Speaker
Description
Recently several exclusive breakup studies have been reported with stable weakly bound $\alpha$ cluster nuclei like $^{6,7}$Li and $^9$Be ($E_{th}$$<$ 2.5 MeV). A number of interesting observations and features related to breakup of projectile/ejectile in the vicinity of target nucleus have been revealed. There are very few exclusive charged particle coincidence studies performed for the investigation of cluster structure of $^{10}$B nucleus. $^{10}$B nucleus can directly break into its various cluster configurations, $\textit{viz.}$, $^{6}$Li+$\alpha$, $\alpha$+$\alpha$+$d$, $^8$Be+$d$, and $^9$Be+$p$ with breakup thresholds ($E_{\rm th}$) of 4.46, 5.93, 6.03, and 6.59 MeV respectively. There can also be transfer of few nucleon(s) between target and projectile followed by the breakup of unbound/weakly bound ejectiles. In the present study we are probing the cluster structure of $^{10}$B nucleus using breakup and transfer followed by breakup reactions.
The experiment was performed using $^{10}$B beam of 54 MeV energy using the 14UD BARC-TIFR Pelletron-LINAC Facility, Mumbai. A self-supporting foil of $^{209}$Bi of thickness $\sim$ 1 mg/cm${^2}$ was used as target. Double sided $\Delta\textit{E-E}$ type Silicon strip detector telescope array covering wide angular range was used for the measurement of the outgoing breakup fragments.
In the present work investigation of 2$\alpha$ coincident events in $^{10}$B+$^{209}$Bi reaction have been performed. The relative energy spectra between two $\alpha$ particles detected in coincidence peaks at $\sim$ 92 keV that corresponds to the decay of $^8$Be nucleus into 2$\alpha$ particles from its ground state. It shows that most of the 2$\alpha$ coincident events are resulting from $^8$Be$_{g.s.}$ decay. The tail part of $^8$Be(2$^+$, 3.03 MeV) was also seen in the relative energy spectra. These 2$\alpha$ coincident events may be produced in various direct breakup of $^{10}$B $\textit{e.g.}$ $^{10}$B$^*$$\rightarrow$ $^{8}$Be+$d$ or there can be transfer followed by breakup of ejectiles. The ejectile breakup modes after $n,p$, and $d$ stripping reactions are: $^{9}$B$\rightarrow\alpha+\alpha+p$, $^{9}$Be$^*\rightarrow\alpha+\alpha+n$ ($E_{th}$=1.57 MeV) and $^{8}$Be$\rightarrow\alpha+\alpha$ respectively. The energy ($\textit{E}_{8_{Be}}$) and angle ($\theta_{8_{Be}}$) of $^{8}$Be prior to the breakup into two $\alpha$ particles were reconstructed using momentum conservation. Kinematical lines of $^8$Be corresponding to direct breakup and nucleon(s) transfer followed by breakup of ejectiles ($^{9}$B, $^{9}$Be$^*$, and $^{8}$Be) on energy ($\textit{E}_{8_{Be}}$)-angle ($\theta_{8_{Be}}$) correlation plot indicates that transfer followed by breakup of ejectiles is a dominant mechanism for 2$\alpha$ coincident events in $^{10}$B+$^{209}$Bi reaction. Also various direct breakup modes of $^{10}$B nucleus is also being investigated. Result from both breakup and transfer followed by breakup reaction will be presented in the conference.
