MKID Camera
forNobeyama 45-m Radio Telescope
Makoto Nagai
Advanced Technology Center (ATC),
National Astronomical Observatory of Japan (NAOJ)

Tsukuba Global Science Week 2021, Session 4-11, 11th Sep. 2021

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Galaxy Evolution and Star Formation

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Credit: NAOJ

How did galaxies
form and evolve inthe Universe?
How are stars
forming in the localUniverse?
Credit: NASA/JPL-Caltech/Univ. of Wisconsin

*** CORPORATIONRadio Continuum Emission from ISM & Galaxies

3M82
dust

Synchrotron

free-free

NIKA2, Rigby+20

SCUBA2, Chen+16

Wide-field surveys reveal thedistribution of the source.

Condon92

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Nobeyama MKID Camera for 100-GHz Band

Calculation by S. Ishii

Observation Frequency

90--110 GHz (Center : 100 GHz)

Field-of-View
Polarization~ 3 arcmin
linear single polarization

Detector

Microwave Kinetic Inductance Detector (MKID)

Cold Optics

Refractive optics with two Si lenses

No. of Pixels

109 pixels

Focal Plane Temperature< 200 mK

Beam Size~ 16.5ʹʹ @100 GHz

Sensitivity (NEFD)＜30 mJy √s （Goal）＜100 mJy √s （Minimum）

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Collaboration for Nobeyama MKID CameraUTsukuba
Tom Nitta ★
Yosuke Murayama ★
Hiromu Miyazawa ★
Ryohei Noji ★
Miwa Aoki(alumni grad/undergrad students)
Nario Kuno

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NAOJ Facilities
Nobeyama Radio Observatory(NRO)
Advanced Technology Center(ATC)LEKID Array

NAOJ
Makoto Nagai
Hiroshi Matsuo
Hitoshi Kiuchi
Wenlei Shan

JAXA
UEC
Yutaro Sekimoto Takashi Noguchi
Saitama U.
Masato Naruse

Kwansei Gakuin U.
Naomasa Nakai★ main members for the 3rd commissioning operation

Institut Néel
Alessandro Manfardini
Johannes Goupy
Martino Calvo
LPSC
Juan Macias-Perez
Andrea Catalano*** CORPORATION

Microwave Kinetic Inductance Detector (MKID)
Resonator of supercondicting films
coupled to a throughline
Suitable for large detector arrays
high sensitivity
frequency-domain multiplexing

Day+03Mazin+126

*** CORPORATIONMKID Readout

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Measures transmission ‘S21’ both amp. & phase.
generates probe tones (PTs), acquires returned PTs

Digital signal processing
Fast Fourier Transform Spectrometer (FFTS)
Direct down conversion (DDC)
FFTS + frequency sweeping (FS)

Fequency sweeping scheme (Nagai+18)“multi-tone VNA”

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Antenna-coupled KID Design

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NbTiN/Al-hybrid MKID (Yates+11)✔ high optical efficiency

CouplerArray mask pattern

Feed point

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Fabrication of NbTiN/Al-hybrid MKID
＠ ATC clean room9

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Fabrication of NbTiN/Al-hybrid MKIDSEM Image of a detector pixel

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Fabrication of NbTiN/Al-hybrid MKID

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SEM Image of Al/NbTiN contact

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Focal Plane Array

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MKID: NbTiN/Al-hybrid, 109pixels, 3-inch Si wafer
Si lens array: anti-reflection (AR) (Stycast & glass beads)
109素子MKIDアレイ
Device holder: made of村山洋佑：修士論文,Nb, closed
2018
服部将吾：修士論文, 2018

0.5 mm

Focal plane array*** CORPORATION

Camera Cryostat

13Dilution refrigerator + GM2 refrigerator
Cold optics
Si lens w/ AR structure
Metal mech filters: 3 LPFs
IR filters: PTFE, RT-MLI

AR on Si lens

Optics design  *** CORPORATION

NbTiN/Al-hybrid MKID: Lab measurements
Transmission spectra

103 resonances(94%)

Optical loads
Hot load (room temp.)
Cold load (liquid N2, 77 K)
Mirror→ Responsivity: ~1.5 kHz/K14

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NbTiN/Al-hybrid MKID: Lab measurements

2019—2018

Figure of beam measurement

Bandpass obtained w/ FTS (Hikawa20)

Beam position determined by knife-edge method15*** CORPORATION

Advantage of hybrid MKID (Murayama21, in prep.) 16

Table for comparison

NEP result

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Commissioning on NRO 45-m Radio Telescope
1st: Dec. 2016—Jan. 2017, Al MKID, 37 pixels
2nd: May—Jun. 2018, Al MKID, 108 pixels
3rd: May—Jun. 2021, NbTiH/Al-hybrid MKID, 108 pixels

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Measurement of Atmosphere (skydip)

Hikawa1818

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Measurement of Planets

19Calibration LoadSkySkyJupiterfrom Nitta’s slide

Observation Time

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Noise Equivalent Flux Density (NEFD) of a Pixel

NEP plot ofcommissioning 201820

yramilrein

NEP plot ofcommissioning 2021

P

from Nitta’s slide

Sensitivity of each pixel improved by factor ~7*** CORPORATION

Efficiencies of Camera+Telescope

FOREST
Plot ofmain beam efficiency

yranimilre21

Plot ofantenna efficiency

FORESTP2018
2018

from Nitta’s slideCamera’s coupling to the telescope became better, andis not much worse than other receivers on the telescope.

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Current Summary of 3rd Commissioning
The instrument works successfully.
The sensitivity is improved as expected.
The coupling btw camera & telescope became better.

To do
Beam map, beam footprint
Map making
Map integration (map of diffuse source)22

*** CORPORATIONLEKID Array on Camera

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CryoNLeKID2u126_s7w7d8_f2.1_0.70_mirror_8cm_20s_noise_1
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down-FS

126 resonances slected
119 PTs used

IQ Amplitude [mV]

302520151050650

700

750
800
Frequency [MHz]850900Resonance spectra obtained w/ FSP (Nagai21)

Figure of beam measurement

Figure of frequency responce
Beam position determined by knife-edge method

Bandpass obtained w/ FTS

*** CORPORATIONConclusions

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The MKID camera had the 3rd commissioning in the last
observation season.
We’d like to confirm the camera sensitivity under thewinter sky (optical depth ~0.1) in the next session.
The MKID camera needs further improvement to achieve
the photon noise limit on Nobeyama site.
MKID noise
Stray light
Readout efficiency

Both technologies (antenna-coupled KID & LEKID) areimportant.
We’d like to establish MKID camera operation in Japan,
to open the way to next-generation radio telescopes.

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Reference
1. Nagai et al., “Data Acquisition System of Nobeyama MKID Camera",
Journal of Low Temperature Physics, Volume 193, Issue 3-4, pp. 585592 (2018)
2. Nagai et al., “Resonance Spectra of Coplanar Waveguide MKIDs
Obtained Using Frequency Sweeping Scheme", Journal of Low
Temperature Physics, Volume 199, Issue 1-2, p.250-257 (2020)

Acknowledgment
KAKENHI (Kiban A: 26247019, Kiban C: 19K03920)
LEKID arrays are provided by the NIKA2 team.

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