First Search for Axion-Like Particles in a Storage Ring Using a Polarized Deuteron Beam

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 performed the first experiment to search for ALPs using a storage ring. For that purpose, we used an in-plane polarized deuteron beam stored at the Cooler Synchrotron COSY, scanning 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.Comment: 25 pages, 24 figures, 7 tables, 67 reference

Reactor rate modulation oscillation analysis with two detectors in Double Chooz

A θ13 oscillation analysis based on the observed antineutrino rates at the Double Chooz far and near detectors for different reactor power conditions is presented. This approach provides a so far unique simultaneous determination of θ13 and the total background rates without relying on any assumptions on the specific background contributions. The analysis comprises 865 days of data collected in both detectors with at least one reactor in operation. The oscillation results are enhanced by the use of 24.06 days (12.74 days) of reactor-off data in the far (near) detector. The analysis considers the ν¯ e interactions up to a visible energy of 8.5 MeV, using the events at higher energies to build a cosmogenic background model considering fast-neutrons interactions and 9Li decays. The background-model-independent determination of the mixing angle yields sin2(2θ13) = 0.094 ± 0.017, being the best-fit total background rates fully consistent with the cosmogenic background model. A second oscillation analysis is also performed constraining the total background rates to the cosmogenic background estimates. While the central value is not significantly modified due to the consistency between the reactor-off data and the background estimates, the addition of the background model reduces the uncertainty on θ13 to 0.015. Along with the oscillation results, the normalization of the anti-neutrino rate is measured with a precision of 0.86%, reducing the 1.43% uncertainty associated to the expectation. [Figure not available: see fulltext.

New developments and experience with real-time signal processing for beam diagnostics at COSY.

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

Orbit Measurement and Control

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

COSY Orbit Control Studies

Orbit control is an essential part of COSY operation. Orbit Correction software (OC) was conceived at IKP and integrated in new EPICS control system in collaboration with Cosylab d.d. and has allowed COSY to deliver required orbit parameters to multiple experiments.The performance of the Orbit Correction hinges on several components, such as ring steerer control, steerer calibration, beam position monitoring (BPM) system measurements, BPM calibration, orbit response matrix (ORM) modeling and thus COSY optics modeling and ORM measurement.Apart from operative considerations the COSY model and ORMs are used for JEDI studies.</p

COSY Orbit Control Studies

Description of requestOrbit control is an essential part of COSY operation. Orbit Correction software (OC) was conceived at IKP and integrated in new EPICS control system in collaboration with Cosylab d.d. and has allowed COSY to deliver required orbit parameters to multiple experiments.The performance of the Orbit Correction hinges on several components, such as ring steerer control, steerer calibration, beam position monitoring (BPM) system measurements, BPM calibration, orbit response matrix (ORM) modeling and thus COSY optics modeling and ORM measurement.GoalsDuring previous OC operation indications arose pointing to non-optimal steerer calibration, precisely for the SH27 and newer BLW-D1/3 steerers. One goal of this beam time is to check steerer calibrations using the BPM data and test with closed orbit bumps. The integration of corrector magnets of the 2 MeV cooler is considered a necessary next step to further improve orbit control.A closed orbit correction at injection energy has not yet been performed with the new system. If applied routinely it could improve the injection efficiency and reduce time for machine development. Another goal of this beam time is to characterize the optics model and steerer calibration at injection energy; measure orbit response matrix and compare it to the model; find optimal OC configuration to optimize injection orbit towards higher beam current, and handle injection scenarios e.g. with and without 100keV and 2MeV solenoids active in the optics.Matching the model-based and measured ORMs is the final goal of the beam time. Using a selection of energies in the range feasible in COSY a measurement of ORM should be performed and compared to the model-based calculation. Check and optimization of the model would be possible with this data. Tentative selection of momenta are the maximum momentum at 3.0GeV/c, momentum close to the gamma-transition at 2.2GeV/c, momentum used for EDM at 0.97GeV/c, momentum used for PANDA target at 0.8GeV/c. Automation of the ORM measurement can be prepared in this step.</p

COSY Machine-Model Optimization

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

Libera Hadron Applications and Operational Experience at COSY

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

Tools for software development at COSY

In 2018 a set of tools was made available at IKP-4 for software development at COSY.The goal is to have a centralized infrastructure to improve collaboration on code development, quality control and integration of software. In addition a central infrastructure for e.g. storage of manuals, decription of practices and conventions needed to be established, as in the past they were scattered over several storage systems or were available on paper only. The newly established tools are used to improve software work flow, but also for documentation and collaboration on scientific publications, as well as issue tracking for both software and hardware.Another usage case is the continuous integration, testing, and deployment of productive code at COSY.Additionally the development environment training delivered by Cosylab is discussed

Experience and Prospects of Real-Time Signal Processing and Representation for the Beam Diagnostics at COSY

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