Atsuhiko Ochi, Kobe University 16/04/2014 MM PCB WG CERN

Large size resistive strip production 2013 October – First trial to make a large size sample 870mm x 425mm trapezoidal shape 8 foils are produced Provided as a MSW resistive strips 2014 March – Second trial Same size as first trial 3 foils are produced 2014 April – Third trial 50cm x 40cm rectangle shape 2 foils are produced Provided as a new test chamber 16/04/2014A. Ochi, MM PCB WG2

Micro scorpic pictures of strips Recent rectangle foil – Strip width: 0.35mm – Gap width: 0.1mm Foils are attached on PET film – To avoid the damage of the sputtered carbon pattern, by bending the foil 50 μm polyimide foil PET FILM Sputtered pattern 16/04/2014A. Ochi, MM PCB WG3

Resistivity check Resistivity from HV source bar Line resistivity : 15MΩ/cm Carbon sputter thickness: 310 nm (cm) (cm) x Y Preliminary Cupper thickness [Ǻ] Surface Resistivity [MΩ/sq.] 16/04/2014A. Ochi, MM PCB WG4

Problem in liftoff process It is not easy to remove the wide resist pattern (correspond to non resistive pattern) – Long exposure in NaOH liquid may cause the damage to sputtered patterns This is more critical for outside of the pattern – Currently, we have masked outside area by tape and other sheet by hand – However, it is time and cost consuming Sputtered carbon Substrate (polyimide) resist On the liftoff process NaOH Sputtered carbon Substrate (polyimide) 16/04/2014A. Ochi, MM PCB WG5

Request for new pattern - Dummy resistive coating - Can we put dummy resistive coating around the resistive strip pattern with < 5mm gap? – Do we have to consider the mesh attachment and O- ring attachment ? Resistive strip pattern Dummy resistive coating 16/04/2014A. Ochi, MM PCB WG6

Feasibility for Module-0 Technical challenging – There are more than 2m long foils! – 16 types 64 foils needed – Are there resistivity variability for different sputtering batch ? It should be checked. – Fast sputtering method should be developed for reducing the cost. Currently: 6 hours/batch Next trial: 2.5hours/batch, using multiple sputtering target Shorter time available ? 16/04/2014A. Ochi, MM PCB WG7

Summary and prospects Currently, resistive foils production using sputtering is succeeded for large foils. To reduce the process and the cost, dummy sputtering is needed. 2.2m long foils can be made! Discussion of the cost should be started. 16/04/2014A. Ochi, MM PCB WG8