Here's the layout of the lens wheel for CD014, looking in from the Dbox wall side. I will update this drawing to include the pot voltages and the position of the UKIRT filter at a later point (I'm keeping the UKIRT filter in vacuum storage until the last minute).
This time we wanted to have the 38 mm KRS5 lens focus the grating onto the detector at its new position (0.125" closer to the grating).
The nominal EFL for the 38mm KRS5 lens is 38mm -- however, it is a 8mm thick meniscus lens and i wasn't sure where the EFL is referenced. So I carefully measured the back FL at optical wavelengths (0.63um, n=2.57) in the lab. I got an average of 31.1 mm. The EFL would have been closer to something like 31.1+4 =35.1mm. At 10.6um (n=2.37), then the EFL is 40.2mm, and the BFL=36.2 mm.
To focus the grating 1000mm away, the back of the lens should be 37.9 mm from the detector.
The distance from the new detector position to the lens barrel is 27.2, so the back of the 38mm KRS5 lens was placed at 10.7 mm into the lens wheel (or 13.8 into the lens barrel).
For the ZnSe lens, I picked a closer distance to the detector of 31.9 mm from the back of the lens.
Note: Drawing updated to actual CD014 configuration on 5/13/2013.
1 comment:
We're always going to want a mirror in, so let's make it position 1. We'll number clockwise from there looking at the wheel from the detector side. We will mark position 2 with two dots before cooldown 14.
Post a Comment