Post on 23-Feb-2016
description
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))
09/Jun/2011 1TIPP11
ContentsMotivation: LiteBIRDSTJ (Superconducting Tunnel Junction)
◦About STJ◦Antenna coupled STJ detectors
Parallel-connected Twin Junction Microstrip Junction
MKID (Microwave Kinetic Inductance Detector)
Summary
09/Jun/2011 TIPP11 2
LiteBIRDLite (light) Satellite for the studies of B-mode polarization andInflation from cosmic background Radiation DetectionPurpose 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/√Hz09/Jun/2011 TIPP11 3
Weight : 391kgelectricity : 480W
LiteBIRD
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: Adnan Ghribi, 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
Superconducting detectorsAntenna 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 STJMKID
◦frequency domain readout thousand detectors can be readout with a single line
◦easy to fabricate◦no bias
TES ◦UC Barkley
09/Jun/2011 TIPP11 5
• The STJ has a structure of SIS with the insulator thickness of about 1nm.
09/Jun/2011
Quasiparticle(electron)Superconductor
SuperconductorInsulator
Cooper Pair
STJSuperconducting Tunnel Junction
S SI S SIDirect Cooper pair breaking Photon assisted TunnelingA 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.
Egap=2D
Antenna coupled STJ: Parallel-connected twin junctionPCTJ (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.
TIPP11 709/Jun/2011
Log-Periodic antenna ( Nb )
wire
STJTransmission line
Log-Periodic antenna
STJ
PCTJ
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8
7μmφSTJ
screen with a pattern
hornpolyethylene lens
the screen pattern
an obtained image
STJ output current
millimeter waveinput
STJ bias
optics
0.3K refrigerator
Fabrication and test for the PCTJ detector
illuminating 80GHz
signature of the photonassisted tunneling
Problems on the PCTJ detectorWe 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. 2011/03/28 2011年日本物理学会年次大会 9
Microstrip STJ
2011/03/282011年日本物理学会年次大会 10
refle
ctiv
ity
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.
refle
ctiv
ity
frequency: 150GHzbandwidth: 30%strip width :2um
antenna coupled Microstrip STJ
antenna coupled PCTJ
simulation resultsfrequency frequency
Antenna-coupled Microstrip STJDesign
◦ The microstrip STJ has a width of 2mm and a length of l/4 at the resonant frequency.
09/Jun/2011 TIPP11 1111
antenna( Nb)
readoutline
Al-STJNb transmissionline
Fabrication of antenna coupled Microstrip STJ
TIPP11 1209/Jun/2011
SEM images
Microstrip STJ design
100GHz60GHz
150GHz
Frequency[GHz]
Length[um]
60 ~60100 ~40150 ~20
We have successfully fabricated a pure Al microstrip STJ.
Three different detectors are fabricated for central frequencies of 60, 100 and 150GHz.
First look at the microstrip pure Al STJ performance
09/Jun/2011 TIPP11 13
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.
0.35K
09/Jun/2011 TIPP11 14
Typical Absorption CPW-MKIDs
Microwave feed line
MicrowaveResonator
Frequency shiftP. K. Day et al., Nature 425 (2003) 817.
Absorption(typical) and Transmission MKIDsZ0 Z0
Z0
Z0 Z0
Z0
Z0 Z0
/ 2l/ 4l
2Δf = 0.04MHz=> Q=150,000 Q = 90,000
This leads to enable feedback readout
CPW Al-MKIDs
96GHzIrradiation
=> Improving quality of process : EV, Wet etching, Target purity etc…
Microstrip Nb-MKIDsNb
Si 基板SiO2
Microstrip
CPW
CPW Feed-line
MicrostripResonator
=> Adjusting coupling etc.
•CPW resonator•Aluminum : Tc = 1.1K
f > 88 GHz
Multichroic Detector Array
Design for Multichroic MKIDs
↑4 Polarization×4 Frequency×5 Antenna = 80 ch
Microwave
Readout
Sinuous Antenna Transmission MKIDs
MicrostripNb-MKIDs
Nb
Si substrate
Al2O3
Al
From antenna
・ Diffusion length 100mm >> Penetration depth・ No diffusion from Al to Nb
SiO2
Based on Transmission Microstrip Nb-MKIDs
Final target :- Multichroic - 2000 ch
SummaryLiteBIRD requires 2,000
superconducting detectorsWe 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.
09/Jun/2011 TIPP11 18
09/Jun/2011 TIPP11 19
backup slides
Nb
Si substrate
Al2O3
AlSiO2
STJ+MKIDs
MicrostripNb-MKIDs
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
Diffusion type MKIDs readout
2010/12/27 202010年KEK年末発表会
From Antenna
・ Diffusion length 100mm >> Penetration depth・ No diffusion from Al to Nb