March 2005 Mimir Servicing
- Inspected camera
and detector bays– found no aluminum chips or dust. Concluded previous
interference problem has been solved.
and installed new pupil mask, based on pupil images from December 2004 engineering
- Moved PK50-1
filter from FW3 to FW2 to support J-band spectroscopy with LM grism with long wavelength blocking
- Added second
Ks filter (Ks-2) in FW2 as alternate for Ks-1, which shows image features
that do not flat-field out.
“beefeater” MLI between floating thermal shields between cold and warm
bulkheads. This MLI was believed to be a cause of the slower vacuum pumpdown in November 2004. The floating SS shields
were left in place.
- Removed 200 W
and 75 W heaters and mounting blocks from cold bulkhead.
- Realigned all
3 grisms to reduce spectral tilt in the images.
Rotated JHK by 1 deg, LM by 1.4 deg, and SED by 2.4 deg.
- Ran full 25
cycle He purge of cold head
- Replaced He
compressor adsorber with “old” one that had been
removed prematurely several years ago in BU lab. Compressor hour clock is
- Added second
flat copper strap from cold head second stage heater block to filter box.
This to increase the cooling of the optics/filter box by the 2nd
- Removed one
of three 1/8” dia copper rods from sapphire
thermal feed through block to detector thermal feed through block.
- Removed POL
wheel encoders with units bits set to one to prevent multiple “home”
positions due to mis-encoding of higher order
bits. Now, there is only one “home” position reporting (it holds the
thermal control and thermal monitoring systems to support new Loop A inputs (primary 2nd stage, secondary 2nd
stage, cold bulkhead).
fabricated new switch plate for back of electronics box to switch Loop
A inputs/control lines for the LS331 among the
- Modified 2nd
stage/getter heater block to host a second cartridge-type resistive heater
(“R2”) and another thermal sensor (“TA2”).
- Installed new
cold bulkhead resistive heaters (“R3”) and thermal sensor (“TA3”), taken
from decker car.
copper thermal straps from slit and decker cars.
- Inspected decker/slit car operations. The cars and their sensors
(limits and detents) seem to work fine, but the software does not.