Abstract Information on the past of Earth's magnetic field can be retrieved from magnetic grains in rock samples. Micromagnetic Tomography (MMT) is a recently developed method that uses magnetic surface scans from a Quantum Diamond Microscope (QDM) combined with the position of magnetic grains in rock samples to calculate the magnetic moments of those grains. An important parameter for these calculations is the sample‐to‐sensor distance during the magnetic measurements. Until recently, sample placement in the QDM was typically done manually. To improve sample placement, we developed an automated sample placement system (JAMES). JAMES eases the sample placement process by enabling the positioning of the sample in the x and y direction, as well as positioning of the sample plan‐parallel against the sensor or at a known distance from the sensor with a precision of 1 μm. We evaluated the importance of a known sample‐to‐sensor distance for retrieving quantitative magnetic information with MMT. With a known distance, individual grain magnetic moments and summed intensities (summed magnetic moments of individual grains) can be accurately determined. The sample‐to‐sensor distance is less important for determining directions, when studying isolated grains with dipolar magnetic surface expressions. However, when grains do not meet those conditions, a known sample‐to‐sensor distance is required to determine accurate directions. JAMES is now a standard element in the MMT procedure, ensuring reliable and repeatable magnetic measurements with the QDM. This greatly improves the precision of the magnetic moment calculations in MMT and advances the extraction of magnetic information from rock samples.
Boer et al. (Mon,) studied this question.