Metallic Magnetic Calorimeters: High Resolution X-ray Detectors Detectors to Study Highly Charged Heavy Ions to Study Highly Charged Heavy IonsONLINE ONLY

An excellent energy resolution (down to 1.6 eV FWHM) combined with a high dynamic range as well as a very good linearity make metallic magnetic calorimeters (MMCs) ideal detectors for different applications in high-resolution X-ray spectroscopy. In this report, I will explain the working principle of MMCs and discuss challenges in the fabrication and operation of such detectors. Different types of MMC arrays optimized for various energy ranges will be presented, giving a special focus to the maXs100 detector array, which was developed within the framework of the SPARC collaboration. It is optimized for the energy range up to 100 keV and features 8x8 pixels with an active detection area of 1 cm2. I will also present preliminary results from this year’s E138 beam time where two maXs100 detectors were used to study X-rays emitted from He-like U90+ and where the splitting of the Ka2 doublet of U90+ with around 140 eV could be clearly resolved for the first time.