Design of the MICE RF Cavity
Module:• Status of the module design• Module flange sealing options
Steve VirostekLawrence Berkeley National Lab
MICE CM17 @ CERN February 23, 2007
Status & Installation of the Spectrometer Solenoids
Page 2
Steve Virostek - - - Lawrence Berkeley National Laboratory
RFCC Module Design Status
•Prototype 201 MHz cavity is at FermiLab awaiting high power RF testing with applied magnetic field.
Status & Installation of the Spectrometer Solenoids
Page 3
Steve Virostek - - - Lawrence Berkeley National Laboratory
RFCC Module Design Status
•Coupling coil design is under way at ICST in Harbin. Details of ICST/LBNL collaboration are being worked out.
Status & Installation of the Spectrometer Solenoids
Page 4
Steve Virostek - - - Lawrence Berkeley National Laboratory
RFCC Module Design Status
•Two 42 cm curved Be windows have been fabricated by Brush Wellman. 3rd window is under way.
Status & Installation of the Spectrometer Solenoids
Page 5
Steve Virostek - - - Lawrence Berkeley National Laboratory
RFCC Module Design Status
•Base mounting scheme for RFCC and other MICE modules has been established by RAL.
Status & Installation of the Spectrometer Solenoids
Page 6
Steve Virostek - - - Lawrence Berkeley National Laboratory
RFCC Module Design Status
•Design and analysis of vacuum manifold system to be done soon. Issues: fields and space constraints.
Status & Installation of the Spectrometer Solenoids
Page 7
Steve Virostek - - - Lawrence Berkeley National Laboratory
Module Joint Sealing Issues
•MICE does not require metal seals on vacuum joints, but a future machine will
•MICE module joints may need somewhat frequent disassembly (maintenance, repair, reconfig.)
•O-rings will provide the most reliable and cost effective (inexpensive and re-useable) solution
•But, MICE should demonstrate all technologies for a future machine including the use of metal seals
•How is this achieved w/o undue burden on MICE?
Status & Installation of the Spectrometer Solenoids
Page 8
Steve Virostek - - - Lawrence Berkeley National Laboratory
Status & Installation of the Spectrometer Solenoids
Page 9
Steve Virostek - - - Lawrence Berkeley National Laboratory
Status & Installation of the Spectrometer Solenoids
Page 10
Steve Virostek - - - Lawrence Berkeley National Laboratory
Status & Installation of the Spectrometer Solenoids
Page 11
Steve Virostek - - - Lawrence Berkeley National Laboratory
Joint Sealing Options
RF ModuleAFC Module
Weld
~36 Bolts
Metal Wire Seal or O-ring
Commercial Bellows
Weld Lip
Status & Installation of the Spectrometer Solenoids
Page 12
Steve Virostek - - - Lawrence Berkeley National Laboratory
O-ring Pros and Cons
PROS
•Extremely reliable for vacuum sealing
•Inexpensive and re-useable seal
•Allows for quick open/close turnaround
CONS
•Cannot be used on a future machine
•Requires unscratched sealing surfaces
Status & Installation of the Spectrometer Solenoids
Page 13
Steve Virostek - - - Lawrence Berkeley National Laboratory
Metal Wire Pros and Cons
PROS
•Demonstrates seal for future machine
•Very reliable once sealed; moderate expense
•May allow for quick open/close turnaround
CONS
•Will require some level of R&D to perfect
•Requires smooth sealing surfaces & high loads
•Seal material is not re-useable
Status & Installation of the Spectrometer Solenoids
Page 14
Steve Virostek - - - Lawrence Berkeley National Laboratory
Weld Lip Pros and Cons
PROS
•Demonstrates seal for future machine
•Extremely reliable long term seal
•Allows for imperfections in mating surfaces
CONS
•Cannot carry loads across bellows with bolts
•Labor intensive for installation and removal
•Limited number of weld/grind cycles allowed
Status & Installation of the Spectrometer Solenoids
Page 15
Steve Virostek - - - Lawrence Berkeley National Laboratory
•Always use O-rings for all module joints
•Always use O-rings for all module joints but demonstrate one of the metal seals off line
•Use O-rings for all joints until final MICE assembly when only one metal seal is used
•Use O-rings for all joints until final MICE assembly when all metal seals are used
•Always use metal seals for all joints
What are the options in our approach?
Status & Installation of the Spectrometer Solenoids
Page 16
Steve Virostek - - - Lawrence Berkeley National Laboratory
•Must develop an approach to demonstrate vacuum sealing technology without future machine excessive burden on MICE
•Need a decision on the preferred approach
•A compromise between O-ring and metal seals is a likely choice
•Off line tests of metal seals recommended
•Metal wire is less complex than welded lip
Summary