The engineer Cristopher Rozas, researcher at the Millennium Institute SAPHIR, is part of the international team developing the Inner Tracker (ITk), the new internal detection system of the ATLAS experiment at CERN, one of the most ambitious scientific projects in the world. This upgrade, part of the Phase-II Upgrade of the Large Hadron Collider (LHC), will multiply the collider's luminosity and increase precision in the search for new particles and fundamental phenomena in physics.
In this context, Rozas is actively participating in the design and development of the Environmental Enclosure (EEn), a modular structure that will play an essential role during the quality control tests of the ITk pixel detector. Its function will be to protect the system components during the integration stages, ensuring optimal conditions of temperature, humidity and hermeticity. The EEn will allow the tests to be carried out in a controlled environment, guaranteeing the stability of extremely sensitive parts before their final installation in the Point 1 sector of CERN, the area where the ATLAS experiment is located.
Currently, the Environmental Enclosure is in a mechanical design stage focused on the main structure and the hermetic panels that will maintain the required environmental conditions inside the enclosure. At this stage, work is focused on the validation of prototypes that will allow consolidating a final design for manufacturing by the end of this year. Once this process is completed, manufacturing is expected to take place during the first quarter of 2026, while assembly and initial tests - known as commissioning or "in vacuum" testing - will be carried out during the second quarter of the same year. Subsequently, during the third quarter, the EEn will be used in integration tests with the Outer Barrel Half Layers, a fundamental stage that will allow validation of parts, detection systems and ITk operating conditions prior to final installation.
The design of the Environmental Enclosure responds to a set of very specific technical requirements. Its modular structure, made of aluminum profiles and removable panels, must meet high standards of precision and strength. Each component of the system must weigh less than 20 kilograms so that it can be handled by one or two people without requiring heavy machinery, while also withstanding multiple assemblies and disassemblies—at least sixteen times during the entire detector integration process—without compromising its structural integrity.
Another key aspect of the design is the system's ability to maintain a completely controlled internal environment. Through the injection of dry air, the aim is to avoid the formation of moisture or ice near the detector's CO₂ cooling system, while the hermeticity of the enclosure prevents air leaks or light ingress, factors that could alter measurements during testing. In parallel, the EEn must incorporate technical interfaces known as feedthroughs, which allow signals, power and services to pass between the inside and outside of the enclosure without compromising the thermal stability or airtightness of the system.
Rozas' participation in this project combines technical expertise, design management and interdisciplinary work. With more than eight years of experience in applied research and technology development projects, he has worked in the design, manufacture and operation of complex equipment, using advanced modeling and simulation tools such as Autodesk Inventor, SolidWorks, CATIA and ANSYS FEA. His experience in precision engineering and structural analysis has been fundamental to optimize decisions prior to manufacturing processes, allowing to validate solutions from early design stages.
Currently, Rozas receives specialized training in CAD-CAE design management for complex equipment, which has allowed him to actively contribute in critical areas of mechanical design and systems integration within the international ATLAS ITk team. This work, in which engineering and physics meet, reflects the importance of multidisciplinary collaboration and the impact of knowledge generated from Chile at the frontier of world science.
For the researcher, being part of this project has been a unique opportunity for professional and personal growth. His work at CERN represents not only a direct contribution to the future of particle physics, but also a concrete example of the value of talent and scientific training promoted by SAPHIR. Through his participation, Rozas strengthens the ties between Chilean engineering and the global scientific community, contributing to the development of technologies that will make it possible to observe the universe with unprecedented precision.
Cristopher Rozas |Mechanical Civil Engineer, Federico Santa María University
