1. Survey of cathode deformations and further actions F. Vercellati – INFN-PV C. Montanari – CERN / INFN-PV WA104@CERN weekly meeting, March 12, 20151

2. Cathode survey and present activities l We completed the mapping of cathode planarity on a grid of points with 300 mm spacing. Data are being transcribed and will be delivered soon. l Please keep this presentation as a reference for the measurements. l We are preparing to dismount the first cathode panel. The cables at the front (HV connection side) and the front “cross” have been dismounted. The first beam holding the first panel and hosting the HV connection cup has been removed. Level meters, position sensors and purity monitors have been removed. l Following a safety review from Olga and Erwan and thanks to Dimiter, we are implementing a protection for the wires (a net) and a working plane all along the TPC. l The first cathode panel will be dismounted between today and tomorrow. l In the next three weeks we will remove the rivets that are holding the pierced sheet and plan for further actions. Slide: 2 WA104@CERN weekly meeting, March 12, 2015

3. Cathode panels Slide: 3 WA104@CERN weekly meeting, March 12, 2015 X Y 145 85 Origin Last column of the grid 118

4. Cathode deformations Slide: 4 WA104@CERN weekly meeting, March 12, 2015 Panel 1 Panel 2 Panel 3 Panel 4

5. View of the TPC front side Slide: 5 WA104@CERN weekly meeting, March 12, 2015 First cathode panel Beams of the “cross”

6. Net to protect the wires Slide: 6 WA104@CERN weekly meeting, March 12, 2015

7. Working plane (to be extended) Slide: 7 WA104@CERN weekly meeting, March 12, 2015