IPAC2016 - List of Authors (Ducimetière, L.)

Paper	Title	Page
TUPMR048	SPS Injection and Beam Quality for LHC Heavy Ions With 150 ns Kicker Rise Time	1360
	B. Goddard, E. Carlier, L. Ducimetière, G. Kotzian, J.A. Uythoven CERN, Geneva, Switzerland F.M. Velotti EPFL, Lausanne, Switzerland
	As part of the LHC Injectors Upgrade project for LHC heavy ions, the SPS injection kicker system rise time needs reduction below its present 225 ns. One technically challenging option under consideration is the addition of fast Pulse Forming Lines in parallel to the existing Pulse Forming Networks for the 12 kicker magnets MKP-S, targeting a system field rise time of 100 ns. An alternative option is to optimise the system to approach the existing individual magnet field rise time (2-98%) of 150 ns. This would still significantly increase the number of colliding bunches in LHC while minimising the cost and effort of the system upgrade. The observed characteristics of the present system are described, compared to the expected system rise time, together with results of simulations and measurements with 175 and 150 ns injection batch spacing. The expected beam quality at injection into LHC is quantified, with the emittance growth and simulated tail population taking into account expected jitter and synchronisation errors, damper performance and SPS non-linear optics behavior. The outlook for deployment is discussed, with the implications for LHC operation and HL-LHC performance.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR048
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TUPMR049	Feasibility Study of the PS Injection for 2 GeV LIU Beams with an Upgraded KFA-45 Injection Kicker System Operating in Short Circuit Mode	1363
	T. Kramer, W. Bartmann, J.C.C.M. Borburgh, L. Ducimetière, L.M.C. Feliciano, A. Ferrero Colomo, B. Goddard, L. Sermeus CERN, Geneva, Switzerland
	Under the scope of the LIU project the CERN PS Booster to PS beam transfer will be modified to match the requirements for the future 2 GeV beams. This paper describes the evaluation of the proposed upgrade of the PS injection kicker. Different schemes of an injection for LIU beams into the PS have been outlined in the past already under the aspect of individual transfer kicker rise and fall time performances. Homogeneous rise and fall time requirements in the whole PSB to PS transfer chain have been established which allowed to consider an upgrade option of the present injection kicker system operated in short circuit mode. The challenging pulse quality constraints require an improvement of the flat top and post pulse ripples. Both operation modes, terminated and short circuit mode are analysed and analogue circuit simulations for the present and upgraded system are outlined. Recent measurements on the installed kickers are presented and analysed together with the simulation data. First measurements verifying the performance of upgrade options have been taken during the last end of the year stop. The paper concludes with an upgrade plan and a brief overview of implementation risks.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR049
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMW028	High Voltage Performance of Surface Coatings on Alumina Insulators	3603
	A. Adraktas, M.J. Barnes, H.A. Day, L. Ducimetière CERN, Geneva, Switzerland
	Alumina insulators and dielectrics are required for a variety of applications in particle accelerators. Their use in high voltage devices, both pulsed and DC, is well established as both insulation and mechanical support. In accelerator equipment the alumina is usually used in ultra-high vacuum and hence charge accumulation can be an issue, especially when the alumina is near to the beam. To address challenges regarding surface flashover and high secondary electron yield in high intensity accelerators, surface treatments and coatings are being considered. This paper presents predictions of the influence of surface coatings, on alumina insulators, upon electric field.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW028
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THPMW029	Feasibility Study of the Fast SPS Ion Injection Kicker System	3607
	A. Ferrero Colomo, P. Burkel, D. Comte, L. Ducimetière, T. Kramer, V. Senaj, L. Sermeus, F.M. Velotti CERN, Geneva, Switzerland
	As part of the upgrade project for ions the rise time of the injection kicker system into the SPS needs to be improved. The changes being studied include the addition of a fast Pulse Forming Line parallel to the existing Pulse Forming Network for the fast kicker magnets MKP-S. With the PFL an improved magnetic field rise time of 100 ns is targeted. Two different configuration utilizing a 2nd thyratron or two fast diode stacks have been outlined in the past. This paper presents the recent progress on the analogue circuit simulations for both options as well as measurements carried out on a test system. Modelling, optimization and simulation of the entire system with diodes and a second configuration with two thyratron switches are outlined. Measurement results are given and the feasibility of the upgrade is discussed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW029
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THPMW030	Studies of Impedance-related Improvements of the SPS Injection Kicker System	3611
	M.J. Barnes, A. Adraktas, M.S. Beck, G. Bregliozzi, H.A. Day, L. Ducimetière, J.A. Ferreira Somoza, B. Goddard, T. Kramer, C. Pasquino, G. Rumolo, B. Salvant, L. Sermeus, J.A. Uythoven, L. Vega Cid, W.J.M. Weterings, C. Zannini CERN, Geneva, Switzerland F.M. Velotti EPFL, Lausanne, Switzerland
	The injection kicker system for the SPS consists of sixteen magnets housed in a total of four vacuum tanks. The kicker magnets in one tank have recently limited operation of the SPS with high-intensity beam: this is due to both beam induced heating in the ferrite yoke of the kicker magnets and abnormally high pressure in the vacuum tank. Furthermore, operation with the higher intensity beams needed in the future for HL-LHC is expected to exacerbate these problems. Hence studies of the longitudinal beam coupling impedance of the kicker magnets have been carried out to investigate effective methods to shield the ferrite yoke from the circulating beam. The shielding must not compromise the field quality or high voltage behaviour of the kicker magnets and should not significantly reduce the beam aperture: results of these studies, together with measurements, are presented. In addition results of tests to identify the causes of abnormal outgassing are presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW030
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THPMW031	Current and Future Beam Thermal Behaviour of the LHC Injection Kicker Magnet	3615
	H.A. Day, M.J. Barnes, L. Ducimetière, L. Vega Cid, W.J.M. Weterings CERN, Geneva, Switzerland
	During Run 1 of the LHC the injection kicker magnets caused occasional operational delays due to beam induced heating with high bunch intensity and short bunch lengths. Significant upgrades were carried out to the injection kicker magnets during long shutdown 1, including a new design of beam screen to reduce the beam induced heating. Nevertheless these kicker magnets may limit the performance of HL-LHC unless additional, mitigating, measures are taken. Hence extensive simulations have been carried out to predict the distribution of the beam induced power deposition within the magnet and detailed thermal analyses carried out to predict the temperature profiles. To benchmark the simulations the predicted temperatures are compared with observables in the LHC. This paper reports on observations of the thermal behaviour of the magnet during run 2 of the LHC, with 25ns beam. In addition the measurement data is used to extrapolate temperature rise for the beam parameters expected for high-luminosity LHC.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW031
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THPMW032	Measurements on Magnetic Cores for Inductive Adders with Ultra-Flat Output Pulses for CLIC DR Kickers	3619
	J. Holma, M.J. Barnes, L. Ducimetière CERN, Geneva, Switzerland
	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 160 ns duration flattop pulses of ±12.5 kV, with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meet the specifications. Two five layer, 3.5 kV, prototype inductive adders have been built at CERN, and used to test passive and active analogue modulation methods to compensate droop and ripple of the output pulses. Recently, magnetic core materials and full-scale magnetic cores have been evaluated for the 12.5 kV prototype inductive adders. These results are presented in this paper and conclusions are drawn concerning the design of the full-scale prototypes.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW032
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THPMW033	Operational Experience of the Upgraded LHC Injection Kicker Magnets	3623
	M.J. Barnes, A. Adraktas, G. Bregliozzi, S. Calatroni, H.A. Day, L. Ducimetière, B. Goddard, V. Gomes Namora, V. Mertens, B. Salvant, J.A. Uythoven, L. Vega Cid, W.J.M. Weterings, C. Yin Vallgren CERN, Geneva, Switzerland
	During Run 1 of the LHC the injection kicker magnets caused occasional operational delays due to beam induced heating with high bunch intensity and short bunch lengths. In addition, sometimes there were also sporadic issues with microscopic unidentified falling objects, vacuum activity and electrical flashover of the injection kickers. An extensive program of studies was launched and significant upgrades were carried out during long shutdown 1. These upgrades include a new design of a beam screen to both reduce the beam coupling impedance of the kicker magnet, and to significantly reduce the electric field associated with the screen conductors, hence decreasing the probability of electrical breakdown in this region. In addition new cleaning procedures were implemented and equipment adjacent to the injection kickers and various vacuum components were modified. This paper presents operational experience of the injection kicker magnets during Run 2 of the LHC and assesses the effectiveness of the various upgrades.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW033
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THPMW034	Review on the Effects of Characteristic Impedance Mismatching in a Stripline Kicker	3627
	C. Belver-Aguilar, M.J. Barnes, L. Ducimetière CERN, Geneva, Switzerland
	A stripline kicker operates as two coupled transmission lines, with two TEM operating modes, known as odd and even modes. The characteristic impedance of these two modes is generally different, both only tend to the same value either when the electrodes are widely separated or when the electrodes are very close to the beam pipe wall. In all other cases, the even mode characteristic impedance is always higher than the odd mode characteristic impedance. The specifications required for a kicker operating in a low emittance ring are usually very challenging. In this situation it is desirable to match the even mode characteristic impedance of the striplines to the resistance of their termination. However a mismatched odd mode impedance can significantly influence the striplines performance. This paper presents predictions for the influence of the odd mode characteristic impedance upon the contribution of each field component, electric and magnetic, to the deflection angle. In addition, the variation of the characteristic impedance and field homogeneity with frequency are presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW034
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMW035	Considerations on an Upgrade Possibility of the LHC Beam Dump Kicker System	3631
	M.A. Fraser, W. Bartmann, C. Bracco, L. Ducimetière, B. Goddard, T. Kramer, V. Senaj CERN, Geneva, Switzerland
	The LHC Beam Dump System (LBDS) is designed to safely dispose the circulating beams over a wide range of energy from 450 GeV up to 7 TeV, where the maximum stored energy is 362 MJ per beam. One of the most critical components of the LBDS are the extraction kickers that must reliably switch on within the 3 us particle-free abort gap. To ensure this functionality, even in the event of a power-cut, the power generator capacitors remain charged and hence the Gate Turn-Off (GTO) switch stack has to hold the full voltage throughout beam operation. The increase of the LHC collision energy to 13 TeV has increased the voltage levels at the GTO stacks and during re-commissioning an increased rate of high-voltage (HV) related issues at the level of the GTO stack was observed. Different solutions have been analysed and an improved GTO stack will be implemented. This paper also outlines the benefit of adding more kicker magnets to improve the voltage hold off issues and to improve the tolerance to missing kickers during extraction.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW035
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THPOR049	Considerations for the Injection and Extraction Kicker Systems of a 100 TeV Centre-of-Mass FCC-hh Collider	3901
	T. Kramer, M.J. Barnes, W. Bartmann, F. Burkart, L. Ducimetière, B. Goddard, V. Senaj, T. Stadlbauer, D.G. Woog CERN, Geneva, Switzerland D. Barna Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary
	A 100 TeV center-of-mass energy frontier proton collider in a new tunnel of ~100 km circumference is a central part of CERN's Future Circular Colliders (FCC) design study. One of the major challenges for such a machine will be the beam injection and extraction. This paper outlines the recent developments on the injection and extraction kicker system concepts. For injection the system requirements and progress on a new inductive adder design will be presented together with first considerations on the injection kicker magnets. The extraction kicker system comprises the extraction kickers itself as well as the beam dilution kickers, both of which will be part of the FCC beam dump system and will have to reliably abort proton beams with stored energies in the range of 8 Gigajoule. First concepts for the beam dump kicker magnet and generator as well as for the dilution kicker system are described and its feasibility for an abort gap in the 1 μs range is discussed. The potential implications on the overall machine and other key subsystems are outlined, including requirements on (and from) dilution patterns, interlocking, beam intercepting devices and insertion design.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR049
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

SPS Injection and Beam Quality for LHC Heavy Ions With 150 ns Kicker Rise Time

1360

B. Goddard, E. Carlier, L. Ducimetière, G. Kotzian, J.A. Uythoven
CERN, Geneva, Switzerland
F.M. Velotti
EPFL, Lausanne, Switzerland

As part of the LHC Injectors Upgrade project for LHC heavy ions, the SPS injection kicker system rise time needs reduction below its present 225 ns. One technically challenging option under consideration is the addition of fast Pulse Forming Lines in parallel to the existing Pulse Forming Networks for the 12 kicker magnets MKP-S, targeting a system field rise time of 100 ns. An alternative option is to optimise the system to approach the existing individual magnet field rise time (2-98%) of 150 ns. This would still significantly increase the number of colliding bunches in LHC while minimising the cost and effort of the system upgrade. The observed characteristics of the present system are described, compared to the expected system rise time, together with results of simulations and measurements with 175 and 150 ns injection batch spacing. The expected beam quality at injection into LHC is quantified, with the emittance growth and simulated tail population taking into account expected jitter and synchronisation errors, damper performance and SPS non-linear optics behavior. The outlook for deployment is discussed, with the implications for LHC operation and HL-LHC performance.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR048

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TUPMR049

Feasibility Study of the PS Injection for 2 GeV LIU Beams with an Upgraded KFA-45 Injection Kicker System Operating in Short Circuit Mode

1363

T. Kramer, W. Bartmann, J.C.C.M. Borburgh, L. Ducimetière, L.M.C. Feliciano, A. Ferrero Colomo, B. Goddard, L. Sermeus
CERN, Geneva, Switzerland

Under the scope of the LIU project the CERN PS Booster to PS beam transfer will be modified to match the requirements for the future 2 GeV beams. This paper describes the evaluation of the proposed upgrade of the PS injection kicker. Different schemes of an injection for LIU beams into the PS have been outlined in the past already under the aspect of individual transfer kicker rise and fall time performances. Homogeneous rise and fall time requirements in the whole PSB to PS transfer chain have been established which allowed to consider an upgrade option of the present injection kicker system operated in short circuit mode. The challenging pulse quality constraints require an improvement of the flat top and post pulse ripples. Both operation modes, terminated and short circuit mode are analysed and analogue circuit simulations for the present and upgraded system are outlined. Recent measurements on the installed kickers are presented and analysed together with the simulation data. First measurements verifying the performance of upgrade options have been taken during the last end of the year stop. The paper concludes with an upgrade plan and a brief overview of implementation risks.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR049

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THPMW028

High Voltage Performance of Surface Coatings on Alumina Insulators

3603

A. Adraktas, M.J. Barnes, H.A. Day, L. Ducimetière
CERN, Geneva, Switzerland

Alumina insulators and dielectrics are required for a variety of applications in particle accelerators. Their use in high voltage devices, both pulsed and DC, is well established as both insulation and mechanical support. In accelerator equipment the alumina is usually used in ultra-high vacuum and hence charge accumulation can be an issue, especially when the alumina is near to the beam. To address challenges regarding surface flashover and high secondary electron yield in high intensity accelerators, surface treatments and coatings are being considered. This paper presents predictions of the influence of surface coatings, on alumina insulators, upon electric field.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW028

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THPMW029

Feasibility Study of the Fast SPS Ion Injection Kicker System

3607

A. Ferrero Colomo, P. Burkel, D. Comte, L. Ducimetière, T. Kramer, V. Senaj, L. Sermeus, F.M. Velotti
CERN, Geneva, Switzerland

As part of the upgrade project for ions the rise time of the injection kicker system into the SPS needs to be improved. The changes being studied include the addition of a fast Pulse Forming Line parallel to the existing Pulse Forming Network for the fast kicker magnets MKP-S. With the PFL an improved magnetic field rise time of 100 ns is targeted. Two different configuration utilizing a 2nd thyratron or two fast diode stacks have been outlined in the past. This paper presents the recent progress on the analogue circuit simulations for both options as well as measurements carried out on a test system. Modelling, optimization and simulation of the entire system with diodes and a second configuration with two thyratron switches are outlined. Measurement results are given and the feasibility of the upgrade is discussed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW029

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

THPMW030

Studies of Impedance-related Improvements of the SPS Injection Kicker System

3611

M.J. Barnes, A. Adraktas, M.S. Beck, G. Bregliozzi, H.A. Day, L. Ducimetière, J.A. Ferreira Somoza, B. Goddard, T. Kramer, C. Pasquino, G. Rumolo, B. Salvant, L. Sermeus, J.A. Uythoven, L. Vega Cid, W.J.M. Weterings, C. Zannini
CERN, Geneva, Switzerland
F.M. Velotti
EPFL, Lausanne, Switzerland

The injection kicker system for the SPS consists of sixteen magnets housed in a total of four vacuum tanks. The kicker magnets in one tank have recently limited operation of the SPS with high-intensity beam: this is due to both beam induced heating in the ferrite yoke of the kicker magnets and abnormally high pressure in the vacuum tank. Furthermore, operation with the higher intensity beams needed in the future for HL-LHC is expected to exacerbate these problems. Hence studies of the longitudinal beam coupling impedance of the kicker magnets have been carried out to investigate effective methods to shield the ferrite yoke from the circulating beam. The shielding must not compromise the field quality or high voltage behaviour of the kicker magnets and should not significantly reduce the beam aperture: results of these studies, together with measurements, are presented. In addition results of tests to identify the causes of abnormal outgassing are presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW030

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THPMW031

Current and Future Beam Thermal Behaviour of the LHC Injection Kicker Magnet

3615

H.A. Day, M.J. Barnes, L. Ducimetière, L. Vega Cid, W.J.M. Weterings
CERN, Geneva, Switzerland

During Run 1 of the LHC the injection kicker magnets caused occasional operational delays due to beam induced heating with high bunch intensity and short bunch lengths. Significant upgrades were carried out to the injection kicker magnets during long shutdown 1, including a new design of beam screen to reduce the beam induced heating. Nevertheless these kicker magnets may limit the performance of HL-LHC unless additional, mitigating, measures are taken. Hence extensive simulations have been carried out to predict the distribution of the beam induced power deposition within the magnet and detailed thermal analyses carried out to predict the temperature profiles. To benchmark the simulations the predicted temperatures are compared with observables in the LHC. This paper reports on observations of the thermal behaviour of the magnet during run 2 of the LHC, with 25ns beam. In addition the measurement data is used to extrapolate temperature rise for the beam parameters expected for high-luminosity LHC.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW031

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THPMW032

Measurements on Magnetic Cores for Inductive Adders with Ultra-Flat Output Pulses for CLIC DR Kickers

3619

J. Holma, M.J. Barnes, L. Ducimetière
CERN, Geneva, Switzerland

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 160 ns duration flattop pulses of ±12.5 kV, with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meet the specifications. Two five layer, 3.5 kV, prototype inductive adders have been built at CERN, and used to test passive and active analogue modulation methods to compensate droop and ripple of the output pulses. Recently, magnetic core materials and full-scale magnetic cores have been evaluated for the 12.5 kV prototype inductive adders. These results are presented in this paper and conclusions are drawn concerning the design of the full-scale prototypes.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW032

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THPMW033

Operational Experience of the Upgraded LHC Injection Kicker Magnets

3623

M.J. Barnes, A. Adraktas, G. Bregliozzi, S. Calatroni, H.A. Day, L. Ducimetière, B. Goddard, V. Gomes Namora, V. Mertens, B. Salvant, J.A. Uythoven, L. Vega Cid, W.J.M. Weterings, C. Yin Vallgren
CERN, Geneva, Switzerland

During Run 1 of the LHC the injection kicker magnets caused occasional operational delays due to beam induced heating with high bunch intensity and short bunch lengths. In addition, sometimes there were also sporadic issues with microscopic unidentified falling objects, vacuum activity and electrical flashover of the injection kickers. An extensive program of studies was launched and significant upgrades were carried out during long shutdown 1. These upgrades include a new design of a beam screen to both reduce the beam coupling impedance of the kicker magnet, and to significantly reduce the electric field associated with the screen conductors, hence decreasing the probability of electrical breakdown in this region. In addition new cleaning procedures were implemented and equipment adjacent to the injection kickers and various vacuum components were modified. This paper presents operational experience of the injection kicker magnets during Run 2 of the LHC and assesses the effectiveness of the various upgrades.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW033

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THPMW034

Review on the Effects of Characteristic Impedance Mismatching in a Stripline Kicker

3627

C. Belver-Aguilar, M.J. Barnes, L. Ducimetière
CERN, Geneva, Switzerland

A stripline kicker operates as two coupled transmission lines, with two TEM operating modes, known as odd and even modes. The characteristic impedance of these two modes is generally different, both only tend to the same value either when the electrodes are widely separated or when the electrodes are very close to the beam pipe wall. In all other cases, the even mode characteristic impedance is always higher than the odd mode characteristic impedance. The specifications required for a kicker operating in a low emittance ring are usually very challenging. In this situation it is desirable to match the even mode characteristic impedance of the striplines to the resistance of their termination. However a mismatched odd mode impedance can significantly influence the striplines performance. This paper presents predictions for the influence of the odd mode characteristic impedance upon the contribution of each field component, electric and magnetic, to the deflection angle. In addition, the variation of the characteristic impedance and field homogeneity with frequency are presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW034

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THPMW035

Considerations on an Upgrade Possibility of the LHC Beam Dump Kicker System

3631

M.A. Fraser, W. Bartmann, C. Bracco, L. Ducimetière, B. Goddard, T. Kramer, V. Senaj
CERN, Geneva, Switzerland

The LHC Beam Dump System (LBDS) is designed to safely dispose the circulating beams over a wide range of energy from 450 GeV up to 7 TeV, where the maximum stored energy is 362 MJ per beam. One of the most critical components of the LBDS are the extraction kickers that must reliably switch on within the 3 us particle-free abort gap. To ensure this functionality, even in the event of a power-cut, the power generator capacitors remain charged and hence the Gate Turn-Off (GTO) switch stack has to hold the full voltage throughout beam operation. The increase of the LHC collision energy to 13 TeV has increased the voltage levels at the GTO stacks and during re-commissioning an increased rate of high-voltage (HV) related issues at the level of the GTO stack was observed. Different solutions have been analysed and an improved GTO stack will be implemented. This paper also outlines the benefit of adding more kicker magnets to improve the voltage hold off issues and to improve the tolerance to missing kickers during extraction.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW035

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THPOR049

Considerations for the Injection and Extraction Kicker Systems of a 100 TeV Centre-of-Mass FCC-hh Collider

3901

T. Kramer, M.J. Barnes, W. Bartmann, F. Burkart, L. Ducimetière, B. Goddard, V. Senaj, T. Stadlbauer, D.G. Woog
CERN, Geneva, Switzerland
D. Barna
Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Budapest, Hungary

A 100 TeV center-of-mass energy frontier proton collider in a new tunnel of ~100 km circumference is a central part of CERN's Future Circular Colliders (FCC) design study. One of the major challenges for such a machine will be the beam injection and extraction. This paper outlines the recent developments on the injection and extraction kicker system concepts. For injection the system requirements and progress on a new inductive adder design will be presented together with first considerations on the injection kicker magnets. The extraction kicker system comprises the extraction kickers itself as well as the beam dilution kickers, both of which will be part of the FCC beam dump system and will have to reliably abort proton beams with stored energies in the range of 8 Gigajoule. First concepts for the beam dump kicker magnet and generator as well as for the dilution kicker system are described and its feasibility for an abort gap in the 1 μs range is discussed. The potential implications on the overall machine and other key subsystems are outlined, including requirements on (and from) dilution patterns, interlocking, beam intercepting devices and insertion design.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR049

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