Dynamic testing and characterization of advanced materials in a new experiment at CERN HiRadMat facility

Bertarelli, A.; Accettura, Carlotta; Berthomé, Emmanuel; Bianchi, Laura; Bolz, Philippe; Carra, Federico; Fichera, Claudio; I., Frankl. Matthias; Furness, Thomas A.; Gobbi, Giorgia; Grosclaude, Philippe; Guardia-Valenzuela, J.; Guinchard, Michael; Lechner, Anton; Mollicone, Pierluigi; Pasquali, Michele; Portelli, Marcus; Redaelli, Stefano; Rigutto, Emilien; Frutos, Óscar Sacristán de; Simon, P.

doi:10.1088/1742-6596/1067/8/082021

Cited by 9 publications

(9 citation statements)

References 9 publications

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“…The damage results seen in these experiments are consistent with those obtained in the earlier material study experiments performed in the HiRadMat test area [30,31]. The damage threshold is ∼200 kJ and the extent of damage is of the order of 10 cm in length and 2 mm in width.…”

Section: Irradiation Test Resultssupporting

confidence: 88%

“…The CERN HiRadMat facility allows for destructive testing of accelerator components, including collimators [28,29] and novel materials [30,31]. It takes proton (or heavy ion) beams from the SPS at a maximum energy of 440 GeV, in a train of up to 288 bunches.…”

Section: A Experimental Setupmentioning

confidence: 99%

“…The beam pulse list used in the experiment is shown in Table III. Based on analytic calculations and the experience with previous experiments (e.g., [30,31]), the first three shots should be below or at the onset of plastic damage, which is estimated to be around 2 × 10 12 p at 440 GeV, i.e., 141 kJ. The fourth shot is an intermediary shot, while the following two shots should correspond to the design failure for the rotatable collimator prototype at 7 TeV (1.5 × 10 13 p at 440 GeV, i.e., 1 MJ).…”

Section: Beam Parameters and Pulse Listmentioning

confidence: 99%

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Design, construction, and beam tests of a rotatable collimator prototype for high-intensity and high-energy hadron accelerators

Markiewicz

Bong

Keller

et al. 2019

Phys. Rev. Accel. Beams

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A rotatable-jaw collimator design was conceived as a solution to recover from catastrophic beam impacts which would damage a collimator at the Large Hadron Collider (LHC) or its High-Luminosity upgrade (HL-LHC). One such rotatable collimator prototype was designed and built at SLAC and delivered to CERN for tests with LHC-type circulating beams in the Super Proton Synchrotron (SPS). This was followed by destructive tests at the dedicated High Radiation to Materials (HiRadMat) facility to validate the design and rotation functionality. An overview of the collimator design, together with results from tests without and with beam are presented.

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Section: Irradiation Test Resultssupporting

confidence: 88%

Section: A Experimental Setupmentioning

confidence: 99%

Section: Beam Parameters and Pulse Listmentioning

confidence: 99%

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Design, construction, and beam tests of a rotatable collimator prototype for high-intensity and high-energy hadron accelerators

Markiewicz

Bong

Keller

et al. 2019

Phys. Rev. Accel. Beams

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“…While the resistivity of the substrate is not important for beam stability, provided that the coating thickness is sufficiently large, studies show that a good adhesion and a low coating resistivity is achieved when using MoGr as substrate material (see Section 4 for details). Alternative coatings such as Cu on CFC or MoGr were also studied in dedicated HiRadMat tests [25] but ultimately deemed unfavorable due to the high risk of radiation damage induced in the coating due to beam scratching or impact. For this reason, we restrict ourselves to the analysis of Mo coating layers.…”

Section: Considered Materials Choices For Collimationmentioning

confidence: 99%

Resistivity Characterization of Molybdenum-Coated Graphite-Based Substrates for High-Luminosity LHC Collimators

et al. 2020

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The High-Luminosity Large Hadron Collider (HL-LHC) project aims at extending the operability of the LHC by another decade and increasing by more than a factor of ten the integrated luminosity that the LHC will have collected by the end of Run 3. This will require doubling the beam intensity and reducing the transverse beam size compared to those of the LHC design. The higher beam brightness poses new challenges for machine safety, due to the large energy of 700 MJ stored in the beams, and for beam stability, mainly due to the collimator contribution to the total LHC beam coupling impedance. A rich research program was therefore started to identify suitable materials and collimator designs, not only fulfilling impedance reduction requirements but also granting adequate beam-cleaning and robustness against failures. The use of thin molybdenum coatings on a molybdenum–graphite substrate has been identified as the most promising solution to meet both collimation and impedance requirements, and it is now the baseline choice of the HL-LHC project. In this work we present the main results of the coating characterization, in particular addressing the impact of coating microstructure on the electrical resistivity with different techniques, from Direct Current (DC) to GHz frequency range.

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“…9). The downside of the coating is its lower tolerance to beam losses compared to Mo, which was observed in HiRadMat tests at CERN [52].…”

Section: B Cu Coatingmentioning

confidence: 99%

Transverse beam stability with low-impedance collimators in the High-Luminosity Large Hadron Collider: Status and challenges

Antipov

Accettura

Amorim

et al. 2020

Phys. Rev. Accel. Beams

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The High-Luminosity LHC Project aims to increase the integrated luminosity that will be collected by the Large Hadron Collider for the needs of the high energy physics frontier by the end of its Run 3 by more than a factor ten. This will require doubling the beam intensity, and in order to ensure coherent stability until the brighter beams are put in collision, the transverse impedance of the machine has to be reduced. As the major portion of the ring impedance is generated by its collimation system, several low resistivity jaw materials have been considered to lower the collimator impedance and a special collimator has been built and installed in the machine to study their effect. In order to assess the performance of each material we performed a series of tune shift measurements with LHC beams. The results show a significant reduction of the resistive wall tune shift with novel materials, in good agreement with the impedance model and the bench impedance and resistivity measurements. The largest improvement is obtained with a molybdenum coating of a molybdenum-graphite jaw. This coating, applied to the most critical collimators, is estimated to lower the machine impedance by up to 30% and the stabilizing Landau octupole threshold by up to 240 A after accounting for uncertainties of the model and other destabilising effects. A half of the overall improvement can be obtained by coating the jaws of a subset of 4 out of 11 collimators identified as the highest contributors to machine impedance. This subset of low-impedance collimators is being installed during the Long

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Dynamic testing and characterization of advanced materials in a new experiment at CERN HiRadMat facility

Cited by 9 publications

References 9 publications

Design, construction, and beam tests of a rotatable collimator prototype for high-intensity and high-energy hadron accelerators

Design, construction, and beam tests of a rotatable collimator prototype for high-intensity and high-energy hadron accelerators

Resistivity Characterization of Molybdenum-Coated Graphite-Based Substrates for High-Luminosity LHC Collimators

Transverse beam stability with low-impedance collimators in the High-Luminosity Large Hadron Collider: Status and challenges

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