Demonstration of a scalable frequency-domain readout of metallic magnetic calorimeters by means of a microwave SQUID multiplexer
We report on the first demonstration of a scalable GHz frequency-domain readout of metallic magnetic calorimeters (MMCs) using a 64 pixel detector array that is read out by an integrated, on-chip microwave SQUID multiplexer. The detector array is optimized for detecting soft X-ray photons and the mu...
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| Main Authors: | , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
5 January 2017
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| In: |
AIP Advances
Year: 2017, Volume: 7, Issue: 1 |
| ISSN: | 2158-3226 |
| DOI: | 10.1063/1.4973872 |
| Online Access: | Verlag, kostenfrei, Volltext: http://dx.doi.org/10.1063/1.4973872 Verlag, kostenfrei, Volltext: https://aip.scitation.org/doi/10.1063/1.4973872 
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| Author Notes: | Sebastian Kempf, Mathias Wegner, Andreas Fleischmann, Loredana Gastaldo, Felix Herrmann, Maximilian Papst, Daniel Richter, and Christian Enss |
| Summary: | We report on the first demonstration of a scalable GHz frequency-domain readout of metallic magnetic calorimeters (MMCs) using a 64 pixel detector array that is read out by an integrated, on-chip microwave SQUID multiplexer. The detector array is optimized for detecting soft X-ray photons and the multiplexer is designed to provide a signal rise time τrise<400nsτrise<400ns<math display="inline" overflow="scroll" altimg="eq-00001.gif"><mrow><msub><mi>τ</mi><mi>rise</mi></msub><mo><</mo><mrow><mn>400</mn><mi>ns</mi></mrow></mrow></math> and an intrinsic energy sensitivity ϵ<30hϵ<30h<math display="inline" overflow="scroll" altimg="eq-00002.gif"><mrow><mi>ϵ</mi><mo><</mo><mrow><mn>30</mn><mi>h</mi></mrow></mrow></math>. This results in an expected energy resolution ΔEFWHM<10eVΔEFWHM<10eV<math display="inline" overflow="scroll" altimg="eq-00003.gif"><mrow><mrow><mi mathvariant="normal">Δ</mi><msub><mi>E</mi><mi>FWHM</mi></msub></mrow><mo><</mo><mrow><mn>10</mn><mi>eV</mi></mrow></mrow></math>. We measured a signal rise time τriseτrise<math display="inline" overflow="scroll" altimg="eq-00004.gif"><msub><mi>τ</mi><mi>rise</mi></msub></math> as low as 90ns90ns<math display="inline" overflow="scroll" altimg="eq-00005.gif"><mrow><mn>90</mn><mi>ns</mi></mrow></math> and an energy resolution ΔEFWHMΔEFWHM<math display="inline" overflow="scroll" altimg="eq-00006.gif"><mrow><mi mathvariant="normal">Δ</mi><msub><mi>E</mi><mi>FWHM</mi></msub></mrow></math> as low as 50eV50eV<math display="inline" overflow="scroll" altimg="eq-00007.gif"><mrow><mn>50</mn><mi>eV</mi></mrow></math> for 5.9keV5.9keV<math display="inline" overflow="scroll" altimg="eq-00008.gif"><mrow><mn>5.9</mn><mi>keV</mi></mrow></math> photons. The rise time is about an order of magnitude faster compared to other multiplexed low-temperature microcalorimeters and close to the intrinsic value set by the coupling between electron and spins. The energy resolution is degraded with respect to our design value due to a rather low intrinsic quality factor of the microwave resonators that is caused by the quality of the Josephson junction of the associated rf-SQUID as well as an elevated chip temperature as compared to the heat bath. Though the achieved energy resolution is not yet compatible with state-of-the-art single-channel MMCs, this demonstration of a scalable readout approach for MMCs in combination with the full understanding of the device performance showing ways how to improve represents an important milestone for the development of future large-scale MMC detector arrays. |
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| Item Description: | Gesehen am 26.03.2018 |
| Physical Description: | Online Resource |
| ISSN: | 2158-3226 |
| DOI: | 10.1063/1.4973872 |