ALMA Band 9 technology for CCAT

Andrey Baryshev

CCAT 2011 Cologne 2

ALMA band 9 groupSRONA. BaryshevB. JacksonR. HesperJ. AdemaF.P. MenaJ. BarkhoffM. BekemaK. KeizerG. GerlofsmaA. KoopsJ. PanmanW. WildTUDelftC. LodewijkT. ZijlstraE. Van ZeijlT.M. KlapwijkNUIMN. TrappeM. WhaleM. CandottiA. Murphy

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Outline

• ALMA band 9 technology• Results of >64 ALMA cartridges• Use of ALMA mixers in FPA (CHAMP+)• 2SB mixer technology

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Main band 9 specification

• RF band 602-720 GHz• DSB mixing scheme• IF band 4-12 GHz (8 GHz bandwidth)• 4 dB IF pass band ripple• 10-8 relative total power stability @ 1s• Sensitivity integrated over IF: 175 K (80% band)

240 K (20% band)• Dual polarization• -20 dB cross - polarization response• Gain compression within 3% @ 400 K load• Phase stbility • No moving parts• Large amount of receivers

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Band 9 cartridge layout

2004 2006

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Cartridge Optics Layout

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SIS mixer

Simple constructionEasy to assemble

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SIS Technology

SIS Junctions (TU Delft)• THz SIS mixers

• quantum-limited sensitivities• 600-720 GHz bandwidth

• LO tuning range• 4-12 GHz IF bandwidth

• 4-8 GHz in HIFI• SIS junctions (TU Delft)

• Nb SIS technology• optimized fabrication

• larger quantities• improved pattern accuracy• 1 µm structures are 1 µm

• waveguide device mounts• optimized for series production

• corrugated horn antennas (RPG)• commercial product• 100 µm structures +/- 5 µm

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4-12 Cryogenic isolator

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8 cartridges

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ALMA 2012

2012!!

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Noise temperature #1..#8

610 620 630 640 650 660 670 680 690 700 7100

50

100

150

200

250

300

Average Tnoise

FLO

(GHz)

Tn

ois

e (K

)

pol. 0 (C1)pol. 1 (C1)pol. 0 (C2)pol. 1 (C2)pol. 0 (C3)pol. 1 (C3)pol. 0 (C4)pol. 1 (C4)pol. 0 (C5)pol. 1 (C5)pol. 0 (C6)pol. 1 (C6)pol. 0 (C7)pol. 1 (C7)pol. 0 (C8)pol. 1 (C8)

4 К

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Noise temperature for 64+ cartridges

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Noise temperature for 64+ cartridges

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Tnoise vs LO per junction technology

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Tnoise vs IF

CHAMP+: A powerfull sub-millimeter heterodyne array

The GREAT team: MPIfR (PI-Institute)

– C. Kasemann– R. Güsten– S. Heyminck– B. Klein– T. Klein– G. Wieching– H. Hafok– A. Korn– G. Schneider– A. Hänseler– C. Castenholz– H-J Wunsch– F. Schäfer– F. Pacek

Mixer development (SRON)– A. Baryshev (SRON)– T.M. Klapwijk (TU Delft)

APEX

Telescope:Location: Llano de Chajnantor,

northern Chile Coordinates: Latitude : 23º00"20.8' South

Longitude :67º45'33.0" WestElevation : 5105 m

Diameter: 12 mf/D: 8

Beam width:(FWHM) 7.8" * (800 / f [GHz])Main reflector: 264 aluminum panels, average

panel surface rms 5 micronSurface accuracy: 17 micron rms

Pointing accuracy: 2" rms over skyMounting: Alt-AzReceiver cabins: 2 Nasmyth + 1 Cassegrain

Mass: 125 000 kgManufacturer: Vertex Antennentechnik

SIS-Mixers

THz SIS mixers– quantum-limited sensitivities– 600-720 & 780-950 GHz RF-bandwidth– 4-8 GHz IF bandwidth

SIS junctions (TU Delft)– Nb SIS technology (660GHz)

– Nb-NbTiN SIS technology (850GHz)

– optimized fabrication• larger quantities• improved pattern accuracy• high reproducibility

waveguide device mounts– optimized for series production

corrugated horn antennas (RPG)

Mixers assembled to the mixer-mount Mixer electronics with connector-block Magnet block

Control electronics

LO-synthesizer

HEMT-BIAS

Magnet-current

Mixer-BIAS

Temperature monitor

Online UPS

LO-Power

Misc. devices

motor controller

810GHz 660GHz

IF-Processor

• 14 input channels• IF bandwidth 4.625 – 7.475

GHz• 28 output channels

• output 0.05 – 1.55 GHz• individual output attenuator• total power detector

• Allan minimum times > 500s(@ 1MHz resolution)

• temperature stabilized• fully remote controlled

“New” backend: FFTS

Array FFTS (Fast Fourier Transform Spectrometer)

32 backend-channels, each providing•1.5GHz instantaneous bandwidth •8192 spectral channels•to be installed at APEX in the next two weeks

more details: talk 6-7 of B. Klein:“The Next Generation of Fast

Fourier Transform Spectrometer”

“Old” backend:MACS auto-correlator system32 backend channels, each providing•1GHz instantaneous bandwidth•1024 spectral channel•operational at APEX since January 2007

The mixer block - assembly

RF input horn

Magnet coil

LO horn

Standard band 9Mixer backpieceIF

connector

RF structure

Impedance-matchedloads

Deflux heater

SIS junction

Spring-loaded

cap

Centering ring

Block size: 45 x 21 x 53 mm3

RF mixer Block

2SB ALMA Cartridge!!!

25

2SB Cartridge. First tests.

600 620 640 660 680 700 7200

5

10

15

20

25

30

35

Fsignal

(GHz)

Sid

e B

an

d R

ati

o(d

B)

Side band Ratio

620 630 640 650 660 670 680 690 700 7100

100

200

300

400

500

FLO

(GHz)

Tn

ois

e (K

)

Average Tnoise

pol. 1 (+s1+s2)pol. 1 (-s1+s2)pol. 1 (+s1-s2)pol. 1 (-s1-s2)

1) Cartridge prototype – fabricated, works!

2) LO optics designed and approved3) New 4-12 GHz Hybrid successfully

tested

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Conclusions

• Good performance large series DSB mixers have been demonstrated, base line for CCAT

• These can be used in large focal plane arrays• 2SB mixer for ALMA band 9 has been demonstrated • Ready for CCAT FPA (classical technology) • Many challenges for real CCAT FPA >64 pixels