ATHENA : the Advanced Telescope for High ENergy Astrophysics. LTD16 Conference. Centre de Congrès WTC, Grenoble, France July 20th - 24th 2015

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1 LTD16 Conference Centre de Congrès WTC, Grenoble, France July 20th - 24th 2015 The Cryogenic AntiCoincidence detector for the ATHENA X-IFU instrument: results from the design performed by GEANT4 simulation, and characterization of the new single pixel prototype as basic-element of the fnal 2x2 array. C. Macculi, A. Argan, M. D'Andrea, S. Lotti, L. Piro, M. Biasotti, D. Corsini, F. Gatti, A. Orlando, G. Torrioli 1

2 Outline From science goals to technologies def inition: the need for the CryoAC GEANT4 simulations impact on design Preliminary characterization of the AC-S7 prototype Summary 2

3 The Athena Observatory: 1 telescope for 2 Ariane V (VI?) class launcher instruments! Satellite mass ~ 5500 kg Power ~5600 W Focal length: 12 m Lifetime: 5 years (10 years) Nandra et al arxiv Silicon Pore Optics: Effective area: 1 kev PSF (HEW): 5 Willingale et al arxiv X-ray Integral Field Unit: E: 2.5 ev Field of view: 5 arcmin Large array of TES cooled at 50 mk Barret et al arxiv: Wide Field Imager: E: 125 ev Field of view: 40 x 40 Rau et al arxiv

4 X-IFU: from the science goals to the technologies def inition Parameter Value What it def ines Def ines the anti Background <5E-3 count/s/cm2/kev coincidence performance level and the passive shielding of the detector Energy bandwidth: kev Main science drivers Matter assembly in clusters - Metal production and dispersal - low surface brightness objects INAF/Ge. Univ./CNR The CryoAC This residual particle bkg level calls for the necessity of an active anticoincidence very close to the main TES array needs of a Cryogenic AntiCoincidence detector 4

5 The CryoAC for enabling X-IFU science about faint and diffuse sources shield 2K f lux Minimum Cryoperm detectable 2K outer structure 0.3 K supporting structure x 20 Size: 5.2 cm2 (in 4 pixel, each ~ 1.3 cm2, no Multiplexing Thickness: 500 μm Distance from X-IFU: < 1 mm Rise Time constant: < 30 μs Time constant Decay: < 300 μs (Goal) Bandpass: 20 kev 0.5 MeV x6 < 1 mm Credits, Henk van Weers (SRON) Lotti et al., A&A 569, A54 (2014) 5

6 Geant4 impacts on the CryoAC design New baseline Old baseline 6

7 The X-IFU schematics The CryoAC is an instrument inside another instrument 4 pixels made of Silicon absorber sensed by Ir TES. Tbath = 50 mk CFEE: SQuID + RF f iltering * SQuID (from VTT): We adopt a single stage SQuID, Series Array, at 50 mk * RF f iltering at 2K to reduce EMI towards the FPA - WFEE (1 board-for-4 pixels) it biases the CryoAC pxl and the SQuIDs; standard FLL WBEE (2 boards: N + R) will process the analog pulses from the WFEE, and HK to the ICU; No VETO onboard. It manages the WFEE in diagnostic mode (FLL, VPHI, test pulses...). - 7

8 CryoAC design and mechanical I/F with the TES array Work started with the SRON team, shared ideas and preliminary size of the CryoAC active area (silicon absorber) which will contribute to the FPA design, to be updated by GEANT4 vs Mass Model Credits Henk van Weers (SRON), preliminary 8

9 The last CryoAC single pixels prototypes 2 samples produced, with and without Al-f ingers (the former to increase the A-thermal collection eff iciency) Al 65 TES each in parallel conf iguration f ingers TES AC-S8 AC-S7 Absorber Silicon size: 10x10 mm2, 380 μm thick TES (x 65) Iridium size: 100x100 um2, ~ 200 nm thick Niobium wiring: ~ 870 nm thick Silicon wafer 5-10 ohm cm Nb wiring 9

10 Preliminary characterization of AC-S7 (65 TES in parallel conf iguration, no Al f ingers): Transition measurement Transition measurement has been performed at diferent labs, by diferent techniques and refrigerators (Dilution and ADR): narrow transition (DT = 2 mk), and a critical temperature of Tc ~ 125 mk close to what expected for Iridium thin f ilm. This test consolidates the manufacturing processes for the pixel develop- 10

11 Summary The TES-based CryoAC enables most of the ATHENA science goal reducing the residual particle bkg, its development is framed in the X-IFU instrument The CryoAC is an independent instrument (detector + cold/warm electronics), sharing the same FPA with the scientifc TES-array instrument The Geant4 toolkit has been used to design the CryoAC in order to get the science goals: Silicon absorbers in planar confguration, gap between pixel < 50 um, ~5 cm2 area Produced 2 new single pixel prototypes: wide area (~cm2), with and without Al-fngers. The transition measurement performed at diferent labs, with diferent techniques and refrigerators it s consistent. This result consolidate the manufacturing processes We plan to illuminate the pixel by the 241Am-60 kev line to probe its response (timing, A-thermal collecting efciency, energy spectrum, threshold etc ) ATHENA Italian Team, LTD16, Grenoble, July, 20-24,

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14 h ~50 um, l~500 um G~2x10-6 W/K 14

15 Conclusion The development of a TES based cryoac detector is framed in the ATHENA X-IFU instrument to actively reduce the residual particle bkg, so enabling most of the ATHENA science goal The CryoAC is an independent instrument (detector + cold/warm electronics), sharing the same FPA with the scientifc TES-array instrument The Geant4 toolkit has been used to design the CryoAC in order to get the science goals: Silicon absorbers in planar confguration, gap between pixel < 50 um We have produced 2 new single pixel prototypes, wide area of cm2, with and without the Al-fngers. The transition measurement has been performed at diferent labs, by different techniques and refrigerators (Dilution and ADR): it s the same. This result consolidate the manufacturing processes of the detector. We plan to illuminate the pixel by the 241Am-60 kev line to probe its response (timing, A-thermal collecting efciency, energy spectrum, threshold etc ) ATHENA Italian Team, LTD16, Grenoble, July, 20-24,