Monthly Update
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1|8J.V. van Heijningen (jvnheijn@nikhef.nl)
Cables finished! Assemble/ Disassemble Type B Payload LED selection measurements
Monthly UpdateNAOJ GW Meeting, May 8th, 2014
2|8J.V. van Heijningen (jvnheijn@nikhef.nl)
Cables finished! Assemble/ Disassemble Type B Payload LED selection measurements
10 cables from bottom filters to OSEMs
3|8J.V. van Heijningen (jvnheijn@nikhef.nl)
Cables finished! Assemble/ Disassemble Type B Payload LED selection measurements
Wire lengths and masses are wrong!
4|8J.V. van Heijningen (jvnheijn@nikhef.nl)
Cables finished! Assemble/ Disassemble Type B Payload LED selection measurements
Measurement set-up intensity noise
Determined with the first (!) fully assembledOSEM what current to run the LED, now with collimator, to have -12V on UTIA output:
Rs,LED = 300W ULED = 8VILED ≈ 25mA
For fast comparative measurement, LED is runin a simple set-up at 25 mA and ASD on theUTIA signal is taken
First, a dependence of intensity noise on theLED intensity magnitude is investigated
5|8J.V. van Heijningen (jvnheijn@nikhef.nl)
Cables finished! Assemble/ Disassemble Type B Payload LED selection measurements
Intensity noise first batch of LEDs
RMS determinedby f df from 1-40 Hz
6|8J.V. van Heijningen (jvnheijn@nikhef.nl)
Cables finished! Assemble/ Disassemble Type B Payload LED selection measurements
Measurement set-up angular distribution
OSEM optics
LED
Lens (f = 8mm)
CCD Camera
1 DoF TrSt
with end-st
op
7|8J.V. van Heijningen (jvnheijn@nikhef.nl)
Cables finished! Assemble/ Disassemble Type B Payload LED selection measurements
Determining the optimal lens position
Image analysis code:• Determine maximum and a radius in which every value is 95% or higher of this value• Middle of this circle is the defined as the middle of the blob• Square with edges equal to the radius (half the diameter) to determine the
fall of intensity with respect to the ‘0mm’ image
When lens is at optimal position, radius shouldn’t change and power shouldn’t fall (as)much
8|8J.V. van Heijningen (jvnheijn@nikhef.nl)
Assemble/ Disassemble Type B Payload LED selection measurementsNext weeks’ plan
In my last weeks here, I’d like to…
I’ll be at NAOJ until May 23, so 2 weeks to go…
• Select the 10 LEDs that will provide low(est) noise, most linear read-out for the OSEMs in their ‘new’ set-up (with collimator lens)
• Calibrate 10 OSEMs using the calibration stage (last part received last week!)
• Attach OSEMs to full type B payload prototype in their individual regions of highest sensitivity and linearity
• Use these 10 OSEMs in a feedback loop to damp the resonant modes of theTest Mass stage (3 DoFs) and Intermediate Mass stage (6 DoFs)
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