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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T.J. Shea, R.A. Baron, C.S. Derrez, E.M. Donegani, V. Grishin, H. Hassanzadegan, I. Kittelmann, H. Kocevar, N. Milas, D. Noll, H.A. Silva, R. Tarkeshian, C.A. Thomas
ESS, Lund, Sweden
I. Bustinduy
ESS Bilbao, Zamudio, Spain
M. Ferianis
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
T. Papaevangelou, L. Seguí
CEA-IRFU, Gif-sur-Yvette, France
In late 2021 through mid 2022, the first protons were accelerated and transported through the European Spallation Source (ESS) Radio Frequency Quadrupole and Medium Energy Transport line at 3.6 MeV, and finally through the first Drift Tube Linac tank at 21 MeV. To enable these achievements, the following beam instrumentation systems were deployed: Ion Source power supply monitors, beam chopping systems, Faraday Cups, Beam Current Monitors (BCM) and Beam Position Monitors (BPM) that also measured phase. Additional systems were deployed for dedicated studies, including Wire Scanners, a slit and grid Emittance Measurement Unit, neutron Beam Loss Monitors and fast BCM and BPM systems. The instrumentation deployment is the culmination of efforts by a partnership of the ESS beam diagnostics section, multiple ESS groups and institutes across the globe. This paper summarizes the beam tests that characterized the performance of the instrumentation systems and verified the achievement of commissioning goals.
A. Brauch, M. Arnold, J. Enders, L.E. Jürgensen, N. Pietralla, S. Weih
TU Darmstadt, Darmstadt, Germany
Funding:*Work supported by DFG (GRK 2128) and the State of Hesse within the Research Cluster ELEMENTS (Project ID 500/10.006). A high-quality beam is necessary for electron scattering experiments at the superconducting Darmstadt electron linear accelerator S-DALINAC. An optimization of the bunch length to typical values of < 2 ps is performed to reach a high energy resolution of 1e-4. Currently, this is accomplished by inducing a linear momentum spread on the bunch in one of the accelerating cavities. The bunch length can then be measured with a target downstream. This method is time consuming and provides only an upper limit of the bunch length. Two new setups for bunch length measurements will improve the optimization process significantly. On the one hand, a new diagnostic beam line is set up in the low energy beam area. It includes a deflecting copper cavity used for measuring the bunch length by shearing the bunch and projecting its length on a target. On the other hand, a streak camera placed at different positions downstream the injector and the main linac will be used to measure the bunch length. Optical transition radiation from an aluminium coated kapton target is used to perform this measurement. The present layout of both systems and their current status will be presented in this contribution.
V. Kedych, T. Galatyuk, W. Krüger
TU Darmstadt, Darmstadt, Germany
T. Galatyuk, S. Linev, J. Pietraszko, C.J. Schmidt, M. Träger, M. Traxler, F. Ulrich-Pur
GSI, Darmstadt, Germany
J. Michel
Goethe Universität Frankfurt, Frankfurt am Main, Germany
A. Rost
FAIR, Darmstadt, Germany
V. Svintozelskyi
Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
Funding:This work has been supported by DFG under GRK 2128 The S-DALINAC is a superconductive linear electron accelerator operating at 3 GHz and allows operation in energy recovery mode (ERL). For the operation in the ERL mode accelerated and decelerated beams travel inside the same beamline but not necessarily share the same orbit. That leads to a bunch rate of 6 GHz. Non-destructive monitoring tools that allow optimization of acceleration and deceleration processes and achieve high recovery efficiency are important for operation in the ERL mode. The Low Gain Avalanche Detector (LGAD) is a silicon detector with internal gain layer optimized for 4-D tracking with timing resolution below 50 ps* which makes it a promising candidate for beam time structure monitoring. In this contribution we present the status of the first proof of principle beam time structure measurement with LGAD sensors at S-DALINAC in normal operation mode together with future activities overview. * J.Pietraszko, et al., Low Gain Avalanche Detectors for the HADES reaction time (T0) detector upgrade, Eur. Phys. J. A 56, 183 (2020)
A.S. Fisher, G.W. Brown, E.P. Chin, C.I. Clarke, W.G. Cobau, T. Frosio, B.T. Jacobson, R.A. Kadyrov, J.A. Mock, J. Park, E. Rodriguez, P.K. Roy, M. Santana-Leitner, J.J. Welch
SLAC, Menlo Park, California, USA
Commissioning of the 4-GeV, 120-kW superconducting linac, an upgrade to the LCLS x-ray FEL at SLAC, began in summer 2022, by accelerating a beam through the first cryomodule to 100 MeV. This autumn the beam will accelerate along the full linac, pass through the bypass transport line above the copper linac, and end at a new high-power tune-up dump at the muon shield wall. The first beam through the undulators is expected by early 2023, at a rate well below the full 1 MHz. A new system of beam-loss detectors will provide radiation protection, machine protection, and diagnostics. Radiation-hard optical fibres span the full 4 km from the electron gun to the undulators and their beam dumps. Diamond detectors cover anticipated loss points. These replace ionization chambers previously used with the copper linac, due to concern about ion pile-up at high loss rates. Signals from the new detectors are integrated with a 500-ms time con-stant and compared to the allowed threshold. If this level is crossed, the beam stops within 0.2 ms. We report on the initial commissioning of this system and on the detection of losses of both photocurrent and of dark current from the gun and cryomodules.
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M. Repovž, M. Cerv, C. Kurfürst, G. Muyan, S. Myalski, A. Pozenel, C. Schmitzer, M. Wolf
EBG MedAustron, Wr. Neustadt, Austria
A. Bardorfer, B. Baričevič, P. Paglovec, M. Škabar
I-Tech, Solkan, Slovenia
The MedAustron Ion Therapy Centre is a synchrotron-based particle therapy facility which delivers proton and carbon beams for clinical treatment. Currently, the facility treats roughly 40 patients per day and is improving its systems and workflows to further increase this number. MedAustron was commissioned and is operational without fully integrated systems for measurements of ’time of flight’ (beam energy) in the MEBT and beam position in the LINAC. This paper presents the newly developed system for these use cases, which will improve the overall commissioning and QA accuracy. It will unify the hardware used for the cavity regulation in the injector LLRF and the synchrotron LLRF. It will also be used for SYNC pickups, Schottky monitors and RF knock-out exciter. The new system is based on the CotS MicroTCA platform, which is controlled by the MedAustron Control System based on NI-PXIe. Currently it supports fiber-optic links (SFP+), but other links (e.g. EPICS, DOOCS) can be established. The modular implementation allows for connections to other components, such as motors, amplifiers, or interlock systems and will increase the robustness and maintainability of the accelerator.
K. Łasocha
Jagiellonian University, Kraków, Poland
For the needs of diagnostics of the longitudinal electron beam characteristics at the first Polish free electron laser (PolFEL) project, a Coherent Diffraction Radiation (CDR) system is being developed and tested. It will allow for nondestructive bunch length measurement based on the power balance of CDR radiation collected by Schottky diodes in different ranges of sub-THz radiation. The first tests and measurements will be performed at the end of the Solaris synchrotron injector linac, where the beam profile is already known from previous studies. In addition the camera system with automatic focus was developed and tested. In this contribution the theoretical background of the measurement, calculations and first experimental steps will be presented.
H. Maesaka, T. Inagaki
RIKEN SPring-8 Center, Hyogo, Japan
H. Dewa, T. Inagaki, H. Maesaka, K. Yanagida
JASRI, Hyogo, Japan
K. Ueshima
QST, Sendai, Miyagi, Japan
We developed a differential current transformer (CT) for electron beam charge measurement in noisy environments, such as near high-power pulse sources. This CT has four pickup wires coiled at equal intervals (90 deg.) on a toroidal core and each coil is wound for two turns. The midpoint of the coil is connected to the body ground so that a balanced differential signal is generated at both ends. A beam pipe with a ceramics insulation gap is inserted into the toroidal core to obtain a signal from a charged-particle beam. The four pairs of signals are transmitted through a CAT6 differential cable and fed into differential amplifiers. The common-mode noise from the noisy ground at the CT is canceled out by the amplifier. The four signals are then summed and digitized by an AD converter. We produced differential CTs and installed them into the new injector linac of NewSUBARU (*). Before the installation, the frequency response was measured in a laboratory and a flat response of up to 100 MHz was obtained as expected. Common-mode noise cancellation was also confirmed at NewSUBARU and the CTs have been utilized for beam charge monitoring stably. *: T. Inagaki et al., ’Construction of a Compact Electron Injector Using a Gridded RF Thermionic Gun and a C-Band Accelerator’, in Proc. IPAC’21, pp. 2687-2689. doi:10.18429/JACoW-IPAC2021-WEPAB039
Y. Levinsen, R.A. Baron, E.M. Donegani, M. Eshraqi, A. Garcia Sosa, H. Hassanzadegan, B. Jones, N. Milas, R. Miyamoto, D. Noll, I. Vojskovic, R.H. Zeng
ESS, Lund, Sweden
M. Akhyani
EPFL, Lausanne, Switzerland
I. Bustinduy
ESS Bilbao, Zamudio, Spain
F. Grespan
INFN/LNL, Legnaro (PD), Italy
The installation and commissioning of the European Spallation Source is currently underway at full speed, with the goal to be ready for first neutron production by end of 2024. This year we accelerated protons through the first DTL tank. This included the RFQ, 3 buncher cavities in the medium energy beam transport as well as the DTL tank itself as RF elements. At the end of the DTL tank we had a Faraday cup acting as the effective beam stop. This marks the first commissioning when RF matching is required for beam transport. In this paper we discuss the phase scan measurements and analysis of the buncher cavities and the first DTL tank.
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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J. Herranz
Proactive Research and Development, Sabadell, Spain
I. Bustinduy, .A. Rodríguez Páramo
ESS Bilbao, Zamudio, Spain
P. Forck, T. Sieber
GSI, Darmstadt, Germany
A. Navarro Fernandez
CERN, Meyrin, Switzerland
New SEM-Grid has been developed for FAIR Proton Linac, the instrument consists of 2 harps fixed together in an orthogonal way. This SEM-Grid will provide higher resolution and accuracy measurements as each harp consists of 64 tungsten wires 100 micro-meter in diameter and 0.5 mm pitch. Each wire is fixed to a ceramic PCB with an innovative dynamic stretching system, this system assures wire straightness under typical thermal expansion due to beam heat deposition. Electric field distribution has been performed, 3 main parameters have been optimized, wires distribution, quantity of polarization electrodes and distance between electrodes and wires. The design and production of the SEM-Grids have been performed by the company Proactive R&D that has count on the expertise of ESS-Bilbao to define safe operation limits and signal estimation by means of a code developed specifically for this type of calculations. Preliminary validations of the first prototypes shown good values of electric field behaviour signal. After additional beam test validations to be performed on June 2022, final series of the SEM-Grid will be produced and installed on FAIR proton LINAC.
R. Kitamura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
At J-PARC Linac, bunch shape monitors (BSMs) have been used to measure a longitudinal profile of high power H− beam. Operational principle of the monitor is similar to that of the streak-camera. The BSM inserts a biased-solid target into H− beam to extract and accelerate secondary electrons. These electrons are then modulated with synchronized RF. After passing through dipole B field, a longitudinal profile is converted to a transverse one. For the BSM, a choice of target material is essential to reduce beam loss and to have sufficient tolerance for breakage by the interaction with high power beams. The BSM with graphite target realized the measurement of high-power 3 MeV beam for the first time.
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