Nuclear mass measurements and ion manipulation

此应用程序是为了继续支持短寿命放射性核的极高精度质量测量。 对这种测量的兴趣在于它们与将原子核结合在一起的核力的直接关系，从而确定原子核的结构。这些力是如此之强，以至于它们赋予原子核的结合能使原子核的质量降低了一个可测量的量。 放射性原子核（即不稳定原子核）特别令人感兴趣，因为原子核越不稳定，核作用力将其结合在一起的强弱就越明显。然而，短寿命放射性核的质量测量本质上比地球上存在的正常稳定原子的测量要困难得多。 这不仅是因为处理放射性的困难，更重要的是，因为原子核的寿命很短，只能在能够产生它们的高能加速器设施中获得，即使在那里，也只有非常微小的数量。这里提出的研究计划使用了一种基于电磁阱的新型高精度高灵敏度质谱仪，该质谱仪由麦吉尔与欧洲科学家合作开发。第一个这样的仪器名为ISOLTRAP，是为欧洲核子研究中心的ISOLDE放射性束设施开发的。 迄今为止，这一仪器已能测量200多个放射性原子核，最短的半衰期为85毫秒。 它还导致在世界各地建造了5台类似的光谱仪，其中新一代光谱仪是TRIUMF ISAC TITAN设施的重要组成部分。这项研究计划的一个重要组成部分是开发仪器，以有效地操纵放射性离子进入质谱仪。这项授权申请是为了进一步开发这种装置，特别是使用高射频四极电场在缓冲气体中操纵微型结构中的离子。这种技术不仅在核物理学中有应用，而且在生物分子研究和纳米科学中也有应用。

This application is for continued support of extreme accuracy mass measurements on short-lived radioactive nuclei.  The interest in such measurements is in their direct relationship to the nuclear forces that hold nuclei together, thereby determining the structure of the nuclei. These forces are so strong that the binding energy they give to a nucleus lowers its mass by a measurable amount.  Radioactive, i.e. unstable, nuclei are particularly interesting because the more unstable a nucleus the more obvious are the strengths, and weaknesses, of the nuclear forces in holding it together. However, mass measurements of short-lived radioactive nuclei are inherently much more difficult than measurements of normal, stable atoms such as exist on Earth.  This is not only because of difficulties in dealing with radioactivity but, more importantly, because the nuclei are short-lived and available only at the high-energy accelerator facilities that can produce them and, even there, only in very minute quantities. The research program proposed here uses a novel form of high-precision high-sensitivity mass spectrometer based on electromagnetic traps that has been developed by a McGill collaboration with European scientists. The first such instrument, named ISOLTRAP, was developed for the ISOLDE radioactive beam facility at CERN.  This instrument has to date allowed measurements on over 200 radioactive nuclei, the shortest half-life being 85 milliseconds.  It has also led to the construction of 5 similar spectrometers around the world, with a new generation of such a spectrometer being an essential part of the TITAN facility of ISAC at TRIUMF. An essential part of this research program is the development of apparatus to manipulate the radioactive ions efficiently into the mass spectrometer. This grant application is for further development of such apparatus, particularly using high radiofrequency quadrupole electric fields in buffer gas to manipulate the ions in miniature structures. Such techniques not only have applications in nuclear physics but also in biomolecular research and nanoscience.