Working Group Summaries: Working Group Summaries: AcceleratorAccelerator

RF Technology and Structures

Systems and Instrumentation

Matthias Liepe

Cornell University

RF Technology and StructuresRF Technology and Structures

We are almost there,

But still a lot can and needs to be done.

Accelerator Working Group: RF Technology and StructuresAccelerator Working Group: RF Technology and Structures

Monday, July 14, 8:30-10:30 a.m.

8:30-8:55 Warm and Cold RF Structures Hasan Padamsee

8:55-9:15 Technology Development Program for a Oleg Nezhevenko / Future 34-GHz Linac Vyacheslav Yakovlev

9:15-9:30 Acoustic Localization of RF Structure Breakdowns George Gollin

9:30-9:45 Optimized Cavity Shape for TESLA Valery Shemelin

9:45-10:00 1500 MHz Nb Cavity made of Electro- polished Half-Cells Rongli Geng

10:00-10:15 DC Breakdown Studies Greg Werner

10:15-10:30 Control of Beam Loss in High-Repetition Rate High-Power PPM Klystrons Mark Hess

Accelerator Working Group: RF Technology and StructuresAccelerator Working Group: RF Technology and Structures

Monday, July 14, 8:30-10:30 a.m.

8:30-8:55 Warm and Cold RF Structures Hasan Padamsee

8:55-9:15 Technology Development Program for a Oleg Nezhevenko Future 34-GHz Linac

9:15-9:30 Acoustic Localization of RF Structure Breakdowns George Gollin

9:30-9:45 Optimized Cavity Shape for TESLA Valery Shemelin

9:45-10:00 1500 MHz Nb Cavity made of Electro- polished Half-Cells Rongli Geng

10:00-10:15 DC Breakdown Studies Greg Werner

10:15-10:30 Control of Beam Loss in High-Repetition Rate High-Power PPM Klystrons Mark Hess

20,600L = 21 km

18,500L = 11.1 km

Why 11.4 GHz?Peak RF Power needed to reach gradient 1/√ frequency

1.3 GHz

Niobium

1 m

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

Start withEa-loaded=50 MV/m(65MV/m-unloaded)Fewer structures

Strategy: start with 23.5 MV/mStructures tested to 35 MV/m before installation Copper

11.4 GHz

The best !

1.0E+09

1.0E+10

1.0E+11

0 10 20 30 40Eacc [MV/m]

Q0

CWCW after 20KCHECHIA 10 Hz ICHECHIA 5 HzCHECHIA 10 Hz IICHECHIA 10 Hz III

AC73 - Vertical and Horizontal Test Results1011

109

1010

37 MV/m in Fully Equppied Cavityi.e. high power test and 1/8th of a TTF Linac module

Accelerator Working Group: RF Technology and StructuresAccelerator Working Group: RF Technology and Structures

Monday, July 14, 8:30-10:30 a.m.

8:30-8:55 Warm and Cold RF Structures Hasan Padamsee

8:55-9:15 Technology Development Program for a Oleg Nezhevenko Future 34-GHz Linac

9:15-9:30 Acoustic Localization of RF Structure Breakdowns George Gollin

9:30-9:45 Optimized Cavity Shape for TESLA Valery Shemelin

9:45-10:00 1500 MHz Nb Cavity made of Electro- polished Half-Cells Rongli Geng

10:00-10:15 DC Breakdown Studies Greg Werner

10:15-10:30 Control of Beam Loss in High-Repetition Rate High-Power PPM Klystrons Mark Hess

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.

Accelerator Working Group: RF Technology and StructuresAccelerator Working Group: RF Technology and Structures

Monday, July 14, 8:30-10:30 a.m.

8:30-8:55 Warm and Cold RF Structures Hasan Padamsee

8:55-9:15 Technology Development Program for a Oleg Nezhevenko Future 34-GHz Linac

9:15-9:30 Acoustic Localization of RF Structure Breakdowns George Gollin

9:30-9:45 Optimized Cavity Shape for TESLA Valery Shemelin

9:45-10:00 1500 MHz Nb Cavity made of Electro- polished Half-Cells Rongli Geng

10:00-10:15 DC Breakdown Studies Greg Werner

10:15-10:30 Control of Beam Loss in High-Repetition Rate High-Power PPM Klystrons Mark Hess

Accelerator Working Group: RF Technology and StructuresAccelerator Working Group: RF Technology and Structures

Monday, July 14, 8:30-10:30 a.m.

8:30-8:55 Warm and Cold RF Structures Hasan Padamsee

8:55-9:15 Technology Development Program for a Oleg Nezhevenko Future 34-GHz Linac

9:15-9:30 Acoustic Localization of RF Structure Breakdowns George Gollin

9:30-9:45 Optimized Cavity Shape for TESLA Valery Shemelin

9:45-10:00 1500 MHz Nb Cavity made of Electro- polished Half-Cells Rongli Geng

10:00-10:15 DC Breakdown Studies Greg Werner

10:15-10:30 Control of Beam Loss in High-Repetition Rate High-Power PPM Klystrons Mark Hess

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

Accelerator Working Group: RF Technology and StructuresAccelerator Working Group: RF Technology and Structures

Monday, July 14, 8:30-10:30 a.m.

8:30-8:55 Warm and Cold RF Structures Hasan Padamsee

8:55-9:15 Technology Development Program for a Oleg Nezhevenko Future 34-GHz Linac

9:15-9:30 Acoustic Localization of RF Structure Breakdowns George Gollin

9:30-9:45 Optimized Cavity Shape for TESLA Valery Shemelin

9:45-10:00 1500 MHz Nb Cavity made of Electro- polished Half-Cells Rongli Geng

10:00-10:15 DC Breakdown Studies Greg Werner

10:15-10:30 Control of Beam Loss in High-Repetition Rate High-Power PPM Klystrons Mark Hess

Motivation: Do heat treatment and electropolishing on half cells to reduce cost in s.c. cavity production.

Accelerator Working Group: RF Technology and StructuresAccelerator Working Group: RF Technology and Structures

Monday, July 14, 8:30-10:30 a.m.

8:30-8:55 Warm and Cold RF Structures Hasan Padamsee

8:55-9:15 Technology Development Program for a Oleg Nezhevenko Future 34-GHz Linac

9:15-9:30 Acoustic Localization of RF Structure Breakdowns George Gollin

9:30-9:45 Optimized Cavity Shape for TESLA Valery Shemelin

9:45-10:00 1500 MHz Nb Cavity made of Electro- polished Half-Cells Rongli Geng

10:00-10:15 DC Breakdown Studies Greg Werner

10:15-10:30 Control of Beam Loss in High-Repetition Rate High-Power PPM Klystrons Mark Hess

• 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

Accelerator Working Group: RF Technology and StructuresAccelerator Working Group: RF Technology and Structures

Monday, July 14, 8:30-10:30 a.m.

8:30-8:55 Warm and Cold RF Structures Hasan Padamsee

8:55-9:15 Technology Development Program for a Oleg Nezhevenko Future 34-GHz Linac

9:15-9:30 Acoustic Localization of RF Structure Breakdowns George Gollin

9:30-9:45 Optimized Cavity Shape for TESLA Valery Shemelin

9:45-10:00 1500 MHz Nb Cavity made of Electro- polished Half-Cells Rongli Geng

10:00-10:15 DC Breakdown Studies Greg Werner

10:15-10:30 Control of Beam Loss in High-Repetition Rate High-Power PPM Klystrons Mark Hess

Pencil Beam Model (Presented at Arlington

Meeting)

Finite Size Beam Model(New)

Diagrams of Bunched Beam Models

L

aVz

r

L

ra Vz

x

y

z

B

Theoretical studies: Why do some klystrons show beam loss (and some don’t)?

0.0 0.3 0.6 0.9 1.2 1.5af/bbc

0.0

0.1

0.2

0.3

0.4

0.5

8c2 I b/

c,

rmsa

2 I A

50 MW XL-PPM75 MW XP-175 MW XP-350 MW (C-Band)75 MW PPM-1

0.0 0.3 0.6 0.9 1.2 1.5af/bbc

Red Curve: Pencil Beam

Blue Curves: rb/a=0.5

bz/a=0.71

Comparison of Bunched Beam Models to Experiment

bz/a=0.36

bz/a=0.0

Systems and InstrumentationSystems and Instrumentation

Good controls and instrumentation are essential for LC.

Much work in progress, but a lot more needs to be done.

Accelerator Working Group: Systems and InstrumentationAccelerator Working Group: Systems and Instrumentation

Monday, July 14, 10:55-12:5510:55-11:15 Accelerator Instrumentation RD Marc Ross11:15-11:35 Prototype Synchrotron Radiation Telescope Jim Alexander11:35-11:55 Design and Fabrication of a Radiation-Hard

500 MHz digitizer K K Gan11:55-12:15 Nanometer resolution Beam Position Monitors Marc Ross12:15-12:35 Nanometer BPM supports and movers Jeff Gronberg

Tuesday, July 15, 1:50-3:50 p.m.1:50-2:10 TTF data acquisition Tim Wilksen2:10-2:30 Beam size diagnostics using diffraction radiation Bibo Feng2:30-2:50 A0 coherent radiation diagnostics Court Bohn

Accelerator Working Group: Systems and InstrumentationAccelerator Working Group: Systems and Instrumentation

Monday, July 14, 10:55-12:5510:55-11:15 Accelerator Instrumentation RD Marc Ross11:15-11:35 Prototype Synchrotron Radiation Telescope Jim Alexander11:35-11:55 Design and Fabrication of a Radiation-Hard

500 MHz digitizer K K Gan11:55-12:15 Nanometer resolution Beam Position Monitors Marc Ross12:15-12:35 Nanometer BPM supports and movers Jeff Gronberg

Tuesday, July 15, 1:50-3:50 p.m.1:50-2:10 TTF data acquisition Tim Wilksen2:10-2:30 Beam size diagnostics using diffraction radiation Bibo Feng2:30-2:50 A0 coherent radiation diagnostics Court Bohn

• 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 BPM’s

• Long. phase space diagnostics based on deflecting RF

• Marc’s Conclusion:

•HEP must aggressively attack Controls/Instrumentation issues

Accelerator Working Group: Systems and InstrumentationAccelerator Working Group: Systems and Instrumentation

Monday, July 14, 10:55-12:5510:55-11:15 Accelerator Instrumentation RD Marc Ross11:15-11:35 Prototype Synchrotron Radiation Telescope Jim Alexander11:35-11:55 Design and Fabrication of a Radiation-Hard

500 MHz digitizer K K Gan11:55-12:15 Nanometer resolution Beam Position Monitors Marc Ross12:15-12:35 Nanometer BPM supports and movers Jeff Gronberg

Tuesday, July 15, 1:50-3:50 p.m.1:50-2:10 TTF data acquisition Tim Wilksen2:10-2:30 Beam size diagnostics using diffraction radiation Bibo Feng2:30-2:50 A0 coherent radiation diagnostics Court Bohn

• Present: explore parameter space, identify key issues.

• Next: system pro-design

• Future: Test structures,…

• Image synchrotron radiation from damping rings

Snapshot from transverse bunch shape, single bunch resolution

Accelerator Working Group: Systems and InstrumentationAccelerator Working Group: Systems and Instrumentation

Monday, July 14, 10:55-12:5510:55-11:15 Accelerator Instrumentation RD Marc Ross11:15-11:35 Prototype Synchrotron Radiation Telescope Jim Alexander11:35-11:55 Design and Fabrication of a Radiation-Hard

500 MHz digitizer K K Gan11:55-12:15 Nanometer resolution Beam Position Monitors Marc Ross12:15-12:35 Nanometer BPM supports and movers Jeff Gronberg

Tuesday, July 15, 1:50-3:50 p.m.1:50-2:10 TTF data acquisition Tim Wilksen2:10-2:30 Beam size diagnostics using diffraction radiation Bibo Feng2:30-2:50 A0 coherent radiation diagnostics Court Bohn

• radiation hard (> 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

Accelerator Working Group: Systems and InstrumentationAccelerator Working Group: Systems and Instrumentation

Monday, July 14, 10:55-12:5510:55-11:15 Accelerator Instrumentation RD Marc Ross11:15-11:35 Prototype Synchrotron Radiation Telescope Jim Alexander11:35-11:55 Design and Fabrication of a Radiation-Hard

500 MHz digitizer K K Gan11:55-12:15 Nanometer resolution Beam Position Monitors Marc Ross12:15-12:35 Nanometer BPM supports and movers Jeff Gronberg

Tuesday, July 15, 1:50-3:50 p.m.1:50-2:10 TTF data acquisition Tim Wilksen 2:10-2:30 Beam size diagnostics using diffraction radiation Bibo Feng2:30-2:50 A0 coherent radiation diagnostics Court Bohn

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.

Accelerator Working Group: Systems and InstrumentationAccelerator Working Group: Systems and Instrumentation

Monday, July 14, 10:55-12:5510:55-11:15 Accelerator Instrumentation RD Marc Ross11:15-11:35 Prototype Synchrotron Radiation Telescope Jim Alexander11:35-11:55 Design and Fabrication of a Radiation-Hard

500 MHz digitizer K K Gan11:55-12:15 Nanometer resolution Beam Position Monitors Marc Ross12:15-12:35 Nanometer BPM supports and movers Jeff Gronberg

Tuesday, July 15, 1:50-3:50 p.m.1:50-2:10 TTF data acquisition Tim Wilksen2:10-2:30 Beam size diagnostics using diffraction radiation Bibo Feng2:30-2:50 A0 coherent radiation diagnostics Court Bohn

• 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.

Accelerator Working Group: Systems and InstrumentationAccelerator Working Group: Systems and Instrumentation

Monday, July 14, 10:55-12:5510:55-11:15 Accelerator Instrumentation RD Marc Ross11:15-11:35 Prototype Synchrotron Radiation Telescope Jim Alexander11:35-11:55 Design and Fabrication of a Radiation-Hard

500 MHz digitizer K K Gan11:55-12:15 Nanometer resolution Beam Position Monitors Marc Ross12:15-12:35 Nanometer BPM supports and movers Jeff Gronberg

Tuesday, July 15, 1:50-3:50 p.m.1:50-2:10 TTF data acquisition Tim Wilksen2:10-2:30 Beam size diagnostics using diffraction radiation Bibo Feng2:30-2:50 A0 coherent radiation diagnostics Court Bohn

•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.

Accelerator Working Group: Systems and InstrumentationAccelerator Working Group: Systems and Instrumentation

Monday, July 14, 10:55-12:5510:55-11:15 Accelerator Instrumentation RD Marc Ross11:15-11:35 Prototype Synchrotron Radiation Telescope Jim Alexander11:35-11:55 Design and Fabrication of a Radiation-Hard

500 MHz digitizer K K Gan11:55-12:15 Nanometer resolution Beam Position Monitors Marc Ross12:15-12:35 Nanometer BPM supports and movers Jeff Gronberg

Tuesday, July 15, 1:50-3:50 p.m.1:50-2:10 TTF data acquisition Tim Wilksen2:10-2:30 Beam size diagnostics using diffraction radiation Bibo Feng2:30-2:50 A0 coherent radiation diagnostics Court Bohn

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

xy

z e-

a

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

Accelerator Working Group: Systems and InstrumentationAccelerator Working Group: Systems and Instrumentation

Monday, July 14, 10:55-12:5510:55-11:15 Accelerator Instrumentation RD Marc Ross11:15-11:35 Prototype Synchrotron Radiation Telescope Jim Alexander11:35-11:55 Design and Fabrication of a Radiation-Hard

500 MHz digitizer K K Gan11:55-12:15 Nanometer resolution Beam Position Monitors Marc Ross12:15-12:35 Nanometer BPM supports and movers Jeff Gronberg

Tuesday, July 15, 1:50-3:50 p.m.1:50-2:10 TTF data acquisition Tim Wilksen2:10-2:30 Beam size diagnostics using diffraction

radiation Bibo Feng2:30-2:50 A0 coherent radiation diagnostics Court Bohn

• 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)

Thank you Speakers!

This was fun!