T. Atkinson, J.-G. Hwang, G. Rehm, M. Ries, G. Schiwietz, S. Wiese
HZB, Berlin, Germany
As part of the global refurbishment of the injector at BESSY II, a new optical beamline has been installed in the booster. This paper covers the conceptual design: incorporating the beamline into an operational facility without downtime, the simulation and expectations of the optical transport line, mechanical installation and commissioning with beam. These first results with the present beam delivery system have already achieved source point imaging and bunch length measurements using a fast diode. With the additional PETRA cavity installed for this booster upgrade and connection to acquire RF power in the 2022 summer shutdown planned, the bunch length diagnostics are critical. The beamline will also undergo a final mechanical upgrade and then see the installation of a streak camera.
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.
A. Lyapin, M.S. McCallum
JAI, Egham, Surrey, United Kingdom
A. Aryshev, K.O. Kruchinin
KEK, Ibaraki, Japan
Funding:This work is supported by Royal Society International Exchanges Grant number IEC\R3\213050 In this contribution we consider a possible solution to long-term stability issues common in cavity BPM systems. The method will see a wider use active in-situ calibration systems injecting a tone into the measurement channel. We plan to compensate the bulk of the beam generated signal and so potentially extend the dynamic range of the electronics, reduce the amount of wakefield seen by the beam. The signal matching the real beam can then be used for mimicking the beam and calibrating out any drifts of the whole sensing and processing chain. We present the concept, give some simulated results and consider possible hardware solutions.
D. Lipka, M. Holz, S. Vilcins
DESY, Hamburg, Germany
The SINBAD facility (Short and INnovative Bunches and Accelerators at DESY) hosts various experiments in the field of production of ultra-short electron bunches and novel high gradient acceleration techniques. The SINBAD facility, also called ARES (Accelerator Research Experiment at SINBAD), is a conventional S-band linear RF accelerator allowing the production of low charge ultra-short electron bunches within a range between 0.5 pC and 1000 pC. The positions of the low charge bunches will be detected by cavity beam position monitors. The principal design is based on the experience from the EU-XFEL cavity beam position monitors. It consists of a 316 LN stainless steel body with a design loaded quality factor of 70, a resonance frequency of 3.3 GHz and a relative wide gap of 15 mm to reach a high peak position sensitivity of 4.25 V/(nC mm). This poster covered, the manufacture of the individual mechanical parts, as well as presents the special features in the manufacture of customer designed UHV feedthroughs.
M. Sapinski, R. Dölling, M. Rohrer
PSI, Villigen PSI, Switzerland
PSI’s Ring cyclotron is a high intensity proton cyclotron producing 2 mA beam. The beam is accelerated over about 180 turns from 72 MeV to 590 MeV. The Long Radial Probe, called RRL, scans the beam along the range of beam radii from 2048 mm to 4480 mm. A replacement for the RRL has been developed in the last years*. The recently installed new probe drives three carbon fibers with 30 ’m diameter through the turns and measures secondary electron currents, providing information on horizontal and vertical beam shape. Additional drives are available for a later extension of measurement capabilities. The main challenges are a coupling of the device elements to RF fields leaking from the accelerating cavities, plasma interfering with the measured signal and performance of the carbon fibers in harsh environment with high intensity beam. We report on commissioning of the probe with RF and beam and discuss measurement results. * doi:10.18429/JACoW-IBIC2020-WEPP33
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.
N. Baboi, H.T. Duhme, B. Lorbeer
DESY, Hamburg, Germany
The superconducting FLASH user facility (Free electron LASer in Hamburg) accelerates 10 electron bunch trains per second, which are mostly used to produce high brilliance XUV and soft X-ray pulses. Each train usually contains up to 600 electron bunches with a typical charge between 100 pC and 1 nC and a minimum bunch spacing of 1 us. Various types of beam position monitors (BPM) are built in three electron beam lines, having a single bunch resolution of 2-100 um rms. This paper presents multi-bunch position measurements for various types of BPMs and built in at various locations. The dependency of the resolution on the beam offset is also shown.
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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.
B. Keil, R. Ditter, M. Gloor, G. Marinkovic, J. Purtschert
PSI, Villigen PSI, Switzerland
We have developed a new BPM electronics platform based on a MultiProcessing System-on-Chip (MPSoC). This contribution introduces the first application of the platform at the Paul Scherrer Institute (PSI), which is the cavity BPM system for the SwissFEL soft X-ray undulator beamline called ’Athos’ [1], where a larger number of systems are now operational. Measurement results and differences to the predecessor system will also be presented.
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.
B. Lorbeer, H.T. Duhme, I. Krouptchenkov, T. Lensch, D. Lipka, S. Vilcins, M. Werner
DESY, Hamburg, Germany
The SINBAD(Short and INnovative Bunches and Accelerators at DESY ) R&D accelerator is planned for studying new concepts for high gradient electron beam acceleration and the generation of ultra-short electron bunches. The accelerator called ARES(Accelerator Research Experiment At DESY) is composed of S-band accelerating structures. In order to achieve the goal of very short electron bunches the electron beam charges generated in the RF Gun can vary in a range from 1nC down to 500fC. In order to measure the beam position with good resolution at the small charge end of 500fC a new cavity BPM(beam position monitor) has been developed. One key component in the BPM system is the custom RF electronics to meet the resolution requirements in the entire charge range. The entire BPM system with a focus on the system design requirements and the utca based RF electronics are presented in this paper.
