spin-distributions of fusion evaporation and direct-α-emitting channels are found to be distinct corroborating the involvement of entirely different reaction dynamics in their production, respectively termed as complete (CF) and incomplete fusion (ICF). The values of mean input angular momenta, obtained from the analysis of the spin-distributions, involved in ICF-α/2α xn channels are estimated to be larger than that observed in CF-xn/α xn channels. For ICF-α/2αxn channels, the multiplicity of fast-α particle emission increases with the magnitude of input angular momentum imparted into the system. The CF residues display a population of broad spin range while the ICF residues are confined to a narrow spin range generally localized in the higher spin states. Findings of the present work conclusively demonstrate the possibility to populate high spin states in final reaction products using ICF, which are otherwise not accessible. Further, an attempt has been made to study the variation of input angular momentum with the choice of different entrance-channel parameters. It has been observed that the value of input angular momentum involved in ICF-α/2α xn channels increases with the deformation and entrance-channel mass-asymmetry parameter, indicating strong entrance-channel dependence of ICF dynamics.

Section: Localization Of -Window and Entrance-channel Dependence Of Icfmentioning

confidence: 99%

Section: Localization Of -Window and Entrance-channel Dependence Of Icfmentioning

confidence: 99%

Disentangling complete and incomplete fusion events in ¹²C + ¹⁶⁹Tm reaction by spin-distribution measurements

Sood¹,

Thakur²,

Sharma³

et al. 2020

“…At energies near and above the Coulomb barrier, complete fusion (CF) is expected to be the dominant reaction mode. However, in the past few decades a number of studies had confirmed that incomplete fusion (ICF) also contributes at such energies [1][2][3][4][5][6]. Britt and Quinton et al [7] first studied ICF reactions in the early sixties, where they experimentally observed fast α-particles in the reaction of 12 C, 14 N and 16 O projectiles with 209 Bi and 197 Au target.…”

Section: Introductionmentioning

confidence: 99%

“…Most of these studies were carried out at beam energies greater than 10 MeV/nucleon. In recent decades, a measurable ICF probability fraction (F ICF (%)) in the energy range 4-7 MeV/nucleon has also been observed which makes it significantly interesting to study dynamics of these reactions [1][2][3][4][11][12][13][14][15]. In the CF reactions, the projectile completely fuses with the target nucleus and forms a compound nucleus (CN).…”

Section: Introductionmentioning

confidence: 99%

Study of incomplete fusion reaction dynamics for the system ¹⁴N + ¹⁶⁹Tm using the forward Recoil Range distribution technique

Kumar¹,

Giri²,

Kumar³

et al. 2022

Self Cite

Studies in the past have demonstrated that complete fusion and incomplete fusion dynamics are both significant just above the Coulomb barrier, yet the dynamics of incomplete fusion are elusive since they are so complex below 10 MeV/nucleon. In order to investigate low-energy incomplete fusion dynamics, we measured the forward recoil range distribution of evaporation residues populated in the system 14N + 169Tm at energy ≈ 5.9 MeV/nucleon. A stack target-catcher activation technique followed by offline-γ- spectroscopy was used to estimate the forward recoil range distribution of the evaporation residues. In order to investigate a new parameter for describing incomplete fusion dynamics, the incomplete fusion fraction (FICF (%)) for the present system was estimated from the range-integrated cross-sections and compared with other systems in the literature. The forward recoil range distribution and range integrated cross-sections of seven evaporation residues have been estimated experimentally. These cross-section results agree well with the experimental results obtained from the excitation functions. On re-investigation of entrance channel systematics for Qα value of projectile, mass-asymmetry (µMA), and Coulomb factor (ZP ZT ), it has been found that the Qα-value systematic for 14N is not valid at all projectile energies. The forward recoil range distribution measurement is one of the direct methods available to probe the complete and incomplete fusion contributions in evaporation residues at low projectile energy. It has also been observed that the dynamics of ICF are not only dependent on the parameters of one entrance channel but on multiple entrance channels. We have also introduced the entrance channel parameter Zeta (ζ) for the first time in Incomplete Fusion reactions to see the combined effect of mass-asymmetry (µMA) and ZP ZT, as this parameter is better suited than µMA and ZP ZT individually and has a linear dependency on FICF (%).

“…However, measurements have shown that 9 Be breakup occurs predominantly via an excited 8 Be nucleus [17], so this approximation is justified. The use of 20 Ne has not been examined thoroughly in current research, since most ICF experimental research uses projectiles with Z10 such as 9 Be, 12 C, 14 N, 16 O and 19 F against medium to heavy targets [5,[18][19][20][21][22]. The result of its breakup is interesting because of the much larger 16 O cluster that provides additional torque to the fusing α nucleus.…”

Section: Introductionmentioning

confidence: 99%

Populating high spin states of a compound nucleus with the incomplete fusion mechanism: the effectiveness of heavy projectiles

Lee¹,

Díaz-Torres²

2019

Using a classical dynamical reaction model, angular momentum (L) values of a compound nucleus due to incomplete fusion (ICF) at energies near and above the Coulomb barrier are studied. In this model, a projectile consisting of two cluster nuclei is fired at a stationary target nucleus. After breakup of the projectile due to Coulombic and nuclear forces, an α-cluster fuses with a 208Pb target, forming an excited 212Po compound nucleus. Results show that all ICF reactions produced higher angular momentum in the compound nucleus compared to a direct beam of α particles at the same incident energy. The highest angular momentum values produced in 212Po for near and above Coulomb barrier energies were obtained using a 20Ne projectile at and , respectively. This produced 25% and 50% L values above the next highest-Z projectile used, 8Be, respectively.