Observation of the 3
evaporation channel in the complete hot-fusion reaction
Mg +
Cm leading to the new superheavy nuclide
Hs
Hot-fusion反応
Mg+
Cmにおける3
蒸発過程の観測; 新しい超重核種
Hsの合成
Dvorak, J.*; Br
chle, W.*; Chelnokov, M.*; D
llmann, Ch. E.*; Dvorakova, Z.*; Eberhardt, K.*; J
ger, E.*; Kr
cken, R.*; Kuznetsov, A.*; 永目 諭一郎
; Nebel, F.*; 西尾 勝久
; Perego, R.*; Qin, Z.*; Sch
del, M.*; Schausten, B.*; Schimpf, E.*; Schuber, R.*; Semchenkov, A.*; Th
rle, P.*; T
rler, A.*; Wegrzecki, M.*; Wierczinski, B.*; Yakushev, A.*; Yeremin, A.*
Dvorak, J.*; Br
chle, W.*; Chelnokov, M.*; D
llmann, Ch. E.*; Dvorakova, Z.*; Eberhardt, K.*; J
ger, E.*; Kr
cken, R.*; Kuznetsov, A.*; Nagame, Yuichiro; Nebel, F.*; Nishio, Katsuhisa; Perego, R.*; Qin, Z.*; Sch
del, M.*; Schausten, B.*; Schimpf, E.*; Schuber, R.*; Semchenkov, A.*; Th
rle, P.*; T
rler, A.*; Wegrzecki, M.*; Wierczinski, B.*; Yakushev, A.*; Yeremin, A.*
Cm+
Mg反応で生成する108番元素ハッシウム(Hs)同位体の生成断面積を迅速気相化学分離装置COMPACTを用いて測定した。入射重イオン
Mgのエネルギーを変化させ
Cm(
Mg,
)反応の励起関数を求めたところ、比較的軽い重イオンとアクチノイドターゲットを組合せた反応、いわゆるHot-fusion反応での3
蒸発過程が初めて観測された。この蒸発過程で生成する新しい超重核種
Hsを同定することに成功した。
The analysis of a large body of heavy ion fusion reaction data with medium-heavy projectiles (6
Z
18) and actinide targets suggests a disappearance of the 3
exit channel with increasing atomic number of the projectile. Here, we report a measurement of the excitation function of the reaction
Cm(
Mg,
)
Hs and the observation of the new nuclide
Hs produced in the 3
evaporation channel at a beam energy well below the Bass fusion barrier with a cross section comparable to the maxima of the 4
and 5
channels. This indicates the possible discovery of new neutron-rich transactinide nuclei using relatively light heavy ion beams of the most neutron-rich stable isotopes and actinide targets.