Mechanical Changes Required Due to Proposed IRMS Rx

V2

R. WeberSeptember 27, 2011

2

Windows & CSU• No changes required for

window mounts• Because of the flip in

curvature of the focal surface, the CSU supports will need to be shortened by ~4 mm so that the focus is at the incoming edge of the central masking bar, rather than the exiting edge. Or, the instrument could be positioned ~4 mm further from NFIRAOS. TMT focus

(blue arc)Keck focus(ends of ray pencils)

Masking bar thickness

9/8/2011

3

Field Lens

• Girdle thickness increased from 11.5 to 12.9 mm- better for bonding

• Center of girdle shifted 2.694 mm towards CSU- lens mount flexure pockets machined deeper in cell

9/8/2011

MOSFIRE (solid)IRMS (transparent)

4

Collimator Barrel• Girdle center shifts: Col

#2= -0.5 mm, Col #3= 2.7 mm, Col #4= 1.6 mm, Col #5= 0.03 mm, Col #6= -0.05 mm.

• These relatively small shifts in the lens girdle centers should be achievable through a combination of cell spacer shim alterations and/or altering mount flexure pocket depths.

• Girdle widths are all comparable or slightly larger than MOSFIRE design- no bonding issues.

9/8/2011

MOSFIRE lenses(solid)

IRMS lenses(transparent)

5

Camera Barrel: (Cells #1-#4)• Cell #1: girdle center shifts -

2.0 mm and girdle thickness increases by 0.8 mm to 12.0 mm; minor cell spacer shim modifications required.

• Cell #2: girdle center shifts -1.6 mm and girdle thickness remains the same; minor cell spacer shim modifications required.

• Cell #3: girdle center shifts -1.9 mm and girdle thickness decreases by 0.7 mm to 52.7 mm; minor cell spacer shim modifications required.

• Cell #4: girdle center shifts -1.9 mm and girdle thickness increases by 0.6 mm to 11.1 mm; minor cell spacer shim modifications required.

9/8/2011

MOSFIRE lenses(solid)

IRMS lenses(transparent)

6

Camera Barrel: (Cells #5, #6, & Field Flattener/Detector)

• Cell #5: girdle center shifts -0.8 mm and girdle thickness increases by 1.8 mm to 9.9 mm; minor cell spacer shim modifications required.

• Cell #6: girdle center shifts -1.4 mm and girdle thickness decreases by 2.2 mm to 26.3 mm; minor cell spacer shim modifications required.

• Field flattener/detector: girdle center shifts -1.2 mm and girdle thickness increases by 0.6 mm to 9.9 mm; minor cell spacer shim modifications required.

9/8/2011 IRMS focal surface

MOSFIRE lenses(solid)IRMS lenses

(transparent)