FUTURE FERMILAB NANOCAM DEVELOPMENT fast NIR/Optical/UV - - PowerPoint PPT Presentation

FUTURE FERMILAB NANOCAM DEVELOPMENT

fast NIR/Optical/UV spectroscopic counters

Estrada / Stebbins Fermilab 2018-04-11 Fermilab Batavia, USA

coherence patches λ distance∕size x c∕Δν

correlations: amplitude ± intensity > 0 (net)

TECHNICAL MILESTONE: GROUND BASED OPTICAL IMAGING LIMITED BY EARTH SIZE : BASELINE ≲10000KM IN OPTICAL: WAVELENGTH ~ 1 MICRON ANGULAR SCALE ≳ 10-9 ARCSEC

SCIENCE GOAL: IMAGE MATTER AS IT FALLS INTO BLACK HOLE HORIZON

dots represent measured population of supermassive black holes lines represent sensitivity limit of technique using giant telescopes

ORIGIN OF MOST HEAVY ELEMENTS IN THE UNIVERSE USE GRAVITY WAVES TO TRIGGER OBSERVATIONS

SCIENCE GOAL: IMAGE EXPANDING EJECTA PRODUCED BY COALESCENCE OF NEUTRON STARS

METHOD: SPECTROSCOPIC COUNT INTENSITY INTERFEROMETRY

Spectroscopic (narrowband) intensity correlations

• split light into narrow frequency channels
• “mixes down” to 1/δt ~ Δν
• “mixes up” to 1/δt ~ 2ν
• at“quantum limit” δt Δν ≲ ½ ⇒ R ~ ν/Δν ≳ 104
• much easier to measure 50% correlations
• increases overall S/N by √R
• /

[ ] μ

• ---- δ Δν = / -----
• /

[ ] μ

• ---- δ Δν = / -----

Broadband intensity correlations

• intensity correlations convolution of spectra with itself:

(δI2)ν =¼∫ⅆν’ fν’ fν-ν’

• intensity “mixes” radiation field with itself
• 1% correlations at (measurable) 10psec timescale
• much larger than field correlations

ENABLING TECHNOLOGY

Intensity interferometry measures the excess rate of “coincident” photon counts from a single source at two (or more) widely separated locations. Requires recording of vast numbers of photon arrival times. Ideally each photon should also have an accurate wavelength determination and precise and accurate time-

• f-arrival.
• large collecting area telescopes (telescope)
• high resolution (R~104) spectrograph to separate frequencies (spectrograph)
• accurate times of arrival (timing)
• precise times of arrival (fast counters)
• detectors with large numbers of independent counters (pixelated counter)

HOW TO MEASURE INTENSITY CORRELATIONS

timetag γs

Record all photon time-of-arrivals at two telescopes

{ r1, r2, r12 }

One possible camera design concept: For each frequency channel compute photon rate, r1 & r2, and rate of “coincident” arrivals r12 Possible Fermilab Role: photon detector/counter readout electronics integration of camera

EXAMPLE DETECTOR: LAPPD?

Large Area Picosecond Photon Detector LAPPD could be centerpiece of fast spectroscopic counters

• precise timing capability (<100psec)
• >104 pixels for spectroscopy on each device
• can handle large count rate (> million counts per second)
• off-the-shelf technology soon?
• Quantum Efficiency 20-40%?
• Photo-cathodes have poor QE in NIR
• better QE (esp. NIR) alternative: nanowire
• 25)

alternately, SiPM, SPAD, nanowire, …

SIMULATED DATA

300 400 500 600 700 800 500 1000 1500 2000 λ (nm) counts

mag 17 D = 30m T = 1sec nch = 5000

• 1.0
• 0.5

0.0 0.5 1.0 100 200 300 400 time offset (nsec) simultaneous counts

mag 17 λ ∈ [300,800] nm D = 30m T = 1hr δt = 10psec

temporal alignment Φ self calibration

3C 273 shadow 3C 273 Schwarzschild

300 400 500 600 700 800 0.0 0.2 0.4 0.6 0.8 1.0 30 nas 50 nas λ (nm) estimated Φ 1 / ℓ = λ / (2 π b⊥)

mag 12.9 D1 = 35m D2 = 22m b⊥ = 434km T = 4hr δt = 10psec Q = 0.3

• each camera is a moderate spectral resolution /

high very high time resolution spectro-photometer

• temporal alignments removes
• tides / astrometric uncertainties / atmospheric refraction
• coherence function is self-calibrated by counts

3C 273 w/ E-ELT GMT

LARGE TELESCOPES WORLDWIDE

APERTURE “DIAMETER” ≥ 200”

SALT E-ELT GMT VLT4 GeminiS Magellan2 Keck2 Subaru Hobby-Eberly LBT2 GeminiN MMT Hale LAMOST GTC LZT BTA TMT

• rdinal by collecting area

effective aperture diameter (meter)

EXTREMELY LARGE TELESCOPES

Jan Apr Jul Oct Jan 2 4 6 8 10 12 time of year night duration (hours)

• bserving / co-observing

E-ELT E-ELT+GMT E-ELT+TMT1 E-ELT+TMT2 GMT GMT+TMT1 GMT+TMT2 TMT1

Giant Magellan Telescope (GMT) Thirty Meter Telescope (TMT)

European Extremely Large Telescope (E-ELT)

canary islands hawaii

SUMMARY

• with technology that exists or will be available in next decade one

is capable of decreasing best astronomical angular resolution to the nano-arc-second scale.

• this can be done in the optical!
• detector technology is what is already used in HEP
• observational targets must emit enough radiation on these small

angular scale: many of these targets black holes / neutron star coalescence are those of most interest for fundamental physics.