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Summary of the RF Parallel
Session
Steve VirostekLawrence Berkeley National Lab
MICE Collaboration Meeting 18 June 16, 2007
Summary of the RF Parallel Session Talks from MICE CM18
Page 2Steve Virostek - Lawrence Berkeley National Lab
RF Session Talks
MuCool RF Program: RF Cavity R & D
(A. Bross)
RFCC Module Design Update
(S. Virostek)
Coupling Coil Integration with the RFCC Module
(S. Virostek)
MuCool RF Program:RF Cavity R & D
805 and 201 MHz Studies
ANL / FNAL / IIT / LBNLU Miss / Cockcroft
Alan Bross
MICE Collaboration Meeting 18 June 13, 2007
Summary of the RF Parallel Session Talks from MICE CM18
Page 4Steve Virostek - Lawrence Berkeley National Lab
MuCool Test Area
Summary of the RF Parallel Session Talks from MICE CM18
Page 5Steve Virostek - Lawrence Berkeley National Lab
MuCool Test Area
• Facility to test all components of cooling channel (not a test of ionization cooling)– At high beam power
• Designed to accommodate full Linac Beam
• 1.6 X 1013 p/pulse @15 Hz
– 2.4 X 1014 p/s
– 600 W into 35 cm LH2 absorber @ 400 MeV
– RF power from Linac (201 and 805 MHz test stands)• Waveguides pipe power to MTA
Summary of the RF Parallel Session Talks from MICE CM18
Page 6Steve Virostek - Lawrence Berkeley National Lab
MTA Hall
Summary of the RF Parallel Session Talks from MICE CM18
Page 7Steve Virostek - Lawrence Berkeley National Lab
805 MHz •Data seem to follow universal curve
– Max stable gradient degrades quickly with B field
•Remeasured– Same results– Does not condition
Gra
die
nt
in M
V/m
Peak Magnetic Field in T at the Window
Summary of the RF Parallel Session Talks from MICE CM18
Page 8Steve Virostek - Lawrence Berkeley National Lab
805 MHz Imaging
Summary of the RF Parallel Session Talks from MICE CM18
Page 9Steve Virostek - Lawrence Berkeley National Lab
805 MHz Sparking Damage Curved Be Window after
Processing in Magnet Field
Small amount of sparking damage on upstream window at 12 o’clock (least damage seen in Studies). Cavity bright & clean. Damage on copper iris is mainly from previous testing.
Summary of the RF Parallel Session Talks from MICE CM18
Page 10Steve Virostek - Lawrence Berkeley National Lab
Next 805 MHz study - Buttons
Button test– Evaluate various materials and coatings– Quick change over
Field Profile
Summary of the RF Parallel Session Talks from MICE CM18
Page 11Steve Virostek - Lawrence Berkeley National Lab
First Set of Button Data – TiN Coated Cu
Summary of the RF Parallel Session Talks from MICE CM18
Page 12Steve Virostek - Lawrence Berkeley National Lab
TiN Coated Cu – After Running
Summary of the RF Parallel Session Talks from MICE CM18
Page 13Steve Virostek - Lawrence Berkeley National Lab
RF R&D – 201 MHz Cavity Design•The 201 MHz Cavity is now operating
– New x-ray background data collected (see Alan’s talk)
Summary of the RF Parallel Session Talks from MICE CM18
Page 14Steve Virostek - Lawrence Berkeley National Lab
201 MHz Cavity Status
•The flat Cu windows have been replaced w/curved Be windows
•Slower conditioning and more sparking than with the Cu. May be due to better clean room at J-Lab during initial installation.– However, MTA CR air quality was measured at class 100 or better
•So far the 201 w/Be windows has been conditioned to ~5MV/m
•No running for >3 weeks due to 201 power source problems – Note: The cavity is now out of tune (beyond the range of power source)
and must be re-tuned via the jacking screws
– Cavity frequency dropped ~400 kHz w/curved Be windows installed
– Will get help @Fermilab from LBNL to do the tuning
Summary of the RF Parallel Session Talks from MICE CM18
Page 15Steve Virostek - Lawrence Berkeley National Lab
Clean Room for 201MHz Cavity
Summary of the RF Parallel Session Talks from MICE CM18
Page 16Steve Virostek - Lawrence Berkeley National Lab
201 MHz Sparking Damage on Flat Copper Window
coated with TiN over center portion
The inside of the cavity appeared bright & clean
•Very little spark damage after RF processing to 18 MV/m
•One copper splatter visible (photo)
Summary of the RF Parallel Session Talks from MICE CM18
Page 17Steve Virostek - Lawrence Berkeley National Lab
Curved Be window Installation
Tyvek-wrapped Mike Dickinson and Ben Ogert installing one of the Be windows
Summary of the RF Parallel Session Talks from MICE CM18
Page 18Steve Virostek - Lawrence Berkeley National Lab
Plans for the MTA
•Continue 805 MHz button tests w/bare & TiN coated buttons
•We have buttons made with the following metals– Tantalum – Tungsten – Molybdenum-zirconium alloy– Niobium– Niobium-titanium alloy– Stainless steel
•Continue conditioning 201 with Be windows (if power ever becomes available) without B field (after re-tuning).
– Then do B field scan • Can go up to few hundred gauss at present• Need new pumping system to go higher • And eventually Coupling Coil
Summary of the RF Parallel Session Talks from MICE CM18
Page 19Steve Virostek - Lawrence Berkeley National Lab
Coupling Coil Layout in the MTA
RFCC Module Design
Update automatic tuners
cavity suspension
cavity installation
Steve VirostekLawrence Berkeley National Lab
MICE Collaboration Meeting 18 June 13, 2007
Summary of the RF Parallel Session Talks from MICE CM18
Page 21Steve Virostek - Lawrence Berkeley National Lab
RF Cavity & Coupling Coil Modules in MICE
RFCC Modules
Summary of the RF Parallel Session Talks from MICE CM18
Page 22Steve Virostek - Lawrence Berkeley National Lab
Updated RFCC Module 3D CAD Model
201 MHz RF cavity
Automatic tuners
Cavity suspension
Summary of the RF Parallel Session Talks from MICE CM18
Page 23Steve Virostek - Lawrence Berkeley National Lab
Cavity Tuner Design Features•Six evenly spaced automatic tuners per cavity provide frequency adjustment
•Layout avoids interference with cavity ports
•Tuners touch cavity and apply loads only at the stiffener rings
•Tuners operate in “push” mode only (i.e. squeezing)
Summary of the RF Parallel Session Talks from MICE CM18
Page 24Steve Virostek - Lawrence Berkeley National Lab
Four Cavity Layout in Vacuum Vessel •Tuner layout
rotated 30º @ cavity pairs
•Actuators are off cavity center plane to avoid coupling coil
•Bellows connections at vacuum vessel feedthroughs
•0 to -460 kHz tuning range (0 to -4 mm)
•1.6 MPa max. actuator pressure (50 mm)
Summary of the RF Parallel Session Talks from MICE CM18
Page 25Steve Virostek - Lawrence Berkeley National Lab
Cavity Tuner Section View
Ball contact only
Dual bellowsfeedthrough
Tuner actuator(likely air)
Pivot point
Fixed (bolted)connection
Summary of the RF Parallel Session Talks from MICE CM18
Page 26Steve Virostek - Lawrence Berkeley National Lab
Tuner component Details
Fixed arm
Pivoting arm
Actuator& bellowsassembly
Forces are transmitted to the stiffener ring by means of “push/pull” loads applied to the tuner lever arms by the actuator assembly
Summary of the RF Parallel Session Talks from MICE CM18
Page 27Steve Virostek - Lawrence Berkeley National Lab
•Six strut system provides kinematic cavity support
•Orthogonal strut layout is stiff and allows accurate cavity positioning
•Kinematic mounts fix cavity without over-constraint
Cavity Suspension System
Summary of the RF Parallel Session Talks from MICE CM18
Page 28Steve Virostek - Lawrence Berkeley National Lab
Cavity Suspension System
1 vertical strut
2 horizontal struts
3 axial struts
Summary of the RF Parallel Session Talks from MICE CM18
Page 29Steve Virostek - Lawrence Berkeley National Lab
Strut End Connection Details
One end of the struts is attached to a fixed lug welded to the ID of the vacuum vessel
The cavity end of the vertical and one of the horizontal struts are attached directly to the stiffener ringThe cavity end of the axial and one of the horizontal struts are attached to the fixed leg of a tuner
Summary of the RF Parallel Session Talks from MICE CM18
Page 30Steve Virostek - Lawrence Berkeley National Lab
Four Cavity Layout in Vacuum Vessel •Dedicated struts
(6) for each cavity
•No contact between cavity pairs
•Struts axially fix the outside walls of the cavity pairs
•Tuning deflections increase cavity gap
Summary of the RF Parallel Session Talks from MICE CM18
Page 31Steve Virostek - Lawrence Berkeley National Lab
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 feedthrus with tuner mounts and cavity ports
•Install struts, tuner actuators and RF couplers
•Repeat same process for outer cavities
Coupling Coil
Integration with the
RFCC Module
Steve VirostekLawrence Berkeley National Lab
MICE Collaboration Meeting 18 June 13, 2007
Summary of the RF Parallel Session Talks from MICE CM18
Page 33Steve Virostek - Lawrence Berkeley National Lab
Coupling Coil Integration Topics
•New coupling coil design developed by LBNL & ICST (Harbin)
•Increased coil length (+35 mm to 285 mm) results in longer vacuum vessel
•Integration issues w/tuners and RF, vacuum & diagnostic cavity ports
•Must transmit magnetic forces from the cold mass supports to the vacuum vessel
•New 3D model developed by LBNL for integration
Summary of the RF Parallel Session Talks from MICE CM18
Page 34Steve Virostek - Lawrence Berkeley National Lab
Reinforcing plates
Indented sections
Servicetower
Cryocoolers
Support cone
Cold mass supports
Coil assembly
He cooling pipes
Coupling Coil Design Configuration
Coupling Coil Gusset Connections
Gussets between cold mass support cones and vacuum shell transmit magnetic forces
Tuner actuators nest between gussets
Summary of the RF Parallel Session Talks from MICE CM18
Page 36Steve Virostek - Lawrence Berkeley National Lab
Upper Cold Mass Support Cones
Weld
Weld
Summary of the RF Parallel Session Talks from MICE CM18
Page 37Steve Virostek - Lawrence Berkeley National Lab
Connection to Support Side Plate
Support stand side plate
Weld
Tuner cutout
Interior gusset
Summary of the RF Parallel Session Talks from MICE CM18
Page 38Steve Virostek - Lawrence Berkeley National Lab
Vacuum Vessel Assembly to Coil
Vacuum weld on interior
Summary of the RF Parallel Session Talks from MICE CM18
Page 39Steve Virostek - Lawrence Berkeley National Lab
RF Coupler/Coil Interface
Coupler vacuum sleeve nests in coil vacuum shell recess (3 mm gap)
Summary of the RF Parallel Session Talks from MICE CM18
Page 40Steve Virostek - Lawrence Berkeley National Lab
Vacuum System/Coil Interface
Vacuum manifold
Vacuum pump
Gate valve
Summary of the RF Parallel Session Talks from MICE CM18
Page 41Steve Virostek - Lawrence Berkeley National Lab
Vacuum System Integration
Inside cavity vacuum connectionOutside cavity vacuum connection
Vacuummanifold
Vacuum pump
Gate valve
Summary of the RF Parallel Session Talks from MICE CM18
Page 42Steve Virostek - Lawrence Berkeley National Lab
Vacuum Manifold/Coil Interface
Vacuum manifold end nests in coil vacuum shell recess (3 mm gap)
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