Focal Plane Array Testing and Applications for Astronomy Donald Figer Space Telescope Science Institute

Focal Plane Array Testing and Applications for Astronomy

• Donald Figer Space Telescope Science Institute

Outline

• The role of detectors in discovery.

• The state of the art in detectors.

• Keck/LGS/AO
• HST
• SOFIA

• Detectors and future Astronomy projects.

• LSST
• SNAP
• JWST

The Role of Detectors

Detector Functions

• Photometry

• Astrometry

• Spectoscopy

• Morphology

• Time Variability

Detector Types

• Eye

• Film

• Photomultiplier tube

• CCD

• Photodiode array

• Radio Antennae

Detector Wavelength Sensitivity

CCD Architecture

Hybrid Architecture

Hybrid Architecture

Keck

Keck

Keck

Keck/AO/LGS

HST: Hubble Space Telescope

• General-purpose orbiting astronomical telescope

HST

HST

HST

HST

HST

SOFIA: Stratospheric Observatory for Infrared Astronomy

LSST: Large Synoptic Survey Telescope

• What is the distribution of dark matter in the Universe?

• What is dark matter?

LSST

SNAP: Supernova Acceleration Probe

• What is dark energy?

SNAP Optical Configuration

SNAP Focal Plane Concept

JWST: James Webb Space Telescope

• What is the shape of the Universe?

• How do galaxies evolve?

• How do stars and planetary systems form and interact?

• How did the Universe build up it present elemental/chemical composition?

• What is dark matter?

JWST

• 6.5m diameter primary mirror

• launch in 2013

• orbit at L2

• four scientific instruments

• JWST deployment movie

IDTL: Independent Detector Testing Laboratory

• Located at Space Telescope Science Institute and Johns Hopkins University

• Founded 1999

• Mission: Serve the astronomical community by developing and testing detectors for space and ground based astronomy programs

Past and Present Personnel

IDTL Test System

IDTL Test System

IDTL Sample Results: Persistence (1200 seconds)

IDTL Sample Results: Read Noise

IDTL Sample Results: Dark Current

IDTL Sample Results

IDTL Comparartive Detector Characterization

Properties of Silicon: Absorption Length

Properties of Silicon: QE

Properties of Silicon: Long Wave QE

Silicon 1 m QE vs. Thickness & Temperature

Properties of HgCdTe

Properties of InGaAs: QE

State of the Art: Thin CCD

State of the Art: LBNL Thick CCD QE

State of the Art: Si PIN

State of the Art: Si PIN RQE (100 m thick)

State of the Art: Si PIN Hybrid Arrays

State of the Art: Si PIN Dark Current

State of the Art: Si PIN Read Noise

State of the Art: HgCdTe

• Mature technology, although short-wave QE is recent development.

• Several vendors.

• Flight heritage

• NICMOS, 256x256, 2.5um cutoff.
• Hubble Wide Field Camera 3, H1RG, 2.3um cutoff. (Launch?)
• Deep Impact MRI spectrometer, H1RG, 5um cutoff.
• JWST NIRCam, NIRSpec, FGS, 2.5um and 5.0um cutoff. (Launch?)

State of the Art: HgCdTe Dark Current

State of the Art: HgCdTe Read Noise

State of the Art: InGaAs

State of the Art: SUI InGaAs QE

State of the Art: Photon Counting CCD

• Emerging technology.

• Two (more?) vendors.

• Low Light Level CCDs (L3CCDs), a.k.a. EMCCDs.

• Realized noise is 1.4 times value for non-photon counting mode.

• High read rate required in photon counting mode implies high power ~10 W per CCD for clocks and outputs.