ESP2013-48637-C2-1-P: Developing the X-IFU x-ray calorimeter for the ATHENA+ mission: technological development of the sensor array and definition of the scientific case
Athena+ is the space mission that will be proposed in response to the early 2014 call by ESA to address “The Hot and Energetic Universe” as the theme for its L2 (launch in 2028) science mission. Athena+ will be a large X-ray observatory in space offering a new window for the study of the Universe, in particular thanks to its revolutionary cryogenic X-ray calorimeter instrument X-IFU, delivering spatially resolved high-resolution X-ray spectroscopic capabilities. This project aims at developing key challenging technologies and associated activities that will conform the basis of a comprehensive Spanish contribution to that ESA mission. The project is structured around 3 activities (WPs), plus an overarching coordinating activity that will also include establishing all necessary contacts with other Spanish interested parties (science groups, R&D institutions in the space area, industries, CDTI) in order to prepare for an appropriate and affordable contribution to the Athena+ mission through the X-IFU instrument.
The first activity represents a fundamental technological challenge where new materials, microelectronics and cryogenics play a leading role and consists in developing the front-end sensor array for the X-IFU instrument. This is based on a Mo/Au Transition Edge Sensor device, topped with an X-ray absorber (where electrodeposited Bi will be the main ingredient). Although significant progress has been achieved by the proposing team and some of the basic performances have been demonstrated, particularly in the development of the superconducting bi-layers, the Technology Readiness Level is still low and needs very significant progress in the coming years, especially in the areas of absorber optimisation, patterning and tests of the device.
The second activity is also a technological challenge and it consists in developing algorithms to reconstruct the events in the detector device from the pulses they generate in the bias current, as well as to build up a laboratory software calibration package for the devices and the X-IFU instrument demonstrator. The former will also be integrated as part of an end-to-end simulator that is being built by the X-IFU consortium.
The third activity consists in preparing for the (astrophysical) science that the X-IFU instrument on Athena+ will deliver, thanks to its spatially resolved high-resolution X-ray spectroscopic capability. A member of the project team will chair the international Science Team of X-IFU so we expect to do significant work in coordinating science activities around the instrument, including the science requirements, simulations, mock observing plan, science management plan, guaranteed observing programmes, calibration strategies etc. Our research team will also aim at ramping up during the coming years in expertise with high-resolution X-ray spectroscopy, in particular with the analysis of X-ray binaries, X-ray active stars and the Warm-Hot Intergalactic Medium, using data from grating spectrometers on board Chandra and XMM-Newton.