Fast-Neutron Activation of Long-Lived Isotopes in Enriched Ge
S. R. Elliott, V. E. Guiseppe, R. A. Johnson, B. H. LaRoque, S. G. Mashnik
备注：
Revised after feedback and further work on extrapolating cross sections to higher energies in order to estimate cosmic production rates. Also a numerical error was found and fixed in the estimate of the Co-57 production rate
We measured the production of \nuc{57}{Co}, \nuc{54}{Mn}, \nuc{68}{Ge}, \nuc{65}{Zn}, and \nuc{60}{Co} in a sample of Ge enriched in isotope 76 due to high-energy neutron interactions. These isotopes, especially \nuc{68}{Ge}, are critical in understanding background in Ge detectors used for double-beta decay experiments. They are produced by cosmogenic-neutron interactions in the detectors while they reside on the Earth's surface. These production rates were measured at neutron energies of a few hundred MeV. We compared the measured production to that predicted by cross-section calculations based on CEM03.02. The cross section calculations over-predict our measurements by approximately a factor of three depending on isotope. We then use the measured cosmic-ray neutron flux, our measurements, and the CEM03.02 cross sections to predict the cosmogenic production rate of these isotopes. The uncertainty in extrapolating the cross section model to higher energies dominates the total uncertainty in the cosmogenic production rate.
The Advanced Molybdenum-based Rare process Experiment (AMoRE) searches for neutrino-less double-beta (0ν\b{eta}\b{eta}) decay of 100Mo in enriched molybdate crystals. The AMoRE crystals must have low levels of radioactive contamination to achieve low background signals with energies near the Q-value of the 100Mo 0ν\b{eta}\b{eta} decay. To produce low-activity crystals, radioactive contaminants in the raw materials used to form the crystals must be controlled and quantified. 100EnrMoO3 powder, which is enriched in the 100Mo isotope, is of particular interest as it is the source of 100Mo in the …
Activation cross sections of proton and deuteron induced nuclear reactions on holmium and erbium, related to the production of $^{161}$Er and $^{160}$Er medical isotopes
First investigation of $^{96}$Zr samples enriched by the gas-centrifuge method for the use in rare-decay studies
Electrochemical Plant（电化学工厂）；NRC Kurchatov Institute（库尔恰托夫国家研究中心）；Université Lyon, Université Lyon 1, CNRS/IN2P3, IP2I-Lyon（里昂大学，里昂第一大学，法国国家科学研究中心/法国国家粒子物理研究所，IP2I-里昂）；Joint Institute for Nuclear Research（俄罗斯联合核子研究所）；Institute for Nuclear Research of the Russian Academy of Sciences（俄罗斯科学院核子研究所）；Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences（保加利亚科学院核子研究与核能研究所）；Institute of Nuclear Physics, Ministry of Energy of the Republic of Kazakhstan（哈萨克斯坦共和国能源部核物理研究所）
A Precision Experiment to Investigate Long-Lived Radioactive Decays
放射性被理解为通过泊松过程来描述，然而核衰变的一些测量似乎表现出意想不到的变化。通常，报告这些变化的同位素具有长半衰期，这受到大的测量不确定性的困扰。除了这些固有的问题，还有一些关于衰变率随时间变化的报道，甚至声称有奇异的中微子引起的变化。我们提出了一个专门的实验稳定的长期测量伽马发射产生的$β$衰变，这将提供高质量的数据，并允许识别潜在的系统影响。放射性同位素由32个76 mm $\times$ 76 mm NaI（Tl）探测器在三大洲的四个独立温控装置中进行冗余监测。在每种设置中，对环境和操作条件的监测有助于相关性研究。数据采集系统的无死区性能由LED脉冲发生器监控。所有事件的数字化光电倍增管波形被单独记录，从而能够使用时间分组和未分组分析来研究跨越微秒到数年的时间依赖效应。我们表征实验的稳定性，并表明，相关的系统学占，使精确测量的影响水平远低于$\mathcal{O}(10^{-4})$。
Underground argon (UAr) with lower cosmogenic activities of $^{39}Ar$ and $^{42}Ar$ has been planned as a detector in detecting scintillation light and charge collection using time projection chambers for dark matter searches and as a veto detector in suppressing backgrounds for neutrinoless double beta decay (0$νββ$) experiments. Long-lived radioactive isotopes, $^{39}Ar$ and $^{42}Ar$, can also be produced on the surface when UAr is pumped out from a deep well. Understanding the production of long-lived isotopes in Ar is important for utilizing UAr for dark matter and 0$νββ$ experiments in t…
On-line Excited-State Laser Spectroscopy of Trapped Short-Lived Ra$^+$ Ions
作为一个单一的捕获Ra $^+$离子的原子宇称破坏实验的重要一步，激光光谱实验进行了与在线产生的短寿命$^{212,213,214}$ Ra $^+$离子。测量了$^{213}$ Ra $^+$中$6\,^2$ D $_{3/2}$ \，-\，$7\,^2$ P $_{1/2}$和$6\,^2$ D $_{3/2}$ \，-\，$7\,^2$ P $_{3/2}$跃迁的同位素位移和$7\,^2$ S $_{1/2}$和$6\,^2$ D $_{3/2}$态的超精细结构常数。这些值为所需的原子理论提供了基准。通过光学搁置测量亚稳态$6\,^2$ D $_{5/2}$状态的寿命的下限$232(4)$ ms。
Isotope shifts of $^{223-226,228}$Ra$^{19}$F were measured for different vibrational levels in the electronic transition $A^{2}{}Π_{1/2}\leftarrow X^{2}{}Σ^{+}$. The observed isotope shifts demonstrate the particularly high sensitivity of radium monofluoride to nuclear size effects, offering a stringent test of models describing the electronic density within the radium nucleus. Ab initio quantum chemical calculations are in excellent agreement with experimental observations. These results highlight some of the unique opportunities that short-lived molecules could offer in nuclear structure and…
The use of active interrogation (AI) to induce delayed neutron emission is a well-established technique for the characterization of special nuclear materials (SNM). Delayed neutrons have isotope-characteristic spectral and temporal signatures, which provide the basis for isotope identification. However, in bulk materials that contain an appreciable fissile (e.g., $^{235}$U or $^{233}$U) fraction, such as highly-enriched uranium (HEU), delayed neutrons have a high probability of inducing additional fissions. As a result, the overall delayed neutron signature consists of two distinct components:…
Nuclear properties across the chart of nuclides are key to improving and validating our understanding of the strong interaction in nuclear physics. We present high-precision mass measurements of neutron-rich Fe isotopes performed at the TITAN facility. The multiple-reflection time-of-flight mass spectrometer (MR-ToF-MS), achieving a resolving power greater than $600\,000$ for the first time, enabled the measurement of $^{63-70}$Fe, including first-time high-precision direct measurements ($δm/m \sim 10^{-7}$) of $^{68-70}$Fe, as well as the discovery of a long-lived isomeric state in $^{69}$Fe.…
