(a) View of the sample stage at the ID13 nano-hutch facility at the ESRF with the nanocalorimetric sensor holder installed. The sensor is positioned vertically on top of a piezo-actuator (black cube) to allow the scanning of the region of interest with nanometre resolution. (b) Closer view of the custom-made modular sensor holder. The nanocalorimetric sensor is mounted onto a flat ceramic base compatible with X-ray diffraction in transmission. (c) A micrometre-sized In particle placed within the active area of the nanocalorimetric sensor. The heating elements and hot junctions of the thermopile are in close vicinity of the particle.