Large high impedance silicon μ-calorimeters for x-rays camera: status and perspectives

In this paper, we present our developments on micro-calorimeter arrays, based on High Impedance Silicon sensors (MIS or resistive TES) micro-calorimeters and GaAS-GaAlAs HEMTs / SiGe cryo-electronics, started 5 years ago. We show the pixel design, the main steps to build a 32x32 array. We are presently developing two kinds of high impedance sensors: Metal-Insulator-Sensors and High Resistivity Transition Edge Sensors. We described our associated FrontEnd electronics and detailed system level analysis of the foreseen camera. We discuss why we will be able to handle a camera with a large number of pixels (thanks to excellent thermal insulation and no electronic power consuming at the 50mK stage). We discuss the main technological building blocks (Absorber, Sensor) and their present status.