Search

The Libera Hadron is in day-to-day use at the COoler SYnchrotron (COSY) since 2017. Since then the standard measurements like ADC, bunch and slow data are in daily use as well as an orbit correction algorithm based on the slow data. The operational experience of the Libera and the EPICS interface will be discussed, as well as new applications presented, whose development is based on the Libera data: tune and chromaticity measurements.

Successful operation of a particle accelerator requires accompanying model calculations. The model helps in understanding the machine and predicts the impact of a change in the settings (e.g. current of magnetic elements). For the COoler SYnchrotron (COSY) at Research Center Jülich the accelerator simulation software MAD-X is used to model the machine. The model parameters are steadily being improved based on various manual adjustments and analytical studies, however are hardly optimized all at once. This can be improved with machine learning methods. The model is used to predict measurable quantities, like Orbit Response Matrix (ORM) or betatron tunes. Several observables for different particle energies have been measured recently and the corresponding machine settings are available. We describe the effort to improve the agreement between measured and calculated ORMs and hence improve the agreement between model and (real) machine and report on the optimization using a multivariate algorithm (e.g. genetic algorithm). This facilitates the setup of COSY and will allow to perform high precision experiments e.g. a measurement of an electric dipole moment of deuterons at COSY., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

Dissertation, RWTH Aachen University, 2021; Aachen : RWTH Aachen University 1 Online-Ressource : Illustrationen, Diagramme (2021). = Dissertation, RWTH Aachen University, 2021, The aim of the Double Chooz experiment is a precise measurement of the neutrino oscillation angle $\theta_{13}$ with the deployment of two liquid scintillator neutrino detectors at $1.05$ km (far) and $400$ m (near) from the reactors of the Chooz-B nuclear power plant in France. The first part of this thesis describes the efforts following the construction of the near detector, i.e. its commissionning with the focus on the trigger system upgrade for two-detector data taking. The upgrade is shown to improve the detector performance. The second part of this thesis analyses the seasonal modulation of the muon rate at the far detector potentially contributing to understanding of the muon spectrum at the detector and improvement of the muon background understanding., Published by RWTH Aachen University, Aachen

Developments in orbit measurement and control at COSY are presented and further plans outlined.

The Cooler Synchrotron COSY operated at the Research Center Jülich is undergoing staged machine control upgrades driven by the requirements of the JEDI (Jülich Electric Dipole moment Investigations) collaboration. The upgrades aim towards better beam control e.g. beam orbit, tune, and chromaticity control improvements. A better orbit control was achieved through the upgrade of BPM electronics and migration from initial Tcl/Tk based control system to Control System Studio (CSS) utilizing EPICS. Currently, a design for improved beam tune control is in development. The main part of work is the transition towards a faster and less restrictive magnet control. It further includes improved tune measurement tools as well as the migration of control for quadrupole magnets to EPICS. Ultimately the control of all systems should be centralized around EPICS to enable ease of operation, automation, setup of services, etc. The decision path, technical details of the upgrade and performance of the upgraded sub-systems are presented. We also showcase how the COSY team’s physics and research goals are complemented by Cosylab’s technical design and implementation to form a synergetic collaboration., Proceedings of the 10th Int. Particle Accelerator Conf., IPAC2019, Melbourne, Australia

The beam position monitoring system of the Cooler Synchrotron (COSY) has been upgraded in 2017. The upgrade was driven by the requirement of the JEDI collaboration to significantly improve the orbit control and by the electronics approaching end-of-life. The entire signal processing chain has been replaced. The new low noise amplifiers, mounted directly on the BPM vacuum feedthroughs, were developed in-house and include adjustable gain in 80 dB rage and in-situ test and calibration capabilities. The signals are digitized and processed by means of commercial BPM signal processing units featuring embedded EPICS IOC. The decision path, technical details of the upgrade and performance of the new system are presented., Proceedings of the 7\textsuperscript{th} Int. Beam Instrumentation Conf., IBIC2018, Shanghai, China

The Cooler Synchrotron COSY can store and deliver proton and deuteron beam in the momentum range from 0.3 GeV/c to 3.65 GeV/c for internal and external experiments. New requirements of the Jülich Electric Dipole Moment Investigation (JEDI) experiment requires a RMS beam orbit distortion smaller than 100 um. This requirement lead so far to the replacement of the BPM readout electronics, an introduction of a slow beam orbit correction and feedback system and the re-alignment of the magnets. All three projects are close to completion, therefore first results are presented., Proceedings of the 6th Int. Beam Instrumentation Conf., IBIC2017, Grand Rapids, MI, USA

The Cooler Synchrotron (COSY) is currently operated mainly for accelerator and detector related preparations for the future accelerator facility FAIR as well as the Electric Dipole Moment (EDM) investigations. In order to reach the goals of current and future experiments, fast and reliable real-time diagnostic of beam parameters is crucial. Therefore many present subsystems are being upgraded and new systems are added. Integration of these systems into the Experimental Physics and Industrial Control System (EPICS) enabling online monitoring and archiving is one of the core activities. These include, but are not limited to, Beam Position Monitors (BPM), Beam Loss Monitors (BLM), Profile Grids and Multi-Wire Proportional Chambers, Spill Detector. Latest activities and achievements are presented.

Diagnostics of beam parameters is vital for the operation of any particle accelerator and contributes to the precision of the physics experiments. At COoler SYnchrotron of the Forschungszentrum Jülich there are several beam instrumentation subsystems with data acquired and processed in real-time for machine and operator use to ensure safe and efficient performance. Here are presented current development for the Beam Loss Monitor (BLM) with regard to usage of field programmable gate arrays (FPGAs) to achieve fast data processing and integration into the Experimental Physics and Industrial Control System (EPICS) used at COSY. Also presented is a way to create and run Graphical User Interfaces based on EPICS variables with Control System Studio (CSS) connected to a data archiving system to display and use previously collected data., Proceedings of the 16th Int. Conf. on Accelerator and Large Experimental Control Systems, ICALEPCS2017, Barcelona, Spain

Journal of high energy physics 1601(1), 163 (2016). doi:10.1007/JHEP01(2016)163, Published by Springer, Berlin

The Double Chooz collaboration presents a measurement of the neutrino mixing angle θ[subscript 13] using reactor [bar over ν[subscript e]] observed via the inverse beta decay reaction in which the neutron is captured on hydrogen. This measurement is based on 462.72 live days data, approximately twice as much data as in the previous such analysis, collected with a detector positioned at an average distance of 1050 m from two reactor cores. Several novel techniques have been developed to achieve significant reductions of the backgrounds and systematic uncertainties. Accidental coincidences, the dominant background in this analysis, are suppressed by more than an order of magnitude with respect to our previous publication by a multi-variate analysis. These improvements demonstrate the capability of precise measurement of reactor [bar over ν[subscript e]] without gadolinium loading. Spectral distortions from the [bar over ν[subscript e]] reactor flux predictions previously reported with the neutron capture on gadolinium events are confirmed in the independent data sample presented here. A value of sin 2[superscript 2] θ[subscript 13] = 0.095 [+ 0.038 over − 0.039] (stat+syst) is obtained from a fit to the observed event rate as a function of the reactor power, a method insensitive to the energy spectrum shape. A simultaneous fit of the hydrogen capture events and of the gadolinium capture events yields a measurement of sin[superscript 2] 2θ[subscript 13] = 0.088 ± 0.033(stat+syst)., United States. Dept. of Energy, National Science Foundation (U.S.)

Based on the notion that the local dark-matter field of axions or axion-like particles (ALPs) in our Galaxy induces oscillating couplings to the spins of nucleons and nuclei (via the electric dipole moment of the latter and/or the paramagnetic axion-wind effect), we establish the feasibility of a new method to search for ALPs in storage rings. Based on previous work that allows us to maintain the in-plane polarization of a stored deuteron beam for a few hundred seconds, we performed a first proof-of-principle experiment at the Cooler Synchrotron COSY to scan momenta near 970 MeV/c. This entailed a scan of the spin precession frequency. At resonance between the spin precession frequency of deuterons and the ALP-induced EDM oscillation frequency there will be an accumulation of the polarization component out of the ring plane. Since the axion frequency is unknown, the momentum of the beam and consequently the spin precession frequency were ramped to search for a vertical polarization change that would occur when the resonance is crossed. At COSY, four beam bunches with different polarization directions were used to make sure that no resonance was missed because of the unknown relative phase between the polarization precession and the axion/ALP field. A frequency window of 1.5-kHz width around the spin precession frequency of 121 kHz was scanned. We describe the experimental procedure and a test of the methodology with the help of a radiofrequency Wien filter located on the COSY ring. No ALP resonance was observed. As a consequence an upper limit of the oscillating EDM component of the deuteron as well as its axion coupling constants are provided., 27 pages, 24 figures, 7 tables, 104 references

Journal of high energy physics : JHEP 2021(1), 190 (2021). doi:10.1007/JHEP01(2021)190, Published by Springer, Berlin ; Heidelberg