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Decommissioning and post-irradiation examination of the LHC beam dumps

N. Solieri*, A. Lund†, A.-P. Bernardes, L. R. Buonocore, A. Cherif, S. De Man, M. Di Castro, S. Di Giovannantonio, G. Dumont et al.

S. El-Idrissi, E. Farina, D. Grenier, E. Grenier-Boley, M. Himmerlich, A. Infantino, A. Lechner, R. Mouret, D. Pazem, A. T. Perez-Fontenla, E. Romagnoli, S. Sgobba, C. Tromel, C. Veiga Almagro, and M. Calviani‡

  • CERN, 1211 Geneva 23, Switzerland

  • *Contact author: nicola.solieri@cern.ch
  • †Contact author: asbjoern.lassen.lund@cern.ch
  • ‡Contact author: marco.calviani@cern.ch
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Phys. Rev. Accel. Beams 28, 083001 – Published 25 August, 2025

DOI: https://doi.org/10.1103/kv1h-3t6z

Abstract

The LHC beam dumps are responsible for the safe absorption of the Large Hadron Collider (LHC) particle beams. In 2018, the two 6.4-tonne beam dumps that had been in operation since the LHC’s startup in 2008 were removed and replaced with upgraded versions. Endoscopic inspections of these beam dumps and experimental high-intensity proton-beam irradiation of material samples raised concerns about the structural integrity of the carbon-based materials in their cores. It was therefore decided to undertake an accelerated project of dismantling and postirradiation examination of the removed dumps as part of a wider program of work to ensure the safe operation of the LHC beam dumps in the coming years. This paper describes the decommissioning process for the two beam dumps carried out at CERN between 2021 and 2023, covering the preparatory studies, practical challenges encountered, and solutions implemented. It details the establishment of an operational framework, including the preparation of the working environment, the development of a method for cutting the irradiated 12-mm-thick duplex stainless-steel vessel, and the cut sequencing. Additionally, the paper presents the findings derived from the postirradiation examination of the different carbon-based core materials subjected to deposited energy densities up to 1.5  kJ/g. The extruded graphite plates within the vessel exhibited a cracking pattern, which was likely due to the dynamic response of the device upon beam impact, and their retaining rings were found to be displaced. Despite minor signs of surface deterioration, the expanded graphite sheets were intact, and the isostatic graphite blocks showed no evidence of material degradation. These findings were consistent across both beam dumps. Finally, this manuscript discusses the implications of these results for the safe operation of the beam dumps during LHC Run 3 (2022–2026) and for the design and construction of Run 3 operational spares.

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References (47)

  1. C. Bracco, W. Bartmann, J. Borburgh, L. S. Ducimetiere, E. Carlier, B. Goddard, N. Magnin, T. D. Mottram, V. Senaj, and C. Wiesner, LBDS Performance in Run 2 (CERN, Geneva, 2019), https://cds.cern.ch/record/2750287.
  2. O. Aberle et al., High-Luminosity Large Hadron Collider (HL-LHC) technical design report, Report No. CERN-2020-010, CERN, Geneva, 2020, https://cds.cern.ch/record/2749422.
  3. J. Maestre et al., Design and behaviour of the Large Hadron Collider external beam dumps capable of receiving 539 MJ/dump, J. Instrum. 16, P11019 (2021).
  4. N. Karastathis et al., LHC Run 3 Configuration Working Group Report (CERN, Geneva, 2019), https://cds.cern.ch/record/2750302.
  5. E. Solfiti, W. Di, A. Celotto, N. Solieri, P. A. Munoz, R. F. Ximenes, A. P. Marcone, F. X. Nuiry, A. Alvaro, F. Berto, and M. Calviani, FIB-SEM investigation and uniaxial compression of flexible graphite, Mater. Des. 233, 112187 (2023).
  6. J. Maestre, P. Andreu-Muñoz, C. Torregrosa, F.-X. Nuiry, K. Kershaw, A. Perillo-Marcone, D. Grenier, R. Franqueira, V. Rizzoglio, A. Lechner, M. Calviani, S. E. Solfiti, F. Berto, and A. Alvaro, Sigraflex® studies for LHC CERN beam dump: Summary and perspective, in Proceedings of the 12th International Particle Accelerator Conference, IPAC-2021, Campinas, SP, Brazil (JACoW, Geneva, Switzerland, 2021), p. 3571, 10.18429/JACoW-IPAC2021-WEPAB368.
  7. P. Andreu Muñoz, M. Calviani, N. Charitonidis, A. Cherif, E. Farina, A. Krainer, A. Lechner, J. Maestre, F.-X. Nuiry, R. Seidenbinder, P. Simon, and C. Torregrosa, Irradiation of low-Z carbon-based materials with 440  GeV/c proton beam for high energy & intensity beam absorbers: The CERN HiRadMat-56-HED experiment, in Proceedings of the 13th International Particle Accelerator Conference, IPAC-2022, Bangkok, Thailand (JACoW, Geneva, Switzerland, 2022), p. 2883, 10.18429/JACoW-IPAC2022-THPOTK049.
  8. International Atomic Energy Agency, Decommissioning of Particle Accelerators, IAEA Nuclear Energy Series No. NW-T-2.9 (IAEA, Vienna, 2020), https://www.iaea.org/publications/12371/decommissioning-of-particle-accelerators.
  9. J. M. Zazula and S. Péraire, LHC beam dump design study; 1, simulation of energy deposition by particle cascades; implications for the dump core and beam sweeping system, Report No. CERN-LHC-Project-Report-80, CERN, Geneva, 1996, https://cds.cern.ch/record/315077.
  10. S. Péraire and J. M. Zazula, LHC beam dump design study; part 2, thermal analysis; implications for abort repetition and cooling system, Report No. CERN-LHC-Project-Report-87, CERN, Geneva, 1996, https://cds.cern.ch/record/318328.
  11. SGL Carbon, SIGRAFINE® R7300 - Fine-grain graphite datasheet (2023), https://www.sglcarbon.com/pdf/SGL-Datasheet-SIGRAFINE-R7300-EN.pdf [accessed July 22, 2025].
  12. SGL Carbon, SIGRAFLEX® APX2, APX-e, C, Z foil - Flexible graphite datasheet (2023), https://www.sglcarbon.com/pdf/SGL-Datasheet-SIGRAFLEX-APX2-APX-E-C-Z-Foil-EN.pdf [accessed July 22, 2025].
  13. SGL Carbon, SIGRAFINE® HLM US—Fine-grain graphite datasheet (2023), https://www.sglcarbon.com/pdf/SGL-Datasheet-SIGRAFINE-HLM-US.pdf [accessed July 22, 2025].
  14. B. Goddard, M. Gyr, J. Uythoven, R. Veness, and W. Weterings, LHC beam dumping system: Extraction channel layout and acceptance, Report No. CERN-LHC-Project-Report-654, 2003, https://cds.cern.ch/record/620648.
  15. J. M. M. Ruiz, K. Kershaw, M. Calviani, D. Grenier, J. Maestre Heredia, C. L. Torregrosa Martin, L. R. Buonocore, P. Serrano Galvez, E. Matheson, J. Sola Merino, M. Guinchard, M. Ferrari, D. Senajova, C. Bertone, M. Perez Ornedo, A. Infantino, and C. Tromel, Practical challenges of the LHC main beam dump upgrades, Report No. CERN-ACC-NOTE-2021-0027, CERN, Geneva, 2021, https://cds.cern.ch/record/2786788.
  16. CERN, The official CERN fluka website, https://fluka.cern/ (2025).
  17. C. Ahdida et al., New capabilities of the fluka multi-purpose code, Front. Phys. 9, 788253 (2022).
  18. G. Battistoni, T. Boehlen, F. Cerutti, P. W. Chin, L. S. Esposito, A. Fassò, A. Ferrari, A. Lechner, A. Empl, A. Mairani, A. Mereghetti, P. Garcia Ortega, J. Ranft, S. Roesler, P. R. Sala, V. Vlachoudis, and G. Smirnov, Overview of the fluka code, Ann. Nucl. Energy 82, 10 (2015).
  19. C. Bracco, M. J. Barnes, W. Bartmann, E. Carlier, L. Ducimetiere, M. Fraser, B. Goddard, A. Lechner, N. Magnin, M. Meddahi, A. P. Marcone, V. Senaj, J. Uythoven, and F. M. Velotti, LBDS and injection system, in Proceedings of the LHC Performance Workshop (Pisa University, Pisa, 2016), https://indico.cern.ch/event/448109/contributions/1942027/.
  20. I. R. Filippini, Dependability analysis of a safety critical system: The LHC beam dumping system at CERN, Ph.D. thesis, Pisa University, 2006, https://cds.cern.ch/record/995680.
  21. E. Carlier, A. Antoine, P. Bobbio, G. Gräwer, A. Marchand, J. Uythoven, and H. Verhagen, Design aspects related to the reliability of the control architecture of the LHC beam dump kicker systems, Report No. CERN-LHC-Project-Report-679, CERN, Geneva, 2003, https://cds.cern.ch/record/684957.
  22. A. Lechner, C. Bracco, M. Calviani, Y. Dutheil, E. Farina, and C. Wiesner, Beam-induced energy deposition on dump block assembly (2021), https://edms.cern.ch/ui/#!master/navigator/document?D:101746510:101746510:subDocs.
  23. R. Bailey and P. Collier, Standard filling schemes for various LHC operation modes, Report No. LHC-PROJECT-NOTE-323, CERN, Geneva, 2003, https://cds.cern.ch/record/691782.
  24. SGL Carbon, SIGRAFLEX® TH, NH, THP, S, HP, UHP foil—Flexible graphite datasheet (2023), https://www.sglcarbon.com/data/pdf/SGL-Datasheet-SIGRAFLEX-TH-NH-THP-S-HP-UHP-Foil-EN.pdf [accessed July 22, 2025].
  25. CERN, Code F Rev. Radiation protection - radiation protection manual radioprotection - manuel de radioprotection, https://edms.cern.ch/document/335729 (2006).
  26. D. Bozzato, P. Dyrcz, R. Froeschl, A. Infantino, T. Lorenzon, M. Tisi, and H. Vincke, Advanced simulation techniques for radiation protection studies at the Large Hadron Collider, Radiat. Phys. Chem. 218, 111573 (2024).
  27. H. Vincke and C. Theis, ActiWiz 3 - An overview of the latest developments and their application, J. Phys. Conf. Ser. 1046, 012007 (2018).
  28. A. Infantino, A.-P. Bernardes, M. Calviani, G. Dumont, S. El-Idrissi, R. Mouret, C. Tromel, and H. Vincke, Radiation protection challenges in the upgrade, autopsy and disposal of the LHC beam dump, Radiat. Prot. Dosim. 199, 891 (2023).
  29. A. Infantino, R. W. Harbron, R. Mouret, P. Bertreix, A.-P. Bernardes, L. Bruno, M. Calviani, G. Dumont, S. El-Idrissi, M. Magistris, N. Menaa, C. Theis, C. Tromel, and H. Vincke, Radiological characterization for the disposal of a decommissioned LHC external beam dump at CERN, Eur. Phys. J. Plus 138, 692 (2023).
  30. M. Di Castro, L. R. Buonocore, M. Ferre, S. Gilardoni, R. Losito, G. Lunghi, and A. Masi, A dual arms robotic platform control for navigation, inspection and telemanipulation, in Proceedings of the 16th International Conference on Accelerator and Large Experimental Control Systems, ICALEPCS-2017, Barcelona, Spain (JACoW, Geneva, Switzerland, 2017), pp. 8–13, https://cds.cern.ch/record/2305665.
  31. CERN, REMUS: Supervisory control and data acquisition (2025), https://hse.cern/content/remus-supervision-control-and-data-acquisition-systems-radiation-and-environmental [accessed July 22, 2025].
  32. International Atomic Energy Agency, Characterization, Treatment and Conditioning of Radioactive Graphite from Decommissioning of Nuclear Reactors, TECDOC Series No 1521 (International Atomic Energy Agency, Vienna, 2006), https://www.iaea.org/publications/7579/characterization-treatment-and-conditioning-of-radioactive-graphite-from-decommissioning-of-nuclear-reactors.
  33. International Atomic Energy Agency, Progress in Radioactive Graphite Waste Management, TECDOC Series No. 1647 (International Atomic Energy Agency, Vienna, 2010), https://www.iaea.org/publications/8421/progress-in-radioactive-graphite-waste-management.
  34. International Atomic Energy Agency, Processing of Irradiated Graphite to Meet Acceptance Criteria for Waste Disposal, TECDOC Series No. 1790 (International Atomic Energy Agency, Vienna, 2016), https://www.iaea.org/publications/10978/processing-of-irradiated-graphite-to-meet-acceptance-criteria-for-waste-disposal.
  35. R. Froeschl, A method for radiological characterization based on fluence conversion coefficients, J. Phys. Conf. Ser. 1046, 012006 (2018).
  36. KUKA Robotics, KR 120 R2700 extra HA - Industrial robot datasheet (2025), https://my.kuka.com/s/product/kr-120-r2700-extra-ha/01t58000002hnhLAAQ?language=en_US&tab=Overview [accessed July 22, 2025].
  37. Keyence Corporation, GT2-P12 contact distance sensor - Technical datasheet (2025), https://www.keyence.eu/products/measure/contact-distance-lvdt/gt2/models/gt2-p12/ [accessed July 22, 2025].
  38. Hoffmann Group, Technical datasheet - Product 22709 (2025), https://cdn.hoffmann-group.com/dsh/en-GB/dsh_en-gb_22709.pdf [accessed July 22, 2025].
  39. Husqvarna, IPL, Husqvarna, WS 220, 2013-10, WALL SAWS, https://www.husqvarnaconstruction.com/int/prime-equipment/ws220/ (2018).
  40. Creaform, MetraSCAN - Optical 3D scanner (2025), https://www.creaform3d.com/en/products/portable-3d-scanners/optical-3d-scanner-metrascan [accessed March 14, 2025].
  41. P. Stefan and P. Ana Teresa, Post-mortem microscopic examination of SIGRAFLEX samples from TDE dump, CERN Technical Report No. 2781278, 2022, https://edms.cern.ch/document/2781278/1.
  42. H. Moreno Fernández, M. Himmerlich, P. Costa Pinto, J. Coroa, D. Sousa, A. Baris, and M. Taborelli, The impact of H2 and N2 on the material properties and secondary electron yield of sputtered amorphous carbon films for anti-multipacting applications, Appl. Surf. Sci. 542, 148552 (2021).
  43. M. Himmerlich, X-ray photoelectron spectroscopy (XPS), CERN Technical Report No. 2791324, 2022, https://edms.cern.ch/document/2791324/1.
  44. M. Dakshinamurthy, Comparative analysis of isostatic graphite samples from TDE dump, Technical Report No. EDMS 3283813, CERN, 2025, https://edms.cern.ch/document/3283813/1.
  45. M. Brice, LHC external beam dump (TDE) autopsy, Report No. CERN-PHOTO-202201-026, CERN, Geneva, 2022, https://cds.cern.ch/record/2801209.
  46. F. Berto, P. Lazzarin, and M. Ayatollahi, Brittle fracture of sharp and blunt V-notches in isostatic graphite under pure compression loading, Carbon 63, 101 (2013).
  47. U. Gruber, O. Öttinger, W. Baur, and L. Fischer, 12.2 carbon fiber reinforced carbon, in Industrial Carbon and Graphite Materials (John Wiley & Sons Ltd., New York, 2021), Chap. 12.2, pp. 740–824, 10.1002/9783527674046.ch12_2.

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Phys. Rev. Accel. Beams 28, 083001– Published 25 August, 2025
  • Received 8 May 2025
  • Accepted 14 July 2025
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