The “Multimat” experiment at CERN HiRadMat facility: advanced testing of novel materials and instrumentation for HL-LHC collimators

Carra, Federico; Bertarelli, A.; Berthomé, Emmanuel; Fichera, Claudio; Furness, Thomas A.; Guinchard, Michael; Mettler, L. K.; Portelli, Marcus; Redaelli, Stefano; Frutos, Óscar Sacristán de

doi:10.1088/1742-6596/874/1/012001

Cited by 8 publications

(3 citation statements)

References 9 publications

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“…18 different materials were tested in total. e acquisition system included electrical strain gauges and temperature probes placed on the material specimens, along with remote instrumentation including a laser Doppler vibrometer (LDV) oriented towards the top face of the specimens and a side-mounted radiation-hard highdefinition camera [12]. e dimensions for CuCD specimens tested and typical positions of strain gauges and thermal probes are shown in Figure 14.…”

Section: Hrmt36mentioning

confidence: 99%

Thermomechanical Characterisation of Copper Diamond and Benchmarking with the MultiMat Experiment

Portelli

Pasquali

Carra

et al. 2021

Shock and Vibration

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The High-Luminosity Large Hadron Collider upgrade at CERN will result in an increase in the energy stored in the circulating particle beams, making it necessary to assess the thermomechanical performance of currently used and newly developed materials for use in beam intercepting devices such as collimators and absorbers. This study describes the thermomechanical characterisation of a novel copper diamond grade selected for use in tertiary collimators of the HL-LHC. The data obtained are used to build an elastoplastic material model and implemented in numerical simulations performed to benchmark experimental data obtained from the recently completed MultiMat experiment conducted at CERN’s HiRadMat facility, where various materials shaped as slender rods were tested under particle beam impact. The analyses focus on the dynamic longitudinal and flexural response of the material, with results showing that the material model is capable of replicating the material behaviour to a satisfactory level in both thermal and structural domains, accurately matching experimental measurements in terms of temperature, frequency content, and amplitude.

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Section: Hrmt36mentioning

confidence: 99%

Thermomechanical Characterisation of Copper Diamond and Benchmarking with the MultiMat Experiment

Portelli

Pasquali

Carra

et al. 2021

Shock and Vibration

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“…In this case, the radial component was in fact the dominating phenomenon in the signal. Similarly, other experiments which plan to reproduce the behavior of components impacted by particle beams, such as the recently completed HRMT36 (MultiMat) [12], require the use of instrumentation having a high sampling rate in order to register the high-frequency signals. Better understanding of such phenomena ultimately benefits the design of full-scale collimators, which are required to operate safely upon impact of high intensity particle beams [13].…”

Section: Numerical Modeling Of Thermally Induced Elastic Stress Wmentioning

confidence: 99%

Numerical simulation of long rods impacted by particle beams

Portelli

Bertarelli

Carra

et al. 2018

Phys. Rev. Accel. Beams

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Analytical solutions detailing the propagation of longitudinal waves in slender rods subjected to a sudden increase of internal energy provide simple tools for the calculation of the temperature distribution in impacted rods as well as the resulting mechanical response. The topic is of great interest in particle accelerator technology, especially with regards to collimation systems, where beam intercepting devices can be generally approximated to one-dimensional (1D) elements potentially subjected, in accidental scenarios, to abrupt thermal energy depositions induced by the impacting particles. In this study, two finite element numerical models are presented and compared to the analytical solutions by Bertarelli, Dallocchio and Kurtyka, discussing the rapid temperature increase in slender rods due to particle beam impacts and the resulting dynamic longitudinal response. The first model is a sequentially coupled thermomechanical analysis; the second is based on a modal analysis to find the harmonic response of the system. The results indicate that phenomena neglected in analytical solutions, primarily dispersion of the longitudinal wave due to interactions with the free external surface of the rod, can be included in numerical models and can be observed in simulation results. The study further shows how numerical methods can be utilized to predict the frequencies and amplitudes of high-frequency disturbances in the longitudinal wave signal, and how these effects can be mitigated in preparation for experimental scenarios by fine-tuning the geometry of the rod and varying the duration of the pulse. This is especially useful with regards to experiments conducted in the HiRadMat facility at CERN, such as the recently conducted HRMT36 experiment, where highfrequency components can distort the signal to be observed.

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“…Among other options under investigation, the possible realization of a muon ( ) collider is providing a challenging though very exciting opportunity, due to its invaluable sensitivity to investigate new realms of physics [ 1 – 3 ]. The production of beams is typically achieved via the interaction of protons with an energy of a few GeV with stationary targets [ 4 – 6 ]. In this classical production scheme, however, the produced muon beam is characterized by a significant angular divergence, being the result of secondary particles decay.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Modeling for the Thermal Stability of Solid Targets in a Positron-Driven Muon Collider

Cesarini

Antonelli

Anulli³

et al. 2021

Int J Thermophys

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A future multi-TeV muon collider requires new ideas to tackle the problems of muon production, accumulation and acceleration. In the Low EMittance Muon Accelerator concept a 45 GeV positron beam, stored in an accumulation ring with high energy acceptance and low angular divergence, is extracted and driven to a target system in order to produce muon pairs near the kinematic threshold. However, this scheme requires an intensity of the impinging positron beam so high that the energy dissipation and the target maintenance are crucial aspects to be investigated. Both peak temperature rises and thermomechanical shocks are related to the beam spot size at the target for a given material: these aspects are setting a lower bound on the beam spot size itself. The purpose of this paper is to provide a fully theoretical approach to predict the temperature increase, the thermal gradients, and the induced thermomechanical stress on targets, generated by a sequence of 45 GeV positron bunches. A case study is here presented for Beryllium and Graphite targets. We first discuss the Monte Carlo simulations to evaluate the heat deposited on the targets after a single bunch of 3 × 1011 positrons for different beam sizes. Then a theoretical model is developed to simulate the temperature increase of the targets subjected to very fast sequences of positron pulses, over different timescales, from ps regime to hundreds of seconds. Finally a simple approach is provided to estimate the induced thermomechanical stresses in the target, together with simple criteria to be fulfilled (i.e., Christensen safety factor) to prevent the crack formation mechanism.

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The “Multimat” experiment at CERN HiRadMat facility: advanced testing of novel materials and instrumentation for HL-LHC collimators

Cited by 8 publications

References 9 publications

Thermomechanical Characterisation of Copper Diamond and Benchmarking with the MultiMat Experiment

Thermomechanical Characterisation of Copper Diamond and Benchmarking with the MultiMat Experiment

Numerical simulation of long rods impacted by particle beams

Theoretical Modeling for the Thermal Stability of Solid Targets in a Positron-Driven Muon Collider

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