Paolo Michelato, July 19-22, 2006 Global Design Effort 1 Vacuum system segmentation Cold vacuum system segmentation reflects the cryogenic structure of the linac. After 6 June videoconference the insulation vacuum breaks should be every 140 m? Tom Peterson, 13 June 2006

Paolo Michelato, July 19-22, 2006 Global Design Effort 2 Beam line vacuum system 1/2 142 m 571 m (4 strings) Ion getter pump LD 2 TMP pumping units with high sensitivity LD and RGA, safety, clean venting system, slow start pumping etc. LD RGA

Paolo Michelato, July 19-22, 2006 Global Design Effort 3 One 55 l/s ion pump should guarantee reasonable low H 2 pressure and He pressure in case of small leaks. Other gases are cryopumped. 2 dry pumping units with LD, RGA, slow pumping, controlled venting are foreseen in case of ion pump replacement. They are also used, during the string connection, for the pumping of the intermediate piece between the two all metal gate valves. Beam line vacuum system 1/2

Paolo Michelato, July 19-22, 2006 Global Design Effort 4 Beam line vacuum system 2/2 571 m 2288 m All metal Gate valve LD 2 TMP pumping units with high sensitivity LD and RGA, safety, clean venting system, slow start pumping etc. LD RGA High speed safety shutter Special cold gate valve 150 l/s Ion pump

Paolo Michelato, July 19-22, 2006 Global Design Effort 5 Special 4K operating gate valves, only for failure scenario, are foreseen between each 571 m segment. The should be leak tight during warm up. Not available on the market: DESY and VAT are working on that. Quite expensive! All metal fast shutters + all metal gate valves protect the two cryogenic units in case of air inrush in the room temperature part. –Distance should be > 10 m between sensor and safety system: protection is not optimized. Beam line vacuum system 2/2

Paolo Michelato, July 19-22, 2006 Global Design Effort 6 A 150 l/s ion pump will ensure proper low pressure in case of relative significant gas production in the room temperature part. 2 dry pumping units with LD, RGA, slow pumping, controlled venting are foreseen for the first pumping and in case of ion pump replacement. Beam line vacuum system 2/2

Paolo Michelato, July 19-22, 2006 Global Design Effort 7 Beam line vacuum system costing The leak detector connected to the TMP is not an usual Leak Detector. It has to work on UHV, and not in counterflow. May be not available directly on the market and needs some effort. Some product on the market may be ok with relative small modification as the LDS 1000 Inficon or equivalent from Varian or Alcatel. Pumping system needs special characteristics as slow pumping, clean venting for the reduction of the risk of moving or producing particles. Safety shutters are expensive (18000€), probably the distance is too small to ensure the best reduction of air inrush.