Delphine Jacquet

JACoW : Online coupling measurement and correction throughout the LHC cycle

With high intensity beams, a precise measurement and effective correction of the betatron coupling is essential for the performance of the Large Hadron Collider (LHC). In order to measure this parameter, the LHC transverse damper (ADT), used as an AC dipole, will provide the necessary beam excitation. The beam oscillations will be recorded by the Beam Position Monitors and transmitted to dedicated analysis software. We set up the project with a 3-layer software architecture: The central part is a Java server, orchestrating the different actors: The Graphical User Interface, the control and triggering of the ADT AC dipole, the BPMs, the oscillation analysis (partly in Python), and finally the transmission of the correction values. The whole system was developed in a team using Scrum, an iterative and incremental agile software development framework. In this paper we present an overview of the system, experience from machine development and commissioning as well as how scrum helped us to achieve our goals. Improvement and re-use of the architecture with a nice decoupling between data acquisition and data analysis are also briefly discussed.

JACoW : Development of a New System for Detailed LHC Filling Diagnostics and Statistics

In the CERN accelerator complex the Super Proton Synchrotron (SPS) is used as injector of the Large Hadron Collider (LHC). Statistics on the injection and beam availability in 2015 showed that too much time is spent at injection. Reducing this time could improve LHC availability and luminosity over the year. Currently, useful data to diagnose the problems is sparse and shown in different applications. Operators time is wasted in debugging and checking for the source of the problem before trying another injection. A new Software application for diagnostics of the LHC Filling is under development which collects data from multiple inputs of the CERN Control System and concentrates them in one central view. The inputs are processed and matched with a set of rules (or assertions) that need to be fulfilled for an injection to be successful. Whenever a problem occurs, the operator can check the Filling Diagnostic for hints on what is the source of the problem during the injection. Filling Diagnostic also produces statistics of the LHC injections and the causes of failed injections, this will allow significantly better analysis of the LHC performance for next year.

JACoW : Phase Advance Interlocking Throughout the Whole LHC Cycle

Each beam of CERN’s Large Hadron Collider (LHC) stores 360 MJ at design energy and design intensity. In the unlikely event of an asynchronous beam dump, not all particles would be extracted immediately. They would still take one turn around the ring, oscillating with potentially high amplitudes. In case the beam would hit one of the experimental detectors or the collimators close to the interaction points, severe damage could occur. In order to minimize the risk during such a scenario, a new interlock system was put in place in 2016. This system guarantees to keep the phase advance within an acceptable range between the extraction kicker and the interaction point. This contribution describes the motivation for this new system as well as the technical implementation and the strategies used to derive appropriate tolerances to allow sufficient protection without risking false beam dump triggers.