Tests performed during the heavy maintenance (2007.06.20)
Goals
Identify the origin(s) of the "acceleration" problem in MAMBO2.
- Is the acceleration problem due to a mechanical or electrical process ?
- What is the influence of the driving program on its intensity (Basic/Cascade) ?
- Any difference in the peak noise whether it is an on-off in elevation or in azimuth ?
People
Pico Veleta: DJ, SL, SN, JP
Methods
- An inclinometer was installed on the Mambo2 platform (see picture below) to measrue the vibrations during the measurements.
attachment:inclinometerPhoto.jpg
On-off measurements on an absorber. The on-off are done w/o the wobbler taking offset in azimuth and elevation to activate the Basic or Cascade controller. The Basic/Cascade limits are (600,400) arcsec in (Azimuth,Elevation). We point out that these observation are not reproducing exactly the standard bolometer observations with wobbler and a throw < 90 arcsec.
- An extra weight was added on the bolometer platform to check the effects of a change in the platform response to the vibration.
- Oscilloscope monitoring directly on Mambo2 was performed during an on-off measurements.
You can find the list of the absorber on-off scans [:AbsorberTests: here]
Results
- Inclinometer measurements for two on-off measurements with the Cascade and the Basic controller.
BR attachment:inclinometerBolo.jpg
- On-off measurements with the offsets in elevation: 360" (scan 47, Cascade) and 440" (scan 50, Basic)
BR Cascade controller attachment:scan47-elev-cascade.jpg
Basic controller attachment:scan50-elev-basic.jpg
- An extra weight was put on the bolometer platform (scan 51)
attachment:scan51.jpg
- Measurements of electrical peak with the oscilloscope during an on-off measurements with the offsets in elevation (scan 53).
No correlation was found between the beginning of the scans where the extra noise peaks appeared and the electric activity. A peak frequency of 5 sec was observed but which may be related to the air conditioned system.