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原子质量的精确测量提供了涉及这些奇异的、短暂的原子核的衰变和核反应中释放的能量的信息。这些结果是预测核反应的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，被认为是较重元素的核合成(通过rp-、nu-p-和r-过程)。这些数据还提供了原子核具有极端中子质子比区域的核结构视图，并为研究粒子物理理论中的基本对称性提供了机会。 目前，加拿大彭宁陷阱质谱仪(Cpt)正被用来测量位于天体物理r过程预期反应路径上或附近的非常丰富的中子同位素的质量，这一区域位于核稳定的边缘，被称为“中子倾斜线”。感兴趣的核是由位于阿贡国家实验室的阿贡串联式直线加速器系统(ATLAS)的Cariu(加利福尼亚放射性离子束升级)设施提供的。这些奇异的、富含中子的原子是在1.7Ci、252Cf的裂变源中自发裂变产生的，并被送到CPT(带有几keV的能量)，用于精确测量它们的质量。或者，离子也可以转移到射频四极离子陷阱(RFQ)，在那里它们悬浮在氦气中。这样一团几乎静止不动的奇异原子核，为研究β粒子、中微子和衰变过程中发射的其他粒子之间的关联，以及在粒子物理理论中测试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(完全由加拿大人拥有)的操作和维护费用、3名研究生津贴、博士后研究员的工资以及往返该设施的旅费。 这项工作是与来自美国圣母大学的J.Clark和G.Savard，阿贡国家实验室物理部，西北大学Ralph Segel，Nicholas Scielzo，Lawrence Livermore国家实验室和Ani Aprahamian合作进行的。

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.