Working Group Summaries: Accelerator

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• Working Group Summaries Accelerator
• RF Technology and Structures
• Systems and Instrumentation
• Matthias Liepe
• Cornell University

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• RF Technology and Structures
• We are almost there,
• But still a lot can and needs to be done.

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Accelerator Working Group RF Technology and
Structures Monday, July 14, 830-1030 a.m.
830-855 Warm and Cold RF Structures
Hasan Padamsee 855-915 Technology
Development Program for a Oleg Nezhevenko /
Future 34-GHz Linac
Vyacheslav Yakovlev
915-930 Acoustic Localization of RF
Structure
Breakdowns George Gollin
930-945 Optimized Cavity Shape for
TESLA Valery Shemelin 945-1000 1500 MHz Nb
Cavity made of Electro-
polished Half-Cells Rongli Geng
1000-1015 DC Breakdown Studies Greg Werner
1015-1030 Control of Beam Loss in
High-Repetition Rate High-Power PPM
Klystrons Mark Hess
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Accelerator Working Group RF Technology and
Structures Monday, July 14, 830-1030 a.m.
830-855 Warm and Cold RF Structures
Hasan Padamsee 855-915 Technology
Development Program for a Oleg Nezhevenko
Future 34-GHz Linac
915-930
Acoustic Localization of RF Structure
Breakdowns
George Gollin 930-945 Optimized
Cavity Shape for TESLA Valery Shemelin
945-1000 1500 MHz Nb Cavity made of Electro-
polished
Half-Cells Rongli Geng 1000-1015 DC
Breakdown Studies Greg Werner 1015-1030
Control of Beam Loss in High-Repetition
Rate High-Power PPM Klystrons Mark Hess
5
Strategy start with 23.5 MV/m Structures tested
to 35 MV/m before installation
20,600 L 21 km
18,500 L 11.1 km
Start with Ea-loaded50 MV/m (65MV/m-unloaded) Few
er structures
Why 11.4 GHz? Peak RF Power needed to reach
gradient a 1/v frequency
RF Losses 55 W ea. Run pulsed at a duty factor
of 0.7 Need RF peak power 1.2x109
watt Dynamic heat load at 2 K 10 kW Static
safety 30 kW refrigerator.. AC power 22 MW
RF Losses 80 MW/m ! Total peak RF power
1012 watt Duty Factor 0.006 AC Power
150 MW
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The best !
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37 MV/m in Fully Equppied Cavity i.e. high power
test and 1/8th of a TTF Linac module
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Accelerator Working Group RF Technology and
Structures Monday, July 14, 830-1030 a.m.
830-855 Warm and Cold RF Structures
Hasan Padamsee 855-915 Technology
Development Program for a Oleg Nezhevenko
Future 34-GHz Linac
915-930
Acoustic Localization of RF Structure
Breakdowns
George Gollin 930-945 Optimized
Cavity Shape for TESLA Valery Shemelin
945-1000 1500 MHz Nb Cavity made of Electro-
polished
Half-Cells Rongli Geng 1000-1015 DC
Breakdown Studies Greg Werner 1015-1030
Control of Beam Loss in High-Repetition
Rate High-Power PPM Klystrons Mark Hess
9

• Technology Development Program for a Future
  34-GHz Linac
  
• Oleg Nezhevenko
• Goal extend present 11 GHz RF technology by a
  factor of 3 to 34 GHz with hope to increase
  achievable gradients.
• Built a 34 GHz magnicon (10 MW, 0.5 ?s) and
  cavity for pulsed heating tests.
• Designed a 34 GHz 19 cell accelerating cavity.

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Accelerator Working Group RF Technology and
Structures Monday, July 14, 830-1030 a.m.
830-855 Warm and Cold RF Structures
Hasan Padamsee 855-915 Technology
Development Program for a Oleg Nezhevenko
Future 34-GHz Linac
915-930
Acoustic Localization of RF Structure
Breakdowns
George Gollin 930-945 Optimized
Cavity Shape for TESLA Valery Shemelin
945-1000 1500 MHz Nb Cavity made of Electro-
polished
Half-Cells Rongli Geng 1000-1015 DC
Breakdown Studies Greg Werner 1015-1030
Control of Beam Loss in High-Repetition
Rate High-Power PPM Klystrons Mark Hess
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Accelerator Working Group RF Technology and
Structures Monday, July 14, 830-1030 a.m.
830-855 Warm and Cold RF Structures
Hasan Padamsee 855-915 Technology
Development Program for a Oleg Nezhevenko
Future 34-GHz Linac
915-930
Acoustic Localization of RF Structure
Breakdowns
George Gollin 930-945 Optimized
Cavity Shape for TESLA Valery Shemelin
945-1000 1500 MHz Nb Cavity made of Electro-
polished
Half-Cells Rongli Geng 1000-1015 DC
Breakdown Studies Greg Werner 1015-1030
Control of Beam Loss in High-Repetition
Rate High-Power PPM Klystrons Mark Hess
14
The hard limit for the increase in accelerating
gradient in s.c. cavities is the surface magnetic
field. Optimize cavity shape One can, for
example, sacrifice 20 of electric field to
gain 10 in magnetic field and so increase the
Acc. Rate by 10 .
old
new
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Accelerator Working Group RF Technology and
Structures Monday, July 14, 830-1030 a.m.
830-855 Warm and Cold RF Structures
Hasan Padamsee 855-915 Technology
Development Program for a Oleg Nezhevenko
Future 34-GHz Linac
915-930
Acoustic Localization of RF Structure
Breakdowns
George Gollin 930-945 Optimized
Cavity Shape for TESLA Valery Shemelin
945-1000 1500 MHz Nb Cavity made of Electro-
polished
Half-Cells Rongli Geng 1000-1015 DC
Breakdown Studies Greg Werner 1015-1030
Control of Beam Loss in High-Repetition
Rate High-Power PPM Klystrons Mark Hess
16
Motivation Do heat treatment and
electropolishing on half cells to reduce cost in
s.c. cavity production.
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Accelerator Working Group RF Technology and
Structures Monday, July 14, 830-1030 a.m.
830-855 Warm and Cold RF Structures
Hasan Padamsee 855-915 Technology
Development Program for a Oleg Nezhevenko
Future 34-GHz Linac
915-930
Acoustic Localization of RF Structure
Breakdowns
George Gollin 930-945 Optimized
Cavity Shape for TESLA Valery Shemelin
945-1000 1500 MHz Nb Cavity made of Electro-
polished
Half-Cells Rongli Geng 1000-1015 DC
Breakdown Studies Greg Werner 1015-1030
Control of Beam Loss in High-Repetition
Rate High-Power PPM Klystrons Mark Hess
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• DC breakdown studies on copper and niobium
  surfaces.
• found starbursts and craters after breakdowns
• found Manganese on all heat treated copper
  samples

50 um
145MV/m
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Accelerator Working Group RF Technology and
Structures Monday, July 14, 830-1030 a.m.
830-855 Warm and Cold RF Structures
Hasan Padamsee 855-915 Technology
Development Program for a Oleg Nezhevenko
Future 34-GHz Linac
915-930
Acoustic Localization of RF Structure
Breakdowns
George Gollin 930-945 Optimized
Cavity Shape for TESLA Valery Shemelin
945-1000 1500 MHz Nb Cavity made of Electro-
polished
Half-Cells Rongli Geng 1000-1015 DC
Breakdown Studies Greg Werner 1015-1030
Control of Beam Loss in High-Repetition
Rate High-Power PPM Klystrons Mark Hess
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Theoretical studies Why do some klystrons show
beam loss (and some dont)?
Diagrams of Bunched Beam Models
Pencil Beam Model (Presented at Arlington Meeting)
Finite Size Beam Model (New)
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Comparison of Bunched Beam Models to Experiment
gbsz/a0.71
gbsz/a0.36
gbsz/a0.0
Red Curve Pencil Beam
Blue Curves rb/a0.5
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• Systems and Instrumentation
• Good controls and instrumentation are essential
  for LC.
• Much work in progress, but a lot more needs to be
  done.

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Accelerator Working Group Systems and
Instrumentation Monday, July 14,
1055-1255 1055-1115 Accelerator
Instrumentation RD Marc Ross 1115-1135
Prototype Synchrotron Radiation Telescope Jim
Alexander 1135-1155 Design and Fabrication of a
Radiation-Hard 500 MHz digitizer K K
Gan 1155-1215 Nanometer resolution Beam
Position Monitors Marc Ross 1215-1235 Nanometer
BPM supports and movers Jeff Gronberg Tuesday,
July 15, 150-350 p.m. 150-210 TTF data
acquisition Tim Wilksen 210-230 Beam size
diagnostics using diffraction radiation Bibo
Feng 230-250 A0 coherent radiation
diagnostics Court Bohn
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Accelerator Working Group Systems and
Instrumentation Monday, July 14,
1055-1255 1055-1115 Accelerator
Instrumentation RD Marc Ross 1115-1135
Prototype Synchrotron Radiation Telescope Jim
Alexander 1135-1155 Design and Fabrication of a
Radiation-Hard 500 MHz digitizer K K
Gan 1155-1215 Nanometer resolution Beam
Position Monitors Marc Ross 1215-1235 Nanometer
BPM supports and movers Jeff Gronberg Tuesday,
July 15, 150-350 p.m. 150-210 TTF data
acquisition Tim Wilksen 210-230 Beam size
diagnostics using diffraction radiation Bibo
Feng 230-250 A0 coherent radiation
diagnostics Court Bohn
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• Overview of beam instrumentations and controls
  importance and influence on cost, performance and
  reliability of LC.
• Examples
• correlation monitors
• Multibunch behavior of u-wave cavity BPMs
• Long. phase space diagnostics based on
  deflecting RF
• Marcs Conclusion
• HEP must aggressively attack Controls/Instrumentat
  ion issues

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Accelerator Working Group Systems and
Instrumentation Monday, July 14,
1055-1255 1055-1115 Accelerator
Instrumentation RD Marc Ross 1115-1135
Prototype Synchrotron Radiation Telescope Jim
Alexander 1135-1155 Design and Fabrication of a
Radiation-Hard 500 MHz digitizer K K
Gan 1155-1215 Nanometer resolution Beam
Position Monitors Marc Ross 1215-1235 Nanometer
BPM supports and movers Jeff Gronberg Tuesday,
July 15, 150-350 p.m. 150-210 TTF data
acquisition Tim Wilksen 210-230 Beam size
diagnostics using diffraction radiation Bibo
Feng 230-250 A0 coherent radiation
diagnostics Court Bohn
27

• Image synchrotron radiation from damping rings
• ? Snapshot from transverse bunch shape, single
  bunch resolution

• Present explore parameter space, identify key
  issues.
• Next system pro-design
• Future Test structures,

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Accelerator Working Group Systems and
Instrumentation Monday, July 14,
1055-1255 1055-1115 Accelerator
Instrumentation RD Marc Ross 1115-1135
Prototype Synchrotron Radiation Telescope Jim
Alexander 1135-1155 Design and Fabrication of a
Radiation-Hard 500 MHz digitizer K K
Gan 1155-1215 Nanometer resolution Beam
Position Monitors Marc Ross 1215-1235 Nanometer
BPM supports and movers Jeff Gronberg Tuesday,
July 15, 150-350 p.m. 150-210 TTF data
acquisition Tim Wilksen 210-230 Beam size
diagnostics using diffraction radiation Bibo
Feng 230-250 A0 coherent radiation
diagnostics Court Bohn
29

• radiation hard (gt 60 MRad)
• somewhat beyond state-of-the-art
• started with design, are funded by DOE for
  design/simulation in first year
• goal has most circuit blocks ready for
  prototyping by end of first year

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Accelerator Working Group Systems and
Instrumentation Monday, July 14,
1055-1255 1055-1115 Accelerator
Instrumentation RD Marc Ross 1115-1135
Prototype Synchrotron Radiation Telescope Jim
Alexander 1135-1155 Design and Fabrication of a
Radiation-Hard 500 MHz digitizer K K
Gan 1155-1215 Nanometer resolution Beam
Position Monitors Marc Ross 1215-1235 Nanometer
BPM supports and movers Jeff Gronberg Tuesday,
July 15, 150-350 p.m. 150-210 TTF data
acquisition Tim Wilksen 210-230 Beam size
diagnostics using diffraction radiation Bibo
Feng 230-250 A0 coherent radiation
diagnostics Court Bohn
31
What are the uses of nanometer-resolution BPMs?
Measure beam position with accuracy better
than support stability Use the beam as a
mechanical device to prove active
stabilization? Measure beam parameters other
than position Many applications in beam
manipulation

• RF BPM ideal
• 3 Balakin BPMs installed at ATF.
• Started to study performance.

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Accelerator Working Group Systems and
Instrumentation Monday, July 14,
1055-1255 1055-1115 Accelerator
Instrumentation RD Marc Ross 1115-1135
Prototype Synchrotron Radiation Telescope Jim
Alexander 1135-1155 Design and Fabrication of a
Radiation-Hard 500 MHz digitizer K K
Gan 1155-1215 Nanometer resolution Beam
Position Monitors Marc Ross 1215-1235 Nanometer
BPM supports and movers Jeff Gronberg Tuesday,
July 15, 150-350 p.m. 150-210 TTF data
acquisition Tim Wilksen 210-230 Beam size
diagnostics using diffraction radiation Bibo
Feng 230-250 A0 coherent radiation
diagnostics Court Bohn
33

• To demonstrate nanometer resolution the BPMs must
  be stable at the nanometer level with respect to
  one another.
• Designed 3 hexapod-structure to hold and align
  BPMs.

• Mechanical modes of the structure should be above
  200 Hz, where they do not harm.
• Vibration simulations are done, alignment frame
  is under construction.
• Beam test at ATF in October 2003.

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Accelerator Working Group Systems and
Instrumentation Monday, July 14,
1055-1255 1055-1115 Accelerator
Instrumentation RD Marc Ross 1115-1135
Prototype Synchrotron Radiation Telescope Jim
Alexander 1135-1155 Design and Fabrication of a
Radiation-Hard 500 MHz digitizer K K
Gan 1155-1215 Nanometer resolution Beam
Position Monitors Marc Ross 1215-1235 Nanometer
BPM supports and movers Jeff Gronberg Tuesday,
July 15, 150-350 p.m. 150-210 TTF data
acquisition Tim Wilksen 210-230 Beam size
diagnostics using diffraction radiation Bibo
Feng 230-250 A0 coherent radiation
diagnostics Court Bohn
35

• Cornell, DESY and OSU initiated a joined project
  to design and develop a TTF 2 data acquisition by
  using collaboration technologies as an example
  for a possible future GAN scenario.
• Built on top of the DOOCS accelerator control
  system.
• Development of collaborative tools.
• First application TTF2 FEL (2004). 50 to 100
  GB/day.

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Accelerator Working Group Systems and
Instrumentation Monday, July 14,
1055-1255 1055-1115 Accelerator
Instrumentation RD Marc Ross 1115-1135
Prototype Synchrotron Radiation Telescope Jim
Alexander 1135-1155 Design and Fabrication of a
Radiation-Hard 500 MHz digitizer K K
Gan 1155-1215 Nanometer resolution Beam
Position Monitors Marc Ross 1215-1235 Nanometer
BPM supports and movers Jeff Gronberg Tuesday,
July 15, 150-350 p.m. 150-210 TTF data
acquisition Tim Wilksen 210-230 Beam size
diagnostics using diffraction radiation Bibo
Feng 230-250 A0 coherent radiation
diagnostics Court Bohn
37
Why use diffraction radiation for beam diagnostic?

• Non-invasive Diffraction radiation through a
  slit.
• Beam size diagnostics longitudinal and
  transverse
• Beam position monitor radiation intensity vs.
  beam position
• More beam information beam energy and emittance

• Status and Plans at Vanderbilt FEL
• Studies of diffraction radiation
• Designed and built a interferometer
• Future
• Radiator vacuum chamber and slit actuator
• Longitudinal bunch length experiments
• Measurement of DR angular distribution
• Transverse beam dimension experiments

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Accelerator Working Group Systems and
Instrumentation Monday, July 14,
1055-1255 1055-1115 Accelerator
Instrumentation RD Marc Ross 1115-1135
Prototype Synchrotron Radiation Telescope Jim
Alexander 1135-1155 Design and Fabrication of a
Radiation-Hard 500 MHz digitizer K K
Gan 1155-1215 Nanometer resolution Beam
Position Monitors Marc Ross 1215-1235 Nanometer
BPM supports and movers Jeff Gronberg Tuesday,
July 15, 150-350 p.m. 150-210 TTF data
acquisition Tim Wilksen 210-230 Beam size
diagnostics using diffraction radiation
Bibo Feng 230-250 A0 coherent radiation
diagnostics Court Bohn
39

• Coherent radiation studies at A0 for beam
  diagnostic
• Built a new, compact Michelson interferometer
• Future goal single shot measurement (with
  Fresnel mirror, no moving parts)

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Thank you Speakers! This was fun!