Virgo Logbook

The analyses of stray light due to dust particle contamination in the SQZ subsystem are ongoing: on Thursday 5th November we placed five 3" silicon dust witness samples (kindly provided by A. Pasqualetti) on ESQB1. In particular:

- On top of AEI squeezer box, horizontal
- On ESB1 bench, near AEI squeezer box, horizontal
- On ESB1 bench, near AEI squeezer box, vertical
- On ESB1 bench, approximately in the middle of the rectangular part of ESQB1, horizontal
- On ESB1 bench, approximately in the middle of the rectangular part of ESQB1, vertical

Horizontal witness samples have been left in their open boxes.
Vertical witness samples have been mounted on a vertical support with two screws.
Each sample has the clean face exposed and the box lid facing down next to it (ready to be closed and transported away).

These samples are likely to be removed and replaced when the superpolished optics will be installed on the bench.

Two additional wafers (one horizontal and one vertical) have been left exposed on the bench for 1' and removed, in order to monitor the dust fallout due to handling.

The control wafers and the leftover clean wafers are now on the desk of DET lab, near the two PCs.

Please do not move the samples and report any activity that may need to be performed in the close proximity of a sample and may compromise its representativity of the average cleanliness condition of its location.

Attached photos show more precisely the location of the samples and the position wrt the ESQB1 scheme (in orange, circles for the horizontal samples, rectangles for the vertical samples).