论文标题
$^{204} $的高旋转状态：异构体和剪切带结构
High spin states of $^{204}$At: isomeric states and shears band structure
论文作者
论文摘要
通过$^{12} $ C + $^{197} $ AU Fusion Fusion Fusion Avaporation Reactions的高旋转不足的trans铅核$^{204} $ at的高旋转状态最多可达$ \ sim 8 \，{\ rm mev} $激发。研究了相关水平通过迅速和延迟的$γ$ - 雷排放的衰减，以评估潜在的核结构。部分众所周知的水平方案进一步扩展。从我们的测量值中建立了一个Isomeric $ 16^+$级别，具有观察到的寿命$τ= 52 \ pm 5 \，{\ rm ns} $。试图根据涉及$ 2F_ {5/2} $，$ 1H_ {9/2} $的多质量和孔结构来解释激发态，以及$ 1I_ {13/2} $ shell Model Model State，以及中等核心的激发。旋转奇偶校验范围内的磁性偶极子带结构：〜$ 16^+ -23^+ $进行了更详细的确认和评估，包括缺失的交叉$ E2 $转换。观察到沿着剪切带的带划线，并将其与相邻中子不足的$^{202} $ bi，$^{205} $ rn同酮和同位素的$^{203} $进行比较。基于与基于半经典模型的估计值的测量$ B（M1）/B（E2）$值的比较，$^{204} $ at的剪切频带与级别方案一起建立了。
High-spin states of neutron deficient Trans-Lead nucleus $^{204}$At were populated up to $\sim 8\,{\rm MeV}$ excitation through the $^{12}$C + $^{197}$Au fusion evaporation reaction. Decay of the associated levels through prompt and delayed $γ$-ray emissions were studied to evaluate the underlying nuclear structure. The level scheme, which was partly known, was extended further. An isomeric $16^+$ level with observed lifetime $τ=52 \pm 5\, {\rm ns}$, was established from our measurements. Attempts were made to interpret the excited states based on multi quasiparticle and hole structures involving $2f_{5/2}$, $1h_{9/2}$, and $1i_{13/2}$ shell model states, along with moderate core excitation. Magnetic dipole band structure over the spin parity range:~$16^+ - 23^+$ was confirmed and evaluated in more detail, including the missing cross-over $E2$ transitions. Band-crossing along the shears band was observed and compared with the evidence of similar phenomena in the neighbouring neutron deficient $^{202}$Bi, $^{205}$Rn isotones and the $^{203}$At isotope. Based on comparison of the measured $B(M1)/B(E2)$ values for transitions along the band with the semiclassical model based estimates, the shears band of $^{204}$At was established along with the level scheme.
