Higher Order Modes (HOMs) can severely limit the operation of superconducting cavities in a linac... more Higher Order Modes (HOMs) can severely limit the operation of superconducting cavities in a linac with high beam current, high duty factor and complex pulse structure. The full HOM spectrum has to be analyzed in order to identify potentially dangerous modes already during the design phase and to define their damping requirements. For this purpose a dedicated beam simulation code focused on beam-HOMinteraction was developed, taking into account important effects like the HOMfrequency spread, beam input jitter, different chopping patterns, as well as klystron and alignment errors. Here, the code is used to investigate in detail the HOM properties of the cavities foreseen in the Superconducting Proton Linac (SPL) at CERN and their potential to drive beam instabilities. Special attention is given to HOM excitation by chopped pulses with high repetition rate.
... the proton-driver front-end test stand was laid by Dr. D. Findlay who was work-package-2 mana... more ... the proton-driver front-end test stand was laid by Dr. D. Findlay who was work-package-2 manager until Mr. A. Letchford took over ... Although a low frequency (ideally suited to the 4-rod type of RFQ) was initially thought preferable, questions remained over its suitability for generic ...
Linac4 is employing three types of accelerating structures after the RFQ: a Drift Tube Linac (DTL... more Linac4 is employing three types of accelerating structures after the RFQ: a Drift Tube Linac (DTL), a Cell- Coupled DTL (CCDTL), and a Pi-Mode Structure (PIMS) to accelerate the beam up to 160 MeV at 352.2MHz. The structures are designed for a peak power of approximately 1 MW per power coupler, which is transported via rectangular waveguides from the klystron
The Superconducting Proton Linac (SPL) at CERN is part of the planned injector upgrade of the LHC... more The Superconducting Proton Linac (SPL) at CERN is part of the planned injector upgrade of the LHC. Initially used at low duty cycle as LHC injector it has the potential to be upgraded as a high power proton driver for neutrino physics and/or radioactive ion beams. In this paper the influence of the beam parameters on the build-up of Higher
The pulse structure of proton linacs is determined by the linac energy, the RF system, and the ma... more The pulse structure of proton linacs is determined by the linac energy, the RF system, and the maximum duty cycle of the source. Short bursts of protons in the microsecond range can be achieved by adding an accumulator ring and a reduction of the bunch length to the order of nanoseconds can be accomplished with an additional bunch compressor ring.
The SPL (Superconducting Proton Linac) study at CERN foresees the construction of a 2.2 GeV linac... more The SPL (Superconducting Proton Linac) study at CERN foresees the construction of a 2.2 GeV linac as a high beam-power driver for applications such as a second-generation radioactive ion beam facility or a neutrino superbeam. At the same time such a high-performance injector would both modernize and improve the LHC injection chain. The 120 MeV normal-conducting section of the SPL
Linac4 is a normal conducting H- linac proposed at CERN to provide a higher proton flux to the CE... more Linac4 is a normal conducting H- linac proposed at CERN to provide a higher proton flux to the CERN accelerator chain. It should replace the existing Linac2 as injector for the PS booster (PSB). The same machine can also operate in the future as the front end of the SPL, a 2.2 GeV superconducting linac with 1.8 mA average current.
We present a summary of simulation results on a muon cooling experiment based on 88MHz cavities. ... more We present a summary of simulation results on a muon cooling experiment based on 88MHz cavities. The systems studied are subsections of the cooling channel in the CERN reference scheme for a neutrino factory. We present two different set-ups using 8 and 4 cavities. For each of these channels we have carried out a beam dynamics study based on engineering
The construction of the Large Hadron Collider at CERN is in its final phase, and commissioning wi... more The construction of the Large Hadron Collider at CERN is in its final phase, and commissioning with beam is scheduled to begin before the end of 2007. It is now time to prepare for increasing as much as possible the performance of this unique instrument to maximize the benefits for physics. An essential part of the proposed luminosity upgrade plan is the replacement of the CERN PS and its injectors by a 50 GeV proton synchrotron (PS2) and a 4 GeV superconducting linac (SPL). The design of the SPL has recently been updated and the optimization of its high-energy part will continue until ~2010. For the foreseen luminosity upgrade of the LHC a low-power version of the SPL (LP-SPL) is under study, which can be upgraded to a multi-megawatt machine providing beam to high-power proton users such as neutrino facilities and/or radio-active beam facilities. The construction start of the low-energy normal conducting SPL front-end, the 160 MeV "Linac4", is scheduled for January 2008, ...
The ultimate luminosity (2.3 x 10<sup>34</sup> cm<sup>-2</sup> s<sup&g... more The ultimate luminosity (2.3 x 10<sup>34</sup> cm<sup>-2</sup> s<sup>-1</sup>) in the LHC can only be reached or even exceeded if a major upgrade of the CERN proton injector complex takes place. The first identified bottleneck towards higher brightness beams is the 50 MeV proton injection of Linac2 into the PS booster (PSB). Doubling the intensity in the PSB can be achieved
The PIMS (Pi-Mode-Structure) cavities for Linac4 are made of 7 coupled cells operating in !-mode ... more The PIMS (Pi-Mode-Structure) cavities for Linac4 are made of 7 coupled cells operating in !-mode at a frequency of 352 MHz. The mechanical concept is derived from the 5-cell cavities used in the LEP machine, whereas cell length and coupling are adapted for proton acceleration in the range from 50 to 160 MeV. Linac4 will be the first machine to employ this type of cavities for low-beta protons. During the first years of operation the PIMS will be used at low duty cycle (0.1%) as part of the consolidated LHC proton injector complex. It is designed, however, to operate eventually in a high duty cycle (10%) proton injector, which could be used as proton front-end for neutrino or RIB applications. To prepare for the series construction of the 12 PIMS units the first cavity (102 MeV beam energy) has been designed and constructed at CERN, to be used as a hot prototype for RF tests and as a pre-series mechanical unit. In this paper we report on some of the design features, the construction ...
Higher Order Modes (HOMs) can severely limit the operation of superconducting cavities in a linac... more Higher Order Modes (HOMs) can severely limit the operation of superconducting cavities in a linac with high beam current, high duty factor and complex pulse structure. The full HOM spectrum has to be analyzed in order to identify potentially dangerous modes already during the design phase and to define their damping requirements. For this purpose a dedicated beam simulation code focused on beam-HOMinteraction was developed, taking into account important effects like the HOMfrequency spread, beam input jitter, different chopping patterns, as well as klystron and alignment errors. Here, the code is used to investigate in detail the HOM properties of the cavities foreseen in the Superconducting Proton Linac (SPL) at CERN and their potential to drive beam instabilities. Special attention is given to HOM excitation by chopped pulses with high repetition rate.
... the proton-driver front-end test stand was laid by Dr. D. Findlay who was work-package-2 mana... more ... the proton-driver front-end test stand was laid by Dr. D. Findlay who was work-package-2 manager until Mr. A. Letchford took over ... Although a low frequency (ideally suited to the 4-rod type of RFQ) was initially thought preferable, questions remained over its suitability for generic ...
Linac4 is employing three types of accelerating structures after the RFQ: a Drift Tube Linac (DTL... more Linac4 is employing three types of accelerating structures after the RFQ: a Drift Tube Linac (DTL), a Cell- Coupled DTL (CCDTL), and a Pi-Mode Structure (PIMS) to accelerate the beam up to 160 MeV at 352.2MHz. The structures are designed for a peak power of approximately 1 MW per power coupler, which is transported via rectangular waveguides from the klystron
The Superconducting Proton Linac (SPL) at CERN is part of the planned injector upgrade of the LHC... more The Superconducting Proton Linac (SPL) at CERN is part of the planned injector upgrade of the LHC. Initially used at low duty cycle as LHC injector it has the potential to be upgraded as a high power proton driver for neutrino physics and/or radioactive ion beams. In this paper the influence of the beam parameters on the build-up of Higher
The pulse structure of proton linacs is determined by the linac energy, the RF system, and the ma... more The pulse structure of proton linacs is determined by the linac energy, the RF system, and the maximum duty cycle of the source. Short bursts of protons in the microsecond range can be achieved by adding an accumulator ring and a reduction of the bunch length to the order of nanoseconds can be accomplished with an additional bunch compressor ring.
The SPL (Superconducting Proton Linac) study at CERN foresees the construction of a 2.2 GeV linac... more The SPL (Superconducting Proton Linac) study at CERN foresees the construction of a 2.2 GeV linac as a high beam-power driver for applications such as a second-generation radioactive ion beam facility or a neutrino superbeam. At the same time such a high-performance injector would both modernize and improve the LHC injection chain. The 120 MeV normal-conducting section of the SPL
Linac4 is a normal conducting H- linac proposed at CERN to provide a higher proton flux to the CE... more Linac4 is a normal conducting H- linac proposed at CERN to provide a higher proton flux to the CERN accelerator chain. It should replace the existing Linac2 as injector for the PS booster (PSB). The same machine can also operate in the future as the front end of the SPL, a 2.2 GeV superconducting linac with 1.8 mA average current.
We present a summary of simulation results on a muon cooling experiment based on 88MHz cavities. ... more We present a summary of simulation results on a muon cooling experiment based on 88MHz cavities. The systems studied are subsections of the cooling channel in the CERN reference scheme for a neutrino factory. We present two different set-ups using 8 and 4 cavities. For each of these channels we have carried out a beam dynamics study based on engineering
The construction of the Large Hadron Collider at CERN is in its final phase, and commissioning wi... more The construction of the Large Hadron Collider at CERN is in its final phase, and commissioning with beam is scheduled to begin before the end of 2007. It is now time to prepare for increasing as much as possible the performance of this unique instrument to maximize the benefits for physics. An essential part of the proposed luminosity upgrade plan is the replacement of the CERN PS and its injectors by a 50 GeV proton synchrotron (PS2) and a 4 GeV superconducting linac (SPL). The design of the SPL has recently been updated and the optimization of its high-energy part will continue until ~2010. For the foreseen luminosity upgrade of the LHC a low-power version of the SPL (LP-SPL) is under study, which can be upgraded to a multi-megawatt machine providing beam to high-power proton users such as neutrino facilities and/or radio-active beam facilities. The construction start of the low-energy normal conducting SPL front-end, the 160 MeV "Linac4", is scheduled for January 2008, ...
The ultimate luminosity (2.3 x 10<sup>34</sup> cm<sup>-2</sup> s<sup&g... more The ultimate luminosity (2.3 x 10<sup>34</sup> cm<sup>-2</sup> s<sup>-1</sup>) in the LHC can only be reached or even exceeded if a major upgrade of the CERN proton injector complex takes place. The first identified bottleneck towards higher brightness beams is the 50 MeV proton injection of Linac2 into the PS booster (PSB). Doubling the intensity in the PSB can be achieved
The PIMS (Pi-Mode-Structure) cavities for Linac4 are made of 7 coupled cells operating in !-mode ... more The PIMS (Pi-Mode-Structure) cavities for Linac4 are made of 7 coupled cells operating in !-mode at a frequency of 352 MHz. The mechanical concept is derived from the 5-cell cavities used in the LEP machine, whereas cell length and coupling are adapted for proton acceleration in the range from 50 to 160 MeV. Linac4 will be the first machine to employ this type of cavities for low-beta protons. During the first years of operation the PIMS will be used at low duty cycle (0.1%) as part of the consolidated LHC proton injector complex. It is designed, however, to operate eventually in a high duty cycle (10%) proton injector, which could be used as proton front-end for neutrino or RIB applications. To prepare for the series construction of the 12 PIMS units the first cavity (102 MeV beam energy) has been designed and constructed at CERN, to be used as a hot prototype for RF tests and as a pre-series mechanical unit. In this paper we report on some of the design features, the construction ...
Uploads
Papers by F. Gerigk