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IOO (Laser Bench)
keiko.kokeyama - 22:11 Wednesday 22 May 2019 (8946) Print this report
MZM removal

Ge, Kokeyama

For removing MZM

BS3 removal
- BS3 on the PSL layout was removed. The mount and pedestal stay there.
- The beam shift due to the absence of the BS3 transmission (thickness with the refravtive index) was unexpectedly large.
- The input to IMC was alined by moving  M12 and 13. The first MZI is still remaining, and was blocked during the alignement.
- TEM00 flash confirmed.
- However IMC lock couldn't be recovered becauce the IO guardian was mess without MZM (MZM node absence, power changes due to the absence of the two MZIs).

BS(M)1 removal
- BS(M)1 was removed and PYD-20 was mounted
- This also caused a large unexpected beam shift. The beam doesn't go into even the EOM2b input hole!
- Because the shift was very large, we are suspecting either BS(M)1 was mounted on the opposite surface to mount (reflecting surface on the bottom), or just mounted badly on the mirror mount.
- Alignment to the IMC hasn't been done. It'll be difficult with this amount of the beam shift. Tomorrow we confirm if the BS(M)1 was mounted opposite or not, by flipping the mirror and seeing the shift recovers or not.

And three more mirrors still to be changed and aligned.

Comments to this report:
keiko.kokeyama - 18:48 Thursday 23 May 2019 (8957) Print this report

[Kokeyama, Ge, Remote Nakano]

Nakano-kun kinbdly modified the IO guardian to skip the MZM node, during the last night.

BS(M)1 removal
- It turned out that the BS was mounted upside down (the reflecting surface on the backside on the mount). Once we mount the HR mirror on the correct side, the beam shifted and didn't go through the EOM2b. So the mirror position was moved and adjusted after all. When we mounted the mirror upside down to simulate the original beam path, multiple beam spots were seen by the innter reflection of the substrate.
- The mounted steering mirror position and angle was optimized by looking at the power meter after EOM2b, with aligning BS(M)1.
- The alignment towards IMC was recovered by walking BS2 and M10. TEM00 flash confirmed.

BS2 removal
- BS2 was found to be mounted with the wrong surface again! Very sad!!
- We swapped the BS to PYD-20 HR mirror. Position was also adjusted.
- The alignment towards IMC was recovered by again BS2 (now HR) and M10. TEM00 flash confirmed.

M15 (IP PZT mount) to a regular mount 
- M15 mirror (IP PZT having PIT and YAW actuator) was removed and a regular 2-inch mirror mount was placed.
- The alignment towards IMC was recovered by walking M15 and BS2 (HR). TEM00 flash confirmed.

PZT1 changed to IP
- PZT1 (1-inch mirror with a PZT for the 1st MZI locking) was removed.
- 2-inch IP PZT (former M15) was replaced. - we tried to use the stable pedestal, but because the optical path was already determined and there was no free DOF, it was not possible. Regular pedestal post was used.
- The alignment towards IMC was recovered by M15 and PZT1 (IP1). TEM00 flash confirmed.

IMC alignment and PSL power adjust
- IMC fine alignment was done by IP2 (top periscope) and IP1 (former PZT1). The alignment recovered fine.
- PSL power was back to 5W at the source. PMC TRANS is 5W, IMC TRANS is something like 3.7W.


PSL layout will be updated asap.

MZM block done

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