标题： 直接质量测量超出质子滴线 显示英文标题

标题： Direct mass measurements beyond the proton drip-line

摘要： 首次在线质量测量是在SHIPTRAP Penning trap 质量质谱仪上进行的。 在铽到铥区域产生的18个中子缺乏同位素的质量通过大约$7\cdot 10^{-8}$的相对不确定度确定，其中九种是首次确定。 四个核素（$^{144, 145}$Ho 和 $^{147, 148}$Tm）被发现是质子不结合的。 通过分析单质子分离能，讨论了这些结果对质子滴线位置的影响。 显示英文摘要

摘要： First on-line mass measurements were performed at the SHIPTRAP Penning trap mass spectrometer. The masses of 18 neutron-deficient isotopes in the terbium-to-thulium region produced in fusion-evaporation reactions were determined with relative uncertainties of about $7\cdot 10^{-8}$, nine of them for the first time. Four nuclides ($^{144, 145}$Ho and $^{147, 148}$Tm) were found to be proton-unbound. The implication of the results on the location of the proton drip-line is discussed by analyzing the one-proton separation energies.