Transcript Status and Installation Plan for the Spectrometer Solenoid

Progress on the MICE RFCC Module
MuCool Test Area RF Workshop
October 15, 2008
Mike Zisman/Steve Virostek
Lawrence Berkeley National Laboratory
Progress Summary
• The MICE cavity design is heavily based on the successful
MuCool 201-MHz prototype RF cavity and lessons learned
– Fabrication and post processing
– Cavity conditioning and operation
• Engineering design of the cavity is complete
– CAD model of the cavity, tuners, support and vacuum
– Fabrication schemes and vendor identification
• RFCC module engineering design nearing completion
• Possible operation at LN temperature?
– Design accommodates LN operation, but is very challenging
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 2
Muon Ionization Cooling Experiment
RFCC
RFCC
Spectrometer
Solenoid 1
AFC
AFC
Absorber and
Focusing Coil (AFC)
Spectrometer
Solenoid 2
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 3
2 RFCC Modules, 8 Cavities
Curved
Be window
SC coupling Coil
201-MHz cavity
Vacuum Pump
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 4
RF Cavity Summary
• Fabrication of the prototype cavity was successful
• A slight reduction in cavity diameter to raise the
frequency has been specified and analyzed
• The fabrication techniques used to produce the
prototype will be used to fabricate the MICE RF
cavities
• A detailed WBS schedule for the design and
fabrication of the MICE RF cavities has been
developed
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 5
Cavity Design Parameters
• Cavity design parameters:
–
–
–
–
–
Frequency: 201.25 MHz
β = 0.87
Shunt impedance (VT2/P): ~ 22 MΩ/m
Quality factor (Q0): ~ 53,500
Be window diameter and thickness: 42-cm and 0.38-mm
• Nominal parameters for MICE and cooling channels in a
neutrino factory:
– 8 MV/m (~16 MV/m) peak accelerating field
– Peak input RF power: 1 MW (~4.6 MW) per cavity
– Average power dissipation per cavity: 1 kW (~8.4 kW)
– Average power dissipation per Be window: 12 watts (~100 watts)
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 6
Recent Progress: RF Cavity Design
– 3-D Microwave Studio RF parameterized
model with ports and curved Be windows
– Hard to reach the design frequency by
spinning
– Frequencies between cavities should be able
to achieve within  100 kHz
– Approaches
• Modification the spinning form
• Targeting for higher frequency
• Fixed tuner to tune cavity close to design
frequency (deformation of cavity body)
• Tuners are in push-in mode  lower
frequency
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 7
Numerical Study with B Field
• Preliminary studies, in collaboration with colleagues at SLAC using
Omega-3P and Track-3P codes
– Cavity with flat windows: 5 MV/m on axis; 2-T uniform external
magnetic field; scan of a few points from one cavity side
E field contour
Trajectories without
external B field
Trajectories with
external B = 2-T field
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 8
High Power RF Tests on Prototype Cavity
• The cavity was first tested with flat copper windows and reached
~ 16 MV/m quickly and quietly
• The cavity then was tested with thin and curved Be windows and
again reached to ~19 MV/m quickly
– Cavity frequency had to be retuned
– Cavity frequency was stable during the operation, however, we did
observe frequency shift due to RF heating on the windows
• Frequency shift of ~ 125 kHz (from 0 to ~ 19 MV/m, 150-micro-second
pulse, 10-Hz repetition rate) in ~ 10 minutes, well within the tuning
range (230 kHz/mm per side,  2-mm range)
– With a few hundred Gauss stray field from Lab-G magnet, the cavity
gradient can be maintained at 19 MV/m
• To test with stronger external magnetic fields
– Move the cavity closer to Lab-G magnet
– SC coupling coil for MuCool
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 9
Tests with Stronger Magnetic Fields
• New vacuum pumping system
• Separation of the nearest curved Be
window from the face of Lab-G magnet
is 10-cm (before was 110-cm)
• Maximum magnetic field near the Be
window 1.5 Tesla (at 5 Tesla in magnet)
Lab-G magnet
Test Results:
• Multipactoring was observed over the entire
magnetic field range up to 1.1-T at nearest
Be window
• A strong correlation exists between cavity
vacuum and radiation levels
• We have achieved ~ 14 MV/m at 0.75-T to
the nearest curved thin Be window
Recent test results show plateau at ~10 MV/m
The 201-MHz cavity
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 10
RF Cavity Assembly
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 11
RF Cavity Fabrication Overview
The same fabrication techniques used to
make the prototype cavity will be used for
the MICE RF cavities
Engineering
CAD Model
of the RF
Cavity
• Cavity half-shells to be formed by metal spinning
• Precision milling of large parts (1.2 m diameter)
• Precision turning of mid-sized parts (0.6 m dia.)
• Precision manufacture of smaller parts
• CMM measurements throughout the process
• To limit any annealing and maintain cavity
strength, e-beam welding will be used for all
cavity welding
• cavity equator, stiffener rings, nose rings,
port annealing and port flanges
Prototype
RF Cavity
• Cavity inside surfaces are finished by electropolishing
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 12
Recent Progress
• RFCC engineering CAD model refined
• RF and engineering design of 201-MHz RF cavity complete
• Integration and interface issues addressed
• Vendor identification and qualification near complete
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 13
Recent Progress (procurement & fab)
•The large copper sheets used in the fabrication of the cavity
shells have been ordered and will arrive at LBNL in mid-December
•A series of vendor qualification visits has been conducted
• Applied Fusion - San Leandro, CA (e-beam welding, machining)
• Meyer Tool & Mfg., Inc. - Chicago, IL (machining)
• Sciaky, Inc. - Chicago, IL (e-beam welding)
• Roark Welding & Engineering - Indianapolis, IN (e-beam welding, machining)
• ACME Metal Spinning – Minneapolis, MN (cavity shell spinning)
•Other vendors have been identified
• Midwest Metal Spinning, Inc. –Bedford, IN (cavity shell spinning)
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 14
Other Module Components
• Beryllium window design is complete; windows are in the
process of being ordered (8 per module needed)
• Design and analysis of the cavity frequency tuners is
complete, drawings to be done soon
• A hexapod cavity suspension system has been
incorporated in the design
• The RF coupler will be based on the SNS design using the
off the shelf Toshiba RF window
• The vacuum system includes an annular feature coupling
the inside and the outside of the cavity (further analysis
of vacuum rupture scenarios TBD)
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 15
Other Module Components
Cavity Suspension
Dynamic Tuners
RF Coupler
Beryllium Window
Vacuum System
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 16
201 MHz Beryllium Windows
• Each cavity has two Be windows
– 42-cm diameter and 0.38-mm thick
– Window is formed at high temperature and later brazed to copper frames
– Thin TiN coatings on both sides of the window
• One window curves into the cavity and one curves out
• Already tested up to 5 MW in 201-MHz cavity at MTA, FNAL
42-cm
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 17
Cavity Tuner Design Features
• Six tuners spaced evenly
around each cavity provide
individual frequency
adjustment through a
feedback loop
• 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 RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 18
Tuner component Details
Actuator
& bellows
assembly
Pivoting arm
Fixed arm
Forces are transmitted to the stiffener ring
by means of “push” loads applied to the
tuner lever arms by the actuator assembly
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 19
Hexapod Strut Arrangement
•Analysis of a hexapod strut
system is complete
•Each cavity will contain a
dedicated set of 6
suspension struts arranged
in a hexapod type formation
•This system spreads the
gravity load of the cavity
across several struts
Example of a hexapod stage
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 20
Hexapod Strut Cavity Mounting
•Copper mounting block
will be e-beam welded
directly to the RF cavity
•The cavity has very little
deformation at the
mounting block location
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 21
Vacuum System
NEG (non-evaporable getter) pump
• A NEG pump has been chosen because it will
be unaffected by the large magnetic field
• A vacuum path between the inside and
outside of the cavity eliminates the risk of
high pressure differentials and the possible
rupture of the thin beryllium window
Cross sectional view of
vacuum system
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 22
Vacuum Vessel and Support Summary
• Engineering 3D CAD model of the vacuum
vessel mechanical design is complete
• Standard machining and manufacturing
methods will be used
• A plan for attaching the coupling coil and the
vacuum vessel together has been developed
• Conceptual design of the support stand is
complete (analysis will need to be
performed)
• A method for assembling the cavities into the
vacuum vessel has been formulated
• A conceptual design of the cavity water
cooling feedthrough system is finished
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 23
Vacuum Vessel Fabrication
• Vacuum vessel material must be non-magnetic and strong therefore 304
stainless steel will be used throughout
• The vacuum vessel will be fabricated by rolling stainless steel sheets into
cylinders
• Two identical vessel halves will be fabricated with all ports and feedthroughs
Main 1400mm
rolled tube
Smaller diameter
rolled tube
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 24
Bellows
flange
Vacuum Vessel and Coupling Coil
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 25
Vacuum Vessel/Coupling Coil Integration
• LBNL will weld in gussets
that fit between the
coupling coil and the
vacuum vessel
• Sixteen special gussets are
welded between the
coupling coil magnet’s cold
mass support tubes and the
magnet housing
• The gussets will transfer the
magnetic loads between the
coupling coil and the
vacuum vessel
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 26
RFCC Attachment to Support Stand
• The vacuum vessel is bolted to a saddle made up of small plates
welded to the support stand
• Stainless steel bars are welded onto the vacuum vessel for
attaching bolted gusset plates
Bolted gusset mounting bars
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 27
RFCC Support Stand
• RFCC support stand must withstand a
longitudinal force of 50 tons transferred
from the coupling coil
• Bolted gussets and cross bracing provide
shear strength in the axial direction
(analysis will confirm the stand design)
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 28
Liquid Nitrogen Cooling Considerations
•Suspension of cavities on struts provides low heat leak from
cavity to vacuum vessel
•Beryllium window FEA thermal analysis will need to be
performed with new parameters
•The cavity frequency will be shifted (approximately 600 kHz),
therefore tuning system or RF power source modifications will
be needed
•Insulators will need to be added to the RF couplers
•Coaxial LN feedthrough tubes will be needed to insulate the
connection outside of vacuum
MICE RFProgress
Cavity –onMechanical
the MICE RFCC
Design
Module
and Analysis
Allan DeMello
Zisman/Virostek
- Lawrence Berkeley
- LBNL -National
OctoberLab
15, -2008
June 4, 2008
Page 29
Module Assembly Sequence
Bare cavity
Beryllium windows are installed
onto the cavities
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 30
Module Assembly Sequence
Assembly of the tuners onto the
cavities (w/o actuators)
Install struts onto the cavity
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 31
Module Assembly Sequence
• Slide the inner cavity into vacuum
vessel using spacer/alignment
blocks for support
• Shim cavity to align tuner and
coupler vacuum feedthroughs with
tuner mounts and cavity ports
• After adjusting their lengths, secure
the struts to the vacuum vessel
mounting blocks
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 32
Module Assembly Sequence
Install tuner actuators
Install RF couplers
Install vacuum couplers
Install cooling water
feedthroughs
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 33
Module Assembly Sequence
Repeat the same
process for the other
cavities
Install vacuum valves
and pumps
Two cavities are
installed from each end
of vacuum vessel
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 34
RFCC Module Shipping Configuration
Cryocoolers removed
Cavities removed
Couplers removed
Vacuum pumps removed
Module short stand used for:
• Initial module assembly
• Shipping to RAL
• Moving into MICE Hall
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 35
MICE Hall Access
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 36
Installation in MICE Hall
•Module assembled on lateral tracks
•Module aligned and shimmed to correct height
•Bellows on either end of module are pulled back
into open position and O-ring in place
•Moved into position w/rails for final alignment
•Bellows are released and flanges are sealed
•Bellows are locked out using bridging bolts
•RF and utilities are connected to module
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 37
Module Flange Connection
End flange
O-ring seal
Formed
bellows
Flange
through
holes
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 38
Flanges and Seals
•Flanges designed to mate with AFC module
•AFC flanges are flat w/no grooves or bellows
•RFCC modules have bellows and O-ring grooves
on flanges at either end
•Bellows have >1 cm of total travel
•Bellows are locked out after installation to
provide a means of transmitting forces between
modules
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 39
Module Mounting Provision
• Six mounting plates welded to the
support base for installation on rails
• Same as spectrometer solenoid mounts
• All magnetic loads carried to the floor
through the mounting plates
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 40
Cavity RF Feeds
RF feeds
•Eight RF feeds/module use
standard 4” RF coax
•Cooling water for loop is
required (<<1 lpm each)
•Adapter on end of couplers
isolates ceramic RF windows
from forces during
installation
•Location of coax interface
w.r.t. module center TBD
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 41
Schedule Overview
•RFCC design and fabrication project originally expected to
be a 3–year project (10/06 to 10/09)
•Coupling coil effort began in 2006 at ICST (Harbin)
•Design and fabrication of other RFCC module components
was scheduled to begin 10/07
•Start was delayed due to lack of availability of qualified
manpower
•Earlier this year, mechanical engineer A. DeMello joined
MICE to work on RFCC module design (FTE)
•Additional manpower required to make up schedule
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 42
Manpower Summary
Primary Manpower
•Allan DeMello: lead ME for RFCC Module design & fab
− 3D engineering CAD model, cavity analysis, design & fab
•Steve Virostek: engineering oversight for MICE at LBNL
•Mechanical Engineer (TBD): design/fab of subcomponents
− Cavity tuners, support structure, large procurements
•Mechanical Designer (TBD): generation of fabrication dwgs
Other
•Derun Li: cavity physics design and oversight
•Mike Green: coupling coil design & interface with module
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 43
Schedule Summary
Progress on the MICE RFCC Module
Zisman/Virostek - LBNL - October 15, 2008
Page 44