JET machine operations in T&D-T

JET, the world's largest operating tokamak with unique Be/W wall and tritium handling capability, completed a Deuterium-Tritium (D-T) campaign in 2021 (Maggi et al 29th Fusion Energy Conf.) following a decade of preparatory experiments, dedicated enhancements, technical rehearsals and training (Horton et al 2016 Fusion Eng. Des. 109-111 925). Operation with tritium raises significant technical, safety and scientific challenges not encountered in standard protium or deuterium operation. This contribution describes the tritium operational requirements, pulses and technical preparations, new operating procedures, lessons learned and details on the achieved operational availability and performance. The preparation and execution of the recent JET tritium experiments benefitted from the previous experience in 1991 (Preliminary Tritium Experiment), 1997 (DTE1 campaign) and 2003 (Trace Tritium Campaigns) and consisted of the following five phases: technical rehearsals and scenario preparation, tritium commissioning, 100% tritium campaign, D-T campaign (DTE2), tritium clean-up. Following the clean-up JET resumed normal operation and is currently undertaking a further D-T campaign (DTE3)

Heart Rate Synchronisations During Movie Watching

When different people watch the same movie, synchronisation of brain activity between individuals is observed (Hasson et al., 2004; Hasson et al., 2008; Hasson et al., 2010). Similarly, heart rate changes synchronise between individuals watching the same movie (Madsen & Parra, 2022; Hammond et al., 2024), suggesting that heart rate synchrony may reflect similar cognitive processing across individuals. Such heart rate synchronisations are thought to be modulated by attention to the movie (Perez et al., 2021), and influenced by how engaging (Hammond et al., 2023) or emotional (Golland et al., 2014; Golland et al., 2015) the video is. To further our understanding of the factors underlying heart rate synchrony, we will conduct a large-scale study investigating intersubject correlations of heart rate (ISC-HR) between individuals watching a movie, titled: “Bang! You’re Dead.” by Alfred Hitchcock. This film has been used previously in ISC-brain studies (e.g. Geerligs & Campbell, 2018), with higher ISC in brain activity linked to the more suspenseful parts of the movie (Naci et al., 2014). We will extract heart rate and calculate ISC-HR values from pulse oximetry data, provided by the Cam-CAN database (Shafto et al., 2014; Taylor et al., 2017), which was collected in an MRI scanner as participants watched the movie. Additionally, we will collect data from two further groups of participants, who will complete one of two tasks - an auditory sustained attention reaction task (SART), to measure how engaging each part of the movie is, or a suspense rating task, to track the level of suspense felt throughout the movie. This data will allow us to determine how time-varying feelings of suspense and engagement are linked to the ISC-HR extracted from the pulse oximetry data. We hypothesise that heart rate fluctuations will correlate with fluctuations in engagement and feelings of suspense reported by this separate group of participants