Production and discovery of neutron-rich isotopes by fragmentation of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Pt</mml:mi><mml:mprescripts/><mml:none/><mml:mn>198</mml:mn></mml:mmultiscripts></mml:math>
K. Haak, O. Tarasov, P. Chowdhury, A. M. Rogers, Kanishka Sharma, T. Baumann, D. Bazin, P. C. Bender, Jun Chen, A. Estradé, M. Famiano, D. Foulds-Holt, N. Fukuda, A. Gade, T. N. Ginter, R. W. Gohier, M. Hausmann, A. M. Hill, D. E. M. Hoff, L. Klankowski, E. Kwan, Jinyang Li, S. N. Liddick, B. Longfellow, S. Lyons, C. Morse, M. Portillo, D. Rhodes, A. L. Richard, S. Samaranayake, B. M. Sherrill, M. K. Smith, M. Spieker, C. Sumithrarachchi, Hideyuki Suzuki, K. Wang, S. Waniganeththi, D. Weisshaar, S. J. Zhu
Abstract
Production cross sections were measured for fragments produced by an 85 MeV/u $^{198}\mathrm{Pt}$ beam incident on a beryllium target. Event-by-event particle identification of $A, Z$, and $q$ for the reaction products was performed by employing energy loss, time-of-flight, magnetic rigidity, and total kinetic energy measurements. Over 70 nuclei in the Hf-Pt region were identified, including three isotopes first observed in this work: $^{191,192}\mathrm{Hf}$ and $^{189}\mathrm{Lu}$. Due to the existence of multiple charge states between H-like and C-like ions, a new analysis method was introduced, incorporating Monte Carlo calculations of charge state fractions for a given charge state of the projectile residue just after the reaction. For the first time, charge-state probability distribution functions after the reaction have been deduced from experimental data. This study provides insight into how to produce key nuclides near $N=126$ and the ability of a fragmentation residue to retain electrons from the primary beam.