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The enigma of sleep: Why it is essential to life and what happens when it fails
No full textAbstract:
Sleep remains one of the most fascinating and indispensable biological functions, yet its fundamental purpose is still not fully understood. If sleep were not essential to survival, its conservation across evolution would represent the greatest mistake of nature. Across species, sleep is remarkably preserved, pointing to critical roles in brain homeostasis, memory consolidation, and systemic physiology. Its regulation relies on a finely tuned interplay between circadian rhythms and homeostatic sleep pressure. When sleep is disrupted through unstable sleep–wake boundaries (parasomnias), abnormal motor activity, or breathing disorders such as sleep apnea, the consequences extend to cognition, metabolism, and cardiovascular health. In this talk, I will explore the key unanswered questions about why we sleep, how sleep disorders can affect our health, and highlight how emerging technologies are reshaping our ability to study and treat them.
Short Bio:
After completing his training in internal medicine, including research stays at the Stanford Sleep Center in Palo Alto and Harvard Medical School, Prof. Heinzer established the sleep research center CIRS in 2006. This center is a collaboration of the University of Lausanne and the University Hospital CHUV, and it is the site of the largest dataset of a population-based sleep cohort. Today, Prof. Heinzer and his team conduct over 1000 sleep examinations annually. His research focuses on the physiology and epidemiology of various sleep disorders - including apnea, insomnia, hypersomnia, parasomnia. He also dedicates part of his work to studying sleep under extreme conditions such as high altitude, solo sailing, or long-duration flights as in the case of Solar Impulse.
This is the first of two CERN Academic Training Lectures on Human Sleep. The second will be given by Francesca Siclari on 20 January 2026 - "The Neuroscience of Dreaming"
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Shutter-type multi-point optical alignment using a Structured Laser Beam in vacuum
No full textThis paper presents an alignment concept employing a Structured Laser Beam (SLB) for offset measurements over a 140 m distance. The prototype consists of an SLB generator and three measurement stations within a vacuum system. The Inner Core (IC) of the SLB establishes an optical axis that serves as a reference line. A comparative assessment is performed against a Wire Positioning System (WPS) and Hydrostatic Levelling System (HLS). Two independent measurements of the prototype show that it exhibits high relative precision, with a standard deviation of offset measurements below 20 μm. The acquisitions reveal that the prototype results are shifted relative to WPS-HLS measurements. This shift, observed in both transverse directions, can be attributed to the multi-stage fiducialisation process, which introduces additional uncertainty. This result can be improved by modifying the prototype design and the fiducialisation measurement method. The SLB-based prototype is a promising candidate for alignment applications in particle accelerators due to its high precision over long distances
Electro-optic frequency combs for high flux X-ray generation via high-intensity laser-particle interactions at CERN
No full textElectro-optic frequency comb (EOFC) technology has undergone a significant development in recent years, driven by the increasing demand for agile ultrafast optical systems in both scientific research and commercial applications. Advances in integrated and fiber-based GHz modulators operating in the near-infrared (NIR) region have enabled the use of modulation techniques to efficiently generate ultrafast laser pulses with arbitrary repetition rates of up to 10s of GHz and tunable pulse duration down to 100s of fs. This technology is particularly well suited for use in high-repetition-rate accelerators, which operate in the 3 – 12 GHz domain and with burst time structures that diverge significantly from the regular pulse trains routinely produced by amplified mode-locked lasers in the MHz and kHz regime.Electro-optic frequency comb (EOFC) technology has undergone a significant development in recent years, driven by the increasing demand for agile ultrafast optical systems in both scientific research and commercial applications. Advances in integrated and fiber-based GHz modulators operating in the near-infrared (NIR) region have enabled the use of modulation techniques to efficiently generate ultrafast laser pulses with arbitrary repetition rates of up to 10s of GHz and tunable pulse duration down to 100s of fs. This technology is particularly well suited for use in high-repetition-rate accelerators, which operate in the 3 - 12 GHz domain and with burst time structures that diverge significantly from the regular pulse trains routinely produced by amplified mode-locked lasers in the MHz and kHz regime
Higgs boson measurements and searches for new scalars with ATLAS
No full textThis talk provides an updated review of the progress made at the ATLAS experiment at the LHC, concentrating particularly on the scalar sector and searches for new particles
Z counting in 2024
No full text yields provide a physics-based cross-check of online luminosity. Fill-level and yearly trends of remain stable at the percent level while reflecting updates to online calibrations (vdM/efficiency), validating the delivered luminosity scale independently of luminometer-specific assumptions
Autoencoder-based time series anomaly detection for ATLAS Liquid Argon calorimeter data quality monitoring
No full textThe ATLAS experiment at the LHC employs comprehensive data quality monitoring procedures to ensure high-quality physics data. This contribution presents an LSTM autoencoder-based algorithm for detecting anomalies in ATLAS Liquid Argon calorimeter data, represented as multidimensional time series of statistical moments of energy cluster properties. Trained unsupervised on good-quality data, the model identifies anomalous intervals of data-taking. Validation is performed using the liquid argon noise burst phenomenon, and the potential for broader application to transient calorimeter issues is discussed
Development of new large area Micromegas detector and its ToRA ASIC-based readout electronics for AMBER experiment at CERN
No full textAs part of the extensive upgrade program of the Apparatus for Mesons and Baryon Experimental Research (AMBER, NA66) spectrometer a resistive bulk MICRO-MEsh-GAseous Structure (micromegas) detectors with an active area of 1x0.5m2 has been selected for the replacement of some Multi-Wires Proportional Chambers. This detector will be made out of three independent modules. Each micromegas detector has two readout planes in a face-to-face configuration and a common cathode providing an XUV measurement. For the lateral modules a uniform 10Ω/cm2 Diamond-Like Carbon (DLC) layer was chosen. The production of the first detector was completed in October 2024 and the test campaign is underway. The first module under test is presently the largest resistive bulk MM in operation. Leveraging results gained from prior tests of smaller MM prototype a new 64-channel mixed-signal front-end Application Specific Integrated Circuit (ASIC) for time and energy measurements is under development at INFN Sezione di Torino. The ongoing work on the detector and on the front-end electronics based on the new ToRA (Torino Readout for AMBER) ASIC, is presented
Developments of GNN Track Reconstruction for the ATLAS ITk Detector
No full textTrack reconstruction is a cornerstone of modern collider experiments, and the HL-LHC ITk upgrade for ATLAS poses new challenges with its increased silicon hit clusters and strict throughput requirements. Deep learning approaches compare favorably with traditional combinatorial ones — as shown by the GNN4ITk project, a geometric learning tracking pipeline that achieves competitive physics performance at sub-second inference times. In this contribution, we evaluate a range of pipeline configurations and machine learning inference strategies that further improve track reconstruction at lower latencies. We present benchmarks for latency, throughput, memory usage, and power consumption across these pipelines. New developments include improved GPU-based module map performance and memory optimizations; model enhancements through pruning, quantization and advanced compilation techniques used in industry; and a custom graph segmentation approach. These upgrades allow the pipeline to target trigger-level track reconstruction in certain conditions. We also discuss improvements in track fitting, integrations into traditional-learned hybrid pipelines, GNN-based seeding, triplet-wise processing of cluster features, and production readiness with inference-as-a-service
Top quark pair production + vector boson in ATLAS
No full textThe high center-of-mass energy of proton-proton collisions and the large available datasets at the CERN Large Hadron Collider allow the study of rare processes of the Standard Model with unprecedented precision. Measurements of rare SM processes provide new tests of the SM predictions with the potential to unveil discrepancies with the SM predictions or provide important input for the improvement of theoretical calculations. In this contribution, total and differential measurements of associated top-quark production are shown using data taken with the ATLAS Experiment at a center-of-mass-energy of 13 TeV. These measurements provide important bounds on the electroweak couplings of the top quark, often with Effective Field Theory interpretations and constrain backgrounds that are important in searches for Higgs production and for new phenomena beyond the SM