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.
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
S. Mazzoni, W. Andreazza, E. Balci, D. Belohrad, E. Bravin, N.S. Chritin, J.C. Esteban Felipe, T. Lefèvre, M. Martin Nieto, M. Palm
CERN, Meyrin, Switzerland
The Beam Rate of Neutrals (BRAN) is a monitor that provides a relative luminosity measurement for the four LHC experiments. BRANs are used during operations as a tool to find and optimise collision and to cross-check experiments luminosity monitors. While each LHC experiments is equipped with BRANs, in this contribution we will focus on the new monitors installed for ATLAS and CMS that will replace the current ageing gas chambers during LHC run 3. These will also serve as as prototypes for the future High Luminosity LHC monitors that will need to sustain an even higher collision rate. A description of the BRAN as well as the first results obtained during the LHC Run 3 start-up will be presented.
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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A. Warner, M.R. Austin, L.R. Carmichael, J.-P. Carneiro, B.M. Hanna, E.R. Harms, M.A. Ibrahim, R. Neswold, L.R. Prost, R.A. Rivera, A.V. Shemyakin, J.Y. Wu
Fermilab, Batavia, Illinois, USA
Funding:* This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics The PIP2IT accelerator was assembled in multiple stages in 2014 - 2021 to test concepts and components of the future PIP-II linac that is being constructed at Fermilab. In its final configuration, PIP2IT accelerated a 0.55 ms x 20 Hz x 2 mA H− beam to 16 MeV. To protect elements of the beam line, a Machine Protection System (MPS) was implemented and commissioned. The beam was interrupted faster than 10 µs when excessive beam loss was detected. The paper describes the MPS architecture, methods of the loss detection, procedure of the beam interruption, and operational experience at PIP2IT.
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.
N. Milas, G.S. Fedel, A.A. Gorzawski, J.J. Jamróz, J.P.S. Martins
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. The commissioning runs of 2021 and early 2022 were the first where the master timing system for the linac was fully available. As a consequence of that, the beam actuators and beam monitoring equipment relied fully on timing events sent accross the machine, not only to be triggered to act but also to get the configuration. In this paper, we describe the timing system as available today, present how we define and create the beam pulses using the available parameters. We also present planned future upgrades and other outlook for the system.
C. Lannoy, D. Alves, N. Mounet
CERN, Meyrin, Switzerland
C. Lannoy, T. Pieloni
EPFL, Lausanne, Switzerland
K. Łasocha
Jagiellonian University, Kraków, Poland
We introduce a method for building Schottky spectra from macro-particle simulations performed with the PyHEADTAIL code, applied to LHC beam conditions. In this case, the use of a standard Fast Fourier Transform (FFT) algorithm to recover the spectral content of the beam becomes computationally intractable memory-wise, because of the relatively short bunch length compared to the large revolution period. This would imply having to handle an extremely large amount of data for performing the FFT. To circumvent this difficulty, a semi-analytical method was developed to compute efficiently the Fourier transform. The spectral content of the beam is calculated on the fly along with the macro-particle simulation and stored in a compact manner, independently from the number of particles, thus allowing the processing of one million macro-particles in the LHC, over 10’000 revolutions, in a few hours, on a regular computer. The simulated Schottky spectrum is then compared against theoretical formulas and measurements of Schottky signals previously obtained with lead ion beams in the LHC.
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.
S. Di Carlo, W. Andreazza, D. Belohrad, J. Emery, J.C. Esteban Felipe, A. Goldblatt, D. Gudkov, A. Guerrero, S. Jackson, G.O. Lacarrere, M. Martin Nieto, A.T. Rinaldi, F. Roncarolo, C. Schillinger, R. Veness
CERN, Meyrin, Switzerland
The ability of reliably measuring the transverse beam profile in its injectors is essential for the operation of the LHC. This report aims to assess the reliability, stability, and reproducibility of the new generation of beam wire scanners developed at CERN in the framework of the LHC Injectors Upgrade (LIU). The study includes data from the over 60000 scans performed in 2021 and 2022, with a special focus on reproducibility, investigation of optimal operational settings to ensure a large dynamic range, and evaluation of absolute accuracy through comparison with other instruments present in the injectors.
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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