1. NIR LOWFS for Keck and TMT Roger Smith & David Hale

2. Comparison Keck IR TTTMT IRIS OIWFS Detector2.5 µm H2RG Subarray, Low noise Acquisition FoV1200 x 12001000 x 1000pixels Plate scale0.1000.002arcsec/pixel Acquisition FoV120~5arcsec PassbandKJ+H OpticsFull field, reimager with cold Lyot stop 3 probe arms with 2x2 lenslet inserted on brightest star. Output frame rate (minimum) 100080Hz # windows, size 1 to few. 2x2 to 4x4 1 or 4, 4x4 nested in 14x14?

3. Topics Thermo-mechanical – For Keck: proposal (optical layout, dewar layout) – For TMT: eDrawing Detectors considered H2RG read mode Resulting noise vs frame size (or rate) – For TMT – For Keck TMT sky coverage Bad pixels: noisy, hot or insensitive

4. Keck 1 Layout LGS AO control schematic with the new NIR TTS system added (upper right). A fold located just in front of the science camera reflects light to the NIR TTS assembly mounted on a focus stage. The TTS output is processed to provide TT control of the Tip-Tilt Mirror (TTM) as an alternative to the existing visible TTS (STRAP) or in combination. Focus information, if available, could be used to control the wavefront sensor (WFS) focus.

5. Keck 1 Pickoff Options

6. Keck 1 reimaging dewar

7. TMT: 3 R-theta probes 1 of 3 sensor dewars

8. Sensor Dewar Focal plane Getter on cold head Cryotiger, decoupled from detector Cold filter location

9. Preliminary Cooling Curve Masses and surface areas are guesses, to be updated from solid model ! Ample power margin; safe cooling rate.

10. Keck 1 noise vs frame rate