T.H. Pacey, D. Angal-Kalinin, A.R. Bainbridge, J. Henderson, J.K. Jones, N.Y. Joshi, S.L. Mathisen, A.E. Pollard, Y.M. Saveliev, E.W. Snedden, C. Tollervey, D.A. Walsh
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
D. Angal-Kalinin, A.R. Bainbridge, J.K. Jones, T.J. Overton, Y.M. Saveliev, C. Swain, J. Wolfenden
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J. Henderson
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
N.Y. Joshi
UMAN, Manchester, United Kingdom
T.J. Overton
The University of Manchester, Manchester, United Kingdom
C. Swain, J. Wolfenden
The University of Liverpool, Liverpool, United Kingdom
The FEBE beamline at the CLARA facility will combine a 250 MeV FEL quality electron beam with a 100 TW class laser. One area of research FEBE will support is novel acceleration schemes; both structure and plasma based. There are stringent diagnostic requirements for measuring the input electron beam and challenges in characterisation of the accelerated beams produced by these novel schemes. Several of these challenges include measurement of: micrometer scale transverse profiles, 10 fs scale bunch lengths, single shot emittance, broadband energy spectra at high resolution, and laser-electron time of arrival jitter. Furthermore, novel shot-by-shot non-invasive diagnostics are required for machine learning driven optimisation and feedback systems. This paper presents an overview of R&D activities in support of developing a 6D diagnostics suite to meet these challenges.
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S. Nagaitsev, A.L. Romanov, A.V. Shemyakin, G. Stancari
Fermilab, Batavia, Illinois, USA
Funding:The work is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Two experiments were carried out to study the statistical properties of undulator radiation in the Integrable Optics Test Accelerator (IOTA) storage ring at Fermilab. The first experiment studied the turn-to-turn fluctuations in the power of the radiation generated by an electron bunch. The magnitude of these fluctuations depends on the 6D phase-space distribution of the electron bunch. In IOTA, we demonstrated that this effect can be used to measure some electron bunch parameters, small transverse emittances in particular. In the second experiment, a single electron was stored in the ring, emitting a photon only once per several hundred turns. In this regime, any classical interference-related collective effects were eliminated, and the quantum fluctuations could be studied in detail to search for possible deviations from the expected Poissonian photon statistics. In addition, the photocount arrival times were used to track the longitudinal motion of a single electron and to compare it with simulations. This allowed us to determine several dynamical parameters of the storage ring such as the rf cavity phase jitter and the dependence of the synchrotron motion period on amplitude.
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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.
G. Brajnik, R. De Monte
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
M. Cargnelutti, U. Dragonja, P. Leban, P. Paglovec, B. Repič, A. Vigali
I-Tech, Solkan, Slovenia
Elettra 2.0 will be the low-emittance upgrade of the present machine, a third-generation lightsource based in Trieste, Italy. The new machine, foreseen to be completed in 2025-2026, will be equipped with 168 beam position readout systems divided into 12 cells. The BPM electronics will be based on the prototypes developed by the laboratory, relying on the pilot-tone compensation technique for assuring the required resolution and long-term stability. The industrialization and production of the BPM electronics system are being carried out in partnership with Instrumentation Technologies, a company that has experience with BPM readout systems within the accelerator field. This paper will present the results of the industrialization of one of BPM system’s key component: the Pilot Tone Front End, focusing on its improvements introduced on electronic and mechanical sides, giving not only a significant performance gain with respect to the previous prototype but also improving robustness and reliability. An overview of the testing procedures that will assure the performance repeatability of the series will also be provided.
C.E. Houghton, C. Bloomer, L. Bobb
DLS, Harwell, United Kingdom
Tungsten blade based photoemission X-ray Beam Position Monitors (XBPMs) are widely used as white beam diagnostics at synchrotrons. Traditionally, the scale factors are determined by stepper motor movements of the XBPM, or by controlled electron beam displacements, and measuring the response. These measurements must be repeated for each ID gap to produce a complete set of scale factors for all operational conditions. This calibration procedure takes time and cannot be done while users are acquiring data. In addition, the scale factors can vary over time due to changes to the storage ring. It is possible for these scale factors to become inaccurate, reducing the accuracy of the beam position measured by the XBPMs. By using the intrinsic kHz electron beam movements and correlating the signals from electron beam position monitors and XBPMs it is possible to have a real-time calculation of the scale factors without the need to disturb user operation. Presented in this paper is a method to non-invasively calculate scale factors during normal user operation. A comparison of the precision of this method versus the traditional stepper motor method is presented.
R.L. Hermann, M. Galonska, Th. Haberer, A. Peters
HIT, Heidelberg, Germany
T. Gehrke
German Cancer Research Center (DKFZ), Heidelberg, Germany
B. Leverington
Universität Heidelberg, Heidelberg, Germany
Funding:Funded by Deutsche Forschungsgemeinschaft (DFG), project number 426970603. The Heidelberg Ion-Beam Therapy Center (HIT) pro-vides proton, helium, and carbon-ion beams with differ-ent energies and intensities for cancer treatment and oxy-gen-ion beams for experimentation. Below the intensities used for therapy, low-intensity ion beams (below 1·105 ions/s) are available for various experiments via manual-ly degrading of the beam. Since there is no built-in beam profile instrumentation device for this intensity region, the development of a transverse ion beam profile monitor for these intensities is therefore of interest. The principle of operation is based on scintillating fibres, particularly those with enhanced radiation hardness. The fibres transform the deposited energy of a traversing ion into photons, which are then converted and amplified via silicon pho-tomultipliers (SiPMs) into electric pulses. These pulses are recorded and processed by a novel and dedicated readout electronics: the front-end readout system (FERS) A5200 by CAEN. A prototype set-up consisting of all the above-mentioned parts was tested in beam and has proven to record the transverse beam profile successfully from intensities of 1·107 ions/s down to 1·102 ions/s.
N. Vitoratou, L. Bobb
DLS, Oxfordshire, United Kingdom
A. Last
KIT, Eggenstein-Leopoldshafen, Germany
G. Rehm
HZB, Berlin, Germany
X-ray pinhole cameras are employed to provide the transverse profile of the electron beam from which the emittance, coupling and energy spread are calculated in the storage ring of Diamond Light Source. Tungsten blades separated by shims are commonly used to form the pinhole aperture. However, this approach introduces uncertainties regarding the aperture size. X-ray lithography, electroplating and moulding, known as LIGA, has been used to provide thin screens with well-defined and high aspect ratio pinhole apertures. Thus, the optimal aperture size given the beam spectrum can be used to improve the spatial resolution of the pinhole camera. Experimental results using a LIGA screen of different aperture sizes have been compared to SRW-Python simulations over the 15-35 keV photon energy range. Good agreement has been demonstrated between the experimental and the simulation data. Challenges and considerations for this method are also presented.
C. Thiebaux, L. Bernardi, F. Gastaldi, Y. Geerebaert, R. Guillaumat, F. Magniette, P. Manigot, M. Verderi
LLR, Palaiseau, France
É. Delagnes, F.T. Gebreyohannes, O. Gevin
CEA-IRFU, Gif-sur-Yvette, France
F. Haddad, N. Servagent
SUBATECH, Nantes, France
F. Haddad, C. Koumeir, F. Poirier
Cyclotron ARRONAX, Saint-Herblain, France
Funding:This study is supported by two programs of the Agence Nationale de la Recherche, ANR-17-CE31-0015 and ANR-11-EQPX-0004. The PEPITES project* consists of a brand new operational prototype of an ultra-thin, radiation-resistant profiler capable of continuous operation on mid-energy (O(100 MeV)) charged particle accelerators. Secondary electron emission (SEE) is used for the signal because it only requires a small amount of material (10 nm); very linear, it also offers good dynamics. The lateral beam profile is sampled using segmented electrodes, constructed by thin film methods. Gold strips, as thin as the electrical conductivity allows (~ 50 nm), are deposited on an insulating substrate as thin as possible. While crossing the gold, the beam ejects the electrons by SEE, the current thus formed in each strip allows the sampling. SEE was characterized at ARRONAX with 68 MeV proton beams and at medical energies at CPO**. Electrodes were subjected to doses of up to 109 Gy without showing significant degradation. A demonstrator with dedicated electronics (CEA) is installed at ARRONAX and will be used routinely with proton beams of 17-68 MeV for intensities of 100fA to 100nA. An overview of the design and first measurements will be presented, and system performances will be assessed. *LLR, ARRONAX cyclotron and CEA **Orsay Protontherapy Center (Institut Curie)
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. Aftab, Z. Aboulbanine, P. Boonpornprasert, G.Z. Georgiev, J. Good, M. Groß, A. Hoffmann, M. Krasilnikov, X.-K. Li, A. Lueangaramwong, R. Niemczyk, A. Oppelt, H.J. Qian, C.J. Richard, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
A.J. Reader
KCL, London, United Kingdom
Methodical studies to improve the longitudinal phase space (LPS) tomography of space-charge dominated electron beams were carried out at the Photo Injector Test facility at DESY in Zeuthen (PITZ). An analytical model was developed to quantify mean momentum, RMS energy spread, bunch length and phase advance. Phase advance analysis determined the booster phase scan range and step size to be used for obtaining momentum projections. A slit was introduced before the booster to truncate the beam in transverse plane to strongly reduce the space charge effects. The signal resolution of this truncated beam was improved by careful beta function control at the reference screen of the momentum measurements. The reconstruction algorithm was changed from Algebraic Reconstruction Technique (ART) to Image Space Reconstruction Algorithm (ISRA) owing to its assurance of non-negative solutions. In addition, the initial physically justified assumption of LPS, based on low-energy section measurements, was established to clear out noise-like artefacts. This paper will highlight the improvements made in the LPS tomography and compare the simulated and experimental results.
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.B. Barboutis, R. Klein, M. Müller
PTB, Berlin, Germany
The electron storage ring MLS (Metrology Light Source) is used by the Physikalisch-Technische Bundesanstalt (PTB), the German metrology institute, as a primary source standard of calculable synchrotron radiation in the ultraviolet and vacuum ultraviolet spectral range. For this, all storage ring parameters have to be appropriately set and measured with high uncertainty. E.g., the electron beam current can be varied by more than 11 orders. This adjustment of the electron beam current, and thus the spectral radiant intensity of the synchrotron radiation, for the specific calibration task is conveniently performed fully automatic by a computer program.
S.L. Mathisen, T.H. Pacey, R.J. Smith
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
As part of the development of the CLARA electron accelerator at Daresbury Laboratory, a new analog front end for bunch charge measurement has been developed to provide accurate measurements across a wide range of operating charges with repetition rates of up to 400 Hz. The qualification tests of the front end are presented. These include tests of the online calibration system, compared to a bench Faraday cup test setup; online beam test data with a Faraday cup from 1 to 200 pC; online beam test data with a wall current monitor from 1 to 200 pC, and tests using signal processing such as singular value decomposition. This is demonstrated to enable the measurement of bunch charges in the order of 100 fC using both Faraday Cups and Wall Current Monitors.
S. Brandenburg, M.J. Goethem
PARTREC, Groningen, The Netherlands
T. Delaviere, L. Dupuy, F. Stulle
BERGOZ Instrumentation, Saint Genis Pouilly, France
In conventional proton therapy (PT) typical beam currents are of the order of 1 nA. At these currents dose monitoring is reliably achieved with an ionization chamber. However, at the very high dose rates used in FLASH irradiations (employing beam currents >100 nA) ionization chambers will exhibit large intensity dependent recombination effects and cannot be used. A possible solution is a current transformer. Here we report on the performance of the LC-CWCT (Bergoz Instrumentation, France) which has been developed to push noise floor of such non-destructive current measurement systems into the nano-ampere range. We present first beam current measurements at the PARTREC cyclotron (Netherlands). Beam currents measured by the LC-CWCT and a Faraday Cup were shown to linearly correlate up to the maximum intensity of 400 nA used in the measurements. For pulsed beams, charge measured by the LC-CWCT linearly correlated with pulse length over the measurement range from 50 to 1000 µs. Measurement noise as low as 2.8 nA was achieved. The results confirm that the LC-CWCT has the potential to be applied in FLASH PT for accurate determination of beam current and macro pulse charge.
Two new X-ray diagnostics have been installed in the Front-Ends of the Storage Ring of the ESRF’s Extremely Brilliant Source (EBS) recently. Two independent optical X-BPMs at 23m distance from their bending magnet source-point are giving extremely useful additional information on the vertical beam stability in comparison to the e-BPMs data. A vertical beam Halo-monitor allows to measure permanently and quantitatively the level the electron density at large distance (1-3mm) from the beam core, in a non-destructive manner.
E. Buratin, N. Benoist, P.B. Borowiec, G. Denat, J. Jacob, K.B. Scheidt, F. Taoutaou
ESRF, Grenoble, France
Several new diagnostics have been installed and exploited at the ESRF’s new Extremely Brilliant Source (EBS) in 2022. A Libera-Spark BPM device has been implemented to measure the phase of Booster and EBS rings, with high resolution and up to turn-by-turn rate. In the Storage Ring we achieved irrefutably the control, injection and measurement of single electron(s) with the use of transfer-line screens, the visible-light extraction system and a low-cost photo-multiplier tube, combined with the commercial Spark Beam Loss Monitor. Further planned developments, like the TCPC technique, on this are on-going and will be essential to verify that our Booster cleaning process reaches a level of zero-electron bunch pollution in EBS.
M.T. Switka, K. Desch, D. Elsner
ELSA, Bonn, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
The Compton Polarimeter at the ELSA 3.2 GeV storage ring has been designed to measure the polarization degree of the stored electron beam by analyzing the profile of the back-scattered gamma-beam with a silicon microstrip detector. Utilizing a scattering asymmetry from interaction with circularly polarized laser light, the electron beam polarization is determined from the vertical shift of the gamma-beam’s center of gravity in respect to the handedness of the laser light. The installation of a new laser source and silicon strip detector has improved the polarimeter’s performance significantly. Additionally, the profile analysis could be enhanced by using a Pearson type peak function fit. The analyzing power was determined through the observation of the Sokolov-Ternov effect and a statistical measurement accuracy of 2 % could be obtained within 5 minutes of measurement time. The polarimeter resolves the expected spin dynamical effects occurring in the storage ring and has shown to be a robust and reliable measurement system for operation with the GaAs source for polarized electrons.
M.C. Paniccia, S.L. Clark, D.M. Gassner, R.L. Hulsart, P. Thieberger
BNL, Upton, New York, USA
Attenuation in a lossy coaxial cable increases over distance and varies over frequency. Having a model of these variations can help predict the expected loss and distortion of a signal. This paper discusses a free web-based application developed to provide accurate SPICE models for various coaxial cable types. The user can specify a length and select between different cable types, or upload their own cable attenuation curve, and receive a SPICE model for that cable. These simulation models have been used to assist the design and development of new instrumentation systems for the future Electron Ion Collider (EIC).
P. Ilinski
MAX IV Laboratory, Lund University, Lund, Sweden
Funding:Research conducted at MAX IV, a Swedish national user facility, is supported by the Swedish Research council, the Swedish Governmental Agency for Innovation Systems, and Formas. A novel photoemission type of X-ray Beam Position Monitor (XBPM) for the ’white’ undulator radiation is proposed. The XBPM employs beamline frontend fixed mask as a source of photocurrent signal. Signal spatial distribution and XBPM response were analyzed for various undulator radiation parameters.
L.T. Stant, M.G. Abbott, L. Bobb, G. Cook, L. Hudson, A.F.D. Morgan, E.P.J. Perez Juarez, A.J. Rose, A. Tipper
DLS, Oxfordshire, United Kingdom
The UK national synchrotron facility, Diamond Light Source, is preparing for a major upgrade to the accelerator complex. Improved beam stability requirements necessitate the fast orbit feedback system be driven from beam position monitors with lower noise and drift performance than the existing solution. Short-term beam motion must be less than 2 nm/sqrt(Hz) over a period of one second with a data rate of 100 kHz, and long-term peak-to-peak beam motion must be less than 1 µm. A new beam position monitor is under development which utilises the pilot-tone correction method to reduce front-end and cabling perturbations to the button signal; and a MicroTCA platform for digital signal processing to provide the required data streams. This paper discusses the challenges faced during the design of the new system and presents experimental results from testing on the existing machine.
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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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J.C. Dooling, M. Borland, A.M. Grannan, C.J. Graziani, Y. Lee, R.R. Lindberg, G. Navrotski
ANL, Lemont, Illinois, USA
N.M. Cook
RadiaSoft LLC, Boulder, Colorado, USA
D.W. Lee
UCSC, Santa Cruz, California, USA
Funding:Work supported by Hard X-ray Sciences LDRD Project 2021-0119 and by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The reduced emittance and concomitant increase in electron beam intensity in Fourth Generation Storage Ring (4GSR) light sources lead to the challenging machine protection problem of how to safely dispose of the circulating charge during unplanned whole-beam loss events. Two recent experiments conducted to study the effects of 4GSR whole-beam dumps showed that damage to candidate collimator materials can be severe. This is a paradigm shift for SR light source machine protection. Typically the biggest threat to the machine is from CW synchrotron radiation. The choice of collimator material is important. High-Z, high-density materials such as tungsten may appear effective for stopping the beam in static simulations; however, in reality, short radiation lengths will cause severe destructive hydrodynamic effects. In our experiments, significant damage was observed even in low-Z aluminum. Thus unplanned, whole-beam dumps cannot be stopped in a single collimator structure. In this tutorial, alternatives such as multiple collimators and fan-out abort kicker systems will be discussed. Collimator design strategy and foreseen diagnostics for their operation will also be presented.
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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. Saccani, E. Effinger, W. Viganò, C. Zamantzas
CERN, Meyrin, Switzerland
Most of the LHC systems at CERN were updated during the Long Shutdown 2, from December 2018 to July 2022, to prepare the accelerator for High-Luminosity. The Beam Loss Monitoring system is a key part of the LHC’s instrumentation for machine protection and beam optimisation by producing continuous and reliable measurements of beam losses along the accelerator. The BLM system update during LS2 aims at providing better gateware portability to future evolutions, improving significantly the data rate in the back-end processing and the software efficiency, and adding remote command capability for the tunnel electronics. This paper first recalls the Run 1 and Run 2 BLM system achievements, then reviews the main changes brought during LS2, before focusing on the commissioning phase of Run 3 and future expectations.
R. Kwiatkowski, R. Nietubyc, J. Szewiński, D.R. Zaloga
NCBJ, Świerk/Otwock, Poland
A.I. Wawrzyniak
NSRC SOLARIS, Kraków, Poland
Funding:European Regional Development Fund in the framework of the Smart Growth Operational Programme and Regional Operational Programme for Mazowieckie Voivodeship. The Beam Loss Monitor (BLM) system is primarily used for machine protection and is especially important in the case of high energy density of accelerated beam, when such a beam could cause serious damages due to uncontrolled loss. PolFEL linear accelerator is designed with the beam parameters, which made BLM an essential system for machine protection. The design of BLM system for PolFEL is composed of several scintillation probes placed along and around the accelerator. The paper reports on design and first tests of prototype detector, which is planned to be used for PolFEL project. The prototype was tested in NCBJ and SOLARIS, using radioactive calibration samples and linear electron accelerator as a sources. We also present results of numerical investigation of radiation generated due to interaction of fast electrons with accelerator components.
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.
S. Strokov, M. Holz, G. Kube, D. Lipka, S. Vilcins
DESY, Hamburg, Germany
A new diffraction limited light source PETRA IV (DESY, Germany) with ultra-low emittance is currently being designed as an upgrade of the 3rd generation light source PETRA III. For transverse beam position measurements, beam position monitors (BPMs) will be used as an essential part of the beam diagnostic system. There will be a total of about 800 BPMs distributed along the 2.3 km storage ring. The inner diameter of the standard beam pipe, and therefore of most of the BPM chambers, will be 20 mm. The primary purpose of the systems is to provide high-resolution measurements of the transverse position of the electron beam. By specification, the impact of the mechanical tolerances on the position readings should be below 150 microns which is essential for the commissioning of the machine. To achieve this goal, the dependence of the accuracy of the beam position measurement on the tolerances of each manufactured part of the BPM was studied. This paper summarizes the development and optimization of each part of the BPM by using EM simulations performed with CST Studio Suite.
M. Siano
Università degli Studi di Milano, Milano, Italy
D. Butti, T. Lefèvre, S. Mazzoni, G. Trad
CERN, Meyrin, Switzerland
G. Geloni
EuXFEL, Schenefeld, Germany
U. Iriso, A.A. Nosych, L. Torino
ALBA-CELLS, Cerdanyola del Vallès, Spain
B. Paroli, M.A.C. Potenza
Universita’ degli Studi di Milano & INFN, Milano, Italy
"Fast Monte-CarlO approach to Coherence of Undulator Sources" (FOCUS) is a new GPU-based code to compute the transverse coherence of X-ray radiation from undulator sources. The code relies on scaled dimensionless quantities and analytic expressions of the electric field emitted by electrons in an undulator, obtained in the frequency domain under paraxial approximation (justified by the assumption of ultra-relativistic electrons) and free space propagation, with the addition of the resonance approximation. We describe the core structure of the code, which exploits GPUs for massively parallel computations. We validate our approach by direct comparison with SRW (Synchrotron Radiation Workshop) simulations. The benchmarks prove that FOCUS yields similar results with respect to SRW, while at the same time reducing the computation times by five orders of magnitude. Finally, we show examples of applications to beam size diagnostics. The aim of the code is to fast evaluating the transverse coherence properties of undulator X-ray radiation as a function of the electron beam parameters, and to support and help preparing more rigorous numerical simulations with traditional codes like SRW.
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.
A.I. Novokshonov, G. Kube, S. Strokov
DESY, Hamburg, Germany
Z. Aboulbanine, G.D. Adhikari, N. Aftab, P. Boonpornprasert, G.Z. Georgiev, J. Good, M. Groß, C. Koschitzki, M. Krasilnikov, X. Li, O. Lishilin, A. Lueangaramwong, D. Melkumyan, F. Mueller, A. Oppelt, H.J. Qian, F. Stephan, G. Vashchenko, T. Weilbach
DESY Zeuthen, Zeuthen, Germany
A standard technique to measure beam profiles in linear accelerators are screen monitors using scintillating screens. This technique is used e.g. at the European XFEL in order to overcome coherence effects in case of OTR usage [*]. During the XFEL commissioning it was found out that screens based on LYSO:Ce as scintillating material revealed a nonproportional light output [**]. Reason for it is the high particle beam density. As consequence it was decided to exchange LYSO:Ce by GAGG:Ce scintillators because the excitation carriers can rapidly transfer their energy to excited states of gadolinium, and a rapid migration of this energy among the Gd sub-lattice is expected. Driven by the observations at XFEL a series of measurements was started to investigate the properties of various scintillator materials (LYSO:Ce, YAP:Ce, YAG:Ce, LuAG:Ce and GAGG:Ce). The last measurement campaign was carried out at PITZ which allows to operate at higher beam charge and lower electron energy compared to the XFEL. The present work summarizes the results of these measurements. * S.Wesch and B.Schmidt, in Proc. DIPAC’11, Hamburg, WEOA01, pp. 539-543. ** G.Kube, A.Novokshonov, S.Liu, M.Scholz, in Proc. FEL’19, Hamburg, WEB01, pp. 301-306.
R. Singh, P. Forck, T. Reichert, A. Reiter
GSI, Darmstadt, Germany
S. Klaproth
THM, Friedberg, Germany
G.O. Rodrigues
IUAC, New Delhi, India
Funding:This work is supported by the German Federal Ministry of Education and Research (BMBF) under contract no. 05P21RORB2. Joint Project 05P2021 - R&D Accelerator (DIAGNOSE) The longitudinal charge profiles of the high intensity heavy ion beam accelerated at the GSI UNILAC upto 11.4 MeV/u can differ significantly in consecutive macro-pulses. Variations in bunch shape and mean energy were also observed within a single macro-pulse. In order to have an accurate and fast determination of bunch shape and its evolution within a macro-pulse, a study of fast Faraday Cup designs is underway at GSI. In this contribution, we present CST particle in cell (PIC) simulations of radially coupled co-axial Fast Faraday Cup (RCFFC) and conventional axially coupled FFC (ACFFC) design. The simulation results are compared to the measurements performed under comparable beam conditions primarily with RCFFCs. A rather large impact of secondary electron emission is observed in simulations and experiments. The biasing of the FFC central electrode as a mitigation mechanism on the measured profiles is discussed.
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
L. Torino, G. Benedetti, F.F.B. Fernández, U. Iriso, Z. Martí, J. Moldes, D. Yépez
ALBA-CELLS, Cerdanyola del Vallès, Spain
The polarization of the synchrotron radiation produced by a bending magnet can be selected by properly choosing the vertical emission angle. At beamlines this can be done by moving a slit to cut out unwanted polarization: this method is time consuming and not very reproducible. Another option is to fix the slit position and generate a local bump with the electron beam, and vary the emission angle at the source point such that the slit is illuminated with the desired polarization. At ALBA, we have implemented this option within the Fast Orbit Feedback, which allows to perform the angle switch in less than one minute without affecting the other beamlines. This report describes the implementation of this technique for the dipole beamline MISTRAL at the ALBA Synchrotron.
R. Broucquart, N. Hubert
SOLEIL, Gif-sur-Yvette, France
In the framework of the SOLEIL II project, the diagnostics group must anticipate ahead of the dark period the upgrade of important system like the BPM electronics, the timing system end the Fast Orbit Feedback (FOFB). The FOFB is a complex system that is currently embedded in the BPM electronics modules (eBPM). A new flexible stand-alone platform is under conception to follow the future upgrades of surrounding equipment, and to allow the integration of future correction schemes. In this paper we will present the current status of technical decisions, tests and developments.
S.H. Mirza, A. Aloev, H.T. Duhme, B. Dursun, A. Eichler, S. Jabłoński, J. Klute, F. Ludwig, S. Pfeiffer, H. Schlarb, B. Szczepanski
DESY, Hamburg, Germany
G. Rehm
HZB, Berlin, Germany
PETRA IV is the upcoming low-emittance, 6 GeV, fourth- generation light source at DESY Hamburg. It is based upon a six-bend achromat lattice with additional beamlines as compared to PETRA III. Stringent stability of the electron beam orbit in the ring will be required to achieve diffraction- limited photon beam quality. In this regard, the requirements and the proposed topology of the global orbit feedback system are discussed for expected perturbations. An initial analysis based upon system requirements, design and modelling of the subsystems of the orbit feedback system is also presented
The demonstrations of GeV electron beams and FEL radiation driven by a centimeter-scale device illustrate the tremendous progress of laser-plasma accelerators. In such applications, beam divergence and size, along with beam energy and charge, are critical parameters of electron beams. An insight on the transverse parameters and their dynamics such as beam decoherence can be obtained by diagnostics complemented by betatron radiation detectors. This talk will also provide a brief overview of recent techniques for accessing the transverse phase space.
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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. Breunlin, G. Felcsuti
MAX IV Laboratory, Lund University, Lund, Sweden
The MAX IV Laboratory, inaugurated in 2016, hosts a 3 GeV ultra-low emittance storage ring, a 1.5 GeV storage ring and a linear accelerator driven Short Pulse Facility to deliver synchrotron radiation to scientific users. A Stability Task Force has been assigned to ensure the delivery of stable beams since early on in the design phase of the laboratory and is continuing its work in an ongoing and multi-disciplinary effort. Measurements of the electron beam stability resulting from the passive stabilization approach taken for the two storage rings will be presented, as well as figures of beam stability with the Fast Orbit Feedback system in operation. Each ID beamline in the 3 GeV storage ring is equipped with a pair photon beam position monitors that are currently used to complement the electron beam position monitors. In the light of the city development around the MAX IV campus, maintaining the good mechanical stability of the laboratory has to be seen as an ongoing effort. A number of studies are being performed to identify possible risks and to decide where measures need to be taken.
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Currently developed nuclear accelerators more and more widely use superconducting elements especially in windings of superconducting electromagnets and current leads to them. These elements are however sensitive to the irradiation caused by primary beam as well as by secondary particles, as it is the case for PolFEL. In the paper it is discussed how this irradiation damages the subtle structure of superconducting materials, leading to columnar defects formation in 2D HTc superconductors. It is analysed, in which way created nano-sized structural defects influence the critical current properties of the superconducting materials, in the process of capturing of the magnetic pancake vortices. Various initial positions of the captured vortices are analysed; their movement leads to potential barrier variations. Influence of the irradiation effects on the current-voltage characteristics of superconductors are investigated then and maximal current density detected as the function of irradiation dose, nano-defects size and physical parameters as magnetic field and temperature.
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.
P. Leban, A. Bardorfer, L. Bogataj, M. Cargnelutti, M.O. Oblak, P. Paglovec, B. Repič
I-Tech, Solkan, Slovenia
G. Kube, F. Schmidt-Föhre, K. Wittenburg
DESY, Hamburg, Germany
Within the PETRA IV project at DESY, the synchrotron radiation source PETRA III will be upgraded into a low-emittance source. The small beam emittance and reduced beam size imply stringent requirements on the machine stability. To meet the requirements on position measurement and orbit stability, a high-resolution BPM system will be installed in the new machine, with about 800 BPMs and MTCA.4-based readout electronics. In the TDR phase of the project, I-Tech and DESY are cooperating on the realization of a BPM prototype that will demonstrate the feasibility of reaching the PETRA IV requirements. Several analog, digital and SW parts are taken from the Libera Brilliance+ instrument and are reused in the MTCA.4 BPM prototype, with some innovations. One of them is the separation of the RF switch matrix used for long-term stabilization: placing it near the BPM enables also the long RF cables to be stabilized. An 8 channel RTM board, able to acquire signals from two BPMs was developed and is also tested. This paper presents an overview of the BPM electronics prototype and the promising test results achieved in the Instrumentation Technologies’ laboratory with the first boards produced.
M. Krupa, I. Degl’Innocenti, D. Gudkov, G. Schneider
CERN, Meyrin, Switzerland
D.R. Bett
JAI, Oxford, United Kingdom
The demanding instrumentation requirements of the future High Luminosity LHC (HL-LHC) require 44 newly designed Beam Position Monitors (BPM) to be installed around the ATLAS and CMS experiments in 2026-2028. Three BPM types are now in pre-series production, with two more variants under design. Close to the collision point, a set of cryogenic directive coupler BPMs equipped with a brand new acquisition system based on nearly-direct digitization will resolve the position of the two counter-rotating LHC beams occupying a common vacuum chamber. Other new button and stripline BPMs will provide not only the transverse beam position, but also timing signals for the experiments, and diagnostics for the new HL-LHC crab cavities. This contribution summarizes the HL-LHC BPM specifications, gives an overview of the new BPM designs, reports on the pre-series BPM production status and plans for series manufacturing, outlines the foreseen acquisition system architecture, and highlights the first beam measurements carried out with the proof-of-concept electronics for the directive stripline BPMs.
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.
U. Iriso, A.A. Nosych, M. Zeus
ALBA-CELLS, Cerdanyola del Vallès, Spain
A.C. Cazorla
ICMAB, Bellatera, Spain
I. Mases Solé
CERN, Meyrin, Switzerland
ALBA is currently equipped with two x-ray pinhole cameras for continuous beam size monitoring using the synchrotron radiation from two different bending magnets. The first pinhole was installed in day-1 and it is working properly since 2012 as the work-horse for the ALBA emittance measurements, while the second one has been commissioned in beginning 2021 for redundancy purposes. This paper summarizes the exercises to characterize the Point Spread Function (PSF) of both pinhole cameras using analytical calculations, SRW simulations, and experimental measurements using the beam lifetime.
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.
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%.
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.
M. Reißig, E. Bründermann, S. Funkner, B. Härer, A.-S. Müller, G. Niehues, M.M. Patil, R. Ruprecht, C. Widmann
KIT, Eggenstein-Leopoldshafen, Germany
Funding:Supported by the Doctoral School KSETA. C. W. achnowledges funding by BMBF contract number 05K19VKD. FCCIS is funded by the EU’s Horizon 2020 research and innovation programme under grant No 951754. At the KIT electron storage ring KARA (Karlsruhe Research Accellerator) an electro-optical (EO) near-field monitor is in operation performing single-shot, turn-by-turn measurements of the longitudinal bunch profile using electro-optical spectral decoding (EOSD). In context of the Future Circular Collider Innovation Study (FCCIS), a similar setup is investigated with the aim to monitor the longitudinal bunch profile of each bunch for dedicated top-up injection at the future electron-positron collider FCC-ee. This contribution presents the status of a monitor design adapted to cope with the high-current and high-energy lepton beams foreseen at FCC-ee.
G.O. Rodrigues, S. Kumar, K. Mal, R. Mehta, C.P. Safvan
IUAC, New Delhi, India
R. Singh
GSI, Darmstadt, Germany
Fast Faraday Cups (FFCs) are interceptive beam diagnostic devices used to measure fast signals from sub-nanosecond bunched beams and the operation of these devices is a well-established technique. However, for short bunch length measurements in non-relativistic regimes with ion beams, the measured profile is diluted due to field elongation and distortion by the emission of secondary electrons. Additionally, for short bunches with the expected intensities envisaged in the High Current Injector at the Inter University Accelerator Centre, the impedance matching of the EM structure puts severe design constraints. This work presents a detailed study on the modification of a radially-coupled coaxial FFC [1]. The field dilution and secondary electron emission aspects are modelled through EM simulations and techniques to minimise these effects are explored. This has resulted in a new design, which has a better signal to noise ratio and benefits from a more accurate bunched beam measurement. [1] Carneiro, J.-P., et al. ’Longitudinal Beam Dynamics Studies at the Pip-II Injector Test Facility.’ International Journal of Modern Physics A, vol. 34, no. 36, 2019, p.1942013
C. Davut
The University of Manchester, Manchester, United Kingdom
Ö. Apsimon
The University of Liverpool, Liverpool, United Kingdom
P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
T. Lefèvre, S. Mazzoni
CERN, Meyrin, Switzerland
G.X. Xia
UMAN, Manchester, United Kingdom
In this paper, a study using the Polarization Current Approach (PCA) model is performed to optimize the design of a short bunch length monitor using two dielectric radiators that produce coherent Cherenkov Diffraction Radiation (ChDR). The electromagnetic power emitted from each radiator is measuring a different part of the bunch spectrum using Schottky diodes. For various bunch lengths, the coherent ChDR spectrums are calculated to find the most suitable frequency bands for the detection system. ChDR intensities measured by each detector are estimated for different impact parameters to explore the dependence of bunch length monitor on beam position and angular jitter. It is found that, in the present configuration, the effects of beam position and angular jitter are negligibly small for bunch length measurement. * Shevelev, M. V., & Konkov, A. S. (2014). Journal of Experimental and Theoretical Physics, 118(4), 501-511. ** Curcio, A. et al. (2020). Physical Review Accelerators and Beams, 23(2), 022802.
F. Falkenstern, J. Kuszynski, G. Rehm
HZB, Berlin, Germany
The "Booster Fillpattern Monitor" is used to measure currents in each individual electron bunch in the booster of the BESSY II machine. The booster with its circumference of 96 meters has space for max.160 electron bunches. The distance between the electron bunches of 60cm (96m/160) is determined by the RF Master Clock ~ 499, 627MHz. In practice, fill patterns of a one to five equally spaced bunches are in use. The fill pattern monitor digitizes electrical pulses generated from a strip line using a broadband ADC. The sampling frequency is selected as an integer fraction of the bunching frequency, acquiring the full fill pattern over a number of turns. Experiments performed at BESSY II demonstrate the performance of the setup and will be discussed.
L. Parsons França, M. Duraffourg, F. Roncarolo, F.M. Velotti
CERN, Meyrin, Switzerland
E. Kukstas, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
Funding:This work was supported by CERN and the STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) under grant agreement ST/P006752/1. The CERN fixed target experimental areas have recently acquired new importance thanks to newly proposed experiments, such as those linked to Physics Beyond Colliders (PBC) activities. Secondary Emission Monitors (SEMs) are the instruments currently used for measuring beam current, position and size in these areas. Guaranteeing their reliability, resistance to radiation and measurement precision is challenging. This paper presents the studies being conducted to understand ageing effects on SEM devices, to calibrate and optimise the SEM design for future use in these beamlines. These include feasibility studies for the application of machine learning techniques, with the objective of expanding the range of tools available for data analysis.
T. Batten, M. Bree, J.M. Vogt
CLS, Saskatoon, Saskatchewan, Canada
The Canadian Light Source is a 3rd generation synchrotron that began user operations in 2005 and now supports 22 operational beamlines. The orbit correction system was upgraded in 2021 to improve machine reliability and performance. This upgrade has also increased the diagnostic capabilities and supports easy integration of new functionality, providing the foundation for future enhancements.
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.
A. Mariet, B. Moser, R. Veness
CERN, Meyrin, Switzerland
M. Devel, J.E. Groetz
UFC, Besançon, France
A. Mikhalchan, J.J. Vilatela
IMDEA, Madrid, Spain
With the planned increase of luminosity at CERN for HL-LHC and FCC, instruments for beam quality control must meet new challenges. The current wires, made up of plain carbon fibers and gold-plated tungsten would be damaged due to their interactions with the higher luminosity beams. We are currently testing a new and innovative material, with improved performance: carbon nanotube fibers (CNTF). The HiRadMat (High Radiation for Material) experimental line at the output of the SPS is a user facility which can irradiate fix targets up to 440 GeV/c. CNTF with various diameters were irradiated in HiRadMat with different intensities, later imaged with a SEM microscope and tested for their mechanical properties. In addition, simulations have been carried out with the FLUKA particle physics Monte-Carlo code, in order to better understand the mechanisms and assess the energy deposition from protons at 440 GeV/c in those CNTF wires, depending mainly on their diameters and densities. This could lead to a good estimation of the CNTF temperature during irradiation. In this contribution, we first present the HiRadMat experimental setup and then we discuss the results of our FLUKA simulations.
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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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C. Szwaj, S. Bielawski, C. Evain, E. Roussel
PhLAM/CERLA, Villeneuve d’Ascq, France
C. Gerth, B. Steffen
DESY, Hamburg, Germany
B. Jalali
UCLA, Los Angeles, California, USA
Funding:ULTRASYNC ANR-DFG project, CPER Photonics for Society, CEMPI LABEX Recording electric field evolutions in single-shot and with sub-picosecond resolution is required in electron bunch diagnostics, and THz applications. A popular strategy consists of transferring the unknown electric field shape onto a chirped laser pulse, which is eventually analyzed. The technique has been investigated and/or been used as routine diagnostics at FELIX, DESY, PSI, Eu-XFEL, KARA, SOLEIL, etc. However fundamental time-resolution limitations have been strongly limiting the potential of these methods. We review recent results on a strategy designed for overcoming this limit: DEOS [1] (Diversity Electro-Optic Sampling). A special experimental design enables to reconstruct numerically the input electric signal with unprecedented temporal resolution. As a result, 200 fs temporal resolution over more than 10 ps recording length could be obtained at European XFEL - a performance that could not be realized using classical spectrally-decoded electro-optic detection. Although DEOS uses a radically novel conceptual approach, its implementation requires few hardware modifications of currently operating chirped pulse electro-optic detection systems. [1] E. Roussel, C. Szwaj, C. Evain, B. Steffen, C. Gerth, B. Jalali and S. Bielawski, Light: Science & Applications 11, 14 (2022). https://www.nature.com/articles/s41377-021-00696-2
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The fast Beam Condition Monitor (BCM1F) for the CMS experiment at the LHC was upgraded for precision luminosity measurement in the demanding conditions foreseen for LHC Run3. BCM1F has been rebuilt with new silicon diodes, produced on the CMS Phase 2 Outer Tracker PS silicon wafers. The mechanical structure was adapted to include a 3D printed titanium circuit for active cooling of BCM1F sensors. The assembly and qualification of the detector quadrants were followed by the integration with Pixel Luminosity Telescope and Beam Conditions Monitor for Losses on a common carbon fibre carriage. This carriage was installed inside the CMS behind the Pixel detector, 1.9 m from the Interaction Point. BCM1F will provide a real-time luminosity measurement as well as a measurement of the beam-induced background, by exploiting the arrival time information of the hits with a sub-bunch crossing precision. Moreover, regular beam overlap scans at CMS were introduced during Run 2, enabling an independent and non-destructive transverse profile measurement for LHC Operators. The paper describes the improved BCM1F detector design, its commissioning and performance during the beginning of Run 3 operation.
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