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Introducing: MAKO

Introducing: MAKO. MAKO is a 350 micron KID based camera designed to be a drop-in replacement to SHARC-II Goal: Demonstrate a scalable 350 micron pathfinder instrument using KIDs for large FOV ground-based telescopes Array should be: Photon-noise limited Simple to fabricate

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Introducing: MAKO

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  1. Introducing:MAKO

  2. MAKO is a 350 micron KID based camera designed to be a drop-in replacement to SHARC-II • Goal: Demonstrate a scalable 350 micron pathfinder instrument using KIDs for large FOV ground-based telescopes • Array should be: • Photon-noise limited • Simple to fabricate • Low per-pixel cost • Highly multiplexed

  3. Can we be photon-noise limited? J Zmuidzinas, “Superconducting Microresonators: Physics and Applications,” Annual Review of Condensed Matter Physics, 3 (March 2012). Noise Source Photon Amplifier GR TLS Knobs:Pa,b ->STLS(T,C,Pa)

  4. Can we be photon-noise limited? Increase Pa Lk(I) = Lk (0) [1 + I2/I*2 + …]

  5. Noroozian et al. Submitted for publication. ILLUMINATE WITH 5 pW OF 215 mm RADIATION

  6. Under 5 pW of loading… Theory Measured

  7. Can we be photon-noise limited? Increase Pa Deep in bifurcation regime: NEP ~ 2 x 10-16 about 3x above photon noise However, requires complicated readout and doesn’t address cost and multiplexing issues…

  8. Can we be photon-noise limited? Noise Source Photon Amplifier GR TLS Knobs:Pa,b ->STLS(T,C,Pa) • a 1/sinh(hw/2kT) ~ 2kT/hw • MAKO: decrease w using Lk of TiNand big C, • keep Pa below bifurcation

  9. Can we be photon-noise limited? We think so. See Chris McKenney’s presentation

  10. Goal: Demonstrate a scalable 350 micron pathfinder instrument using KIDs for large FOV ground-based telescopes • Array should be: • Photon-noise limited …. (see Chris’ talk) • Simple to fabricate • Direct absorption LEKID (see Chris’ talk) • Maximum 3 layers lithography • Low per-pixel cost • Highly multiplexed

  11. Why focus on cost and simplicity? http://ccatobservatory.org/ Steve Padin: “CCAT optical design for 1° FOV” fl/2 at 350 mm: 6 Million w/ corrector plate 1° FOV 1 Million w/o corrector plate ~ 30’ FOV Soft goal: ~ $1 per pixel including everything. In particular, electronics cost dominates. DENSE MULTIPLEXING REQUIRED

  12. Multiplexing density limited by per-resonator bandwidth. Constant power astronomy Minimum per-pixel bandwidth: Df ~200 Hz set by telescope scan speed Min f0 if we can achieve a Q = 105 : 20 MHz

  13. per octave

  14. MAKO 1 Octave Nmux 1k – 3k Q few x 105 per octave

  15. MAKO: low frequency advantage • Improved NEPfreq (see Chris’ talk) • More octaves per fixed electronic bandwidth. ie 500 MHz ADC spans ½ octave in 1-2 GHz compared with more than 3 octaves below 500 MHz • Start designing array with the lowest frequencies first. • Low end set by BW needs and fabrication considerations. • High Lk material needed to get low frequencies (TiNetc) • Eliminate mixing stage and the need for IQ ADC/DAC pairs

  16. Build system • Cryostat • Readout

  17. Cooldown by Cryomech PT410 pulse tube Cryostat • Vibration isolation for pulse tube, • compliant straps at 50 and 4-K • Aluminum vacuum jacket (two section) • Warm magnetic shield: • 2-layer Amumetal~100 attenuation • Aluminum 50-K cold plate + radiation shield • Copper 4-K cold plate, aluminum rad shield • G-10 CR supports • Aluminum 1-K stage, CFRP hexapod • support • Copper UC stage 12” D= 21” 50 K 4 K 34” 1 K D= 18”

  18. Cryostat – Cold head 3He head 1μW @ < 220 mK 3He buffer head 30μW @ < 350 mK 1 K head 250μW @ < 1 K Cycle time ~3 hours Hold time 24 – 36 hours

  19. Cryostat – Filter Stack • 300 K: 1 mm HDPE window, 2.5” diameter • 50 K: 2 mm quartz blocking filter, LDPE AR coat • 4 K: 2 mm quartz block filter, clear + black LDPE • AR coat. (Porex scattering filter?) • 1 K: QMC 300 μmlow pass • FP: QMC 350 μm band pass (10% bandwidth) • 32 mm diameter ~ 1256 fl/2 pixels

  20. Cryostat - Optics Tertiary focus Cold Aperture Stop Filters Cryostat bottom Dewar Entrance Plane Relay Optics Ellipsoid • Focal plane fed at f/# = 4.48 • fl/2 = .78 mm • Entrance plane – aperture stop 2” • Aperture stop – focal plane 5.6”

  21. Everything in hand: Commissioning

  22. Readout Server price $2k C++ (CUDA) cuFFT CPU or Disk Nvidia m2090 ~$2.8k Pentek 2x ADC, 2x DAC 500 MSPS $15k 1st stage: $3500 WeinrebSiGeCryo Amps 2st stage: $500 Miteq.001-500 MHz Full instrument. C/C++ programming. 250 MHz bandwidth $30k for 2 lines ($15k/line)

  23. Need appropriate reconstruction/ anti-aliasing filters here. 500 MHz BW. PLLs used to upconvert SRS rubidium 10 MHz source. Separate A/D, D/A & FPGA PLLs D/A: 2 Bytes/S A/D: 1.5 Bytes/S Use minimum FPGA to keep $/pixel down. x8 PCIe Gen2 supports 4 GB/s transfer rates. Data rate is only 1.5 GB/s

  24. Readout - GPU Can the GPU keep up? FFT Costs: 5Nln(N) FLoating-pointOPerations (FLOP) for N = 2^25, 3 GFLOP-per-fft Rate: (1e9 Samples-per-second/2^25 samples-per-fft)*3 GFLOP-per-fft = 89 GFLOPS or 60% of benchmarked rate. (m2090 has 25% greater max capacity, thus ~47% of GPU potential)

  25. Readout – ADC Performance Texas Instruments ADS5463 500 MSPS, 12-bit A/D Does the ADC have enough dynamic range? Worst SNR ~ 65 dBFS PSD = (N/BW)/S = 1/[SNR*BW] = 1/[SNR*(fs/2)] Noise-to-carrier PSD (dB): -65-10log(250e6) = -148 dBc/Hz Compare with kTn/Pread where Tn is ~ 3.5 K and Pread is max before bifurcation, 4 K TiN: 10*log(1.38e-23*3.5/129e-15) = -94 dBc/Hz …. 54 dB cushion

  26. Thank you! Loren Swenson Chris McKenney Tony Mroczkowski Hien Nguyen Peter Day Matt Hollister OmidNoroozian • Erik Shirokoff • Steve Hailey-Dunsheath • Rick Leduc • Matt Bradford • Attila Kovacs • Byeong Ho Eom • Jonas Zmuidzinas

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