IPAC2014 - List of Authors (Barnes, M.J.)

Paper	Title	Page
MOPRO027	Measurements and Laboratory Tests on a Prototype Stripline Kicker for the CLIC Damping Rings	125
	C. Belver-Aguilar, A. Faus-Golfe IFIC, Valencia, Spain M.J. Barnes, H.A. Day CERN, Geneva, Switzerland F. Toral CIEMAT, Madrid, Spain
	The Pre-Damping Rings (PDRs) and Damping Rings (DRs) of CLIC are required to reduce the beam emittances to the small values required for the main linacs. The injection and extraction, from the PDRs and DRs, are performed by kicker systems. To achieve both low beam coupling impedance and reasonable broadband impedance matching to the electrical circuit, striplines have been chosen for the kicker elements. Prototype striplines have been built: tests and measurements of these striplines have started. The goal of these tests is to characterize, without beam, the electromagnetic response of the striplines. The tests have been carried out at CERN. To study the signal transmission through the striplines, the measured S-parameters have been compared with simulations. In addition, measurements of longitudinal beam coupling impedance, using the coaxial wire method, are reported and compared with simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO027
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO028	Measurements on Prototype Inductive Adders with Ultra-flat-top Output Pulses for CLIC DR Kickers	128
	J. Holma, M.J. Barnes CERN, Geneva, Switzerland C. Belver-Aguilar IFIC, Valencia, Spain
	The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the DR kicker systems must provide extremely flat, high-voltage, pulses. The specifications for the DR extraction kickers call for a 160 ns duration flat-top pulses of ±12.5 kV, 250 A, with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meeting the specifications because this topology allows the use of both passive and analogue modulation methods to adjust the output waveform. Recently, two five-layer, 3.5 kV, prototype inductive adders have been built at CERN. The first of these has been used to test the passive and active analogue modulation methods to compensate voltage droop and ripple of the output pulses. Pulse waveforms have been recorded with ±0.05 % relative (±1.0 V) stability for 160 ns flat-top duration at 1.823 kV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO028
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO032	Upgrades to the LHC Injection and Beam Dumping Systems for the HL-LHC Project	141
	J.A. Uythoven, M.J. Barnes, B. Goddard, J. Hrivnak, A. Lechner, F.L. Maciariello, A. Mereghetti, A. Perillo Marcone, N.V. Shetty, G.E. Steele CERN, Geneva, Switzerland
	The HL-LHC project will push the performance of the LHC injection and beam dumping systems towards new limits. This paper describes the systems affected and presents the new beam parameters for these systems. It also describes the studies to be performed to determine which sub-components of these systems need to be upgraded to fulfill the new HL-LHC requirements. The results from the preliminary upgrade studies for the injection absorbers TDI are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO032
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME074	High Voltage Performance of the Beam Screen of the LHC Injection Kicker Magnets	541
	M.J. Barnes, P. Adraktas, G. Bregliozzi, S. Calatroni, P. Costa Pinto, H.A. Day, L. Ducimetière, V. Gomes Namora, T. Kramer, V. Mertens, M. Taborelli CERN, Geneva, Switzerland
	The LHC injection kicker magnets include beam screens to shield the ferrite yokes against wakefields resulting from the high intensity beam. The screening is provided by conductors lodged in the inner wall of a ceramic support tube. The design of the beam screen has been upgraded to overcome limitations and permit LHC operation with increasingly higher bunch intensity and short bunch lengths: the new design also significantly reduces the electric field associated with the screen conductors, decreasing the probability of electrical breakdown. The high voltage conditioning process for the upgraded kicker magnets is presented and discussed. In addition a test setup has been utilized to study flashover, on the inner wall of the ceramic tube, as a function of both applied voltage and vacuum pressure: results from the test setup are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME074
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPME075	Cooling of the LHC Injection Kicker Magnet Ferrite Yoke: Measurements and Future Proposals	544
	M.J. Barnes, S. Bouleghlimat, L. Ducimetière, M. Garlaschè, V. Gomes Namora, T. Kramer, R. Noulibos, Y. Sillanoli, Z.K. Sobiech, W.J.M. Weterings CERN, Geneva, Switzerland
	LHC operation with high intensity beam, stable for many hours, resulted in significant heating of the ferrite yoke of the LHC Injection Kicker Magnets. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the yoke can require several hours to cool sufficiently to allow re-injection of beam, thus limiting the running efficiency of the LHC. The beam screen, which screens the ferrite yoke from wakefields, has been upgraded to limit ferrite heating. In addition it is important to improve the cooling of the ferrite yoke: one method is to increase the internal emissivity of the cylindrical vacuum tank, in which the kicker magnet is installed. This paper describes a method developed for measuring the emissivity of the inside of the tanks, which has been benchmarked against measurements of the ferrite yoke temperature during heat treatment in an oven and transient thermal simulations. Conclusions are drawn regarding an ion bombardment technique evaluated for improving emissivity without degrading vacuum properties. In addition initial concepts for improved cooling are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME075
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRI030	Beam Coupling Impedance of the New Beam Screen of the LHC Injection Kicker Magnets	1627
	H.A. Day, M.J. Barnes, F. Caspers, E. Métral, B. Salvant, J.A. Uythoven CERN, Geneva, Switzerland
	The LHC injection kicker magnets experienced significant beam induced heating of the ferrite yoke, with high intensity beam circulating for many hours, during operation of the LHC in 2011 and 2012. The causes of this beam coupling impedance were studied in depth and an improved beam screen implemented to reduce the impedance. Results of measurements and simulations of the new beam screen design are presented in this paper: these are used to predict power loss and temperature of the ferrite yoke for operation after long shutdown 1 and for proposed HL-LHC operational parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI030
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPME072	Delivery of Special Magnets for the MedAustron Project	3403
	T. Kramer, M.G. Atanasov, R.A. Barlow, M.J. Barnes, J. Borburgh, L. Ducimetière, T. Fowler, M. Hourican, V. Mertens, A. Prost CERN, Geneva, Switzerland T. Stadlbauer EBG MedAustron, Wr. Neustadt, Austria
	Ten different types of kickers, bumpers, and electrostatic and magnetic septa, along with certain power supplies and associated control system components, have been designed in a collaboration between CERN and MedAustron for an ion therapy centre in Wr. Neustadt (Austria). This paper focuses on the status of the special magnets work package and the improvements applied during the production. The design parameters are compared with data from measurements, hardware tests and initial commissioning. The major factors contributing to the successful completion of the work package are highlighted.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME072
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Measurements and Laboratory Tests on a Prototype Stripline Kicker for the CLIC Damping Rings

125

C. Belver-Aguilar, A. Faus-Golfe
IFIC, Valencia, Spain
M.J. Barnes, H.A. Day
CERN, Geneva, Switzerland
F. Toral
CIEMAT, Madrid, Spain

The Pre-Damping Rings (PDRs) and Damping Rings (DRs) of CLIC are required to reduce the beam emittances to the small values required for the main linacs. The injection and extraction, from the PDRs and DRs, are performed by kicker systems. To achieve both low beam coupling impedance and reasonable broadband impedance matching to the electrical circuit, striplines have been chosen for the kicker elements. Prototype striplines have been built: tests and measurements of these striplines have started. The goal of these tests is to characterize, without beam, the electromagnetic response of the striplines. The tests have been carried out at CERN. To study the signal transmission through the striplines, the measured S-parameters have been compared with simulations. In addition, measurements of longitudinal beam coupling impedance, using the coaxial wire method, are reported and compared with simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO027

Export •

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

MOPRO028

Measurements on Prototype Inductive Adders with Ultra-flat-top Output Pulses for CLIC DR Kickers

128

J. Holma, M.J. Barnes
CERN, Geneva, Switzerland
C. Belver-Aguilar
IFIC, Valencia, Spain

The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the DR kicker systems must provide extremely flat, high-voltage, pulses. The specifications for the DR extraction kickers call for a 160 ns duration flat-top pulses of ±12.5 kV, 250 A, with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meeting the specifications because this topology allows the use of both passive and analogue modulation methods to adjust the output waveform. Recently, two five-layer, 3.5 kV, prototype inductive adders have been built at CERN. The first of these has been used to test the passive and active analogue modulation methods to compensate voltage droop and ripple of the output pulses. Pulse waveforms have been recorded with ±0.05 % relative (±1.0 V) stability for 160 ns flat-top duration at 1.823 kV.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO028

Export •

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

MOPRO032

Upgrades to the LHC Injection and Beam Dumping Systems for the HL-LHC Project

141

J.A. Uythoven, M.J. Barnes, B. Goddard, J. Hrivnak, A. Lechner, F.L. Maciariello, A. Mereghetti, A. Perillo Marcone, N.V. Shetty, G.E. Steele
CERN, Geneva, Switzerland

The HL-LHC project will push the performance of the LHC injection and beam dumping systems towards new limits. This paper describes the systems affected and presents the new beam parameters for these systems. It also describes the studies to be performed to determine which sub-components of these systems need to be upgraded to fulfill the new HL-LHC requirements. The results from the preliminary upgrade studies for the injection absorbers TDI are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO032

Export •

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

MOPME074

High Voltage Performance of the Beam Screen of the LHC Injection Kicker Magnets

541

M.J. Barnes, P. Adraktas, G. Bregliozzi, S. Calatroni, P. Costa Pinto, H.A. Day, L. Ducimetière, V. Gomes Namora, T. Kramer, V. Mertens, M. Taborelli
CERN, Geneva, Switzerland

The LHC injection kicker magnets include beam screens to shield the ferrite yokes against wakefields resulting from the high intensity beam. The screening is provided by conductors lodged in the inner wall of a ceramic support tube. The design of the beam screen has been upgraded to overcome limitations and permit LHC operation with increasingly higher bunch intensity and short bunch lengths: the new design also significantly reduces the electric field associated with the screen conductors, decreasing the probability of electrical breakdown. The high voltage conditioning process for the upgraded kicker magnets is presented and discussed. In addition a test setup has been utilized to study flashover, on the inner wall of the ceramic tube, as a function of both applied voltage and vacuum pressure: results from the test setup are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME074

Export •

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

MOPME075

Cooling of the LHC Injection Kicker Magnet Ferrite Yoke: Measurements and Future Proposals

544

M.J. Barnes, S. Bouleghlimat, L. Ducimetière, M. Garlaschè, V. Gomes Namora, T. Kramer, R. Noulibos, Y. Sillanoli, Z.K. Sobiech, W.J.M. Weterings
CERN, Geneva, Switzerland

LHC operation with high intensity beam, stable for many hours, resulted in significant heating of the ferrite yoke of the LHC Injection Kicker Magnets. For one kicker magnet the ferrite yoke approached its Curie temperature. As a result of a long thermal time-constant the yoke can require several hours to cool sufficiently to allow re-injection of beam, thus limiting the running efficiency of the LHC. The beam screen, which screens the ferrite yoke from wakefields, has been upgraded to limit ferrite heating. In addition it is important to improve the cooling of the ferrite yoke: one method is to increase the internal emissivity of the cylindrical vacuum tank, in which the kicker magnet is installed. This paper describes a method developed for measuring the emissivity of the inside of the tanks, which has been benchmarked against measurements of the ferrite yoke temperature during heat treatment in an oven and transient thermal simulations. Conclusions are drawn regarding an ion bombardment technique evaluated for improving emissivity without degrading vacuum properties. In addition initial concepts for improved cooling are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME075

Export •

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

TUPRI030

Beam Coupling Impedance of the New Beam Screen of the LHC Injection Kicker Magnets

1627

H.A. Day, M.J. Barnes, F. Caspers, E. Métral, B. Salvant, J.A. Uythoven
CERN, Geneva, Switzerland

The LHC injection kicker magnets experienced significant beam induced heating of the ferrite yoke, with high intensity beam circulating for many hours, during operation of the LHC in 2011 and 2012. The causes of this beam coupling impedance were studied in depth and an improved beam screen implemented to reduce the impedance. Results of measurements and simulations of the new beam screen design are presented in this paper: these are used to predict power loss and temperature of the ferrite yoke for operation after long shutdown 1 and for proposed HL-LHC operational parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI030

Export •

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

THPME072

Delivery of Special Magnets for the MedAustron Project

3403

T. Kramer, M.G. Atanasov, R.A. Barlow, M.J. Barnes, J. Borburgh, L. Ducimetière, T. Fowler, M. Hourican, V. Mertens, A. Prost
CERN, Geneva, Switzerland
T. Stadlbauer
EBG MedAustron, Wr. Neustadt, Austria

Ten different types of kickers, bumpers, and electrostatic and magnetic septa, along with certain power supplies and associated control system components, have been designed in a collaboration between CERN and MedAustron for an ion therapy centre in Wr. Neustadt (Austria). This paper focuses on the status of the special magnets work package and the improvements applied during the production. The design parameters are compared with data from measurements, hardware tests and initial commissioning. The major factors contributing to the successful completion of the work package are highlighted.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME072

Export •

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