Detector and readout development for XEUS

The acronym XEUS stands for 'X-ray Evolution of Early Universe', and it is a mission by the European Space Agency, which aims to launch a large orbiting X-ray space telescope around the year 2020. A paper-format description of the mission is found here .

The main X-ray camera of XEUS is planned to consist of an array of microfabricated Transition Edge Sensors (TES), read out by superconducting electronics based on Superconducting Quantum Interference Devices (SQUIDs). VTT and SRON collaborate in developing such a sensor array, the main reponsibility of VTT being the SQUID readout, and main responsibility of SRON being the TES calorimeter array.

Currently this work is carried on within the EURECA consortium. This work takes place in the Quantronics Team of VTT , the Technical Research Centre of Finland.

• Read more about our SQUID development.
• Read more about Transition Edge Sensors.
• Some pictures of our experimental setup.

Some preprints

• Four quadrant flux quanta counting for wide-range SQUID amplifiers. Published in SuST.
• Fully differential cryogenic transistor amplifier. Published in Cryogenics.
• Some phenomena due to SQUID input properties when local feedback is present, presented in the EUCAS 2013 conference.
• Cryogenic time-domain multiplexer based on SQUID arrays and superconducting/normal switches, presented in the EUCAS 2013 conference.
• Viewgraphs from the 2012 Applied Superconductivity Conference, held in Portland OR.
• An experiment on Hadamard code multiplexing, with a timestamp.
• Amplifier development for multiplexed cryogenic detectors, to be presented in the LT26 conference.
• The unshunted SQUID revisited, submitted to Superconductor Science and Technology.
• Two-stage locally linearized SQUID readout for frequency domain multiplexed calorimeter arrays, published in Superconductor Science and Technology.
• Progress towards large locally linearized SQUID arrays presented at the LTD-13 workshop.
• SQUID linearization with current-sampling feedback published in Superconductor Science and Technology.
• High dynamic range SQUID readout for frequency domain multiplexers, presented in the 12th International Workshop on Low Temperature Detectors.
• SQUID readout and flux feedback based on SiGe bipolar transistor at 4.2K, submitted to the 7th International workshop on low-temperature electronics (WOLTE-7).
• A post-SQUID ac amplifier aimed for multiplexed detector readouts, presented at the 10th International superconductive electronics Conference (ISEC'05), published in Superconductor Science and Technology. See also the conference poster.
• Design and performance of multiloop and washer SQUIDs intended for sub-kelvin operation, presented at the 6th European conference on applied superconductivity (EUCAS2003), published in Superconductor Science and Technology.
• SQUID Multiplexers for Transition-Edge Sensors, presented in the NASA 2002 Far-IR, Sub-mm & mm Detector Technology Workshop .
• DC and UN SQUIDs for Readout of Ac-biased Transition Edge Sensors, presented in ASC'02. An un SQUID biasing demo
• SQUID-based readout schemes for microcalorimeter arrays, the paper and the viewgraphs (with a timestamp), presented at the LTD-9
  
• Un-SQUID based integrated magnetometer utilizing superconduccting flip-chip, presented in 6th International Superconductive Electronics Conference, Berlin, Germany, June 25-28, 1997.

Some relevant links

• The calorimeter and imager array pages at SRON (Space Research Organization of the Netherlands).
• The Sensors centre of the VTT.
• Device fabrication capabilities at the Micronova clean room, collaboratively operated by VTT and the Helsinki University of Technology: the VTT part and the HUT part.
• Design rules for the E-SQUID process
• Examples of other space-related work at VTT.
• We are located in the same building and collaborate with the Millimetre Wave Laboratory of Finland (Millilab).