New neutron-rich isotopes Mg-38, Al-40, and Al-41 produced by fragmentation of a 70A MeV Ca-48 beam

Abstract

The results of an experiment by the RIKEN (Institute of Physical and Chemical Research)-JINR collaboration on search for new Ne, Na, Mg, and Al isotopes close to the neutron drip-line are presented. Three new neutron-rich nuclei, Mg-38, Al-40, and Al-41, were found for the first time. These nuclei were produced by the projectile fragmentation of a 70AMeV Ca-48 beam. The 64 percent enriched Ca-48 oxide powder was used to produce the Ca-48 ions at the ECR source of the AVF cyclotron. The Ca-48 beam struck a Ta-181 target. Reaction fragments were collected and analyzed with the RIPS (RIKEN Projectile fragment Separator) spectrometer operated in the achromatic mode. Data were accumulated for one day with an average beam intensity of 2 pnA. Significant numbers of events were observed for new isotopes, Mg-38, Al-40, and Al-41. No events associated with Ne-33 were observed.

理化学研究所-JINRによる中性子ドリップラインに近いNe、Na、Mg、そしてAlの新しい同位体の共同研究の結果を示す。3つの新たな中性子過剰核、Mg-38、Al-40、Al-41を初めて発見した。これらの核を70AMeVのCa-48ビームの入射核破砕によって生成した。64%に濃縮した酸化Ca-48粉末をAVFサイクロトロンのECR源でCa-48イオン生成に使った。このCa-48ビームをTa-181標的と反応させた。反応破砕核をアクロマティックモードのRIPS(理化学研究所破砕核分離装置)スペクトルメータで解析した。平均ビーム強度2pnAで1日間収集したデータから結果を得た。新しい同位体Mg-38、Al-40、そしてAl-41の多数の現象を観測した。しかし、Ne-33の現象を発見できなかった。