20180222
Today's activities
Workers: Simon, Miyo, Akutsu
- (The WAB was locked yesterday.)
- Attached a reflector to the WAB -Y side, and the counter mass (the same shape as the reflector) +Y side.
- Installed three photosensors; positions were at +X, -Y, and the bottom, and they faced -X, +Y, and +Z, respectively, to look at the reflector.
The distance from the sensor head to the reflector are each 17mm; see here.
- Due to the 50-mm pitch of the M6 screw holes on the optical table in the chamber, it was impossible to install the photosensor supports to the positions we like to put; so far a breadboard with 25-mm pitch M6 screw holes was inserted, and this will be replaced to a vacuum compatible one later.
- Connected the pins.
Attached a set of SmCo magnets for a coil-mag actuator; the magnets were attached at -X,-Y, about 45-deg clockwise from the bottom.
- Installed a coil magnet actuator in -X direction.
- Before the installation, the coil's pins were connected to electric wires with copper pipes; because the net diameter of each pin was thicker than that of photosensor, new pipe (phi 1.2mm) was bought and adopted.
- Connected the pins of the coil to U and V of P23.
- The coil's resistance was measured as 13 ohm, while the resistance measured at the distributor was 75+75+13 = around 163 ohm due to the one-way 75 ohm electric wires.
- Unlocked the suspension; The WAB is now floating.
- Tried to exert a force by the coil-magnet actuator, but failed. This would be due to the too large total resistance so the current flow was not enough.
- Should we use the other pins of 4-ohms, which are reserved for a thermometer???
[Ongoing] Need cares of water springs from anchor bolts for oplev pylons.
[Ongoing] Need to confirm what are the scratch lines made by the measurement by the KEK team last week.
Next plan
- Change the pin assign so that enough current can flow to the coil.
- Add capacitors to the transimpedances in the OSEM satellite box.
- Complete the calibration of the oplev; the arm length was reported by Simon, so....
- Check the balance of the suspended WAB with some wires and sensors are attached.
- Check how the damping would be now after the replacement of the damping magnets.
- Check the reproducibility of the alignment of the suspension among several modes.
- Check heights of several points.
- Take care of water spring??
Wanted!
- Two burndy connectors, vacuum compatible.
Stages outside the chamber to ease wiping our legs.
Good rail(?) to move the WAB suspension in the cryostat in the main beam direction.
Chain block? to support the load in the chamber.
- A clock to know the time easily.
- M6 screw set.