激光电离飞行时间质谱用于矿石表面元素成像

高功率密度激光电离飞行时间质谱法(Laser ionization time-of-flight mass spectrometry,LI-TOF-MS)是一种先进的固体元素直接分析法.与传统的固体分析方法相比,其样品前处理简单、分析速度快,而且消耗样品量少、无毒、绝对灵敏度高,已广泛应用于地质、环境等领域[1～3].与同类的固体直接分析法相比,激光电离飞行时间质谱法具有谱图干扰少,可同时分析金属和非金属元素以及多元素同

中国沙漠的风沙地貌与环境研究

1.项目的简要说明 本项目属地球科学领域,自然地理学地貌与第四纪环境变化方向,根据国务院下达的西北和内蒙六省区沙漠综合考察与治沙试验研究,省部委委托的沙漠地区公路和铁路防沙专题研究,以及国家基金、国家重点实验室的研究项目取得的科研成果,由本项目由中国科学院新疆生态与地理研究所、华南师范大学、北京师范大学等7家单位的吴正、李保生、邹学勇等12位教授或研究员组成的研究团队,进行了集成研究取得的总结性成果。系统的研究了中国沙漠的类型和分布、形成演变、风沙地貌形成发育、自然环境、自然资源及其开发利用,沙害的治理等科学问题。 2.主要技术指标 本项成果旨在提炼主要完成人近5..

激光电离飞行时间质谱用于矿石表面元素成像

An elemental imaging system was developed based on the high irradiance laser ionization time-of-flight mass spectrometry(LI-TOF-MS), which could be applied to analyze all elements simultaneously and sensitively, including metals and non-metals. A stibnite sample was analyzed and elemental images of Sb, S, Si, Al, K, Ca, and Fe were subsequently acquired. Standardless semi-quantitation of detected elements on the stibnite surface was thus performed and the results indicate that the surface elemental imaging system associated with the LI-TOF-MS was a promising tool for elemental imaging Of solid surface and standardless elemental semi-quantitation

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel