CMB instrumentation anddetectors
Thuong Duc HOANG
University of Science and Technology of Hanoi (USTH), Vietnam

June 8 2021

Horn antenna
Microwaves
Radiometer
Microwaves
Radiometer•The energy of CMB photons

Antenn+ bolometers(54 detectors)    

aThousandSuperconducting
Transition Edge
Sensor (TES)ECMB = ∼ 1 meVGeneration 4•CMB is a black body, thepeak frequency

νmax ∼ 150 GHz or
λmax ∼ 2 mm .

2

Superconducting Transition Regime
ΔT

Temperature
measurement!

ΔR
CMB photons

Material∼ 1meVTransition
regime ofsuperconductors

Heat transfer
Thermal link

Bath temperaturefi • Transition Edge Sensor (TES): A thermometer made from a superconducting lm operated near its transition temperature.

TES Array Technology (mm scale)Absorber

TES
Thermometer

Thermallink

500μm

NIST: feed-horn technology: ACT, SPT, LiteBIRD (High frequency)

An array of 256 pixels, NbSi superconducting material (450 mK)

APC-France: no antenna technology: QUBIC

2 mm

Berkeley: Planar sinuous antenna coupled TES: ACT, POLARBEAR,LiteBIRD (low-mid frequency)

Caltech: Planar antenna coupled TES: BICEP/KECK4CMB space mission: LiteBIRDnoceSzradrorriyM

Incoming CMBphotonsyPrimaryMirror
Focal plane• Two detector architectures: Feed horn andsinuous antenna• Thousand TES detectors in the focal plane5Horn-couple TES
1 mm

300 μm500 μm

125 μm.

.

A planar polarization antenna
Transmission lines
Bandpass lters for multifrequencies per chip
Hybrid tees which propagate the desirable mode
TES: AlMn (160 mK).
.

.

fia)
b)
c)
d)
e)

500 μm6

Horn-couple detectors•A single wafer ~ 15 c•~2000 TE•Range of frequenciesNIST: OMT technology,
feed-horn: ACT, SPT,SO, LiteBIRD (Highfrequency)mS

7

Lenslet-couple sinuous antenna TES
2 mm250 μm500 μma) Sinuous antenna collects photons over wide frequency rangeb) On-chip lters which separate into two frequency bands (e.g. 90/150 GHz)c) TES, superconducting AlMn (160 mK).
.

.

fi

Berkeley: Planar sinuous antenna coupled TES: ACT, POLARBEAR, LiteBIRD (low-mid frequency)

8

TES electronic system
27 C~300 K•TES operates at very low temperature,electronic system to read data fromthousand of TES is a challenge•There are a lot of developments ofelectronic system• Need careful tests at the laboratory.

Readout chain

∘

40 K
4K

1K
10 mK.

.

Cryogenics system

9Testbed example on ground:
Particles with Transition Edge Sensor array.
Radioactiv
Americium

Americiumtime constants. 

e•256 pixels array with radioactive Americium•When particles hit the TES, similarly CMB
photons hit TES.

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Testbed example on ground for TES array
Feedhorn

Lenslet15cm~1 kg

15cm

2cm

4cm

DC + RF ex cable~0.6 kg

DC + RF ex cableMagnetic shield

Magnetic shield

3. Universal
Microwave
Multiplexing(UMM)

Heat clamp + springs
Posts/walls
RF wafer with MUX windows

DC wafer + MUX chips
Backshort cap

Heat clamp + springs
RF wafer with MUX windows
DC wafer + MUX chips
Copper back re ector+absorber

2. TES Detector
stack

Backshort cavity
NIST detector wafer
Waveguide interface plate

Copper extension
Invar mount
Berkeley detector wafer
Invar clips

Choke

1. photons
coupling

Al feed horn

LensletSky side

Sky sideffiflflfl• Many stacked wafers to improve bolometer e ciency• The Transition Edge Sensor (TES) will be AlMn alloys with critical temperature 160 mK• ~ 2000 TES per detector wafer, the normal resistance target is 8 mΩ

11

Testbed system for TES array
2. Magnetic eld1K
7 mK• Characterize the focal plane system at Cornell U.
fi12Summary•TES is a very sensitive detector operating atvery low temperature•TES readout is a complex system thatrequires a lot of testing, characterizations,especially for a satellite mission•We don’t have TES testbed facilities inVietnam. CMB-In ate project brings USTHresearchers a chance to work at advanced
institutes in Europe, Japan.
• Detector sensitivity has been limited by photon
shot noise. Increase number of detector to improvesensitivity.

13.

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flCMB S4 Science book: arXiV.1610.02743