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Results of initial measurement of temperature sensitivity of Hartmann sensor
"Cold" images were taken at the following temperature:
| before | 32.3 | 45.3 | 37.0 |
| after | 32.4 | 45.6 | 37.3 |
"Hot" Images were taken at the following temperature:
| before | 36.5 | 48.8 | 40.4 |
| after | 36.4 | 48.8 | 40.4 |
"before" are the temperatures just before taking 5000 images, and "after" are
the temperatures just after taking the images. First column is the temperature
measured using the IR temp sensor pointed at the heat sink, the second column the
camera temperature, and the third column the sensor board temperature.
Temperature change produced by placing a "hat" over the top of the HP assembly and the top of the heatsinks.
Averaged images "cool" and "hot" were created using 200 frames (each).
Aberration parameter values are as follows:
Between cool and hot images (cool spots - hot spots)
p: 4.504320557133363e-005
al: 0.408248504544179
phi: 0.444644135542724
c: 0.001216006036395
s: -0.002509569677737
b: 0.054773177423349
be: 0.794567342929695
a: -1.030687344054648
Between cool images only
p: 9.767143368103721e-007
al: 0.453972584677992
phi: -0.625590459774765
c: 2.738206187344315e-004
s: 1.235384158257808e-006
b: 0.010135170457321
be: 0.807948378729832
a: 0.256508288049258
Between hot images only
p: 3.352035441252169e-007
al: -1.244075541477539
phi: 0.275705676833192
c: -1.810992355666772e-004
s: 7.076678388064736e-005
b: 0.003706221758158
be: -0.573902879552339
a: 0.042442307609231
Attached are two contour plots of the radial spot displacements, one between
cool and hot images, and the other between cool images only. The color
bars roughly indicate the values of maximum and minimum spot
displacements.
Possible causes:
1. anisotropy of the thermal expansion of the invar foil HP caused by the rolling
2. non-uniform clamping of the HP by the clamp plate
3. vertical thermal gradient produced by the temperature raising method
4. buckling of the HP due to slight damage (dent)
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