Transcript Status and Installation Plan for the Spectrometer Solenoid

Progress on the MICE 201 MHz
Cavity Design

automatic tuners

cavity suspension
cavity installation

RF Working Group Meeting @ Fermilab
August 22, 2007
Steve Virostek
Lawrence Berkeley National Lab
RF Cavity & Coupling Coil Modules in MICE
RFCC Modules
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 2
Updated RFCC Module 3D CAD Model
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 3
Updated RFCC Module 3D CAD Model
Cavity suspension
Automatic tuners
201 MHz RF cavity
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 4
Cavity End View with Tuners and Struts
•Six tuners per cavity
provide individual
frequency adjustment
•Tuning automatically
achieved through a
feedback loop
•Six struts per cavity
provide a kinematic
mounting system
•Struts fix cavity
position without overconstraint
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 5
Cavity Tuner Design Features
•Tuners are spaced evenly
every 60º around cavity
•Layout is offset by 15º
from vertical to avoid
conflict with cavity ports
•Tuners touch cavity and
apply loads only at the
stiffener rings
•Tuners operate in “push”
mode only (i.e. squeezing)
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 6
Four Cavity Layout in Vacuum Vessel
•Clocking of tuner
position between
adjacent cavities
avoids interference
•Actuators offset
from cavity center
plane due to width
of coupling coil
•Soft connection only
(bellows) between
tuner/actuators and
vacuum vessel shell
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 7
Cavity Tuner Section View
Tuner actuator
(likely air)
Pivot point
Dual bellows
feedthrough
Fixed (bolted)
connection
Ball contact only
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 8
Tuner component Details
Actuator
& bellows
assembly
Pivoting arm
Fixed arm
Forces are transmitted to the stiffener ring
by means of “push/pull” loads applied to the
tuner lever arms by the actuator assembly
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 9
Cavity Tuning Parameters
The following parameters are based on a finite
element analysis of the cavity shell. Tuning range
is limited by material yield stress.
•Overall cavity stiffness: 6120 N/mm
•Tuning sensitivity: +115 kHz/mm
•Tuning range: 0 to -460 kHz (0 to -4 mm)
•Number of tuners: 6
•Maximum ring load/tuner: 4.1 kN
•Max actuator press. (50 mm): 1.6 MPa (230 psi)
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 10
Cavity Suspension System
•Six strut system provides
kinematic cavity support
•Orthogonal layout of struts
allows accurate cavity
alignment and positioning
•Kinematic mounts prevent
high cavity stresses
caused by thermal
distortion and overconstraint
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 11
Cavity Suspension System
1 vertical strut
3 axial struts
2 horizontal struts
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 12
Strut End Connection Details
The cavity end of the
vertical and one of
the horizontal struts
are attached directly
to the stiffener ring
The cavity end of the
axial and one of the
horizontal struts are
attached to the fixed
leg of a tuner
One end of the struts is attached to a fixed
lug welded to the ID of the vacuum vessel
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 13
Four Cavity Layout in Vacuum Vessel
•Each cavity contains
a dedicated set of
suspension struts
•No contact between
pairs of close
packed cavities
•Struts designed to
axially fix outside
end of cavity pairs
•Tuning deflections
increase cavity gap
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 14
Cavity Installation Sequence
•Pre-assemble cavities with Be windows and
tuners (w/o actuators)
•Slide inner cavities into vacuum vessel using
spacer/alignment blocks
•Shim cavity to align tuner & coupler vacuum
feedthus with tuner mounts and cavity ports
•Install struts, tuner actuators and RF couplers
•Repeat same process for outer cavities
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 15
Upcoming Cavity Work
•Integrate the latest coupling coil design with
the RFCC module 3D CAD model
•Develop final cavity detail fabrication drawings
•Order OFHC copper cavity shell material
•Re-qualify cavity shell spinning vendor
•Complete the detailed design and component
specification of the cavity tuner mechanisms
•Build and test a prototype tuner system
Progress on the MICE 201 MHz Cavity Design
Steve Virostek - Lawrence Berkeley National Lab
Page 16