 counts/s. For STJ operation by non-expert users, we have built a liquid-cryogen-free spectrometer with a mechanical pulse-tube cryocooler and a two-stage adiabatic demagnetization refrigerator. It is fully automated for cooldown to a base temperature of 0 days between demagnetization cycles for STJ operation at 0.0 K. The STJ spectrometers are used for speciation measurements on dilute samples by fluorescence-detected X-ray absorption spectroscopy, and can achieve sensitivities below 000 ppm. We discuss the spectrometer performance in representative applications on metals in meteorites in the context of geological signatures of biological activity  Superconducting tunnel junctions (STJs) are being developed as energy-dispersive soft X-ray detectors, because they combine the high energy resolution of low-temperature detectors with the comparably high count rates of non-thermal devices. We have built a 00-pixel spectrometer based on 000 