IPAC2017 - List of Authors (Calaga, R.)

Paper	Title	Page
MOPVA095	First RF Performance Results for the DQW Crab Cavities to be Tested in the CERN SPS	1077
	A. Castilla, R. Calaga, O. Capatina, K.M. Dr. Schirm, K.G. Hernández-Chahín, A. Macpherson, N.C. Shipman, K. Turaj CERN, Geneva, Switzerland I. Ben-Zvi BNL, Upton, Long Island, New York, USA G. Burt, J.A. Mitchell Lancaster University, Lancaster, United Kingdom K.G. Hernández-Chahín DCI-UG, León, Mexico N.C. Shipman Cockcroft Institute, Lancaster University, Lancaster, United Kingdom N.C. Shipman UMAN, Manchester, United Kingdom
	As part of the High Luminosity LHC (HL-LHC) project strategy, crab cavity correctors shall be installed around CMS and ATLAS experiments of the LHC. To accommodate the different crossing angle planes, two distinct cavity designs have been selected: the RF Dipole (RFD) and the Double Quarter Wave resonator (DQW). CERN has fabricated two double quarter wave resonators (DQW_SPS), for validation with a proton beam at the CERN SPS accelerator. Standard superconducting rf surface preparation protocols have been applied to the two bulk niobium cavities, followed by cryogenic testing in a vertical cryostat at CERN's SM18 facility. The performance results obtained after the first bare cavity tests for cavities DQW_SPS₀01 and DQW_SPS₀02 are shown in this paper, and include Q0 vs Vt curves, Lorentz Force Detuning (LFD) analyses and pressure sensitivity of a higher order mode.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA095
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MOPVA096	The Crab Cavities Cryomodule for SPS Test	1081
	C. Zanoni, A. Amorim Carvalho, K. Artoos, S. Atieh, K. Brodzinski, R. Calaga, O. Capatina, T. Capelli, F. Carra, L. Dassa, T. Dijoud, K. Eiler, G. Favre, P. Freijedo Menendez, M. Garlaschè, L. Giordanino, S.A.E. Langeslag, R. Leuxe, H. Mainaud Durand, P. Minginette, M. Narduzzi, V. Rude, M. Sosin, J.S. Swieszek CERN, Geneva, Switzerland T.J. Jones, N. Templeton STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
	RF Crab Cavities are an essential part of the HL-LHC upgrade. Two concepts of such systems are being developed: the Double Quarter Wave (DQW) and the RF Dipole (RFD). A cryomodule with two DQW cavities is in advanced fabrication stage at CERN for their tests with protons in the SPS during the 2018 run. The cavities must be operated at 2 K, without excessive heat loads, in a low magnetic environment and in compliance with CERN safety guidelines on pressure and vacuum systems. A large set of components, such as a thermal shield, a two layers magnetic shield, RF lines, helium tank and tuner is required for the successful and safe operation of the cavities. The assembly of all these components with the cavities and their couplers forms the cryomodule. An overview of the design and fabrication strategy of this cryomodule is presented. The main components are described along with the present status of cavity fabrication and processing and cryomodule assembly. The lesson learned from the prototypes, the helium tank above all, and first manufactured systems is also included.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA096
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TUPVA008	Assessment of Thermal Loads in the CERN SPS Crab Cavities Cryomodule	2047
	F. Carra, J. Apeland, R. Calaga, O. Capatina, T. Capelli, C. Zanoni CERN, Geneva, Switzerland S. Verdú-Andrés BNL, Upton, Long Island, New York, USA
	Funding: Work supported by the European Union HL-LHC Project and by US DOE through Brookhaven Science Associates LLC under contract No. DE-AC02-98CH10886 and the US LHC Accelerator Research Program (LARP). Research supported by the HL-LHC project. As a part of the HL-LHC upgrade, a cryomodule is designed to host two crab cavities for a first test with protons in the SPS machine. The evaluation of the cryomodule heat loads is essential to dimension the cryogenic infrastructure of the system. The current design features two cryogenic circuits. The first circuit adopts superfluid helium at 2 K to maintain the cavities in the superconducting state. The second circuit, based on helium gas at a temperature between 50 K and 70 K, is connected to the thermal screen, also serving as heat intercept for all the interfaces between the cold mass and the external environment. An overview of the heat loads to both circuits, and the combined numerical and analytical estimations, is presented. The heat load of each element is detailed for the static and dynamic scenarios, with considerations on the design choices for the thermal optimization of the most critical components. #Federico.carra@cern.ch*
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA008
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TUPVA034	SPS Studies in Preparation for the Crab Cavity Experiment	2133
	A. Alekou, A. Alekou, F. Antoniou, F. Antoniou, G. Arduini, G. Arduini, H. Bartosik, H. Bartosik, R. Calaga, R. Calaga, Y. Papaphilippou, Y. Papaphilippou, Y. Papaphilippou CERN, Geneva, Switzerland A. Alekou, R.B. Appleby, R.B. Appleby UMAN, Manchester, United Kingdom R.B. Appleby, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	A local Crab Cavity (CC) scheme will recover head-on collisions at the Interaction Points (IPs) of the High Luminosity LHC (HL-LHC), which aims to increase the LHC luminosity by a factor of 3-10. The first time that CC will ever be tested with proton beams will be in 2018 in the SPS machine. The available dedicated Machine Development (MD) time after the installation of the cavities will be limited and therefore good preparation is essential in order to ensure that the MDs are as efficient as possible. This paper presents the simulations and experimental studies performed in preparation for the future MDs and discusses the next steps.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA034
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WEYA1	Crab Cavity Systems for Future Colliders	2474
	S. Verdú-Andrés, I. Ben-Zvi, Q. Wu BNL, Upton, Long Island, New York, USA I. Ben-Zvi Stony Brook University, Stony Brook, USA R. Calaga CERN, Geneva, Switzerland
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy, by the US LARP program and by the HL-LHC project. KEKB was the first facility to implement the crab crossing technique in 2007, for the interaction of electron and positron beams. The High Luminosity Large Hadron Collider (HL-LHC) project envisages the use of crab cavities for increasing and levelling the luminosity of proton-proton collisions in LHC. Crab cavities have also been proposed and studied for future colliders like CLIC, ILC and eRHIC. This contribution will focus on the near and far future of crab cavities for particle colliders.
	Slides WEYA1 [6.571 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEYA1
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THPAB057	Method to Calculate the Longitudinal Impedance From a Partial Wakefield Simulation	3844
	N.C. Shipman UMAN, Manchester, United Kingdom G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom R. Calaga CERN, Geneva, Switzerland J.A. Mitchell Lancaster University, Lancaster, United Kingdom
	When simulating modes with high Q-factors, the wakefield length necessary to calculate the impedance spectrum can often mean a computation time of several weeks or more. A method has been developed which enables the longitudinal impedance and Q-factors of multiple modes to be calculated from a partially decayed wakefield simulation. This paper presents an overview of the method along with preliminary, proof of principle, results showing that considerable simulation time can be saved whilst maintaining a good degree of accuracy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB057
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Paper

Title

Page

First RF Performance Results for the DQW Crab Cavities to be Tested in the CERN SPS

1077

A. Castilla, R. Calaga, O. Capatina, K.M. Dr. Schirm, K.G. Hernández-Chahín, A. Macpherson, N.C. Shipman, K. Turaj
CERN, Geneva, Switzerland
I. Ben-Zvi
BNL, Upton, Long Island, New York, USA
G. Burt, J.A. Mitchell
Lancaster University, Lancaster, United Kingdom
K.G. Hernández-Chahín
DCI-UG, León, Mexico
N.C. Shipman
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
N.C. Shipman
UMAN, Manchester, United Kingdom

As part of the High Luminosity LHC (HL-LHC) project strategy, crab cavity correctors shall be installed around CMS and ATLAS experiments of the LHC. To accommodate the different crossing angle planes, two distinct cavity designs have been selected: the RF Dipole (RFD) and the Double Quarter Wave resonator (DQW). CERN has fabricated two double quarter wave resonators (DQW_SPS), for validation with a proton beam at the CERN SPS accelerator. Standard superconducting rf surface preparation protocols have been applied to the two bulk niobium cavities, followed by cryogenic testing in a vertical cryostat at CERN's SM18 facility. The performance results obtained after the first bare cavity tests for cavities DQW_SPS₀01 and DQW_SPS₀02 are shown in this paper, and include Q0 vs Vt curves, Lorentz Force Detuning (LFD) analyses and pressure sensitivity of a higher order mode.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA095

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MOPVA096

The Crab Cavities Cryomodule for SPS Test

1081

C. Zanoni, A. Amorim Carvalho, K. Artoos, S. Atieh, K. Brodzinski, R. Calaga, O. Capatina, T. Capelli, F. Carra, L. Dassa, T. Dijoud, K. Eiler, G. Favre, P. Freijedo Menendez, M. Garlaschè, L. Giordanino, S.A.E. Langeslag, R. Leuxe, H. Mainaud Durand, P. Minginette, M. Narduzzi, V. Rude, M. Sosin, J.S. Swieszek
CERN, Geneva, Switzerland
T.J. Jones, N. Templeton
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

RF Crab Cavities are an essential part of the HL-LHC upgrade. Two concepts of such systems are being developed: the Double Quarter Wave (DQW) and the RF Dipole (RFD). A cryomodule with two DQW cavities is in advanced fabrication stage at CERN for their tests with protons in the SPS during the 2018 run. The cavities must be operated at 2 K, without excessive heat loads, in a low magnetic environment and in compliance with CERN safety guidelines on pressure and vacuum systems. A large set of components, such as a thermal shield, a two layers magnetic shield, RF lines, helium tank and tuner is required for the successful and safe operation of the cavities. The assembly of all these components with the cavities and their couplers forms the cryomodule. An overview of the design and fabrication strategy of this cryomodule is presented. The main components are described along with the present status of cavity fabrication and processing and cryomodule assembly. The lesson learned from the prototypes, the helium tank above all, and first manufactured systems is also included.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA096

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPVA008

Assessment of Thermal Loads in the CERN SPS Crab Cavities Cryomodule

2047

F. Carra, J. Apeland, R. Calaga, O. Capatina, T. Capelli, C. Zanoni
CERN, Geneva, Switzerland
S. Verdú-Andrés
BNL, Upton, Long Island, New York, USA

Funding: *Work supported by the European Union HL-LHC Project and by US DOE through Brookhaven Science Associates LLC under contract No. DE-AC02-98CH10886 and the US LHC Accelerator Research Program (LARP). Research supported by the HL-LHC project.
As a part of the HL-LHC upgrade, a cryomodule is designed to host two crab cavities for a first test with protons in the SPS machine. The evaluation of the cryomodule heat loads is essential to dimension the cryogenic infrastructure of the system. The current design features two cryogenic circuits. The first circuit adopts superfluid helium at 2 K to maintain the cavities in the superconducting state. The second circuit, based on helium gas at a temperature between 50 K and 70 K, is connected to the thermal screen, also serving as heat intercept for all the interfaces between the cold mass and the external environment. An overview of the heat loads to both circuits, and the combined numerical and analytical estimations, is presented. The heat load of each element is detailed for the static and dynamic scenarios, with considerations on the design choices for the thermal optimization of the most critical components.
#Federico.carra@cern.ch

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA008

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TUPVA034

SPS Studies in Preparation for the Crab Cavity Experiment

2133

A. Alekou, A. Alekou, F. Antoniou, F. Antoniou, G. Arduini, G. Arduini, H. Bartosik, H. Bartosik, R. Calaga, R. Calaga, Y. Papaphilippou, Y. Papaphilippou, Y. Papaphilippou
CERN, Geneva, Switzerland
A. Alekou, R.B. Appleby, R.B. Appleby
UMAN, Manchester, United Kingdom
R.B. Appleby, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

A local Crab Cavity (CC) scheme will recover head-on collisions at the Interaction Points (IPs) of the High Luminosity LHC (HL-LHC), which aims to increase the LHC luminosity by a factor of 3-10. The first time that CC will ever be tested with proton beams will be in 2018 in the SPS machine. The available dedicated Machine Development (MD) time after the installation of the cavities will be limited and therefore good preparation is essential in order to ensure that the MDs are as efficient as possible. This paper presents the simulations and experimental studies performed in preparation for the future MDs and discusses the next steps.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA034

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEYA1

Crab Cavity Systems for Future Colliders

2474

S. Verdú-Andrés, I. Ben-Zvi, Q. Wu
BNL, Upton, Long Island, New York, USA
I. Ben-Zvi
Stony Brook University, Stony Brook, USA
R. Calaga
CERN, Geneva, Switzerland

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy, by the US LARP program and by the HL-LHC project.
KEKB was the first facility to implement the crab crossing technique in 2007, for the interaction of electron and positron beams. The High Luminosity Large Hadron Collider (HL-LHC) project envisages the use of crab cavities for increasing and levelling the luminosity of proton-proton collisions in LHC. Crab cavities have also been proposed and studied for future colliders like CLIC, ILC and eRHIC. This contribution will focus on the near and far future of crab cavities for particle colliders.

Slides WEYA1 [6.571 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEYA1

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB057

Method to Calculate the Longitudinal Impedance From a Partial Wakefield Simulation

3844

N.C. Shipman
UMAN, Manchester, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R. Calaga
CERN, Geneva, Switzerland
J.A. Mitchell
Lancaster University, Lancaster, United Kingdom

When simulating modes with high Q-factors, the wakefield length necessary to calculate the impedance spectrum can often mean a computation time of several weeks or more. A method has been developed which enables the longitudinal impedance and Q-factors of multiple modes to be calculated from a partially decayed wakefield simulation. This paper presents an overview of the method along with preliminary, proof of principle, results showing that considerable simulation time can be saved whilst maintaining a good degree of accuracy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB057

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)