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Development of Superconducting Detectors for Measurements of Cosmic Microwave Background.

Development of Superconducting Detectors for Measurements of Cosmic Microwave Background. Mr. MIMA, Satoru (Okayama University) Co-Authors:

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Development of Superconducting Detectors for Measurements of Cosmic Microwave Background.

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  1. Development of Superconducting Detectors for Measurements of Cosmic Microwave Background. Mr. MIMA, Satoru (Okayama University) Co-Authors: ISHINO, Hirokazu (Okayama University)KIMURA, Nobuhiro (High Energy Accelerator Research Organization (KEK))KAWAI, Masanori (High Energy Accelerator Research Organization (KEK))NOGUCHI, Takashi (National Astronomical Observatory of Japan)WATANABE, Hiroki (The Graduate University for Advanced Studies)HATTORI, Kaori (Okayama University)KIBAYASHI, Atsuko (Okayama University)HAZUMI, Masashi (High Energy Accelerator Research Organization (KEK))YOSHIDA, Mitsuhiro (High Energy Accelerator Research Organization (KEK))SATO, Nobuaki (High Energy Accelerator Research Organization (KEK))TAJIMA, Osamu (High Energy Accelerator Research Organization (KEK))OKAMURA, Takahiro (High Energy Accelerator Research Organization (KEK))TOMARU, Takayuki (High Energy Accelerator Research Organization (KEK)) TIPP11

  2. Contents • Motivation: LiteBIRD • STJ (Superconducting Tunnel Junction) • About STJ • Antenna coupled STJ detectors • Parallel-connected Twin Junction • Microstrip Junction • MKID (Microwave Kinetic Inductance Detector) • Summary TIPP11

  3. LiteBIRDLite (light) Satellite for the studies of B-mode polarization andInflation from cosmic background Radiation Detection • Purpose and concept • B-mode polarization detection • Whole sky scan • Small & compact design • Orbit：L2 or LEO • Detector requirements • 2,000 Detectors • Frequency 50-250GHz • Noise Equivalent Power ~10-18W/√Hz LiteBIRD Weight : 391kg electricity : 480W TIPP11

  4. LiteBIRD Collaboration • ISAS/JAXA: TAKEI Yoh, FUKE Hideyuki, MATSUHARA Hideo, MITSUDA Kazuhisa, YAMASAKI Noriko, YOSHIDA Tetsuya • ARD/JAXA: SATO Yoichi, SHINOZAKI Keisuke, SUGITA Hiroyuki • Okayama Universiry: ISHINO Hirokazu, KIBAYASHI Atsuko, HATTORI Kaori, MISAWA Naonori, MIMA Satoru • UC Berkeley: AdnanGhribi, William Holzapfel, Bradley Johnson, Adrian Lee, Paul Richards, Aritoki Suzuki, Huan Tran • LBNL:Julian Borrill • Kinki University: OHTA Izumi • ACCL/KEK: YOSHIDA Mitsuhiro • IPNS/KEK: ISHIDOSHIRO Koji, KATAYAMA Nobuhiko, SATO Nobuaki, SUMISAWA Kazutaka, TAJIMA Osamu, NAGAI Makoto, NAGATA Ryo, NISHINO Haruki , HAZUMI Masashi , HASEGAWA Masaya, HIGUCHI Takeo, MATSUMURA Tomotake • CSC/KEK:KIMURA Nobuhiro, SUZUKI Toshikazu, TOMARU Takayuki • SOKENDAI: YAGINUMA Eri • UT Austin: Eiichiro Komatsu • ATC/NAOJ: UZAWA Yoshinori, SEKIMOTO Yutaro, NOGUCHI Takashi • Tohoku University: CHINONE Yuji, HATTORI Makoto • Tsukuba University: TAKADA Suguru • RIKEN: OTANI Chiko • Yokohama National University: TAKAGI Yuta, NAKAMURA Shogo, MURAYAMA Satoshi

  5. Superconducting detectors • Antenna coupled STJ • fast response • can reduce the dead time caused by the cosmic ray attack • wide frequency range • achievable for 50-250GHz using either photon assisted tunneling or Cooper pair breaking with a pure Al STJ • MKID • frequency domain readout • thousand detectors can be readout with a single line • easy to fabricate • no bias • TES • UC Barkley TIPP11

  6. STJSuperconducting Tunnel Junction Superconductor • The STJ has a structure of SIS with the insulator thickness of about 1nm. Insulator Superconductor Quasiparticle(electron) Cooper Pair Egap=2D S I S I S S Photon assisted Tunneling Direct Cooper pair breaking A photon having energy greater than 2D can break a Cooper pair and generate two quasiparticles, which penetrate the insulator layer by the tunnel effect and are detected as an electric current. A photon having energy less than 2D can also be detected using photon assisted tunneling effect. The valence electron can directly penetrate the insulator and go up to the conducting band with the assist of the photon energy.

  7. Antenna coupled STJ: Parallel-connected twin junction Log-Periodic antenna • PCTJ(Parallel-Connected Twin Junction） • The twin parallel STJs and the inductance form a resonant circuit. • The circuit accumulates the millimeter wave power that generates the quasiparticles. Transmission line STJ PCTJ wire Log-Periodic antenna ( Nb ) TIPP11 STJ

  8. Fabrication and test for the PCTJ detector 7μmφSTJ 8 illuminating 80GHz STJ output current 0.3K refrigerator STJ bias the screen pattern millimeter wave input optics horn an obtained image polyethylene lens signature of the photon assisted tunneling screen with a pattern TIPP11

  9. Problems on the PCTJ detector • We have successfully detected 80GHz millimeter wave with the photon assisted tunneling effect using the PCTJ detector. • However, there are some difficulties on fabricating the PCTJ detector. • The impedance matching between the antenna and the PCTJ is not easy. • We need a fine tuning control for the fabrication on the insulator thickness and character. • related with the Josephson current control • It is not easy to increase the bandwidth. • the current design up to ~10% • LiteBIRD requires 30% bandwidth, however. 2011年日本物理学会年次大会

  10. Microstrip STJ • The microstrip STJ has been proposed by Prof. T. Noguchi (NAO). • The condition to match the impedances between the antenna and the STJ is easier for the microstrip STJ than the PCTJ. • In addition, we have found the microstrip STJ can have wider bandwidth than the PCTJ. frequency: 150GHz bandwidth: 30% strip width :2um antenna coupled Microstrip STJ antenna coupled PCTJ reflectivity reflectivity frequency frequency 2011年日本物理学会年次大会 simulation results

  11. Antenna-coupled Microstrip STJ • Design • The microstrip STJ has a width of 2mm and a length of l/4 at the resonant frequency. Nb transmission line Al-ＳＴＪ readout line antenna（Nb) TIPP11 11

  12. Fabrication of antenna coupled Microstrip STJ MicrostripSTJ design 60GHz • We have successfully fabricated a pure Al microstrip STJ. • Three different detectors are fabricated for central frequencies of 60, 100 and 150GHz. 100GHz 150GHz SEM images TIPP11

  13. First look at the microstrip pure Al STJ performance 0.35K The IV curve seems to be good : the gap energy is measured to be 0.34mV, consistent with the pure Al SIS behavior. But we found the normal resistance is higher than expected by an order. We need more tuning on the fabrication. TIPP11

  14. Typical Absorption CPW-MKIDs Microwave Resonator Microwave feed line Frequency shift P. K. Day et al., Nature 425 (2003) 817. TIPP11

  15. Z0 Z0 Z0 Z0 Absorption(typical) and Transmission MKIDs Z0 Z0 Z0 Z0 2Δf = 0.04MHz => Q=150,000 Q = 90,000 This leads to enable feedback readout

  16. Nb CPW CPW Feed-line SiO2 Microstrip Si 基板 Microstrip Resonator Microstrip Nb-MKIDs CPW Al-MKIDs • CPW resonator • Aluminum : Tc = 1.1K f > 88 GHz 96GHz Irradiation => Improving quality of process : EV, Wet etching, Target purity etc… => Adjusting coupling etc. Multichroic Detector Array

  17. Design for Multichroic MKIDs Transmission MKIDs Sinuous Antenna • Based on Transmission MicrostripNb-MKIDs Microwave Readout ↑4 Polarization×4 Frequency×5 Antenna = 80 ch From antenna SiO2 Al Nb • Final target : • Multichroic • 2000 ch Microstrip Nb-MKIDs Al2O3 Si substrate ・Diffusion length100mm >> Penetration depth ・No diffusion from Al to Nb

  18. Summary • LiteBIRD requires 2,000 superconducting detectors • We are developing STJ and MKID: • PCTJ STJ has detected 80GHz successfully. • Microstrip STJ has been newly developed. • An antenna coupled MKID has been proposed for the multichroic readout. TIPP11

  19. backup slides TIPP11

  20. ＳＴＪ＋ＭＫＩＤｓ • Diffusion typeMKIDs readout From Antenna Al-STJ == Merit== ・design is easy (can use current design) ・keep up the Q factor ・we can inject electromagnetic wave arbitarily place == Problem== ・increasing layer SiO2 Al Nb Microstrip Nb-MKIDs Al2O3 Si substrate ・Diffusion length100mm >> Penetration depth ・No diffusion from Al to Nb 2010年ＫＥＫ年末発表会

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