N. Milas, M. Akhyani, R.A. Baron, C.S. Derrez, M. Eshraqi, Y. Levinsen, R. Miyamoto, D. Noll, R. Tarkeshian, I. Vojskovic, R.H. Zeng
ESS, Lund, Sweden
The European Spallation Source (ESS), currently under construction and initial commissioning in Lund, Sweden, will be the brightest spallation neutron source in the world, when its driving proton linac achieves the design power of 5 MW at 2 GeV. Such a high power requires production, efficient acceleration, and almost no-loss transport of a high current beam, thus making design and beam commissioning of this machine challenging. During the the commissioning time in 2022 a campaign for a full characterisation of the ESS Medium Beta Transport session (MEBT) was carried out. Both transverse optics and longitudinal parameters were measured and compared to simulation, amongst them: buncher cavity tunning, trasnverse emittance and initial twiss parameters. In this paper we present the results and future plans.
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C. Ozkan Loch, R. Ischebeck, N. Samadi, A.M.M. Stampfli, J. Vila Comamala
PSI, Villigen PSI, Switzerland
This poster will give an overview of the diagnostics development for SLS 2.0. Details on the beam size monitors in the storage ring, the screen monitors for the booster to ring transfer line, and beam loss monitors for the linac and storage ring will be presented. Test results carried out at the SLS will also be presented. BPMs and feedback systems are not covered in this contribution.
C.J. Richard, Z. Aboulbanine, G.D. Adhikari, N. Aftab, P. Boonpornprasert, G.Z. Georgiev, M. Groß, A. Hoffmann, M. Krasilnikov, X.-K. Li, A. Lueangaramwong, R. Niemczyk, H.J. Qian, F. Stephan, G. Vashchenko, T. Weilbach
DESY Zeuthen, Zeuthen, Germany
Funding:This work was supported by the European XFEL research and development program The Photo Injector Test Facility at DESY in Zeuthen (PITZ) characterizes and optimizes electron sources for use at FLASH and European XFEL. AT PITZ, the transverse phase space is measured using a single slit scan and scintillator screen method. With the trend in photoinjectors towards lower current and emittance, these measurements become increasingly influenced by systematic errors including camera resolution and scintillator response due to smaller spot sizes. This study investigates the effects and corrections of the systematic errors for phase space measurements at PITZ.
J. Yang, P. Boutachkov, P. Forck, T. Milosic, R. Singh, S. Sorge
GSI, Darmstadt, Germany
Funding:This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under GA No 101004730. The quality of slowly, typically several seconds, extracted beams from the GSI synchrotron SIS18 is characterized with respect to the temporal beam stability, the so-called spillμstructure on the 100 µs scale. A pilot experiment was performed utilizing transverse emittance exchange to reduce the beam size in the extraction plane, and the improvement of spillμstructure was found. Important beam instrumentation comprises an Ionization Profile Monitor for beam profile measurement inside the synchrotron and a plastic scintillator at the external transfer line for ion counting with up to several 106 particles per second and 20 µs time slices. The performant data acquisition systems, including a scaler and a fast Time-to-Digital Converter (TDC), allow for determining the spill quality. The application of the TDC in the measurement and related MAD-X simulations are discussed.
Funding:The presented work has been achieved in collaboration with AGH University of Science and Technology in Kraków as a part of a PhD thesis. The main goal of NSRC SOLARIS is to provide scientific community with high quality synchrotron light. To achieve this, it is necessary to constantly monitor many subsystems responsible for beam stability and to analyze data about the beam itself from various diagnostic beamlines. In this work a deep neural network for transverse beam profile classification is proposed. Main task of the system is to automatically assess and classify transverse beam profiles based solely on the evaluation of the beam image from the Pinhole diagnostic beamline at SOLARIS. At the present stage, a binary assignment of each profile is performed: stable beam operation or unstable beam operation / no beam. Base model architecture consists of a pre-trained convolutional neural network followed by a densely-connected classifier and the system reaches accuracy at the level of 90%. The model and the results obtained so far are discussed, along with plans for future development.
A. Goldblatt, O.O. Andreassen, T. Hofmann, F. Roncarolo, J. Tagg
CERN, Meyrin, Switzerland
G.E. Boorman, A. Bosco, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
The LINAC4 is now equipped with two laser profile and emittance meters, basically non destructive and not limited by beam power density. A pulsed laser is transported through fibres and focused into the 160 MeV H− beam. Its interaction with the H− ions detaches electrons that are collected by an electron-multiplier, while the resultingH0 particles, after being separated from the main H− beam by a dipole magnet, are recorded by a diamond strip detector, few meters away from the interaction point. The emittance and profile are reconstructed from the laser step by step scan of the beam. After several years of feasibility tests and prototyping, this paper will present all details about the final HW and SW implementation and the 2022 experimental results.
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N. Samadi, G. Lovric, C. Ozkan Loch
PSI, Villigen PSI, Switzerland
X. Shi
ANL, Lemont, Illinois, USA
The advance in low-emittance x-ray sources urges the development of novel diagnostic techniques. Existing systems either have limited resolution or rely heavily on the quality of the optical system. An x-ray beam property analyzer based on a multi-crystal diffraction geometry was recently introduced. By measuring the transmitted beam profile of a dispersive Laue crystal downstream of a double-crystal monochromator, the system can provide a high-sensitivity characterization of spatial source properties, namely, size, divergence, position, and angle in the diffraction plane of the system at a single location in a beamline. In this work, we present the experimental validation at a super-bending magnet beamline at the Swiss Light Source and refine the method to allow for time-resolved characterization of the beam. Simulations are then carried out to show that the system is feasible to characterize source properties at undulator beamlines for fourth-generation light sources.
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The Large Hadron Collider (LHC) is protected against potentially dangerous beam losses by a distributed system based on some four thousand beam loss monitors. To provide an additional level of safety, the LHC has been equipped with a system to detect fast beam intensity drops and trigger a beam dump for potentially dangerous rates. This paper describes the architecture of the system and its signal processing, optimized to cope with dump thresholds in the order of 0.01 % of the circulating beam intensity. The performance of the installed system is presented based upon beam measurements.
G. Kube, F. Schmidt-Föhre, K. Wittenburg
DESY, Hamburg, Germany
A. Bardorfer, L. Bogataj, M. Cargnelutti, P. Leban, M.O. Oblak, P. Paglovec, B. Repič
I-Tech, Solkan, Slovenia
PETRA IV at DESY will be an upgrade of the present synchrotron radiation source PETRA III into an ultra low-emittance source with beam emittance of about 20 pm.rad which imposes stringent requirements on the machine stability. In order to measure beam positions and control orbit stability to the required level of accuracy, a high resolution BPM system will be installed which consists of about 800 monitors with the readout electronics based on MTCA.4. In order to fulfill the requested long-term drift requirement (< 1 micron over 7 days), also the BPM cable paths have to be stabilized because of the PETRA-specific machine geometry. To achieve this, the crossbar switching concept was extended such that the analogue switching part is separated from the read-out electronics and brought as close as possible to the BPM pickup. While first measurements were presented before, meanwhile the system has undergone a major revision, especially the external switching matrix changed from a prototype setup to a system close to the final design. This contribution summarizes the latest measurements from PETRA III, demonstrating the high performance of the external stabilization concept.
M. Marongiu, G. Kube, M. Lantschner, A.I. Novokshonov, K. Wittenburg
DESY, Hamburg, Germany
The PETRA IV project will be a Diffraction Limited Light Source designed to be the successor of PETRA III, the 6 GeV 3rd generation hard X-Ray synchrotron light source at DESY in Hamburg. It will operate at a beam energy of 6 GeV with a design emittance of 20/4 pm rad. For a precise emittance online control, two dedicated diagnostics beamlines will be built up to image the beam profile with synchrotron radiation in the X-Ray region. With two beamlines, it will be possible to extract both the transverse beam emittances and the beam energy spread. Both beamlines will be equipped with two interchangeable X-Ray optical systems: a pinhole camera system to achieve high dynamic range and a Fresnel Diffractometry system for high resolution measurements in the range 1-18 um. This paper describes the planned setup and deals with the possible limitations.
K. Satou, Y. Sato
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
S. Igarashi
KEK, Ibaraki, Japan
Funding:Accelerator and Beamline Research and Technology Development for High-Power Neutrino Beams in the U.S.-Japan Science and Technology Cooperation Program in High Energy Physics. The measurement accuracy of the ionization profile monitor (IPM) of J-PARC main ring (MR) depends on the flatness and stability of the gain of the position-sensitive microchannel plate (MCP). The flatness of the MCP deteriorates after long-term operation; the gain of the central area selectively decreases as the integrated output charge increases. The beam-based calibration, where the local bump shifts the beam and the reconstructing beam profiles determine the gain distribution, is used to calibrate the flatness. The immediate gain drop occurs when the output current from the MCP becomes comparable to the bias current is problematic. This gain drop depends on the bias voltage and the output current; thus, it is difficult to calibrate. A pulsed HV module of 30 kV, which collects ionized electrons and ions, was installed to solve these problems. The pulse mode operation can modulate the averaged output current from the MCP to improve gain stability. Profiles of the intense beam up to 3.3·1013 ppb were measured and compared with those measured by destructive profile monitors in beam transport lines 3’50 BT, and the Abort line. Estimated emittances were consistent at ±20%.
S. Di Carlo, W. Andreazza, D. Belohrad, J. Emery, J.C. Esteban Felipe, A. Goldblatt, D. Gudkov, A. Guerrero, S. Jackson, G.O. Lacarrere, M. Martin Nieto, A.T. Rinaldi, F. Roncarolo, C. Schillinger, R. Veness
CERN, Meyrin, Switzerland
The ability of reliably measuring the transverse beam profile in its injectors is essential for the operation of the LHC. This report aims to assess the reliability, stability, and reproducibility of the new generation of beam wire scanners developed at CERN in the framework of the LHC Injectors Upgrade (LIU). The study includes data from the over 60000 scans performed in 2021 and 2022, with a special focus on reproducibility, investigation of optimal operational settings to ensure a large dynamic range, and evaluation of absolute accuracy through comparison with other instruments present in the injectors.
S. Preston, L. Bobb, A.F.D. Morgan, T. Olsson
DLS, Oxfordshire, United Kingdom
In the Diamond storage ring, the vertical emittance is kept at 8 pm rad by an emittance feedback which modifies the strengths of skew quadrupoles. A new feedback using a stripline kicker to control the vertical emittance by exciting the beam resonantly at a synchrotron sideband is planned to avoid modification of the optics. This is crucial for the anticipated Diamond-II upgrade of the storage ring, which will have a much smaller equilibrium emittance than the existing machine. A larger coupling is therefore needed to keep the vertical emittance at the same level, potentially reducing the off-axis injection efficiency and lifetime. Measurements of the beam oscillation and emittance have been performed at the existing storage ring to characterise the effects of chromaticity and impedance on the optimal excitation frequency, where the emittance is increased significantly while the beam oscillation is kept low. The implications for simulating the emittance feedback for the Diamond-II storage ring are also discussed.
