SRF2015 - List of Authors (Li, Z.)

Paper	Title	Page
THPB007	A Study of Resonant Excitation of Longitudinal HOMs in the Cryomodules of LCLS-II	1073
	K.L.F. Bane, C. Adolphsen, A. Chao, Z. Li SLAC, Menlo Park, California, USA
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 The Linac Coherent Light Source (LCLS) at SLAC, the world's first hard X-ray FEL, is being upgraded to the LCLS-II. The major new feature will be the installation of 35 cryomodules (CMs) of TESLA-type, superconducting accelerating structures. It is envisioned that LCLS-II will eventually be able to deliver 300 pC, 1 kA pulses of beam at a rate of 1 MHz. At a cavity temperature of 2K, any heat generated (even on the level of a few watts) is expensive to remove. In the last linac of LCLS-II, L3–-where the peak current is highest–-the power radiated by the bunch in the CMs is estimated at 14 W (charge 300 pC option, rep rate 1 MHz). But this calculation ignores resonances that can be excited between the bunch frequency and higher order mode (HOM) frequencies in the CMs, which in principle can greatly increase this number. In this report we develop a theory of resonant build up. Then, using 500 numerically obtained modes over the frequency range 3–5 GHz, we estimate the probability of significant resonant build up in L3 of LCLS-II. The effects of small random bunch phase and charge errors will also be addressed.
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THPB008	RF Simulations for an LCLS-II 3rd Harmonic Cavity Cyromodule	1078
	L. Xiao, C. Adolphsen, Z. Li, T.O. Raubenheimer SLAC, Menlo Park, California, USA
	The FNAL designed 3.9 GHz third harmonic cavity for XFEL will be used in LCLS-II for linearizing the longitudinal beam profile. The 3.9 GHz SRF cavity is scaled down from the 1.3 GHz TESLA cavity shape, but has a disproportionately large beampipe radius for better higher-order mode (HOM) damping. The HOM and fundamental power (FPC) couplers will generate asymmetric field in the beam region, and thereby dilute the beam emittance. Meanwhile, due to the large beampipe, all but a few of the HOMs are above the beampipe cutoff. Thus the HOM damping analyses need to be performed in a full cryomodule, rather than in an individual cavity. The HOM damping in a 4-cavity cryomodule was investigated to determine possible trapped modes using the parallel electromagnetic code suite ACE3P developed at SLAC. The coupler RF kicks induced by the HOM and FPC couplers in the 3.9 GHz cavity were evaluated. A possible cavity-to-cavity arrangement is proposed which could provide effective cancellation of these RF kicks. In this paper we present and discuss the RF simulation results in the 3.9 GHz third harmonic cavity cryomodule. Work supported by Department of Energy under contract Number DE-AC02-76SF00515.
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THPB052	Thermal Losses in Couplers and Ports of a SPS Double-Quarter Wave Crab Cavity	1219
	S. Verdú-Andrés, S.A. Belomestnykh, Q. Wu, B. P. Xiao BNL, Upton, Long Island, New York, USA S.A. Belomestnykh Stony Brook University, Stony Brook, USA G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom G. Burt Lancaster University, Lancaster, United Kingdom R. Calaga, O. Capatina, F. Carra, C. Zanoni CERN, Geneva, Switzerland F. Carra Politecnico di Torino, Torino, Italy T.J. Jones STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom Z. Li SLAC, Menlo Park, California, USA
	Funding: Supported by US DOE via US LARP, through BSA LLC under contract No. DE-AC02-98CH10886 and using NERSC resources under contract No. DE-AC02-05CH11231. Also supported by EU FP7 HiLumi LHC No.284404. The Double-Quarter Wave Crab Cavity for beam tests at SPS will be equipped with a Fundamental Power Coupler (FPC), three HOM filters and one pickup. FPC and HOM couplers are located in high magnetic field region and have a hook shape. The FPC will be made in copper while HOM and pickup are in niobium. This paper explains the material choice for the FPC, HOM and pickup couplers given the calculated power dissipation for fundamental and selected high order modes. It also describes the envisaged cooling system and corresponding thermal distribution for each coupler.
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THPB053	Electromagnetic Design of 400 MHz RF-Dipole Crabbing Cavity for LHC High Luminosity Upgrade	1222
	S.U. De Silva, J.R. Delayen, H. Park ODU, Norfolk, Virginia, USA Z. Li SLAC, Menlo Park, California, USA
	The beam crabbing proposed for the LHC High Luminosity Upgrade requires two crabbing systems operating in both horizontal and vertical planes. In addition, the crabbing cavity design needs to meet strict dimensional constraints and functional specifications of the cavities. This paper presents the detailed electromagnetic design including em properties, multipole analysis, multipacting levels of the 400 MHz rf-dipole crabbing cavity.
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THPB069	Engineering Design and Prototype Fabrication of HOM Couplers for HL-LHC Crab Cavities	1279
	C. Zanoni, S. Atieh, I. Aviles Santillana, R. Calaga, O. Capatina, T. Capelli, F. Carra, P. Freijedo Menendez, M. Garlaschè, J.-M. Geisser, R. Leuxe, L. Marques Antunes Ferreira, E. Rigutto CERN, Geneva, Switzerland S.A. Belomestnykh, S. Verdú-Andrés, Q. Wu, B. P. Xiao BNL, Upton, Long Island, New York, USA G. Burt Lancaster University, Lancaster, United Kingdom S.U. De Silva, J.R. Delayen, R.G. Olave, H. Park ODU, Norfolk, Virginia, USA T.J. Jones, N. Templeton STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom Z. Li SLAC, Menlo Park, California, USA A.J. May, S.M. Pattalwar STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom T.H. Nicol Fermilab, Batavia, Illinois, USA A. Ratti LBNL, Berkeley, California, USA
	The High-Luminosity upgrade for the LHC relies on a set of RF Crab Cavities for reaching its goals. Two parallel concepts, the Double Quarter Wave (DQW) and the RF Dipole (RFD), are going through a comprehensive design process along with preparation of fabrication in view of extensive tests with beam in SPS. High Order Modes (HOM) couplers are critical in providing damping in RF cavities for operation in accelerators. HOM prototyping and fabrication have recently started at CERN. In this paper, an overview of the final shape is provided along with an insight in the mechanical and thermal analyses performed to validate the design of these critical components. Emphasis is also given to test campaigns, material selection, prototyping and initial fabrication that are aimed at fulfilling the highly demanding tolerances of the couplers.
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THPB070	Design of Dressed Crab Cavities for the HL-LHC Upgrade	1284
	C. Zanoni, K. Artoos, S. Atieh, I. Aviles Santillana, J.P. Brachet, R. Calaga, O. Capatina, T. Capelli, F. Carra, L. Dassa, G. Favre, P. Freijedo Menendez, M. Garlaschè, M. Guinchard, N. Kuder, S.A.E. Langeslag, R. Leuxe, L. Prever-Loiri, G. Vandoni CERN, Geneva, Switzerland S.A. Belomestnykh, I. Ben-Zvi, S. Verdú-Andrés, Q. Wu, B. P. Xiao BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA G. Burt Lancaster University, Lancaster, United Kingdom S.U. De Silva, R.G. Olave, H. Park ODU, Norfolk, Virginia, USA J.R. Delayen JLab, Newport News, Virginia, USA T.J. Jones, N. Templeton STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom Z. Li SLAC, Menlo Park, California, USA K.B. Marinov, A.J. May, S.M. Pattalwar STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom T.H. Nicol Fermilab, Batavia, Illinois, USA A. Ratti LBNL, Berkeley, California, USA
	The HL-LHC upgrade relies on a set of RF crab cavities for reaching its goals. Two parallel concepts, the Double Quarter Wave (DQW) and the RF Dipole (RFD), are going through a comprehensive design process along with preparation of fabrication in view of extensive tests with beam in SPS. High Order Modes (HOM) couplers are critical in providing damping in RF cavities for operation in accelerators. HOM prototyping and fabrication have recently started at CERN. In this paper, an overview of the final geometry is provided along with an insight in the mechanical and thermal analyses performed to validate the design of this critical component. Emphasis is also given to material selection, prototyping, initial fabrication and test campaigns that are aimed at fulfilling the highly demanding tolerances of the couplers.
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THPB077	Modified TTF3 Couplers for LCLS-II	1306
	C. Adolphsen, K. Fant, Z. Li, C.D. Nantista, G. Stupakov, J. Tice, F.Y. Wang, L. Xiao SLAC, Menlo Park, California, USA I.V. Gonin, K. Premo, N. Solyak Fermilab, Batavia, Illinois, USA
	The LCLS-II 4 GeV SC electron linac will use 280 TESLA cavities and TTF3 couplers, modified for CW operation with input power up to about 7 kW. The coupler modifications include shortening the antenna to achieve higher Qext and thickening the copper plating on the warm section inner conductor to lower the peak temperature. Another change is the use a waveguide transition box that is machined out of a solid piece of aluminum, significantly reducing its cost and improving its fit to the warm coupler window section. This paper describes the changes, simulations of the coupler operation (heat loads and temperatures), rf processing results and CW tests with LCLS-II dressed cavities.
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THPB081	FPC and HOM Coupler Test Boxes for HL-LHC Crab Cavities	1321
	A.R.J. Tutte, G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom R. Calaga, A. Macpherson, E. Montesinos CERN, Geneva, Switzerland S.U. De Silva ODU, Norfolk, Virginia, USA Z. Li SLAC, Menlo Park, California, USA B. P. Xiao BNL, Upton, Long Island, New York, USA
	The LHC luminosity upgrade will involve the installation of thirty-two 400 MHz SRF crab cavities. The cavities have two variants known as the RF dipole and double quarter-wave crab cavities. Each cavity has a fundamental power coupler (FPC) at 400 MHz and two or three HOM couplers. Before integration onto the cavities it is necessary to condition the FPC, and to measure the transmission on the HOM couplers at low power to ensure the operate as designed, each requiring a special test box. The FPC test box should provide a high transmission between two couplers without creating high surface fields. The low power HOM test boxes should be terminated to a load such that the natural stop and pass-bands of the couplers are preserved allowing the reflection to me measured and compared to simulations. In addition, due to the possibility of high HOM power in the LHC crab cavities, the concept of creating a broadband high power HOM coupler test box in order to condition and test the couplers at high power has been investigated. The Rf design of all test boxes is presented and discussed.
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FRBA02	Crab Cavity and Cryomodule Development for HL-LHC	1460
	F. Carra, A. Amorim Carvalho, K. Artoos, S. Atieh, I. Aviles Santillana, A.B. Boucherie, J.P. Brachet, K. Brodzinski, R. Calaga, O. Capatina, T. Capelli, L. Dassa, T. Dijoud, H.M. Durand, G. Favre, L.M.A. Ferreira, P. Freijedo Menendez, M. Garlaschè, M. Guinchard, N. Kuder, S.A.E. Langeslag, R. Leuxe, A. Macpherson, P. Minginette, E. Montesinos, F. Motschmann, C. Parente, L. Prever-Loiri, D. Pugnat, E. Rigutto, V. Rude, M. Sosin, G. Vandoni, G. Villiger, C. Zanoni CERN, Geneva, Switzerland S.A. Belomestnykh, S. Verdú-Andrés, Q. Wu, B. P. Xiao BNL, Upton, Long Island, New York, USA G. Burt Lancaster University, Lancaster, United Kingdom S.U. De Silva, J.R. Delayen, R.G. Olave, R.G. Olave, H. Park ODU, Norfolk, Virginia, USA T.J. Jones, N. Templeton STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom Z. Li SLAC, Menlo Park, California, USA K.B. Marinov, S.M. Pattalwar STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom T.H. Nicol Fermilab, Batavia, Illinois, USA A. Ratti LBNL, Berkeley, California, USA
	The HL-LHC project aims at increasing the LHC luminosity by a factor 10 beyond the design value. The installation of a set of RF Crab Cavities to increase bunch crossing angle is one of the key upgrades of the program. Two concepts, Double Quarter Wave (DQW) and RF Dipole (RFD) have been proposed and are being produced in parallel for test in the SPS beam before the next long shutdown of CERN accelerator’s complex. In the retained concept, two cavities are hosted in one single cryomodule, providing thermal insulation and interfacing with RF coupling, tuning, cryogenics and beam vacuum. This paper overviews the main design choices for the cryomodule and its different components, which have the goal of optimizing the structural, thermal and electro-magnetic behavior of the system, while respecting the existing constraints in terms of integration in the accelerator environment. Prototyping and testing of the most critical components, manufacturing, preparation and installation strategies are also described.
	Slides FRBA02 [4.678 MB]
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Paper

Title

Page

A Study of Resonant Excitation of Longitudinal HOMs in the Cryomodules of LCLS-II

1073

K.L.F. Bane, C. Adolphsen, A. Chao, Z. Li
SLAC, Menlo Park, California, USA

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515
The Linac Coherent Light Source (LCLS) at SLAC, the world's first hard X-ray FEL, is being upgraded to the LCLS-II. The major new feature will be the installation of 35 cryomodules (CMs) of TESLA-type, superconducting accelerating structures. It is envisioned that LCLS-II will eventually be able to deliver 300 pC, 1 kA pulses of beam at a rate of 1 MHz. At a cavity temperature of 2K, any heat generated (even on the level of a few watts) is expensive to remove. In the last linac of LCLS-II, L3–-where the peak current is highest–-the power radiated by the bunch in the CMs is estimated at 14 W (charge 300 pC option, rep rate 1 MHz). But this calculation ignores resonances that can be excited between the bunch frequency and higher order mode (HOM) frequencies in the CMs, which in principle can greatly increase this number. In this report we develop a theory of resonant build up. Then, using 500 numerically obtained modes over the frequency range 3–5 GHz, we estimate the probability of significant resonant build up in L3 of LCLS-II. The effects of small random bunch phase and charge errors will also be addressed.

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THPB008

RF Simulations for an LCLS-II 3rd Harmonic Cavity Cyromodule

1078

L. Xiao, C. Adolphsen, Z. Li, T.O. Raubenheimer
SLAC, Menlo Park, California, USA

The FNAL designed 3.9 GHz third harmonic cavity for XFEL will be used in LCLS-II for linearizing the longitudinal beam profile. The 3.9 GHz SRF cavity is scaled down from the 1.3 GHz TESLA cavity shape, but has a disproportionately large beampipe radius for better higher-order mode (HOM) damping. The HOM and fundamental power (FPC) couplers will generate asymmetric field in the beam region, and thereby dilute the beam emittance. Meanwhile, due to the large beampipe, all but a few of the HOMs are above the beampipe cutoff. Thus the HOM damping analyses need to be performed in a full cryomodule, rather than in an individual cavity. The HOM damping in a 4-cavity cryomodule was investigated to determine possible trapped modes using the parallel electromagnetic code suite ACE3P developed at SLAC. The coupler RF kicks induced by the HOM and FPC couplers in the 3.9 GHz cavity were evaluated. A possible cavity-to-cavity arrangement is proposed which could provide effective cancellation of these RF kicks. In this paper we present and discuss the RF simulation results in the 3.9 GHz third harmonic cavity cryomodule.
Work supported by Department of Energy under contract Number DE-AC02-76SF00515.

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THPB052

Thermal Losses in Couplers and Ports of a SPS Double-Quarter Wave Crab Cavity

1219

S. Verdú-Andrés, S.A. Belomestnykh, Q. Wu, B. P. Xiao
BNL, Upton, Long Island, New York, USA
S.A. Belomestnykh
Stony Brook University, Stony Brook, USA
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
G. Burt
Lancaster University, Lancaster, United Kingdom
R. Calaga, O. Capatina, F. Carra, C. Zanoni
CERN, Geneva, Switzerland
F. Carra
Politecnico di Torino, Torino, Italy
T.J. Jones
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
Z. Li
SLAC, Menlo Park, California, USA

Funding: Supported by US DOE via US LARP, through BSA LLC under contract No. DE-AC02-98CH10886 and using NERSC resources under contract No. DE-AC02-05CH11231. Also supported by EU FP7 HiLumi LHC No.284404.
The Double-Quarter Wave Crab Cavity for beam tests at SPS will be equipped with a Fundamental Power Coupler (FPC), three HOM filters and one pickup. FPC and HOM couplers are located in high magnetic field region and have a hook shape. The FPC will be made in copper while HOM and pickup are in niobium. This paper explains the material choice for the FPC, HOM and pickup couplers given the calculated power dissipation for fundamental and selected high order modes. It also describes the envisaged cooling system and corresponding thermal distribution for each coupler.

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THPB053

Electromagnetic Design of 400 MHz RF-Dipole Crabbing Cavity for LHC High Luminosity Upgrade

1222

S.U. De Silva, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA
Z. Li
SLAC, Menlo Park, California, USA

The beam crabbing proposed for the LHC High Luminosity Upgrade requires two crabbing systems operating in both horizontal and vertical planes. In addition, the crabbing cavity design needs to meet strict dimensional constraints and functional specifications of the cavities. This paper presents the detailed electromagnetic design including em properties, multipole analysis, multipacting levels of the 400 MHz rf-dipole crabbing cavity.

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THPB069

Engineering Design and Prototype Fabrication of HOM Couplers for HL-LHC Crab Cavities

1279

C. Zanoni, S. Atieh, I. Aviles Santillana, R. Calaga, O. Capatina, T. Capelli, F. Carra, P. Freijedo Menendez, M. Garlaschè, J.-M. Geisser, R. Leuxe, L. Marques Antunes Ferreira, E. Rigutto
CERN, Geneva, Switzerland
S.A. Belomestnykh, S. Verdú-Andrés, Q. Wu, B. P. Xiao
BNL, Upton, Long Island, New York, USA
G. Burt
Lancaster University, Lancaster, United Kingdom
S.U. De Silva, J.R. Delayen, R.G. Olave, H. Park
ODU, Norfolk, Virginia, USA
T.J. Jones, N. Templeton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
Z. Li
SLAC, Menlo Park, California, USA
A.J. May, S.M. Pattalwar
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
T.H. Nicol
Fermilab, Batavia, Illinois, USA
A. Ratti
LBNL, Berkeley, California, USA

The High-Luminosity upgrade for the LHC relies on a set of RF Crab Cavities for reaching its goals. Two parallel concepts, the Double Quarter Wave (DQW) and the RF Dipole (RFD), are going through a comprehensive design process along with preparation of fabrication in view of extensive tests with beam in SPS. High Order Modes (HOM) couplers are critical in providing damping in RF cavities for operation in accelerators. HOM prototyping and fabrication have recently started at CERN. In this paper, an overview of the final shape is provided along with an insight in the mechanical and thermal analyses performed to validate the design of these critical components. Emphasis is also given to test campaigns, material selection, prototyping and initial fabrication that are aimed at fulfilling the highly demanding tolerances of the couplers.

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THPB070

Design of Dressed Crab Cavities for the HL-LHC Upgrade

1284

C. Zanoni, K. Artoos, S. Atieh, I. Aviles Santillana, J.P. Brachet, R. Calaga, O. Capatina, T. Capelli, F. Carra, L. Dassa, G. Favre, P. Freijedo Menendez, M. Garlaschè, M. Guinchard, N. Kuder, S.A.E. Langeslag, R. Leuxe, L. Prever-Loiri, G. Vandoni
CERN, Geneva, Switzerland
S.A. Belomestnykh, I. Ben-Zvi, S. Verdú-Andrés, Q. Wu, B. P. Xiao
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA
G. Burt
Lancaster University, Lancaster, United Kingdom
S.U. De Silva, R.G. Olave, H. Park
ODU, Norfolk, Virginia, USA
J.R. Delayen
JLab, Newport News, Virginia, USA
T.J. Jones, N. Templeton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
Z. Li
SLAC, Menlo Park, California, USA
K.B. Marinov, A.J. May, S.M. Pattalwar
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
T.H. Nicol
Fermilab, Batavia, Illinois, USA
A. Ratti
LBNL, Berkeley, California, USA

The HL-LHC upgrade relies on a set of RF crab cavities for reaching its goals. Two parallel concepts, the Double Quarter Wave (DQW) and the RF Dipole (RFD), are going through a comprehensive design process along with preparation of fabrication in view of extensive tests with beam in SPS. High Order Modes (HOM) couplers are critical in providing damping in RF cavities for operation in accelerators. HOM prototyping and fabrication have recently started at CERN. In this paper, an overview of the final geometry is provided along with an insight in the mechanical and thermal analyses performed to validate the design of this critical component. Emphasis is also given to material selection, prototyping, initial fabrication and test campaigns that are aimed at fulfilling the highly demanding tolerances of the couplers.

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THPB077

Modified TTF3 Couplers for LCLS-II

1306

C. Adolphsen, K. Fant, Z. Li, C.D. Nantista, G. Stupakov, J. Tice, F.Y. Wang, L. Xiao
SLAC, Menlo Park, California, USA
I.V. Gonin, K. Premo, N. Solyak
Fermilab, Batavia, Illinois, USA

The LCLS-II 4 GeV SC electron linac will use 280 TESLA cavities and TTF3 couplers, modified for CW operation with input power up to about 7 kW. The coupler modifications include shortening the antenna to achieve higher Qext and thickening the copper plating on the warm section inner conductor to lower the peak temperature. Another change is the use a waveguide transition box that is machined out of a solid piece of aluminum, significantly reducing its cost and improving its fit to the warm coupler window section. This paper describes the changes, simulations of the coupler operation (heat loads and temperatures), rf processing results and CW tests with LCLS-II dressed cavities.

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THPB081

FPC and HOM Coupler Test Boxes for HL-LHC Crab Cavities

1321

A.R.J. Tutte, G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R. Calaga, A. Macpherson, E. Montesinos
CERN, Geneva, Switzerland
S.U. De Silva
ODU, Norfolk, Virginia, USA
Z. Li
SLAC, Menlo Park, California, USA
B. P. Xiao
BNL, Upton, Long Island, New York, USA

The LHC luminosity upgrade will involve the installation of thirty-two 400 MHz SRF crab cavities. The cavities have two variants known as the RF dipole and double quarter-wave crab cavities. Each cavity has a fundamental power coupler (FPC) at 400 MHz and two or three HOM couplers. Before integration onto the cavities it is necessary to condition the FPC, and to measure the transmission on the HOM couplers at low power to ensure the operate as designed, each requiring a special test box. The FPC test box should provide a high transmission between two couplers without creating high surface fields. The low power HOM test boxes should be terminated to a load such that the natural stop and pass-bands of the couplers are preserved allowing the reflection to me measured and compared to simulations. In addition, due to the possibility of high HOM power in the LHC crab cavities, the concept of creating a broadband high power HOM coupler test box in order to condition and test the couplers at high power has been investigated. The Rf design of all test boxes is presented and discussed.

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FRBA02

Crab Cavity and Cryomodule Development for HL-LHC

1460

F. Carra, A. Amorim Carvalho, K. Artoos, S. Atieh, I. Aviles Santillana, A.B. Boucherie, J.P. Brachet, K. Brodzinski, R. Calaga, O. Capatina, T. Capelli, L. Dassa, T. Dijoud, H.M. Durand, G. Favre, L.M.A. Ferreira, P. Freijedo Menendez, M. Garlaschè, M. Guinchard, N. Kuder, S.A.E. Langeslag, R. Leuxe, A. Macpherson, P. Minginette, E. Montesinos, F. Motschmann, C. Parente, L. Prever-Loiri, D. Pugnat, E. Rigutto, V. Rude, M. Sosin, G. Vandoni, G. Villiger, C. Zanoni
CERN, Geneva, Switzerland
S.A. Belomestnykh, S. Verdú-Andrés, Q. Wu, B. P. Xiao
BNL, Upton, Long Island, New York, USA
G. Burt
Lancaster University, Lancaster, United Kingdom
S.U. De Silva, J.R. Delayen, R.G. Olave, R.G. Olave, H. Park
ODU, Norfolk, Virginia, USA
T.J. Jones, N. Templeton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
Z. Li
SLAC, Menlo Park, California, USA
K.B. Marinov, S.M. Pattalwar
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
T.H. Nicol
Fermilab, Batavia, Illinois, USA
A. Ratti
LBNL, Berkeley, California, USA

The HL-LHC project aims at increasing the LHC luminosity by a factor 10 beyond the design value. The installation of a set of RF Crab Cavities to increase bunch crossing angle is one of the key upgrades of the program. Two concepts, Double Quarter Wave (DQW) and RF Dipole (RFD) have been proposed and are being produced in parallel for test in the SPS beam before the next long shutdown of CERN accelerator’s complex. In the retained concept, two cavities are hosted in one single cryomodule, providing thermal insulation and interfacing with RF coupling, tuning, cryogenics and beam vacuum. This paper overviews the main design choices for the cryomodule and its different components, which have the goal of optimizing the structural, thermal and electro-magnetic behavior of the system, while respecting the existing constraints in terms of integration in the accelerator environment. Prototyping and testing of the most critical components, manufacturing, preparation and installation strategies are also described.

Slides FRBA02 [4.678 MB]

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