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AOS (Baffles & Beam dumps)
simon.zeidler - 0:14 Friday 23 February 2018 (4259) Print this report
Installing Photosensors, Reflector, and Coil-Magnet in IYC for WAB Cooling Test

Akutsu, Miyo, Simon

We have set all photosensors in their destinated position for the cooling test (facing +Y, -X, +Z; in KAGRA-VIS terms, see picture 1). But we have encountered another issue which forced us to make the installation only temporarily.
After setting each reflector in its position at the bottom edge of the baffle and confirming they are plane parallel to the optical table, we set the photosensors on the posts and tried to clamp them on the optical table. However, the screw-hole density on the table is very low (distance to each hole is 50mm) and thus, in the desired position, with ~15mm distance to the reflector for each photosensor, the clamps could not be fixed on the table.

Solution: installing an adapter-plate with a higher density of screw holes on the optical table in the IYC. But it will take some time until the plate will be delivered...

Temporary Solution: for the sensor-ensemble-test, we used one of the OpLev breadboards for hosting the photosensors. The board is just lying on the optical table (with an Aluminum foil sheet in between) as its weight pushes it enough (see also picture 1).

With this breadboard, we could set the photosensors and connected them to the DAQ.

Then, we put two magnets on the -Y baffle-edge (~45° toward -X,-Z side) and set the coil-magnet on a post. The post was moved then toward the magnets so that its distance to each other was about 20mm (see picture 2).
After connecting the coil to the current source, we released the baffle, injected some current into the coil and watched the response of the photosensors.
Unfortunately, we could not recognize any reaction of the photosensors to the injected current, even when we moved the coil further to the magnets.
The reason is that the used Burndy connector is a 75Ohm link which is by far too much for the current source. We would need a 4Ohm link but any other connection is occupied.
Possible Solution: disconnect one of the temperature sensors (we might not need so many anyway) and use the free 4Ohm connection for the coil.

We will try this solution maybe tomorrow.

Images attached to this report
Comments to this report:
simon.zeidler - 13:44 Friday 23 February 2018 (4265) Print this report
Note: the distance of photosensor to reflector was set to 17mm for all photosensors (measured before releasing the baffle)!
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