TAN (Target Absorber Neutral)
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| TAN (Target Absorber Neutral) | |
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| Name | TAN (Target Absorber Neutral) |
| Facility | CERN |
| Country | Switzerland/France |
| Status | Decommissioned (some elements upgraded) |
| Primary beam | Large Hadron Collider (LHC) |
| Function | Neutral particle absorber / collimation support |
TAN (Target Absorber Neutral) The Target Absorber Neutral was a specialized absorber assembly installed in the complex of the Large Hadron Collider at CERN near Point 1 and other interaction regions, designed to intercept neutral particles and protect downstream equipment. It served as an interface between the interaction regions hosting experiments such as ATLAS, CMS, LHCb, and ALICE and the accelerator beamline, integrating with systems developed by collaborations and organizations including European Organization for Nuclear Research, ITER (technology exchanges), and industrial partners. The device linked beam optics considerations from groups like the Beams Department (CERN) with detector operations influenced by teams from Fermilab, DESY, and SLAC National Accelerator Laboratory.
Introduction
The absorber assembly was conceived during upgrades planned after projects such as the LEP shutdown and in parallel with designs for the High-Luminosity Large Hadron Collider that involved coordination among institutes like Imperial College London, University of Oxford, Université de Genève, and ETH Zurich. Engineering drew on experience from machines including the Super Proton Synchrotron and concepts tested in facilities at Brookhaven National Laboratory, KEK, and TRIUMF. The TAN balanced requirements from accelerator physicists associated with LHC Machine Committee and detector physicists linked to collaborations like ATLAS Collaboration and CMS Collaboration.
Design and Function
The absorber consisted of heavy-metal blocks, cooling channels, motorized supports, and instrumentation developed by teams at CERN in partnership with contractors such as Chantiers de l'Atlantique-type industry suppliers and research groups from École Polytechnique Fédérale de Lausanne and Politecnico di Milano. Its role was to intercept secondary neutral particles, integrate with collimation schemes from groups like the LHC Collimation Working Group, and protect downstream equipment such as quadrupoles from beam debris seen in studies by John Adams Institute and simulations performed with codes from GEANT4 developers and FLUKA teams. Design reviews involved experts from ITER Organization, European XFEL, and industrial advisory panels tied to CERN Technology Department.
Location within CERN Facilities
Installed near interaction points used by experiments such as ATLAS and CMS, the absorber sat between detector cavern interfaces and accelerator cryostats supplied by vendors like Air Liquide and Siemens. Layout decisions considered constraints from tunnels like the LEIR connection and surface buildings managed by the CERN Site Management teams as well as civil engineering standards upheld by authorities in Geneva and Haute-Savoie. Its position was coordinated with adjacent systems developed by groups including Magnet Section (CERN) and Cryogenics Group (CERN).
Operational History
Commissioning drew on expertise from accelerator operations teams led by figures associated with the LHC Commissioning Team, and early operation phases were synchronized with detector commissioning by ATLAS Collaboration, CMS Collaboration, and ALICE Collaboration. Operational incidents and performance assessments involved input from safety reviewers from institutions like European Council agencies and were documented alongside machine studies by colleagues from Brookhaven and Fermilab. Upgrades during LHC Run 2 and planning for Run 3 saw collaboration with groups such as High Luminosity LHC Project engineers and researchers at CERN and partner laboratories.
Radiation Shielding and Safety Measures
Shielding design referenced standards from bodies such as the International Commission on Radiological Protection and used materials characterized by teams at Paul Scherrer Institute and CEA. Safety integration required coordination with the CERN Radiation Protection Group, regulatory authorities in Switzerland and France, and technical contributions from European Space Agency-affiliated radiation experts. Monitoring employed detectors and readout systems developed in collaboration with researchers from INFN, Max Planck Society, and national laboratories like JINR.
Role in Beam Loss Management and Collimation
The absorber functioned as part of the multi-stage collimation system developed with input from the LHC Collimation Working Group, simulation support from CERN openlab partners, and theoretical modelling from groups at University of Manchester, University of California, Berkeley, and Technische Universität Dresden. It interacted with primary and secondary collimators influenced by designs from Diamond Light Source engineering teams and contributed to beam loss maps used by the Machine Protection System (CERN) and studies conducted with software tools maintained by CERN IT Department and collaborators from LAPP.
Decommissioning, Upgrades, and Future Plans
As the LHC evolved toward the High-Luminosity LHC era, plans for replacement, upgrade, or decommissioning involved consortia including CERN departments, universities such as University College London, and national laboratories including SLAC and KEK. Future absorber concepts draw on research from projects like FCC studies, approved upgrade roadmaps from the European Strategy for Particle Physics and technical proposals presented to committees such as the Update of the European Strategy for Particle Physics. Decisions considered lessons from incident reports involving teams at CERN and partner institutions, and potential re-use or recycling strategies were evaluated with industrial partners like Veolia and ArcelorMittal.
Category:CERN infrastructure