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Luminosity levelling by β∗ is the baseline scenario for HL-LHC and will possibly be used in 2018 LHC operation. In this MD, we commissioned a novel controls approach to β∗ levelling using improved LSA trims and automatic orchestration. Compared to the regular squeeze using sequences, this approach is aimed to be minimally invasive to LHC operation in Stable Beams. Using this tool, we demonstrated the feasibility of β∗ levelling between 1 m and 30 cm.

Among other functionalities, the tensorics library provides a framework to declaratively describe expressions of arbitrary values and resolve these expressions in different contexts. The Streaming Pool framework provides a comfortable way to transform arbitrary signals from devices into long-living reactive streams. The combination of these two concepts provides a powerful tool to describe modules for online analysis. In this paper we describe this approach, elaborate on the general concepts and give an overview of actual and potential use cases as well as ideas and plans for future evolution., Proceedings of the 16th Int. Conf. on Accelerator and Large Experimental Control Systems, ICALEPCS2017, Barcelona, Spain

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 Positions Monitors and transmitted to dedicated analysis software. We set up the project with a 3-layer software architecture: The central node 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, is currently being developed in a team using Scrum, an iterative and incremental agile software development framework. In this paper we present an overview of this 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., Proceedings of the 16th Int. Conf. on Accelerator and Large Experimental Control Systems, ICALEPCS2017, Barcelona, Spain

Transverse coupling has been linked to instabilities and reduction in dynamic aperture and is hence a crucial parameter to control in the LHC. In this article we describe the development to use driven oscillations to measure the transverse coupling with high intensity beams. The method relies on the use of the transverse damper to drive an oscillation in a similar way as with an AC-dipole. The calculation of the coupling is based on the turn-by-turn data from all available BPMs gated for the excited bunch., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

A common use case in accelerator control systems is subscribing to many properties and multiple devices and combine data from this. A new technology which got standardized during recent years in software industry are so-called reactive streams. Libraries implementing this standard provide a rich set of operators to manipulate, combine and subscribe to streams of data. However, the usual focus of such streaming libraries are applications in which those streams complete within a limited amount of time or collapse due to errors. On the other hand, in the case of a control systems we want to have those streams live for a very long time (ideally infinitely) and handle errors gracefully. In this paper we describe an approach which allows two reactive stream styles: ephemeral and long-living. This allows the developers to profit from both, the extensive features of reactive stream libraries and keeping the streams alive continuously. Further plans and ideas are also discussed., Proceedings of the 16th Int. Conf. on Accelerator and Large Experimental Control Systems, ICALEPCS2017, Barcelona, Spain

This contribution reviews the novel LHC luminosity control software stack. All luminosity-related manipulations and scans in the LHC interaction points are managed by the LHC luminosity server, which enforces concurrency correctness and transactionality. Operational features include luminosity optimization scans to find the head-on position, luminosity levelling, and the execution of arbitrary scan patterns defined by the LHC experiments in a domain specific language. The LHC luminosity server also provides full built-in simulation capabilities for testing and development without affecting the real hardware. The performance of the software in 2016 and 2017 LHC operation is discussed and plans for further upgrades are presented., Proceedings of the 16th Int. Conf. on Accelerator and Large Experimental Control Systems, ICALEPCS2017, Barcelona, Spain