IPAC2017 - List of Authors (Weterings, W.J.M.)

Paper	Title	Page
MOPIK041	Commissioning of the Stripping Foil Units for the Upgrade of the PSB H⁻ Injection System	595
	C. Bracco, S. Burger, V. Forte, B. Goddard, G. Guidoboni, L.O. Jorat, B. Mikulec, A. Navarro Fernandez, R. Noulibos, F. Roncarolo, P. Van Trappen, W.J.M. Weterings CERN, Geneva, Switzerland
	The PSB will be extensively upgraded during the next long shutdown of the CERN accelerator complex, to double the brightness of the stored beams. The existing multi-turn injection will be replaced by a charge exchange system designed for the 160 MeV hydrogen ions provided by Linac4. Part of the injection equipment has been temporarily installed along the Linac4-to-PSB transfer line and tested with beam. This allowed to gain experience with the system, test the related diagnostics and benchmark calculations with measurements. An additional permanent stripping foil test stand is also installed right after the Linac and will be used to characterise new foils for possible future applications. The main outcomes, issues and applied or planned mitigations are presented for both installations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK041
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MOPIK047	Commissioning and Results of the Half-Sector Test Installation with 160 MeV H⁻ beam from Linac4	619
	B. Mikulec, D. Aguglia, J.C. Allica Santamaria, C. Baud, C. Bracco, S. Burger, G. Guidoboni, L.O. Jorat, C. Martin, A. Navarro Fernandez, R. Noulibos, F. Roncarolo, J.L. Sanchez Alvarez, J. Tan, T. Todorcevic, P. Van Trappen, W.J.M. Weterings, C. Zamantzas CERN, Geneva, Switzerland
	During the Long Shutdown 2 (LS2) at CERN in 2019/20, the Proton Synchrotron Booster (PSB) will undergo a profound upgrade in the framework of the LHC Injector Upgrade (LIU) project involving also the connection to the new Linac4 injector. The 160 MeV Linac4 H' injection entails a complete replacement of the PSB injection section, including a stripping foil system, injection chicane, an H⁰/H' dump and novel beam instrumentation. The equivalent of half of this new injection chicane was temporarily installed in the Linac4 transfer line to evaluate the performance of the equipment and prepare controls, interlocks and applications for the connection. Outcomes of this so-called Half-Sector Test (HST) are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK047
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WEPVA094	Study of an Improved Beam Screen Design for the LHC Injection Kicker Magnet for HL-LHC	3471
	V. Vlachodimitropoulos, M.J. Barnes, L. Ducimetière, L. Vega Cid, W.J.M. Weterings CERN, Geneva, Switzerland
	During Run 1 of the LHC, one of the injection kicker magnets (MKIs) occasionally exhibited an excessively high ferrite temperature, caused by coupling of the high intensity beam to the real impedance of the magnet. Beam-screen upgrades have been very effective in reducing beam coupling impedance during Run 2. However, temperature measurements during LHC operation have shown that one end of the MKIs ferrite yoke is consistently hotter than the other: this effect is due to highly non-uniform beam induced power deposition along the kicker. Electromagnetic and thermal simulations show that part of the ferrite yoke will be above its Curie temperature when the LHC is operated with HL-LHC beam parameters, which could increase the turn-around time between fills of the LHC. An impedance mitigation study is presented in this paper with emphasis on the effect of the beam screen layout upon both total beam induced power deposition and its longitudinal distribution. Results of complex thermal simulations, to benchmark the effectiveness of the proposed schemes, are reported. To validate the proposed modification a test bench measurement was performed and preliminary results are discussed
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA094
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WEPVA096	Thermal Analysis of the LHC Injection Kicker Magnets	3479
	L. Vega Cid, M.J. Barnes, V. Vlachodimitropoulos, W.J.M. Weterings CERN, Geneva, Switzerland A. Abánades ETSII UPM, Madrid, Spain
	Funding: Research supported by the HL-LHC project. The CERN Large Hadron Collider LHC is equipped with two fast pulsed magnet systems (MKIs) that inject particle beams coming from the injector chain. Operation with high intensity beams for many hours can lead to significant beam induced heating of the ferrite yokes of the MKIs. When the ferrite exceeds the Curie temperature of 125°C it loses its magnetic properties, preventing further injection until the ferrite cools down, potentially causing a delay of several hours. Hence important upgrades of the beam-screen were implemented after Run 1 of LHC. However, the High-Luminosity (HL) LHC will be operated with significantly higher intensity beams and hence additional measures are required to limit the ferrite temperature. These magnets operate under ultra-high vacuum conditions: convection is negligible and, as a result of low emissivity of the inside of the vacuum tanks, thermal radiation is limited. A detailed study of the thermal behaviour of these magnets is reported and compared with measurements. In addition several options to improve cooling of the ferrites are presented and analysed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA096
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WEPVA097	Upgrading the SPS Fast Extraction Kicker Systems for HL-LHC	3483
	M.J. Barnes, M.S. Beck, H.A. Day, L. Ducimetière, E. Garcia-Tabares Valdivieso, B. Goddard, H. Neupert, A. Romano, L. Vega Cid, W.J.M. Weterings CERN, Geneva, Switzerland C. Zannini ADAM SA, Geneva, Switzerland
	The CERN SPS has two fast extraction systems, each consisting of travelling wave kicker magnets (MKEs). The beam induced heating in the ferrite yoke of these magnets was historically kept to an acceptable level by implementing water cooling of the kicker magnets: in addition serigraphy was applied on the surfaces of the ferrite yoke facing the beam. Nevertheless, high intensity beams needed in the future for HL-LHC will significantly increase the beam induced heating, potentially raising the MKE ferrite yoke temperature to its Curie point. Hence detailed studies of longitudinal beam coupling impedance were carried out to identify simple but effective methods of further reducing beam induced power deposition. Based on the results of these studies, and in the framework of the LHC Injectors Upgrade (LIU) project, an upgraded MKE kicker magnet was installed during the 2015-2016 shutdown. This paper reports and compares results of predictions, laboratory measurements, temperature measurements during SPS operation, and machine development studies. Measurements of both dynamic pressure rise in the upgraded magnet and Secondary Electron Yield, on samples, are also reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA097
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WEPVA100	Operational Experience of the Upgraded LHC Injection Kicker Magnets During Run 2 and Future Plans	3495
	M.J. Barnes, A. Adraktas, G. Bregliozzi, L. Ducimetière, B. Goddard, B. Salvant, J. Sestak, L. Vega Cid, W.J.M. Weterings, C. Yin Vallgren CERN, Geneva, Switzerland
	During Run 1 of the LHC, one of the injection kicker magnets caused occasional operational delays due to beam induced heating with high bunch intensity and short bunch lengths. In addition, there were also sporadic issues with 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 (LS 1). These upgrades included a new design of beam screen to reduce both beam coupling impedance of the kicker magnet and the electric field associated with the screen conductors, hence decreasing the probability of electrical breakdown in this region. This paper presents operational experience of the injection kicker magnets during the first years of Run 2 of the LHC, including a discussion of faults and kicker magnet issues that limited LHC operation. In addition, in light of these issues, plans for further upgrades are briefly discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA100
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Paper

Title

Page

Commissioning of the Stripping Foil Units for the Upgrade of the PSB H⁻ Injection System

595

C. Bracco, S. Burger, V. Forte, B. Goddard, G. Guidoboni, L.O. Jorat, B. Mikulec, A. Navarro Fernandez, R. Noulibos, F. Roncarolo, P. Van Trappen, W.J.M. Weterings
CERN, Geneva, Switzerland

The PSB will be extensively upgraded during the next long shutdown of the CERN accelerator complex, to double the brightness of the stored beams. The existing multi-turn injection will be replaced by a charge exchange system designed for the 160 MeV hydrogen ions provided by Linac4. Part of the injection equipment has been temporarily installed along the Linac4-to-PSB transfer line and tested with beam. This allowed to gain experience with the system, test the related diagnostics and benchmark calculations with measurements. An additional permanent stripping foil test stand is also installed right after the Linac and will be used to characterise new foils for possible future applications. The main outcomes, issues and applied or planned mitigations are presented for both installations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK041

Export •

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

MOPIK047

Commissioning and Results of the Half-Sector Test Installation with 160 MeV H⁻ beam from Linac4

619

B. Mikulec, D. Aguglia, J.C. Allica Santamaria, C. Baud, C. Bracco, S. Burger, G. Guidoboni, L.O. Jorat, C. Martin, A. Navarro Fernandez, R. Noulibos, F. Roncarolo, J.L. Sanchez Alvarez, J. Tan, T. Todorcevic, P. Van Trappen, W.J.M. Weterings, C. Zamantzas
CERN, Geneva, Switzerland

During the Long Shutdown 2 (LS2) at CERN in 2019/20, the Proton Synchrotron Booster (PSB) will undergo a profound upgrade in the framework of the LHC Injector Upgrade (LIU) project involving also the connection to the new Linac4 injector. The 160 MeV Linac4 H' injection entails a complete replacement of the PSB injection section, including a stripping foil system, injection chicane, an H⁰/H' dump and novel beam instrumentation. The equivalent of half of this new injection chicane was temporarily installed in the Linac4 transfer line to evaluate the performance of the equipment and prepare controls, interlocks and applications for the connection. Outcomes of this so-called Half-Sector Test (HST) are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPIK047

Export •

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

WEPVA094

Study of an Improved Beam Screen Design for the LHC Injection Kicker Magnet for HL-LHC

3471

V. Vlachodimitropoulos, M.J. Barnes, L. Ducimetière, L. Vega Cid, W.J.M. Weterings
CERN, Geneva, Switzerland

During Run 1 of the LHC, one of the injection kicker magnets (MKIs) occasionally exhibited an excessively high ferrite temperature, caused by coupling of the high intensity beam to the real impedance of the magnet. Beam-screen upgrades have been very effective in reducing beam coupling impedance during Run 2. However, temperature measurements during LHC operation have shown that one end of the MKIs ferrite yoke is consistently hotter than the other: this effect is due to highly non-uniform beam induced power deposition along the kicker. Electromagnetic and thermal simulations show that part of the ferrite yoke will be above its Curie temperature when the LHC is operated with HL-LHC beam parameters, which could increase the turn-around time between fills of the LHC. An impedance mitigation study is presented in this paper with emphasis on the effect of the beam screen layout upon both total beam induced power deposition and its longitudinal distribution. Results of complex thermal simulations, to benchmark the effectiveness of the proposed schemes, are reported. To validate the proposed modification a test bench measurement was performed and preliminary results are discussed

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA094

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

WEPVA096

Thermal Analysis of the LHC Injection Kicker Magnets

3479

L. Vega Cid, M.J. Barnes, V. Vlachodimitropoulos, W.J.M. Weterings
CERN, Geneva, Switzerland
A. Abánades
ETSII UPM, Madrid, Spain

Funding: Research supported by the HL-LHC project.
The CERN Large Hadron Collider LHC is equipped with two fast pulsed magnet systems (MKIs) that inject particle beams coming from the injector chain. Operation with high intensity beams for many hours can lead to significant beam induced heating of the ferrite yokes of the MKIs. When the ferrite exceeds the Curie temperature of 125°C it loses its magnetic properties, preventing further injection until the ferrite cools down, potentially causing a delay of several hours. Hence important upgrades of the beam-screen were implemented after Run 1 of LHC. However, the High-Luminosity (HL) LHC will be operated with significantly higher intensity beams and hence additional measures are required to limit the ferrite temperature. These magnets operate under ultra-high vacuum conditions: convection is negligible and, as a result of low emissivity of the inside of the vacuum tanks, thermal radiation is limited. A detailed study of the thermal behaviour of these magnets is reported and compared with measurements. In addition several options to improve cooling of the ferrites are presented and analysed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA096

Export •

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

WEPVA097

Upgrading the SPS Fast Extraction Kicker Systems for HL-LHC

3483

M.J. Barnes, M.S. Beck, H.A. Day, L. Ducimetière, E. Garcia-Tabares Valdivieso, B. Goddard, H. Neupert, A. Romano, L. Vega Cid, W.J.M. Weterings
CERN, Geneva, Switzerland
C. Zannini
ADAM SA, Geneva, Switzerland

The CERN SPS has two fast extraction systems, each consisting of travelling wave kicker magnets (MKEs). The beam induced heating in the ferrite yoke of these magnets was historically kept to an acceptable level by implementing water cooling of the kicker magnets: in addition serigraphy was applied on the surfaces of the ferrite yoke facing the beam. Nevertheless, high intensity beams needed in the future for HL-LHC will significantly increase the beam induced heating, potentially raising the MKE ferrite yoke temperature to its Curie point. Hence detailed studies of longitudinal beam coupling impedance were carried out to identify simple but effective methods of further reducing beam induced power deposition. Based on the results of these studies, and in the framework of the LHC Injectors Upgrade (LIU) project, an upgraded MKE kicker magnet was installed during the 2015-2016 shutdown. This paper reports and compares results of predictions, laboratory measurements, temperature measurements during SPS operation, and machine development studies. Measurements of both dynamic pressure rise in the upgraded magnet and Secondary Electron Yield, on samples, are also reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA097

Export •

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

WEPVA100

Operational Experience of the Upgraded LHC Injection Kicker Magnets During Run 2 and Future Plans

3495

M.J. Barnes, A. Adraktas, G. Bregliozzi, L. Ducimetière, B. Goddard, B. Salvant, J. Sestak, L. Vega Cid, W.J.M. Weterings, C. Yin Vallgren
CERN, Geneva, Switzerland

During Run 1 of the LHC, one of the injection kicker magnets caused occasional operational delays due to beam induced heating with high bunch intensity and short bunch lengths. In addition, there were also sporadic issues with 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 (LS 1). These upgrades included a new design of beam screen to reduce both beam coupling impedance of the kicker magnet and the electric field associated with the screen conductors, hence decreasing the probability of electrical breakdown in this region. This paper presents operational experience of the injection kicker magnets during the first years of Run 2 of the LHC, including a discussion of faults and kicker magnet issues that limited LHC operation. In addition, in light of these issues, plans for further upgrades are briefly discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPVA100

Export •

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