1. Scientific DetectorWorkshop, 2005 Taormina Characterization of 1.7um cutoff detectors for SNAP Roger Smith Caltech

2. SuperNova / Acceleration Probe A 2m class wide field survey telescope in L2 orbit… …will use supernovae and gravitational lensing to begin to unravel the mysteries of Dark Energy and Dark Matter.

3. SuperNova / Acceleration Probe Precision photometery … <2% error, including systematics No cryogens

4. Mixed CCD and NIR focal plane 36 x 2Kx2K NIR arrays 1.7um cutoff Radiative cooling to 120- 140K 3 NIR bandpasses Fixed filters 18-20um pixels under- sample diffraction profile Caltech U.Michigan IDTL JPL GSFC 560mm diameter 36 NIR Detectors 3 bandpasses Guiders (4) 36 CCDs, 6 bandpasses Spectrograph slit

5. QE SNAP Spec. Without AR Coating Substrate removed with 1.7um AR coat RSC RSC WFC3-094 SUBSTRATE REMOVED (DCL) Smaller telescope, cheaper mission

6. Intra-Pixel Response [Total signal from 5um spot, vs. position] RaytheonRockwell HgCdTe

7. Dark Current vs T

8. CDS noise

9. Fowler Sampled noise (spatial)

10. Cosmic Rays Raytheon HgCdTe Single 1000s dark (CDS) Rockwell HgCdTe Difference of 1000s darks Fowler 32, 80K

11. Best efforts so far… At 140K….Rockwell HgCdTe Raytheon HgCdTe Rockwell+SU InGaAs Raytheon+SU InGaAs QE (no AR coat) 60-80%, substrate removed 80%, flat substrate on 75-85%, cutoff shorter at low T Intrapixel response (p-p, 2.3um spot) 20%<2% Dark current (e-/s)0.07 0.25 * 3 Diffuse Cosmic Rays ? Yes substrate on CDS Noise (e-), 140K 33 1636 89 Fowler16 noise, (e-) min.exp, 100K 7.66.630 RTS Noise in mux ?YesNo Rad hardness (mux)ExcellentTBD soon * Manufacturer’s measurement