STATUS REPORT OF FPC SPICA Task Force Meeting March 29, 2010 MATSUMOTO, Toshio (SNU)

Concept of FPC FPC consists of two instruments FPC-G: Focal plane guiding camera FPC-S: Near infrared camera for scientific observation FPC-S has a back up function of FPC-G FPC-G and S must have a same FOV and pixel scale with same detector. 1K x 1K InSb array (25  m pixel) ROIC developed for MIRI/JWST by Raytheon 5 arc-minutes FOV for 1 frame 0.3 arc-second FOV for 1 pixel (~diffraction limit at 5  m)

Detector proposed by Raytheon Format: 1024 x 1024 active (plus two columns of reference pixels) Pixel Pitch: 25 μm Input Circuit: SFD (source follower per detector) Active Fill Factor: > 98% Spectral Response: μm Average Quantum Efficiency: > 90% (1 - 5 μm) Typical Response Uniformity: ≤ 5% (1σ) Average Dark Current: ≤ 0.02 e-/sec at 30 K Read Noise: 25 ~ 30 e - for single CDS (~20 e - for 0.4 Hz eadout) Power Dissipation: 0.5 mW (0.4 Hz readout), 1.2 mW ( 1Hz readout) Well Capacity: 2x10 5 e- Outputs: 4 Reset Modes Global Reset or reset by Row pair Operating temperature>10 K

Optical design of FPC-G Optical axes of lens group are shifted to improve off axis image 7 lenses with 4 aspherical surfaces Lens materials are ordinary used ones Spot size ( I and z band) is typically 10  m. Maximum size is ~35  m at a far end from the telescope axis Distortion effect can be corrected by interpolation formula.

Structure of FPC-G Cross sectional view of FPC-G Weight ~ 4kg (Support structure and FPA are not included)

Performance of FPC-G Required accuracy of the determination of centroid: 0.05 arcsec Wavelength band: I band (0.8  m) Detection limit: 18.6 mag (1Hz read out, 25  ) Number of stars in 1 frame: ~12 stars (GSCII Catalog) FPC-G can achieve required accuracy Power dissipation 1.2 mW (1 Hz readout), 0.5 mW (0.4 Hz readout)

Optical design of FPC-S FPC-S covers wavelength range from 0.5  m to 5 m  one more optical element a little longer than previous design (520 mm)

Spot diagram for white light (0.8-5  m) Typical spot size 24  m Max spot size31  m For monochromatic light 2-5  m max spot size ~34  m  m max spot size ~42  m Distortion effect can be corrected by interpolation formula. Error of centroid for 4’x4’ field is average:0.03”, Max 0.06” Error of centroid for 5’x5’ field is average:0.07”, Max 0.37”

Structure of FPC-S Weight ~ 6kg (Support structure and FPA are not included) Filter wheel10 positions (blank, diffuser, 8 filters)

New mode: LVF Spectroscopy Three LVFs (Linear Variable Filter) are installed on the filter wheel cf , , LVF has transmission depending on the physical position (scanning direction). Wavelength coverage is factor 2 Wavelength resolution is ~ Slit less spectroscopy at the wavelength range from 0.8 to 5  m Combined with slow scan, surface spectroscopy can be done efficiently for diffuse extended source Scan direction ↓ ← 5 arc-minute →LVF 0.8  m 1.6  m

Expected performance of FPC-S Assumed parameters Telescope3-m aperture (7m 2 ) Efficiency0.5 (Optical + quantum efficiency) Read out noise20 e - image size4 pixels 3  detection limit for point sources (100 sec integration, R~5) 26.3mag(AB) for all bands Vega magnitude J(1.25  m)H(1.6  m)K(2.2  m)L(3.5  m)M(5.0  m) Photon noise becomes dominant for integration time lon ger than 100 sec 3  detection limit for surface brightness (100sec integration, R~5) 81 nW.m -2.sr -1 3  detection limit fro LVF mode, R~50, integration time ~t Point sources, F 3.4x t -1 W.m -2.  m -1 Extended source,.F 8.1x t -1 nW.m -2.sr -1 Line intensity for point source6.84x t -1 W.m -2 Line intensity for extended source1.62x t -1 nW.m -2.sr -1

Comparison with JWST Larger field of view JWST2.2x4.4 arcmin FPC-SPICA5x5 arcmin Much larger throughput x 20 of JWST Capability of surface spectroscopy New science that can not be done with JWST will be possible