FADC/Hybrid cable production 21 Jan 2015 T. Tsuboyama

Situation Hybrid cable: From Hybrid (FR4 or Origami) to the DOCK box inside the Belle II structure. FADC cable: From DOCK to FADC on top of the Belle2 structure. The budget for the FADC and Hybrid cables expires at this March. We have to finish production by then. We have all cables and connectors. Tentative specification is set. I asked the company to produce 10 cables. Depending on the result, I will propose the final specifications.

Electrical test The following test will be done by the company Conductivity can be measured with 0.01 Ohm precision. HV duration: Only 1 wire in the hybrid cable is connected to the common ground level and voltage difference with other wires will be around ±50 V. So I chose 200 V for the test. The leak current or resistance is will be measured. Insulation: Not only the cable dielectric but also the quality of connector assembly can be monitored. We will set the upper or lower limit values after the first 10 cables will be assembled and tested.

Hybrid cables Parts: – The half-pitch, half-twisted and half-loosened Polyethylene or Polyolefin cable, as known as the thin-SCSI cable. – The production is discontinued in Europe, Japan and US, however, HEPHY group knew CERN has some stock. They bought the cable and sent to KEK. – JAE connectors and SAMTEC connectors are more or less on the catalog. The pin-clamping machine, so called “the applicator”, will be delivered soon to the company. The production will start then. Layer 3 cables will be prepared in HEPHY not by KEK.

FADC cables Using the 3D CAD data, Markus decided the length to be 12.5 meter, however, I added 0.5 meter for the case. The connectors are assembled at the flat part on both ends. Flat part appears every 25 ±1.3 cm. For the 13m long cable, the length tolerance will accumulate to 60 cm. It means we can not make the length more precise than 25 cm. Markus accepted this condition from viewpoint of electronics. I ordered the production of the first 10 cables. Final specification is set after examine the result.

Summary FADC and Hybrid cables should be produced by end of March. First 10 samples will be produced, tested and shipped to KEK. Specification will be settled and full production will be done.