110 likes | 221 Views
Status of HER Arc RF Seals. M. Sullivan For the PEP-II team Machine Advisory Committee Review October 25-27, 2006. Example of a melted RF seal. These Cu fingers are brazed onto the SS mounting plate. Inside of ring. RF seal from Arc 7. Inside of ring. Ag melts at 1200 deg C
E N D
Status of HER Arc RF Seals M. Sullivan For the PEP-II team Machine Advisory Committee Review October 25-27, 2006
Example of a melted RF seal These Cu fingers are brazed onto the SS mounting plate Inside of ring
RF seal from Arc 7 Inside of ring
Ag melts at 1200 deg C and boils at 2400 deg C Melted the Ag plating These omega fingers are over crushed
Some Numbers • Each arc has 32 cells. Each cell has a bellows module with 2 RF seals and a zero length bellows with one RF seal. • Arc 9 • 11 cells worth of bellows and flex flange RF seals checked • All bellows ok • 3 flex flange RF seals melted • Arc 7 • 18 cells worth of bellows and flex flange RF seals checked (8 cells checked in July of these 8 four were rechecked) • 3 bellows replaced in July • 1 bellows found with several disconnected fingers • 1 bellows found with 1-2 displaced fingers • 2 flex flange RF seals melted • Arc 1 (Have some evidence of a problem but have not looked here yet) • No problems with any of the RF seals at the bellows
Mechanics Plan View The zero length bellows is located on the long ~6 m dipole chamber where it attaches to the quadrupole chamber
New Designs New design 1. Same as the old design but omega fingers made out of Ag or Au plated Inconel 2. New “J” type finger attached to one side only
Summary • In looking for bad bellows we have uncovered a problem with some of the RF seals at the flex flange in the HER • So far we have found 5 bad seals out of a total of 87 inspected. We have looked at 29 of the type that have failed. • We also suspect a problem with either a bellows or an RF seal in arc 1 but have not looked there yet • We have enough seals to replace all the damaged ones we have found and we are working on two different upgrade designs • We are also investigating the possibility of installing a thermocouple at the flex flange seal