D.Proch EuCARD kick-off, CERN,Dec.08 WP10 SRF: SC RF technology for higher intensity proton...

D.Proch EuCARD kick-off, CERN,Dec.08

WP10SRF: SC RF technology for higher intensity proton

accelerators & higher energy electron linacs


WP 10 SRF

COSTDESY IPJBessy STFC TotalCEA TUL 7.730 M€CERN ULANCCNRS UNIMAN EC supportFZD UROS 2.466 M€IFJPAN WUTINFN

Participants


10: SRF

10.1: SRF Coordination & CommunicationD. Proch/DESY, dep. O. Napoly/CEA

10.2: SC Cavities for proton Linacs S. Chel/CEA 10.3: LHC Crab Cavities P. McIntosh/UNIMAN10.4: Thin Films M. Lindroos/CERN10.5: HOM Distribution N. Baboi/DESY10.6: LLRF at FLASH S. Simrock/DESY10.7: SCRF Gun at ELBE J. Teichert/FZD10.8: Coupler Development at LAL A. Variola/LAL

WP 10 Organisation


WP10 Objectives

• The main activities in the SC RF Technology WP concentrate on two different areas: – cavity improvements and beam experiments. – Improved methods for cavity treatment such as

vertical electro-polishing or sputter coating will be investigated.

– Prototype work on superconducting (SC) crab cavities will be launched with the goal to increase the luminosity of colliders such as LHC, CLIC or ILC.


Objectives, cont.

• The second research activity concentrates on further developing Low Level RF techniques and on new diagnostic tools based on the analysis of Higher Order Modes (HOM). These advanced and challenging concepts and ideas will be tested in the FLASH linac, and they are important for the extreme beam stability requirements and control problems in future projects.


WP10.1 SRF Coordination and communication

• Coordination and scheduling of the WP tasks.

• Monitoring the work, informing the project management and participants within the JRA.

• WP budget follow-up.

• Deliverable:

10.1.1 SRF web-site linked to the technical and administrative databases


WP10.2 SC Cavities for Proton Linacs, Electropolishing and surface

investigations

• Sub-task 1: Design and fabrication of b = 0.65 ; 704 MHz elliptical cavity equipped with a titanium helium reservoir. Preparation and assembly in clean room. Test of the cavity in vertical cryostat.

• Sub-task 2: Design and fabrication of b = 1 ; 704 MHz elliptical cavity. Preparation of the cavity and assembly in clean room. Development of a vertical EP bench.

• Sub-task 3: Study of interfaces between the cavity and the cryomodule.


WP10.2 Deliverables

10.2.1Results of SC proton cavity tests (b = 1 and b = 0.65)

R M33

10.2.2Reproducibility of the process as a Function of

the EP-MixtureR M36

10.2.3 Summary of test results with vertical EP R M42

10.2.4Evaluation of enhanced field emission in Nb

samplesR M48


SC Cavities for Proton Linacs General background :

Upgrade of the LHC luminosity by replacing the injectors

of the CERN complex by LINAC4, (LP-)SPL and PS2

Superconducting Proton Linac


The optimized design of the SPL accelerator is based on two families of SC cavities (beta=0.65 and beta=1.0) operating at 704.4 MHz at gradients of 19 MV/m and 25 MV/m, respectively.

MeV

LINAC 4 (fRF=352.2 MHz)

ββ==00..6655

50

HH--

ssoouurrccee RRFFQQ cchhooppppeerr DDTTLL CCCCDDTTLL PPIIMMSS

3 102 160

LP-SPL (fRF=704.4 MHz)

ββ==11..00

643 4000

LP-SPL cavities freq = 704.4 MHz 2 families :

=0.65 Eacc = 19MV/m 5 cells 42 cavités=1.0 Eacc = 25MV/m 5 cells 200 cavités

RF Power per coupler : 1MW (for =1 cavities)

New Injectors

Normal Conducting Super Conducting


1) Study and prototyping of 704 MHz cavities (=0.65 and =1.0) ; Tests in vertical cryostat

Task : SC Cavities for Proton Linacs

+

= vertical EP for multicells

CARE/SRF : 1-cell EP set-up Vertical Chemical

Polishing

2) Development at Saclay of a vertical ElectroPolishing set-up which fits the dimensions of both cavity families


WP10.3 Crab cavities

• Design, build and test a single LHC and CLIC crab cavity module, including input coupler, mode couplers and tuners.

• Design, build and test a LLRF and synchronization system that meets the crab cavity phase and amplitude control specifications for LHC and CLIC.

• If the beam time and the necessary hardware become available, validate and test the assembled crab system solutions and LLRF control systems on LHC and CTF3 in 2011; otherwise make performance predictions based on the measured noise characteristics.


WP10.3 Deliverables

10.3.1 LHC crab cavity final report R M36

10.3.2 CLIC crab cavity final report R M36

10.3.3 LHC and CLIC LLRF final reports R M36


LHC-CC Local vs Global

• Small crossing angle (~0.5 mrad):• Global crab scheme is ideal choice for prototype

Phase-I:– Test feasibility of crab crossing in hadron colliders,– Address all RF and beam dynamic issues, – Small orbit excursion and tune shifts, – Compatible with nominal and upgrade options to

recover the geometric luminosity loss,– Collimation optimisation!– These cavities are feasible using available

technology and the gradient requirements are within reach of current technology.

• Local crab crossing preferable (Phase-II):– Independent control at IPs,– Avoid collimation/impedance issues.

• Need compact cavities to fit in the IR region of the ring.

• Lower frequency hopefully!


CLIC-CC Developments


WP10.4 Thin Films

• Improve the Nb sputtering technology for low beta cavities (magnetron sputtering) such as QWR to reach 6 MV/m at a Q-value of 5•108.

• Perform arc sputtering of photo cathodes (Pb) and test the performance of the developed systems.

• Research on new technologies for thin film depositing of superconductors for SC cavity applications (e.g. atomic layer deposition).


WP10.4 Deliverables

10.4.1QE data for Pb/Nb deposited photo cathode

samplesR M12

10.4.2RF measurements on thin film deposited QRW

prototypeR M36

10.4.3Cold test results for the test cavities w/out the

deposited lead photo cathodeR M36

10.4.4New thin film techniques for SC cavities and

photo cathodesD M30


SCRF – thin film task

CERN – INFN – DESY –CI – IPNO -IPJObjectives – Improve the Nb

sputtering technology for low beta cavities such as QWR to reach 6 MV/m at a Q-value of 5 108.

– Perform arc sputtering of photo cathodes (Pb) and test the performance of the developed systems

– Research on new technologies for thin film depositing of superconductors for SC cavity applications

D.Proch EuCARD kick-off, CERN,Dec.08Courtesy J. Sekutowicz


WP10. 5 HOM Distribution

• Development of HOM based beam position monitors (HOMBPM).

• Development of HOM Cavity Diagnostics and ERLP (HOMCD).

• Measurement of HOM Distributions and Geometrical Dependences (HOMDG).


WP10. 5 Deliverables

10.5.1HOM electronics and code to probe

beam centring on 3.9 GHz cavitiesR M48

10.5.2Report on HOM experimental methods

and codeR M48


Task 10.5 HOM based Monitors•HOM based monitors for

– beam diagnostics– cavity/cryo-module diagnostics– DESY, Manchester Univ. / Cockcroft Inst.,

Rostock Univ.– experimental studies at FLASH, ERLP, the

wire test facility at CI

•Sub-task 1: HOM-BPMs– monitor 1 dipole mode and calculate

beam position– proof of principle already made– resolution expected ~ 1 m– advantages:

• center beam minimize wakes critical for 3.9 GHz cav. and at low energies for the 1.3 GHz

• no new vacuum component

HOM-couplers (pick-ups)


Task 10.5 HOM based Monitors (2)

•Sub-task 2: Cavity diagnostics– study the HOM spectrum in each

cavity to determine:– cavity alignment– cell geometry

•Sub-task 3: Geometrical dependencies of HOM distributions

– simulations combining finite element and S-matrix cascading techniques

– multi-cavities, cell deformation, influence of couplers on spectrum etc.

~100 m rms

~300 m rms

Cavity alignment in ACC4

y [m

m]

x [m

m]


WP 10.6 LLRF at FLASH

• ATCA developments of carrier boards with FPGA and DSP.

• Development of AMC modules with fast analogue IO and digital IO.

• Development of special power drivers for AMC modules.

• Development of beam based feedback.


WP 10.6 Deliverable

10.6.1 Report on system test and performance R M42

Institutions

DESY Deutsches Elektronen-Synchrotron, Hamburg, Germany

DMCS Department of Microelectronics and Computer Science, Technical University of Lodz, Poland

ISE Institute of Electronic Systems, Warsaw University of Technology, Poland

INP Niewodniczanski Institute of Nuclear Physics, Krakow, Poland

IPJ The Andrzej Soltan Institute for Nuclear Studies, Swierk, Poland

Task 6: LLRF at FLASH

• The present LLRF control system at FLASH does not fulfill the long term (3-10 years) requirements in several areas: Field regulation, availability, maintenance and operability.

• The demand for high availability (HA), modularity, standardization and long time support favours the choice of the ATCA standards with carrier boards and AMC modules.

• The ATCA technology comes from telecommunication industry and therefore availability of commercial boards needed for instrumentation is presently very limited but growing.

• The LLRF control system for FLASH will be build using a modular approach basing on ATCA architecture.

• The boards developed for the LLRF system can be used for other accelerator instrumentation needs including the control system.

Concept for LLRF based on ATCA

Concept for LLRF based on ATCACharacteristic signals for the LLRF system

AMC Boards:ADC (8 inputs)TimingVMCommunication modulePiezo controllerDiagnostic ADCDigital I/O

RTM Modules:32 ch. down-converter

Carrier Board:32 ch. down-converter

AMC

AMC

AMC

Zo

ne

1Z

on

e 2

Zo

ne

3

DSP

25 x 25

DSP

25 x 25

DSP

25 x 25

ATC210Main power

regulator

M M

M M

M M

M MMM

M MM M

M MM M

Powerreg.

Powerreg.

Powerreg.

Powerreg.

Powerreg.

Powerreg.

MainframeFPGA

Powerreg.

Powerreg.

Powerreg.

clk

PCIe

switch

clk

Gbitswitch

clk

User FPGA

FF1513


WP10.7 SCRF gun at ELBE

• Installation of an energy spectrometer in the ELBE beam line for slice diagnostics and slice emittance measurements for different emittance compensation schemes.

• Design, build and test the set-up for preparation and application of GaAs photo cathodes in the SRF-Gun.

• Evaluation of critical R&D issues of SRF guns like photocathode compatibility, advanced emittance compensation and application as a high-brightness polarized electron source.


WP10.7 Deliverables

10.7.1 Results of slice measurements R M24

10.7.2 Results for GaAs photocathodes R M33


EUCard - FZD


Superconducting RF Photo Gun at ELBE

Unique test bench for SRF gun studies


1. New diagnostics: Slice emittance

2. Upgrade of cathode preparation & transfer system for GaAs photo cathodes

3. Study of photo cathodes (CsTe + alternative GaAs) in SRF Gun

4. Improved high-gradient cavity for SRF gun funding by German government


Photo cathode preparation lab at FZD

Motivation:GaAs cathodes in a SCRF gun could producehigh-brightness & polarized electron beams- injector with low emittance for ILC

cathode transfer system

SRF gun has sufficient vacuum (cryo pump) Modification of the preparation system Cs2Te -> GaAsVacuum improvement 10-9 mbar -> 10-11 mbar


WP10.8 Coupler Development at LAL

• Cleaning, HP rinsing and tests results on samples copper plated ad TiN coated ceramics.

• Argon discharge cleaning measurements and coupler test

• Realization of a system for automatic couplers cleaning


WP10.8 Deliverables

10.8.1Test and operation of the upgraded

coupler coating bench and coupler processing stations at LAL-Orsay

R M36


TTF-III: DESY design

TTF-V (LAL): based on TTF-III design

TW60: LAL design

Conditioning & multipacting studies on TTF-III couplers (prototypes for XFEL)

Power coupler prototypes: TTF-V & TW60

Titanium-Nitride (TiN) sputtering technology against multipacting on coupler ceramic windows

TiN sputtering machine

OutlineOutline


TTF-V RF conditioning

TTF-V coupler pair assembled for the RF tests

Easy conditioning in 24 h only

Next step:

A TTF-V coupler pair will be conditioned at KEK following their conditioning procedure for ILC couplers (January 2009)

TTF-V coupler RF conditioningTTF-V coupler RF conditioning

Published in LINAC’08 (2008)

S21

-40

-35

-30

-25

-20

-15

-10

-5

0

1,280E+09 1,284E+09 1,288E+09 1,292E+09 1,296E+09 1,300E+09 1,304E+09 1,308E+09 1,312E+09 1,316E+09 1,320E+09

S11

S22

S12

S21

Frequency (GHz)

(dB)

1.3 GHz

-30 dB

-35 dB

Low level RF measurements

(TTF-V pair)


Sample holder

Sample of ceramic window

Titanium target

Magnetron

The sputtering machine

Sputtering machine overview

Sample pretreatment: RF Etching

Reactive magnetron sputtering of TiN


WP10SRF: SC RF technology for higher intensity proton

accelerators & higher energy electron linacs

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D.Proch EuCARD kick-off, CERN,Dec.08 WP10 SRF: SC RF technology for higher intensity proton...

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