TU2 —  Tuesday Session 2   (13-Sep-22   11:00—13:00)
Chair: K. Wittenburg, DESY, Hamburg, Germany
Paper Title Page
TU2T1 Collimation and Machine Protection for Low Emittance Rings 196
  • 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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slides icon Slides TU2T1 [16.661 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TU2T1  
About • Received ※ 08 September 2022 — Revised ※ 09 September 2022 — Accepted ※ 12 September 2022 — Issue date ※ 04 October 2022
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TU2C2 The Diamond Beam Loss Monitoring System at CERN LHC and SPS 202
  • E. Calvo Giraldo, E. Effinger, M. Gonzalez Berges, J. Martínez Samblas, S. Morales Vigo, B. Salvachúa, C. Zamantzas
    CERN, Meyrin, Switzerland
  • J. Kral
    CTUP/FNSPE, Prague, Czech Republic
  The Large Hadron Collider (LHC) and the Super Proton Synchrotron (SPS) accelerators are equipped with 17 pCVD diamond based Beam Loss detectors at strategical locations where their nanosecond resolution can provide insights into the loss mechanisms and complement the information of the standard ionization chamber type detectors. They are used at the injection and extraction lines of the LHC and SPS, to analyse the injection or extraction efficiency, and to verify the timing alignment of other elements like kicker magnets. They are used at the betatron collimation region and are being also explored as detectors to analyse slow extractions. The acquisition chain was fully renovated during the second LHC long shutdown period (from December 2018 to July 2022) to provide higher resolution measurements, real-time data processing and data reduction at the source as well as to integrate seamlessly to the controls infrastructure. This paper presents the new hardware platform, the different acquisition modes implemented, the system capabilities and initial results obtained during the commissioning and operation at the beginning of the LHC’s Run 3.  
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slides icon Slides TU2C2 [4.414 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TU2C2  
About • Received ※ 06 September 2022 — Revised ※ 09 September 2022 — Accepted ※ 12 September 2022 — Issue date ※ 14 September 2022
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TU2C3 Commissioning Beam-Loss Monitors for the Superconducting Upgrade to LCLS 207
  • 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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slides icon Slides TU2C3 [4.388 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TU2C3  
About • Received ※ 08 September 2022 — Revised ※ 09 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 12 October 2022
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Acceleration, Transport and Diagnostic of Protons from Laser-Matter Interaction  
  • G. Petringa, G.A.P. Cirrone
    INFN/LNS, Catania, Italy
  Laser-generated radiation represent one of the frontiers of the acceleration techniques. When a TW level, fs duration laser is focused in small spot size, the radiation pressure triggers physics processes able to accelerate ions with intensities of the order of E9-E11 particles/steradians. Laser driven ion acceleration has several applications. The development of laser-accelerated proton irradiation systems was proposed by many research group. The Czech pillar of ELI site, includes the ’ELIMED’ beamline, devoted to exploring medical applications of laser-driven proton beams. Radioisotope production is another potential medical application, but many other are of interest such as high-resolution proton radiography, nuclear reactions and the development of laser-driven high-brightness injectors. All these applications require the detectors and diagnostic systems able to detect these high intense beams. In this talk an overview on the last approaches of laser-driven ion acceleration and diagnostic will be presented. Advanced solutions on detectors development will be presented with a critical discussion on the current limitations and potential future achievable progresses.  
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slides icon Slides TU2I4 [13.652 MB]  
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