Mainz 2026 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 42: Atomic Systems in External Fields II
A 42.1: Vortrag
Freitag, 6. März 2026, 11:00–11:15, N 3
3Helium magnetometers for high fields — •Peter Blümler1, Martin Fertl1, Hans-Joachim Grafe2, Robert Graf3, and Werner Heil1 — 1Institute of Physics, University of Mainz, 55128 Mainz, Germany — 2Leibniz Institute for Solid State and Materials Research (IFW), 01069 Dresden, Germany — 3MPI for Polymer Research, 55128 Mainz, Germany
Low magnetic fields (< 10−12 T) can be measured with extreme precision using SQUID or SERF sensors. But at higher fields nuclear magnetic resonance provides the greatest accuracy. Continuous frequency measurements require samples with long coherence times, as obtainable from motionally averaged hyperpolarized nobel gases at a few millibar pressure. 3He is ideal because it can be hyperpolarized by metastability optical pumping, interacts only weakly with its environment, and has an independently determined gyromagnetic ratio. With suitable low-susceptibility containers, extremely long T2* times (100 - 200 s) and absolute field measurements are possible. In addition to low-pressure hyperpolarized 3He for ultra-precise magnetometry (< 10−12), we have also produced high-pressure (up to 50 bar) thermally polarized 3He-filled cells for applications where optical polarization is impractical. These robust NMR magnetometers can operate from 1 - 300 K, and we describe methods to tune T1 for rapid sampling across 5 - 300 K (DOI: 10.1063/5.0258240). Overall, 3He magnetometers show strong potential as a new standard for high-precision magnetometry at high magnetic fields.
Keywords: magnet; nuclear magnetic resonance; 3-Helium; low temperature