Observation of new neutron-rich isotopes in the vicinity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Zr</mml:mi><mml:mprescripts/><mml:none/><mml:mn>110</mml:mn></mml:mmultiscripts></mml:math>
T. Sumikama, N. Fukuda, N. Inabe, D. Kameda, T. Kubo, Y. Shimizu, Hiroaki Suzuki, H. Takeda, K. Yoshida, H. Baba, F. Browne, A. M. Bruce, R. Carroll, N. Chiga, R. Daido, F. Didierjean, P. Doornenbal, Y. Fang, G. Gey, E. Ideguchi, T. Isobe, S. Lalkovski, Z. Li, G. Lorusso, R. Lozeva, H. Nıshıbata, S. Nishimura, I. Nishizuka, A. Odahara, Z. Patel, Zs. Podolyák, P. H. Regan, S. Rice, O. J. Roberts, H. Sakuraï, G. S. Simpson, L. Sinclair, P.-A. Söderström, M. Tanaka, J. Taprogge, H. Watanabe, V. Werner, O. Wieland, J. Wu, Z. Y. Xu, A. Yagi
Abstract
Neutron-rich radioactive isotope (RI) beams in the vicinity of $^{110}\mathrm{Zr}$ were produced using the in-flight fission of a 345-MeV/nucleon $^{238}\mathrm{U}$ beam at the RIKEN Radioactive Isotope Beam Factory. The RI beams were separated in flight by the large-acceptance two-stage fragment separator BigRIPS. Isotopes were clearly identified in a low-background particle-identification plot, which was obtained from the measurements of time of flight, magnetic rigidity, and energy loss using beam-line detectors placed in the BigRIPS separator and the ZeroDegree spectrometer. Nine new isotopes, $^{101}\mathrm{Br}, ^{102}\mathrm{Kr}, ^{105,106}\mathrm{Rb}, ^{108}\mathrm{Sr}, ^{110,111}\mathrm{Y}, ^{114}\mathrm{Zr}$, and $^{117}\mathrm{Nb}$, are reported for the first time, with their measured production cross sections compared with the extrapolations of lighter isotopes down to the femtobarn regime.