Development of Position‐Sensitive Magnetic Calorimeter X‐ray Detectors

We are developing arrays of position‐sensitive magnetic calorimeter (PoSM) X‐ray detectors for future astronomy missions. The PoSM consists of multiple absorbers thermally coupled to one magnetic sensor. Each absorber element has a different thermal coupling to the sensor. This results in a distribution of different pulse shapes and enables position discrimination between the absorber elements. PoSMs are motivated by the desire to achieve the largest possible focal plane area with the fewest number of readout channels without compromising on spatial sampling. Optimizing the performance of PoSMs requires careful design of key parameters such as the thermal conductances between the absorbers, magnetic sensor and the heat sink, as well as the absorber heat capacities. We report on the first experimental results from four‐absorber PoSMs, each absorber consisting of a two layer composite of bismuth and gold. The measured energy resolution (FWHM) was less than 5 eV for 6 keV X‐rays into all four absorbers. Stra...