Benders, StefanStefanBendersMetzger, JensJensMetzgerSuter, MathieuMathieuSuterDudle, AliceAliceDudleNussbaum, JeniferJeniferNussbaumGross, Simon P.Simon P.GrossSerial, M. RaquelM. RaquelSerialMüller, ChristophChristophMüllerPrüssmann, Klaas P.Klaas P.PrüssmannPenn, AlexanderAlexanderPenn2026-05-272026-05-272026-05-19Journal of Magnetic Resonance 389: 108092 (2026)https://hdl.handle.net/11420/63233Magnetic Resonance Imaging (MRI) has been recently applied to decipher the complex flow of dry granular materials, which play an important role in a variety of chemical engineering applications. In these materials, the short apparent transverse relaxation time of the constituent grains, T2∗, leads to rapid signal decay and hence limits the choice of suitable pulse sequences. While oil-rich agricultural seeds and oil-filled core–shell particles containing substantial amounts of liquids have been used to generate MRI signals, these particles still suffer from T2∗ values much shorter than the transverse relaxation time T2 of the contained liquid. This work investigates the effect of magnetic susceptibility on T2∗ through numerical simulations and experiments. Numerical results demonstrate that matching the magnetic susceptibility of the particles, χp, to that of the air between them, χair, reduces dipolar magnetic field inhomogeneities, theoretically enabling T2∗=T2. We also found that common imperfections in core–shell particles — such as asphericity, non-concentricity of core and shell, and uneven shell thickness — cause significant field inhomogeneities. These inhomogeneities can only be mitigated if both the core and shell materials have a magnetic susceptibility matching that of air. Based on these findings, we designed and manufactured core–shell particles with doped cyclooctane (CO) encapsulated in doped gelatin with χcore≈χshell≈χair. These particles exhibited a T2∗ of 3.85 ms, more than twice that of previously available materials, thus improving the signal-to-noise ratio and enhancing pulse sequence flexibility. This advancement opens up new possibilities for applications in engineering and the study of granular physics.en1096-08562026Elsevierhttps://creativecommons.org/licenses/by-nc/4.0/Fluidized bedsMRINMRParticlesTechnology::610: Medicine, HealthJournal Articlehttps://doi.org/10.15480/882.1720210.1016/j.jmr.2026.10809210.15480/882.17202