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arXiv · 2511.11401

GRANITE: High-Resolution Imaging and Electrical Qualification of Large-Area TPC Electrodes

Shumit A. Mitra·Alexander Deisting·Jan Lommler·Uwe Oberlack·Fabian Piermaier·Quirin Weitzel·Daniel Wenz
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Abstract

Next-generation dual-phase time projection chambers (TPCs) for rare event searches will require large-scale, high-precision electrodes. To meet the stringent requirements for high-voltage performance of such an experiment, we have developed a scanning setup for comprehensive electrode quality assurance. The system is built around the GRANITE (Granular Robotic Assay for Novel Integrated TPC Electrodes) facility: a gantry robot on top of a $2.5\,\text{m}\times1.8\,\text{m}$ granite table, equipped with a suite of non-contact metrology devices. We developed a coaxial wire scanning head to measure and correlate localized high-voltage discharge currents in air with high-resolution surface images. We find that the identified discharge 'hotspots' are transient and show no significant correlation with static visual features. Next, we established a quantitative relationship between artificially induced abrasive surface damage on the wires and a reduction in the discharge inception voltage. This work provides a novel non-invasive tool for qualifying wires dedicated for use in electrodes for future low-background experiments.

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Shumit A. Mitra, Alexander Deisting, Jan Lommler, Uwe Oberlack, Fabian Piermaier, Quirin Weitzel, Daniel Wenz. 2025-11-14. GRANITE: High-Resolution Imaging and Electrical Qualification of Large-Area TPC Electrodes. https://doi.org/10.1088/1748-0221%2F21%2F01%2Fp01034

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