The superconducting high-resolution soft X-ray spectrometer at the advanced biological and environmental X-ray facility

We have built a 36-pixel superconducting tunnel junction X-ray spectrometer for chemical analysis of dilute samples in the soft X-ray band. It offers an energy resolution of ∼10–20 eV FWHM below 1 keV, a solid angle coverage of ∼10−3, and can be operated at total rates of up to ∼106 counts/s. Here, we describe the spectrometer performance in speciation measurements by fluorescence-detected X-ray absorption spectroscopy at the Advanced Biological and Environmental X-ray facility at the ALS synchrotron.