The main differences of this design comparing to the last one are:

1. The components are rearranged to fit the available space (Fig.1).

2. The cold load design is added. SHARCII is used as the cold load (Fig.1, 2)

3. All pixels see exactly the primary (Fig. 3)

4. All optics are over sized by factor of two of the geometric beam size, except for some beams,

which have factor 1.5 near the last mirror (the one before m4).

5. The Nys. focus is reimaged on the combiner, which is oversized by 8 pixels in all direction

except toward the center.

Fig.1 Totally 10 reflections for each polarization component. The idea of the cold load

is to let the bolometer see SHARCII cryostat through the blue curved mirrors.

Fig.2 The clod load region (yellow) inside SHARCII. (for one component)

Fig.3 The boundaries of 9 field bundles on the surfaces of the pupil (baffle1 in Fig.2) and

the bolometer array with (lower) or without (upper) the module.

Huabai 7/26/’04