Development of Microwave Kinetic
Inductance Detector for AstronomicalObservations
Yosuke Murayama(University of Tsukuba)

March 27, 2018

Inaugural Symposium, TCHoU

Outline• Background- Scientific Motivation- Microwave Kinetic Inductance Detector; MKID

• How to fabricate MKID device?
• Measurement MKID device• Future developments• Summary2

1 Background

1.1 Survey of Distant Universe
How galaxies were formed and evolved?
• The dust emission from unknown distantgalaxies could be observed in mm/submm/THz
T. Suwa, et al.(2010)

band.
100 GHz

850 GHz

400 GHz
1.3 THzExample galaxy spectrum=> color difference correspond to
the difference of redshift z=>at high-z, spectrum is shifted tolower frequency

color: opticalcontour: submm

R. J. Ivison, et al.(2000)

Multiband observation of the dust=> redshift, temperature, luminosity• For efficient survey of distant galaxies, we plan
Multipixel Camera

to construct Antarctic 10m Terahertz Telescope✓ Wide-field of view antennaSingle Beam

✓ Multi-pixel radio camera Main topic in this talk3

1 Background

1.2 Antarctic 10m Terahertz Telescope
Signal from galaxyDesigned by H. Imada

Sub-reflector

CameraMain Reflector

Heterodyne
Receiver

Rotation
Mirror• Wide field of view :1deg.
• Observation band (camera)• 0.4 THz, 0.85 THz, 1.3 THz

MKIDCamera

Survey of young,distant galaxies

MKID is one of the important technology for realizing wide-field camera

1 Background

1.3 Microwave Kinetic
Inductance Detector; MKID
Day, et al.(2003)

Superconducting Resonator operated in Microwave range
Resonant frequency in microwave 𝑓0:

1 111
𝑓0 ==4𝑙 𝐿𝐶 4𝑙 (𝐿𝑚 + 𝐿𝑘 )𝐶

Afterincidence

Beforeincidencetwo quasiparticles

𝑙: Length of resonator, 𝐶: Capacitance,
𝐿𝑚: Magnetic inductance, 𝐿𝑘: Kinetic inductance(depend on density of cooper pair)- The power of incident photon can be monitored fromthe change of resonant spectrum.

cooper pair𝑓0

Microwave Frequency [GHz]

Equivalentcircuit

 100-GHz band camera- mm-wavelength observation- This camera will be installed toNobeyama 45m telescope=> prototype of Antarctic telescope camera
52. Fabrication of 109-pixel MKID device
MKID devices have been fabricated in ATC cleanroom, National
Astronomical Observatory in Japan
1. Si wafer cleaning
remove contamination

4. UV exposure
patterning using mask

olifra : <100>
resistance: ≥10 kΩ*m

Si (𝜙 = 3")

AlSiAlSiSi

7. Acetone cleaning;
remove resist
5. Developing;
remove exposed resist

1 μm

Al

AlSi～150 nm

3. Resist coating
to protect Al film
ResistUV

115 mJ/cm2mask

2. Al deposition with e-beamdeposition system

6. Wet-etching
removeAlSiAlSi6

3. Measurement of 109-pixel MKID device
Measurement condition:
Dark (MKID device was enclosedby 1-Kelvin shield)
Cryostat and Measurement system in ATC

By using measured parameters, we can calculate NEP2𝑁𝐸𝑃𝐴𝑚𝑝
𝜔 = 𝑆𝐴 𝜔OUT1𝜂𝜏 𝜕𝐴𝛥 𝜕𝑁𝑞𝑝

2 22 22 (1 + 𝜔 𝜏 )(1 + 𝜔 𝜏𝑟 )Baselmans et al., 2008

INFrequency dependent of dark 𝑁𝐸𝑃𝐴𝑚𝑝
5 MKIDs(Al thickness:150nm)
NEP(mean of 5-kids)@1kHz:
𝟏. 𝟎𝟑 × 𝟏𝟎−𝟏𝟔 W/√Hz𝟏𝟎−𝟏𝟔 𝐖/√𝐇𝐳:Sensitivity limit byAtmosphere

There were 95 resonances in the signal.
Yield: 87%(=95/109)

5 MKIDs in the device :We got good NEP(1kHz) around10-16 W/√Hz in dark condition
Next step: optical NEP measurement 7

5. Future development
MKID camera for Antarctic 10m Terahertz Telescope
Sekimoto et al., 2014

• 0.85 THz band camera

Lens Array- based on NRO45m MKID camera- First light module: ~3000-pixel (right fig.)• 3-bands(0.4, 0.85, 1.3 THz) camera~ 55 mm- totally 20000-pixel

3000 pixels
camera for FL
observation

Subreflector
20000 pixels
camera~ 160mm

Main Reflector

Telescope Focus Cold Optics MKID8

5. Summary✓ Microwave Kinetic Inductance Detector; MKID

• Pair breaking photon detector by using Superconducting resonator• Highly frequency domain multiplexing• Simple structure and easy to fabrication✓ MKID Camera for mm~THz Astronomical Observation• 100GHz band 109-pixel MKID camera for NRO45m
Yield ~87% and 𝑁𝐸𝑃𝐴𝑚𝑝 (1𝑘𝐻𝑧) ≅ 10−16 W/√Hz (5MKIDs,dark)• MKID camera for Antarctic 10m Terahertz Telescope
Totally 20000-pixel camera(0.4, 0.85, 1.3 THz bands)
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