After 9 months of intense activity, the 2024 T8 proton beam run came to an end on November 13, passing the relay for the last two weeks of operations to lead ions and related test activities. Consequently, the CHARM and IRRAD facilities also concluded their proton testing activities on the same day, after a record-breaking run in several respects:
Increased beam intensity in T8. Since 2024, the CHARM facility has benefited from a higher intensity extracted beam in the T8 line. Thanks to the collaborative efforts of the BE, PH, HSE, and SY departments, a thorough study on the feasibility of increasing the T8 line beam from 6•10¹¹ to 8•10¹¹ protons per spill was conducted in 2023.
Beam instrumentation properties, beam extraction parameters, target thermo-mechanical properties, and residual activation of the zone were verified. As a result of these studies, from April to November 2024, BE-OP-PS colleagues managed to direct an unprecedented number of protons to the T8 line during 30 weeks of beam time: 8.4•10¹⁷ protons were delivered in 2024, an impressive 30% increase over 2023. The increase was also consistent week by week: on average, 2.5•10¹⁶ protons per week were delivered, compared to 2.0•10¹⁶ p/w in 2023. Additionally, 97% of weeks received more than 2.2•10¹⁶ protons, while this target was reached only in 33% of weeks in 2023.
Improved delivered radiation levels per week. Thanks to the excellent performance of the T8 beam, CHARM users in 2024 consistently met their testing goals more quickly than planned. This year, 85% of tests had a target of 500 Gy Total Ionizing Dose or more. This goal was achieved by rack users in 93% of cases within just one week, whereas in past years, users with this goal typically required 2 weeks of allocated time in CHARM. High-energy hadron and 1 MeV equivalent neutron fluences also increased significantly, allowing Single-Event Effects and Displacement Damage tests to be completed in shorter timeframes.
Increased number of tests. The higher intensity of the proton beam, and consequently of the mixed-field radiation, allowed an increased number of tests to be performed in CHARM: 172 radiation tests were completed in 2024. 55 of these were system-level tests, of which 53% were from the RCS sector and 47% from the ATS sector. 117 
tests were instead component-level tests, that benefited from another major improvement. This year, a new modular test vessel for component tests was installed in CHARM racks, significantly increasing available testing capacity and reducing installation time. The system uses daughterboards connected to a larger main board for component testing. A single cable with a multipin connector hosting 260 leads connects the main board to acquisition and power supply systems in the control room, reducing setup preparation time in CHARM and minimizing dose exposure to personnel.
More protons on target, same dose to personnel. The higher dose delivered to user setups during irradiation led to increased activation of the controlled area where these setups are finalized before being sent to the irradiation point via robotic devices. This posed additional constraints on planning activities involving user and CHARM team access to the controlled area. Several beam stop schedules were tested to optimize cooldown, maximizing radiation to the test setups while keeping residual activation low. Due to careful planning and continuous monitoring of personnel doses during activities, the collective dose was maintained at 2023 levels, despite a 27% increase in primary protons delivered in 2024.
Soon after the end of the ion run, CHARM and IRRAD will begin their EYETS maintenance, perform routine equipment and infrastructure checks, and prepare for another year of testing starting in April 2025.