BROOKHAVEN SCIENCE ASSOCIATES SR Chambers & RF Bellows ASAC Review, 3/26-27/2009 1 of 21 SR Chambers...
-
Upload
gregory-fisher -
Category
Documents
-
view
215 -
download
0
Transcript of BROOKHAVEN SCIENCE ASSOCIATES SR Chambers & RF Bellows ASAC Review, 3/26-27/2009 1 of 21 SR Chambers...
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
1 of 21
SR Chambers & RF Bellows
H. Hseuh, Vacuum GroupASAC Review of NSLS-II
Mar 26-27, 2009
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
2 of 21
Acknowledgements
BNL: A. Blednykh, P. Cameron, C. De la Parra, S. DiStefano, L. Doom, M. Ferreira, E. Hu, F. Lincoln, C. Longo, S. Krinsky, V. Ravindranath, P. Settepani, S. Sharma, O. Singh, J. Skaritika, J. Sullivan, K. Wilson, ….
ANL: J. Gagliano, G. Goeppner, …
ESRF: R. Kersevan
Diamond: M. Cox
KEK: Y. Suetsugu
SLAC: N. Kurita, M. Sullivan, L. Wang, U. Wienands, …
TPS: J.R. Chen, G-Y. Hsiung, …
and many others.
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
3 of 21
Outline• SR Vacuum Chambers and FY08 Effort
– Material, quantity, types, fabrication– Extrusions w/ two vendors– Weld development of multipole chambers at APS
• Prototyping and Testing Effort in FY09– Bending of dipole extrusions– Extrusion of new multipole cross section– Weld development at APS– Testing of NEG strips and cal rod heaters– Interface with Magnets, AP, Diag. etc
• RF Shielded Bellows- Design options and prototyping
• Recent Review Recommendations
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
4 of 21
Cell Vacuum Chamber Layout
BM Beamline
ID Beamline
L.S.
S.S.
S2 S3S4
S5
S6
Stainless chambers
S1
S1
• 60 stainless steel chambers, 1-2 m long
• 5 types (cross sections, length, flanges, etc)
• Stainless sheets, rolled, welded and brazed w/ Cu absorbers
• 191 aluminum chambers, 3 – 6 m long
• Extruded, two cross sections (dipole and multipole)
• > 12 types (length, magnet cutouts, flanges, etc.)
• Precision machining & welding to meet beam requirement
Dipole
Multipole
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
5 of 21
S3
S5
S3-DW
90mm S3 & S5
S2-DW
S2E
S2O
S4
S6E
S6O
Multipolealso for day-1 straight
Dipole
Cell Aluminum Chamber TypesE: even cell; O: odd cell; DW: canted by ± 1.8 mrad
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
6 of 21
End adaptor
Multi-step Fabrication of Al Chambers
Extrusion Bending Machining Cleaning Welding Assembly…➾ ➾ ➾ ➾ ➾V #1,2 BNL BNL, V # 3,4,5. APS APS BNL
Extrusions
Machined extrusion
Machined end End adaptors
End assemblyBi-metal flanges
Robotic welding at APS
Pump port
Lewis DoomLewis Doom
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
7 of 21
Prototyping in FY08
Prototype multipole chamber for alignment, BPM mounting, NEG carriers and bakeout
Test extrusions completed Fabrication process fully developed
for ‘old’ multipole chambers
4mm
X15
Micrographs of welds show• Full fusion, no micro cracks• No void and trapped gas• Step ≤ 0.5 mm
X50
APS/ANLAPS/ANL
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
8 of 21
• 50 ton press break with 18-inch throat
• W/ garnet filler, w/o filler
• Change punch heights and load distributions – curvature to within 1 mm
• Little spring back w/ thermal cycling to 180C
• Gap reduction by 1 – 2.5 mm
Bending of Dipole Extrusion at BNL
BNL CS break
Spread the load outboard from the center will give more bending
toward the ends.
Fine tweaking the punch & shimms to get the exact bend!
Lewis Doom Phil Settepani
Lewis Doom Phil Settepani
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
9 of 21
New Multipole Extrusion & Weld Development
Test extrusion orders placed To be completed by
May
Increase wall from 12 to 16 mm for improved BPM dual buttons/flange
NewNew BPM flange Old
Short dipole chambers and flanges
Multipole extrusion w/ exit port cutout
Welding development at APS
dipole, new multipole & exit port
A multi-yr contract w/ APS is in place
CD-2 Design
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
10 of 21
NEG Strips and Carriers
NEG carriers and feedthruNEG carriers and feedthru
NEG strips in antechamber
Two NEG strips in each aluminum chamber as main distributed pumping – total ~ 1,200mRiveted mounting every 10 cm
w/ ceramic insulators and carrier plates
Fully tested in prototype chambers
Modified carriers for BPM TE modes?
Activation at 4500C x 30 min with 70 A thru NEG strips
Feedthru
Lewis Doom Phil Settepani
Lewis Doom Phil Settepani
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
11 of 21
FY09 – One Cal rod heater (10 mm φ) inserted in unused cooling channel> 120 C and ΔT < 5 C
simple & versatile – to be tested for easy of installation and reliability
In-situ Bake with External Heaters
Baseline design: 135oC x 150 psi water (as in APS and Spring-8) A major ES&H concern
FY08 - T < 150oC achieved with foil heaters and insulation attached to limited magnet-free space
(not a neat solution)
Marcelo FerreiraMarcelo Ferreira
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
12 of 21
Interface with Magnets, AP and DiagnosticsProvide AP vacuum component models for impedance simulation and approval
Worked with Magnet Measurement and identified issues with invar chamber supports, and fast corrector response over RF bellows/Al chambers – separate and relocate SC & FC
Worked closely with AP on lattice improvement - 3rd family sextupoles, locations of 3PW, moving of sextupoles, etc
RF shielding to shift the resonance frequencies of multipole chambers to > 550 MHz
Interference from invar standsInterference from invar stands
Separate SC & FCSeparate SC & FC
Om SinghOm Singh
Animesh JainAnimesh Jain
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
13 of 21
Resonant Frequencies in Multipole Chamber
400MHz 1400MHz
Resonant frequencies measured in a 3.4m multipole chamber.
Agreed well with calculated H101 modes in a rigid waveguide.
Can be shifted by altering the chamber cross sections
Electric field
To shift the frequencies to > 550 MHz :
- increase the slot height to > 15 mm - No
- chamber width to < 80mm - No
- ante-chamber height to 20 mm - No
H101 Mode in a Rigid Waveguide
Alexei BlednykhAlexei Blednykh
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
14 of 21
Suppression of Rogue ModesUse modified NEG carriers to create shields in the ante-chamber
~ 150 mm from beam center, installed through end flanges
~ 500 mm long and ~ 300 mm spacing to shift Fo to > 550 MHz
exact lengths and locations to be decided for each chamber type
Fo ~ 385 MHz due to S4 absorber in extraction channel?
Shields to be outside of SR fan or d/s of absorbers
To be designed, prototyped and fully tested with NEG activations
Alexei BlednykhAlexei Blednykh
S4 S4
150 mm
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
15 of 21
inside fingersoutside fingers
Choice of RF Shielded Bellows
inconel springs
Be-Cu fingers
Inside fingers Outside fingers
(APS, LNLS) (PEP II, Soleil, DLS, …)
Simple, reliable Lower impedance
$$ $$$
NSLS-II approach - outside fingers, few & wider fingers
Solid sleeve
Lewis Doom Marcelo Ferreira
Lewis Doom Marcelo Ferreira
NSLS-II RF Bellows Requirements:
Max mis-alignment: ± 2 mm
Max comp/extension: -15/+10 mm
Max angle deviation: ±15 mrad
Low impedance and low loss
Consulted with many experts in other light sourcesConsulted with many experts in other light sources
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
16 of 21
4 Inconel outer springs (Ag plated )
Prototype Bellows Design
Hydro formed bellows welded to flanges with cooling channels
4 stainless inner support (Rh plated)
6 GlipCop fingers (0.9 mm thick Ag plated )
2 stainless clamping plate w/ groove for
contact springs
Lewis Doom Marcelo Ferreira
Lewis Doom Marcelo Ferreira
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
17 of 21
Simulation w/ and w/o offsets
At nominal positionKloss ≈ 2.0 x10-2 V/pC
With ± 2 mm offsetKloss ≈ 3.7 x10-2 V/pC
Simulations of narrow finger bellows:Inside fingers : Kloss ≈ 1.9 x10-2 V/pC ± 2 mm offset ≈ 21.4 x10-2 V/pCOutside fingers : Kloss ≈2.1 x10-2 V/pC ± 2 mm offset ≈ 8.7 x10-2 V/pC
With ± 2 mm offsetKloss ≈ 10 x10-2 V/pC
6” bellows
5” bellows
• Thermal analysis with possible heat loads
• Detailed production drawings and prototyping
• Test for ease of assembly, mechanical stability with thermal cycling, etc.
Alexei BlednykhAlexei Blednykh
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
18 of 21
• TE mode interference to BPM– Extensive studies by AP and Diag groups using chamber extrusions– Modify NEG carriers to shift the frequency to > 550 MHz
• Clearance between magnets and vacuum chambers– Increased from 1.5 mm to 2 mm at sextupole poles– No foil heaters and insulation – cal rod heater in cooling channel– To be tested with magnets
• RF shielded bellows design and RF fingers– Consulted with colleagues from other light sources– Preliminary design completed, being detailed and prototyped
• EPU gap (~ 8 mm) and maximum K values– EDM the top and bottom walls of extraction gap in the S3 dipole (&
S2 multipole) chambers to accommodate vertical photon fans
ASAC Recommendations – July 08
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
19 of 21
• Insitu bakeout and temperature uniformity - improved (ΔT < 5oC) with cal rod heater
• Extrusion tolerance and stress relief – straightened by machining vendor, < 1 mm relaxation after thermal cycling of bended extrusion
• NEG supports and protection – will be fully tested and with ground fault protected PS
• Effect of the vacuum components to magnets – ion pumps ok, invar supports not ok
• Asymmetric load on chambers due to thermal and mechanical force – analysis continues
• BPM buttons by welding – long development effort, can’t meet our current schedule
• 10,000 l/s pumping required at canted DW absorbers – pressure decreases with conditioning, only 1-2 locations
• Fast valve, Be window & RGA at FE – FV and RGA in the budget, Be windows to be reviewed together with BL
Vacuum, FE & Support Review Recommendations – Aug 08
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
20 of 21
• BPM position stability after repeated bakeouts
– To be tested using the prototype chambers
• Possible electron cloud
– Use CLOUDLAND by Lanfa Wang (SLAC) and NSLS-II staff with worst case parameters
– Ex & Ey mainly by electrons from reflected photons
– No multipacting, no instability, no emittance blowup
– H tune shift < -0.001, V tune shift < 0.0006
• Fast ion instability
– High pressure d/s of canted DW, small impact only be ≤ 2 locations
– Need to simulate with beam fill patterns for ion clearing
Construction Readiness Review Recommendations – Sept 08
-40 -20 0 20 40-0.5
0
0.5
1
1.5
2
2.5
3
3.5x 10
10
X/Y (mm)
Ex/
Ey
Total field
ExEy
Lanfa WangLanfa Wang
BROOKHAVEN SCIENCE ASSOCIATES
SR Chambers & RF BellowsASAC Review, 3/26-27/2009
21 of 21
Summary
• Cell vacuum chamber detail drawings continue – minor adjustment possible• Test extrusion of ‘new’ multipole cross sections continues• Machining and weld development of prototype chambers are underway• NEG strip supports developed and tested• Chamber bakeouts with cal rod heaters being tested• RF shielded bellows concept done, to be detailed, prototyped and tested• Work with AP & Diag. on shifting resonance frequencies using NEG carriers• Production of dipole chambers starts this summer, multipole by Dec• Next - Design and prototyping of absorbers and stainless chambers