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An X-Ray Calorimeter Spectrometer for IXO – the X-Ray Microcalorimeter Spectrometer (XMS) Superconducting Transition Edge Thermometer A fundamentally new approach for imaging x-ray spectroscopy: Measure energies of individual x-ray photons as heat Measure position using array of calorimeters X-Ray Calorimeter Technology – Transition Edge Sensor 8 x 8 array of TES devices ~ 4000 pixel array Cryogen-free design Multiplexed SQUID readout: enables larger arrays and low power dissipation Multi-stage ADRs Cryocooler (Joule-Thomson + Pulse Tube) X-ray CCDs provide excellent imaging but have low spectral resolution Transition at ~ 100 mK and only about 1 mK wide. The Implementation of an Imaging X-Ray Spectrometer for the International X-Ray Observatory Cooling Stage Temperature Cooling Power Temperature Stability Heat Rejection Temperature Detectors, 1st stage SQUIDs 50 mK 5 µW 2 µK rms 2nd stage SQUIDs 1 K (TBR) 230 µW TBD 6 K High Technology Readiness Reference Design: • 32 x 32 TES microcalorimeter array • MUX SQUID readout • Continuous ADR • Cryocoolers TES x-ray calorimeter: Mo/Au superconducting thermometer with Au/Bi absorber Absorber extends above and out from thermometer area to cover traces and provide high fill factor. substrate TES technology well-suited for high-speed SQUID multiplexing. 8 8 TES calorimeter array (GSFC) NASA/Goddard Spectral resolution of ~ 2 eV possible throughout 1-10 keV band with ~ arcsec imaging at the focus of IXO R.L. Kelley 1 , S. R. Bandler 2 , R. P. Brekosky 3 , A.D. Brown 1 , J. A. Chervenak 1 , M. J. DiPirro 1 , W. B. Doriese 4 , M. E. Eckart 1 , F. M. Finkbeiner 1 , G. C. Hilton 4 , K. D. Irwin 4 , C. A. Kilbourne 1 , F. Porter 1 , C. D. Reintsema 4 , P. Shirron 1 , S. J. Smith 1 , J. N. Ullom 4 , P. L. Whitehouse 1 1 NASA's GSFC, 2 CRESST and University of Maryland, 3 Northrop Grumman Corporation, 4 National Institute of Standards and Technology. Results of a 2-column by 8-row multiplexing demonstration using a microcalorimeter array developed at Goddard and SQUID multiplexing electronics developed at NIST/Boulder (see Poster 457.13 - Randy Doriese et al. "Progress Toward A Kilopixel Time-division Multiplexer For IXO”) The black points show histograms of MnK X-rays from an 55 Fe source for each pixel acquired simultaneously, with vertical offsets for clarity and fits overlaid in blue/red. Multi-stage adiabatic demagnetization refrigerator (ADR) works by continuously transferring heat of magnetization to “upstream” salt pill, and eventually to cryocooler. Continuous removal of up to 5 μW at 50 mK. Front View Rear View X-Ray Mirror XMS Functional Block Diagram Main Shell Preamplifier/ Bias Box (PBB) Pulse Processing Electronics (PPE) Filter Wheel Control Power Distribution Unit (PDU) 115V From S/C Bus Cryocooler Control Electronics (CCE) ADR Electronics (ADR) SpaceWire To Spacecraft CPU/Storage 0.9 K 5.0 K ADR Stage 2 45 mK 0.275 K 50 mK ADR Stage 3 0.25 K 1 K 1 K 4.5 K 50 mK 15 K 45 K 150 K Loop Heat Pipe to Radiator 260-300 K Precooler Compressor Precooler Compressor Calorimeter/ADR insert heat switch detector package filters thermal link superconducting cable conductive bond cryostat shells Cryocooler cold head JT stage x-rays filter s x-rays filter s Antico detector Microcalorimeter Antico detector Antico detector Microcalorimeter Readout Amplifier (SQUIDs) JT Compressor JT Compressor Filter wheel Vent Valve Pyro Drivers SpaceWire To S/C CPU Instrument Radiator On AFT sunshade Loop Heat Pipe Condenser Gate Valve Impedance Network ADR Stage 5 S/C Power Spacewire I/F ADR Stage 4 Feedback/Controller Box (FCB) Pyro Control From S/C Bus 0.25 K 1 K Translation Mechanism Focus Mechanism Mechanical Control Electronics (MCE) Power Control From S/C S/C function (Not part of XMS instrument) Multi Absorber TES - 1 TES, 4 absorbers absorber R 1 R 3 R 4 R 2 thermometer Heat sink Simple approach to extend focal plane coverage: Separate absorbers (e.g., 4) connected to a single TES, each with a different thermal conductance. Rise times easily distinguished 5-6 eV already demonstrated! Reference Array Design: Inner array with 300 μm pixels 3 arcsec pixels; 2.1 arc min FOV 2.5 eV energy resolution (FWHM) ~ 150 - 300 μsec time constants Outer Array with 600 μm pixels 6 arcsec pixels; 5.4 arcmin FOV < 10 eV energy resolution (FWHM) ~ 1-2 msec time constant Demonstration of multiplexed read-out of TES array
