A. Lyapin, W. Shields
JAI, Egham, Surrey, United Kingdom
Funding:This work was supported by STFC Follow on Fund grant number ST/T003413/1 A mode-selective waveguide beam position monitor is under development. It is aimed primarily at electron linacs, although with its low impedance and wide bandwidth it could find alternative applications. In this paper we go over the design of the waveguide BPM system including the sensor and analog electronics, consider requirements to the digital processing and present some simulated results.
M. Colja, S. Carrato
University of Trieste, Trieste, Italy
G. Brajnik, R. De Monte
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
Digital processing systems have been proven to often outperform analog elaboration. Indeed, thanks to high-density DSPs and FPGAs, operations in digital domain give results that are impossible to achieve in other ways. On the other side, dealing with this great performance and flexibility is not always straightforward: the processing chain needs to be accurately planned to reach the desired goals, avoiding erratic behaviours in the digital domain. In this paper, we focus on the design and implementation of an FPGA-based digital processor that will be used in the electron beam position monitors of Elettra 2.0. After digitizing the 500 MHz beam signals from the pickups, the system executes a digital down conversion, followed by several filtering and demodulating stages, in order to have a selectable data rate that is suitable for both diagnostics and feedback. The position calculation is also performed in FPGA as well, with the well-known difference-over-sum algorithm. According to results provided by a fixed-point simulation, the overall system has been implemented in an Intel Arria 10 FPGA, demonstrating the correct design functionality that meets the specified requirements.
S.M. Gibson, A. Arteche
Royal Holloway, University of London, Surrey, United Kingdom
T. Lefèvre, T.E. Levens
CERN, Meyrin, Switzerland
An Electro-Optic Beam Position Monitor (EO-BPM) is being developed as a high-frequency (up to 10 GHz) diagnostic for crabbing and Head-Tail intra-bunch detection at the HL-LHC. Following an earlier prototype at the SPS that demonstrated single-pickup signals, an upgraded design of an interferometric EO-BPM has been beam-tested at the HiRadMat facility for validation and characterisation studies. In the new design, the fibre-coupled Mach-Zehnder interferometer arms are modulated by lithium niobate waveguides integrated in an upgraded opto-mechanical arrangement that has been developed to produce a highly magnified image field replica of the passing Coulomb field. A new detection technique that is directly sensitive to the interferometric optical difference signal from opposite EO buttons has been applied to measure single-shot bunches for the first time. A transverse resolution study over a ±20 mm range at 3 GHz bandwidth produced the first successful electro-optic bunch-by-bunch position measurement at the HiRadMat in-air extraction line. The results of this campaign show promise for an in-vacuum design that is in production for beam tests at the SPS during Run-3 of the LHC.
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C.D. Nantista, A.A. Haase, P. Krejcik
SLAC, Menlo Park, California, USA
The new superconducting undulator beamline at LCLS requires the BPMs to be operated at cryogenic temperatures alongside the undulator magnets. They are used for beam-based alignment of the undulator magnets and quadrupole and require submicron resolution to achieve good FEL performance. This is to be achieved with X-band RF cavity BPMs, as is done now on the permanent undulator beamline. However, operating the cavities at cryogenic temperatures introduces significant challenges. We review the changes in RF properties of the cavities that result from cooling and how the design is changed to compensate for this. This includes a novel approach for employing a rectangular cavity with split modes to separately measure the X and Y position without coupling.
Modeling and Experimental Evaluation of a Bunch Arrival-Time Monitor with Rod-Shaped Pickups and a Low-Pi-Voltage Ultra-Wideband Traveling Wave Electro-Optic Modulator for X-Ray Free-Electron Lasers
K. Kuzmin, E. Bründermann, A.-S. Müller, G. Niehues
KIT, Karlsruhe, Germany
W. Ackermann, H. De Gersem
TEMF, TU Darmstadt, Darmstadt, Germany
M.K. Czwalinna, H. Schlarb
DESY, Hamburg, Germany
C. Eschenbaum, C. Koos, A. Kotz, A. Schwarzenberger
IPQ KIT, Karlsruhe, Germany
A. Penirschke, B.E.J. Scheible
THM, Friedberg, Germany
X-ray Free-Electron Laser (XFEL) facilities, such as the 3.4-km European XFEL, use all-optical links with electro-optic bunch arrival-time monitors (BAM) for a long-range synchronization. The current BAM systems achieve a resolution of 3.5 fs for 250 pC bunches. Precise bunch arrival timing is essential for experiments, which study ultra-fast dynamical phenomena with highest temporal resolution. These experiments will crucially rely on femtosecond pulses from bunch charges well below 20 pC. The state-of-the-art BAMs are not allowing accurate timing for operation with such low bunch charges. Here we report on the progress in development of an advanced BAM (system) based on rod-shaped pickups mounted on a printed circuit board and ultra-wideband travelling-wave electro-optic modulators with low operating voltages. We perform modeling and experimental evaluation for the fabricated pickups and electro-optic modulators and analytically estimate timing jitter for the advanced BAM system. We discuss an experimental setup to demonstrate joint operation of new pickups and wideband EO modulators for low bunch charges less than 5 pC.
T.B. Ilhan, A. Caglar, D. Halis
YTU, Istanbul, Turkey, Turkey
A. Adiguzel, S. Oz
Istanbul University, Istanbul, Turkey
H. Cetinkaya
Dumlupinar University, Faculty of Science and Arts, Kutahya, Turkey
E. Elibollar, M.F. Er, A. Inanc, E.V. Ozcan
Bogazici University, Bebek / Istanbul, Turkey
U. Kaya
Istinye University, Institute of Sciences, Istanbul, Turkey
A. Ozbey
IUC, Istanbul, Turkey
G. Türemen
TENMAK-NUKEN, Ankara, Turkey
G. Unel
UCI, Irvine, California, USA
KAHVE Laboratory has two functional particle sources: thermal electrons and ionized hydrogen. Each of these are followed by DC acceleration sections, for obtaining an electron beam to accelerate electrons MeV energy level and for providing protons to the radio frequency quadrupole accelerator which are being built. So far both systems have keV energy levels. Both systems employ LabVIEW based GUIs to interact with the user and to control and monitor the DC power supplies. The vacuum gauges, turbomolecular pumps, stepper motors and high voltage power supplies are all controlled with PLCs. The equipment under high voltage, are monitored and controlled via Arduino based wifi and bluetooth wireless communication protocols. The proton beamline has additional devices for beam diagnostics which are being commissioned like pepper pot plate, scintillator screen and faraday cup. Both systems are being standardize before MeV energy level for generalize to national labs which are working on detectors and accelerators. We believe such a setup could be a low budget control and readout example for modern small experiments and educational projects.
