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Mobile Magnetic Ressonance Sensor utilizing a superconductive coil for prepolarisation in the near subsurface (MORE SPIN)

利用超导线圈在近地表下进行预极化的移动磁共振传感器 (MORE SPIN)

基本信息

批准号：
326934898
负责人：
Professor Dr. Mike Müller-Petke
金额：
--
依托单位：
Leibniz-Institut für Photonische Technologien (IPHT)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/326934898?language=en
关键词：
Mobile Magnetic Ressonance Sensor utilizing

项目摘要

The aim of the proposed project is the development of a highly mobile NMR sensor to detect lateral and vertical changes in the soil moisture content down to about 2 m depth.Soil moisture is important for numerous processes. As soil is the interface between the atmosphere and the subsurface it is relevant for fluid and mass transport processes. However, up to now, there are no adequate methods that can directly map the soil moisture content at all demanded time and spatial scales. Either the methods are direct but cannot be used on a large scale or they can be used on the large scale such as common geophysical methods but are indirect and therefore suffer from ambiguities.As a non-destructive direct method nuclear-magnetic-resonance (NMR) and its application from the surface of the Earth (SNMR) has gained increasing interest in the geophysical community to target hydrological questions. Unfortunately, SNMR is not capable to deliver soil parameters for the very near surface (dm) due to insufficiently low sensitivity at that depth range and furthermore SNMR measurement are too time consuming to map large (km) areas. Recently, theoretical concepts were presented lately that suggest the development of a new NMR-based sensor to overcome these restrictions of measurement progress and sensitivity.The proposed concept of a proper, highly mobile NMR sensor is based on prepolarisation using a superconducting coil together with adiabatic pulses and small point-like receivers. While prepolarisation is used to increase the macroscopic magnetisation, adiabatic pulses ensure a more homogeneous excitation of the subsurface. Both features combined promise an increase in signal amplitude of at least a decade whereas point-like receivers will help to increase lateral resolution.The full-functional new sensor enables to access the soil moisture distribution at a large scale and at selected depths (e.g., top soil, root zone, subsoil) down to 2 m. Therefore, it has the potential to become a ground-breaking tool to obtain information on mass transport (in connection with permafrost or climate change modelling), groundwater recharge, soil protection or even precision agriculture. Consequently, soil scientists from the Leibniz University Hanover, the Berlin Technical University, the Federal Institute for Geosciences and Natural Resources and the RWTH Aachen support the proposal as they have great interest to use the developed instrument for their own research.

该项目的目标是开发一种高度移动的核磁共振传感器，用于检测深达约 2 m 深度的土壤水分含量的横向和垂直变化。土壤水分对于许多过程都很重要。由于土壤是大气和地下之间的界面，因此它与流体和质量传输过程相关。然而，到目前为止，还没有足够的方法可以直接绘制所有所需时间和空间尺度的土壤水分含量。这些方法要么是直接的，但不能大规模使用，要么可以像常见的地球物理方法那样大规模使用，但是间接的，因此存在模糊性。作为一种非破坏性的直接方法，核磁共振（NMR）及其在地球表面的应用（SNMR）越来越受到地球物理界针对水文问题的兴趣。不幸的是，SNMR 无法提供非常近地表 (dm) 的土壤参数，因为该深度范围的灵敏度不够低，而且 SNMR 测量对于绘制大面积 (km) 区域的地图来说太耗时。最近提出的理论概念表明，建议开发一种新的基于 NMR 的传感器，以克服测量进度和灵敏度的这些限制。所提出的适当的、高移动性 NMR 传感器的概念基于使用超导线圈以及绝热脉冲和小型点状接收器的预极化。虽然预极化用于增加宏观磁化强度，但绝热脉冲可确保地下更均匀的激发。这两个功能相结合有望将信号幅度增加至少十年，而点状接收器将有助于提高横向分辨率。全功能的新型传感器能够在大范围和低至 2 m 的选定深度（例如表土、根区、底土）获取土壤湿度分布。因此，它有潜力成为一种突破性的工具，用于获取有关大众运输（与永久冻土或气候变化建模有关）、地下水补给、土壤保护甚至精准农业的信息。因此，来自汉诺威莱布尼茨大学、柏林工业大学、联邦地球科学与自然资源研究所和亚琛工业大学的土壤科学家支持这一提议，因为他们非常有兴趣将开发的仪器用于自己的研究。