Precision measurements with trapped radioactive ions using the Canadian Penning Trap Mass spectrometer and associated ion traps at the Argonne National Laboratory

对远离稳定性的核素的原子质量的精确测量提供了关于衰变和核反应中释放的能量的信息，这些信息涉及这些外来的、短寿命的核。这些结果是预测核反应速率和路径的重要组成部分，这些核反应为爆炸性天体物理事件提供动力，这些事件被认为是重元素核合成（通过rp-，nu-p-和r-过程）的原因。这些数据还提供了在核具有极端中子质子比的区域中的核结构的视图，并为粒子物理理论中的基本对称性研究提供了机会。 目前，加拿大的潘宁阱质谱仪（CPT）正被用于测量位于或接近天体物理r过程预期反应路径的非常富含中子的同位素的质量，这一区域靠近核稳定性的边缘，称为"中子倾角线"。感兴趣的原子核由位于阿贡国家实验室的阿贡串列直线加速器系统（ATLAS）的CARIBU（加利福尼亚放射性离子束升级）设施提供。这些奇异的、富含中子的原子是在1.7 Ci，252 Cf裂变源中通过自发裂变产生的，并被输送（几keV的能量）到CPT以精确测量它们的质量。或者，离子也可以被转移到射频四极离子阱（RFID），在那里它们悬浮在氦气中。这样一个几乎处于静止状态的奇异核云，为研究β粒子、中微子和其他衰变中发射的粒子之间的相关性以及测试粒子物理学理论中的对称性提供了一个独特的机会。 申请的数额将用于支付加拿大Penning Trap质谱仪（完全为加拿大所有）的操作和维护费用、3名研究生的津贴、一名博士后研究员的工资以及往返该设施的旅费。 这项工作是与J.Clark和G. Savard，物理部，阿贡国家实验室，Ralph Segel，西北大学，Nicholas Scielzo，劳伦斯利弗莫尔国家实验室和Ani Aprahamian，来自圣母大学，都来自美国。

Precision measurements of the atomic masses of nuclides far from stability provide information on the energy released in the decay and nuclear reactions involving these exotic, short-lived, nuclei. The results are an important ingredient in predicting the rates and pathways of nuclear reactions that power explosive astrophysical events thought to be responsible for the nucleosynthesis of the heavier elements (through the rp-, nu-p- and r-processes). The data also provides a view of nuclear structure in regions where the nuclei have extreme neutron to proton ratios and, provide an opportunity for the study of fundamental symmetries in particle physics theories. Currently, The Canadian Penning Trap Mass Spectrometer (CPT) is being used to measure the masses of very neutron-rich isotopes that lie on or near the expected reaction path for the astrophysical r-process, a region that lies near the edge of nuclear stability called the "neutron dip line". The nuclei of interest are provided by the CARIBU (Californium Radioactive Ion Beam Upgrade) facility at the Argonne Tandem Linear Accelerator System (ATLAS) at the Argonne National Laboratory. The exotic, neutron-rich, atoms are produced by spontaneous fission, in a 1.7 Ci, 252Cf fission source and delivered (with a few keV of energy) to the CPT for a precise measurement of their mass. Alternately, the ions can also be transferred to a radio-frequency quadrupole ion trap (RFQ) where they are suspended in helium gas. Such a cloud of exotic nuclei, nearly at rest, provides a unique opportunity to study the correlations between the beta particles, the neutrinos and other particles emitted in their decay and test symmetries in particle physics theories. The amount requested will cover the operation and maintenance costs of the Canadian Penning Trap mass spectrometer (which is entirely Canadian owned), 3 graduate student stipends , the salary for a post-doctoral fellow and, travel costs to and from the facility. This work is carried out in collaboration with J. Clark and G. Savard, Physics Division, Argonne National Laboratory, Ralph Segel, Northwestern University, Nicholas Scielzo, Lawrence Livermore National Laboratory and Ani Aprahamian from Notre Dame University, all from the USA.