Instrumentations and Beam Material Interactions
Paper Title Page
MOPAB41 Feasibility Study of a Novel, Fast Read-out System for an Ionization Profile Monitor Based on a Hybrid Pixel Detector 128
 
  • O. Keller, B. Dehning, M. Sapinski, L.S. Swann
    CERN, Geneva, Switzerland
  
  The ability to continuously monitor the transverse beam size is one of the priorities for the upgrade and consolidation of the CERN Proton Synchrotron for the High Luminosity LHC era. As well as providing an average beam size measurement throughout the acceleration cycle, the requirements also cover bunch-by-bunch measurements of up to 72 bunches with a bunch spacing of 25 ns within 1 ms. An ionization profile monitor with a hybrid pixel detector read-out is therefore being investigated as a possible candidate to provide such measurements. In this contribution the concept, based on a Timepix chip, is presented along with first laboratory measurements showing the imaging of low-energy electrons in a vacuum.  
 
MOPAB42 Investigation of the Effect of Beam Space-charge on Electron Trajectories in Ionization Profile Monitors 133
 
  • D.M. Vilsmeier, B. Dehning, M. Sapinski
    CERN, Geneva, Switzerland
  
  The correct measurement of beam size using an ionization profile monitor relies on the confinement of electron trajectories from their source to the electron-sensitive detector. This confinement is provided by a magnetic field aligned with electric extraction field. As the initial electron velocities are boosted by the presence of a high-charge density beam, the value of the magnetic field depends on both the beam size and on the charge density. If the magnetic field is not strong enough a deformation of the observed beam profile occurs. In this paper the results of a study of electron trajectories in the presence of high charge density beams is presented along with an estimation of the required magnetic field for various scenarios. A correction procedure for compensating any residual distortions in the measured profile is also discussed.  
 
MOPAB43 Studies on Heavy Ion Losses from Collimation Cleaning at the LHC 138
 
  • P.D. Hermes, R. Bruce, J.M. Jowett, S. Redaelli, B. Salvachua, G. Valentino, D. Wollmann
    CERN, Geneva, Switzerland
  
  The LHC collimation system protects superconducting magnets from beam losses. By design, it was optimized for the high-intensity proton challenges but so far provided adequate protection also during the LHC heavy-ion runs with 208 Pb 82+ ions up to a beam energy of 4 Z TeV. Ion beam cleaning brings specific challenges due to different physical interactions with the collimator materials and might require further improvements for operation at 7 Z TeV. In this article, we study heavy-ion beam losses leaking out of the LHC collimation system, both in measurement and simulations. The simulations are carried out using both ICOSIM, with a simplified ion physics model implemented, and SixTrack, including more detailed starting conditions from FLUKA but without including online scattering in subsequent collimator hits. The results agree well with measurements overall, although some discrepancies are present. The reasons for the discrepancies are investigated and, on this basis, the requirements for an improved simulation tool are outlined.  
 
MOPAB44 Beam Halo Measurement Using a Combination of a Wire Scanner Type Beam Scraper and Some Beam Loss Monitors in J-PARC 3-GeV RCS 143
 
  • M. Yoshimoto, H. Harada, M. Kinsho, K. Okabe
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  
  Transverse beam halo is one of the most important beam parameters due to limit the performance of the high intensity beam accelerator. Therefore, the transverse beam halo measurement is required to increase the beam power of the J-PARC 3-GeV RCS. New beam halo monitor, which is combined a wire type beam scraper and some beam loss monitors, are installed in the extraction beam transport line. In order to use some beam loss monitors with a plurality of different sensitivities, it's ultra wide dynamic range can be achieved and beam profile including both of the beam core and halo can be obtained.  
 
MOPAB46 Proposed Varying Amplitude Raster Pattern to Uniformly Cover Target for the Isotope Production Facility (IPF) at LANSCE 148
 
  • J.S. Kolski
    LANL, Los Alamos, New Mexico, USA
  
  The Isotope Production Facility (IPF) at LANSCE produces medical isotopes strontium-82 and germanium-68 by bombarding rubidium chloride and gallium metal targets respectively with a 100 MeV proton beam, 230 uA average current. Rastering the proton beam is necessary to distribute heat load on the target and target window, allowing higher average beam current for isotope production. Currently, we use a simple circular raster pattern with constant amplitude and frequency. The constant amplitude raster pattern does not expose the target center to beam and few isotopes are produced there. We propose a raster pattern with varying amplitude to increase isotope production at the target center, achieve uniform beam flux over the target, and expose more of the target surface to beam heating. Using multiparticle simulations, we discuss the uniformity of target coverage using the proposed varying amplitude raster pattern, compare with the constant amplitude raster pattern currently used, and consider dependencies on transverse beam size, beam centroid offset, and macropulse length and repetition rate.  
poster icon Poster MOPAB46 [7.847 MB]  
 
MOPAB47 Simulation of a New Beam Current Monitor Under Heavy Heat Load 151
 
  • J.L. Sun, P.-A. Duperrex
    PSI, Villigen PSI, Switzerland
  
  Funding: "The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n.°290605 (PSIFELLOW/ COFUND)"
At the Paul Scherrer Institute (PSI), the High Intensity Proton Accelerator (HIPA) feeds a spallation source target with protons. A beam current monitor installed 8 meters downstream from the target is heated by the scattered particles from the target. This thermal load on the monitor causes the resonance frequency to drift much more than expected. A novel new beam current monitor using graphite has been developed. In order to have a good understanding of its performance, the simulation software ANSYS has been used to carry out thermal and high frequency simulations. With this software, it was possible to perform a detailed design of the thermal self-compensation scheme and to check the structural stability of the whole system. In this paper, simulation results are presented to show that frequency and sensitivity drifts can be reduced to 8 kHz from previous 730 kHz when realistic operating conditions are assumed. 		 
 
MOPAB48 Design of a New Beam Current Monitor Under Heavy Heat Load 154
 
  • J.L. Sun, P.-A. Duperrex, G. Kotrle
    PSI, Villigen PSI, Switzerland
  
  Funding: The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n.°290605 (PSI-FELLOW/COFUND)
At the Paul Scherrer Institute (PSI), a 590 MeV 50 MHz High Intensity Proton Accelerator (HIPA) has been operated for many years at 2.2 mA / 1.3 MW and it will be soon upgraded to 3 mA / 1.8 MW. A spallation source target is driven from the HIPA. Downstream from this target is a beam current monitor, called MHC5. The thermal load in MHC5 induced by the scattered particles from the target causes the resonance frequency of the current monitor to drift. Even with an active cooling system, the drift remains a problem. A new beam current monitor has been designed to overcome this shortcoming. The mechanical design of the new monitor has been completed and manufacturing will start soon. A novel feature is the use of graphite for the resonator cavity to give thermal self-compensation, structural stability and improved thermal load distribution. The design and the preliminary lab test results are presented in this paper. 		 
 
TUO2AB01
 Beam Instrumentation and Limitations for Multi MW Pulsed Proton Linacs  
 
  • A. Jansson
    ESS, Lund, Sweden
  
  This presentation focuses on the challenges and limitations related to measuring some of the relevant properties of very high intensity pulsed proton beams in linear accelerators. Among such properties are the transverse and longitudinal distributions, including the tails (halo). Challenges include energy deposition in invasive devices, as well as as very short bunches in combination with slow (beta<1) beams. An overview of methods used or currently considered will be given.  
slides icon Slides TUO2AB01 [7.484 MB]  
 
TUO2AB02
 Halo Matching for High Intensity Linacs and Dedicated Diagnostics  
 
  • N. Chauvin, J. Marroncle, P.A.P. Nghiem
    CEA/DSM/IRFU, France
  • P. Abbon, D. Uriot
    CEA/IRFU, Gif-sur-Yvette, France
  
  Minimizing beam losses is one of the biggest challenge of very high power linac (MW range). In some cases, beam matching concentrating on minimizing emittance growth is not the most appropriate approach; a direct matching of the halo itself is preferable. We propose a method consisting in minimizing the beam extent, using the Particle Swarm Optimization algorithm that is well suitable to nonlinear systems governed by many parameters. In this article, an application of halo matching simulations is given in the case of the IFMIF superconducting linac. Development of dedicated diagnostics for in-situ implementation of this method on linacs are briefly presented. The beam diagnostic types and locations needed for machine tuning with halo matching are detailed.  
slides icon Slides TUO2AB02 [7.922 MB]  
 
TUO2AB03 Beam Diagnostics for the Detection and Understanding of Beam Halo 183
 
  • K. Wittenburg
    DESY, Hamburg, Germany
  
  A general view that has been recently reached by different methods of halo diagnostics of high brightness hadron beams will be given. The performance (dynamic range, accuracy …) of various monitor types will be combined with the demands from beam dynamics of different machines to discuss which methods can be envisaged for the future. The discussion will include low and high energy machines and their related halo detection schemes.  
slides icon Slides TUO2AB03 [3.154 MB]  
 
TUO2AB04 Two-Dimensional and Wide Dynamic Range Profile Monitor Using OTR / Fluorescence Screens for Diagnosing Beam Halo of Intense Proton Beams 187
 
  • Y. Hashimoto, M. Tejima, T. Toyama
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • A. Akino, Y. Omori, S. Otsu, H. Sakai
    Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
  • T.M. Mitsuhashi
    KEK, Ibaraki, Japan
  
  An instrument which can diagnose a two-dimensional beam profile of the beam core together with the beam halo in wide dynamic range has been developed in the J-PARC. The instrument consists of OTR (Ti foil of 10 μm) screen, fluorescence (Cr doped alumina) screen, an Offner type imaging system, and a camera with image intensifier. The beam core is observed with OTR and the beam halo is observed with fluorescence screen, respectively. A combination of observations of beam core and halo with these two different screens that have different sensitivities allowed us an observation in wide-dynamic range. The four fluorescence screens are set in vertical and horizontal arrangement. Both the OTR and fluorescence are focused by an Offner type optics having a very wide incident pupil makes these images. This instrument is set in the beam transport line between the rapid cycling synchrotron and the main ring. A two dimensional profile of the beam core and the halo were successfully observed in six order of magnitude at projected plane using intense 3 GeV proton beams of 1.5 x 1013 protons. This monitor has a big advantage for the diagnostic of beam core and halo shapes in real space.
[1] Y. Hashimoto, et al., A Development of High Sensitive Beam Profile Monitor Using Multi-Screen, Proc. IBIC2013, 338-341. 		 
slides icon Slides TUO2AB04 [3.172 MB]  
 
TUO3AB01 Present Status of the High Current Proton Linac at Tsinghua University and Its Beam Measurements and Applications 208
 
  • Q.Z. Xing, D.T. Bin, C. Cheng, C.T. Du, L. Du, X. Guan, G. Hui, C. Jiang, C.-X. Tang, R. Tang, X.W. Wang, Y.S. Xiao, Y.G. Yang, H.Y. Zhang, S.X. Zheng
    TUB, Beijing, People's Republic of China
  • W.Q. Guan, Y. He, J. Li
    NUCTECH, Beijing, People's Republic of China
  • B.C. Wang
    NINT, Xi'an, People's Republic of China
  • S.L. Wang
    Institute of High Energy Physics (IHEP), People's Republic of China
  
  The CPHS (Compact Pulsed Hadron Source) linac at Tsinghua University, is now in operation as an achievement of its mid-term objective. The 3 MeV proton beam with the peak current of 22 mA, pulse length of 100 μs, and repetition rate of 20 Hz has been delivered to the Beryllium target to produce the neutron beam from the year of 2013. We present in this paper the development and application of the high current linac, together with the measurement of the proton and neutron beams. The beam energy of the CPHS linac will be enhanced to 13 MeV after the DTL is ready in 2015.  
slides icon Slides TUO3AB01 [4.599 MB]  
 
WEO2AB01 Instrumentation Design and Challenges at FRIB 267
 
  • S.M. Lidia
    FRIB, East Lansing, Michigan, USA
  
  Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC000061, the State of Michigan and Michigan State University.
The Facility for Rare Isotope Beams (FRIB) requires a drive linac to produce ion species from protons to uranium which will extend the heavy ion high intensity frontier. The unique design of the twice-folded linac coupled with the functional dynamic range of beam intensities over more than 5 orders of magnitude present new challenges to beam detection and measurement, instrumentation, and machine protection systems. Additional challenges to longitudinal tuning and transverse orbit optimization of multi-charge state beams drive the design of measurement systems and techniques in the low energy linac and dispersive arc regions. Finally, beam loss monitoring and detection systems must respond within 10 microseconds to prevent catastrophic damage to beamline components from high power, heavy ion beams. We present an overview of beam diagnostic systems and detection networks that enable tuning of FRIB over the operating intensity range, while ensuring adequate machine protection. Comparisons to other proposed and existing hadron facilities will be made. 		 
slides icon Slides WEO2AB01 [5.229 MB]  
 
WEO2AB02 Beam Loss Mechanisms, Measurements and Simulations at the LHC (Quench Tests) 273
 
  • M. Sapinski
    CERN, Geneva, Switzerland
  
  Monitoring and minimization of beam losses is increasingly important for high-intensity and superconducting machines. In the case of the LHC, the collimation system is designed to absorb the energy of lost particles and confine the main multi-turn losses to regions without sensitive equipment. However many loss mechanisms produce local loss events which can be located elsewhere in the machine. A beam loss monitoring system, covering the whole machine circumference is therefore essential, and is used for both machine protection and diagnostics. In order to fully understand the measured signals and set-up the beam abort thresholds, extensive simulation work is required, covering particle tracking in the accelerator and the generation of the particle showers created by the lost particles. In order to benchmark these simulations and verify beam-abort thresholds, special tests have been performed where beam losses are provoked in a controlled manner over a wide range of durations. This work summarizes the experience in understanding beam losses in the LHC during Run 1.  
slides icon Slides WEO2AB02 [4.364 MB]  
 
WEO2AB03 Beam Instrumentation at the 1 MW Proton Beam of J-PARC RCS 278
 
  • K. Yamamoto, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, K. Okabe, P.K. Saha, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • Y. Hashimoto, T. Toyama
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  
  Rapid Cycling Synchrotron(RCS) of Japan Proton Accelerator Complex(J-PARC) is providing more than 300 kW of proton beam to Material and Life science Facility(MLF) and Main Ring(MR). Last summer shutdown, a new ion source was installed to increase output power to 1 MW. In order to achieve reliable operation of 1 MW, we need to reduce beam loss as well. Beam quality of such higher output power is also important for users. We present beam monitor systems for these purposes.  
slides icon Slides WEO2AB03 [3.242 MB]  
 
WEO2AB04 Beam Diagnostic Challenges for High Energy Hadron Colliders 283
 
  • E.B. Holzer
    CERN, Geneva, Switzerland
  
  Two high energy hadron colliders are currently in the operational phase of their life-cycle, RHIC and LHC. A major upgrade of the LHC, HL-LHC, planned for 2023 aims at accumulating ten times the design integrated luminosity by 2035. Still further in the future, studies of SppC and FCC are investigating machines with a center-of-mass energy of up to 100 TeV and up to 100 km circumference. The existing machines pose considerable diagnostic challenges, which will become even more critical with any increase in size and energy. Cryogenic environments lead to additional difficulties for diagnostics and further limit the applicability of intercepting devices, making non-invasive profile and halo measurements essential. The sheer size of these colliders requires the use of radiation tolerant read-out electronics in the tunnel and low noise, low loss signal transmission. It also implies a very large number of beam position and loss monitors, all of which have to be highly reliable. To fully understand the machine and tackle beam instabilities bunch-by-bunch measurements become increasingly important for all diagnostic systems. This contribution discusses current developments in the field.  
slides icon Slides WEO2AB04 [10.201 MB]  
 
THO4AB01
 Material Response to High-Power Beams  
 
  • G. Škoro
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  The main issue for the materials used in the target systems (targets, beam windows, beam dumps, the pipes for contained liquid/powder jets, etc.) is the magnitude and the rate of change of deposited energy density. As the beam power increases, and the beam pulse length decreases, the estimate of material strength and corresponding lifetime based on simple, quasi-static equations is no longer accurate. In these cases the materials are tested dynamically and they behave differently than under quasi-static loading. The overview of the challenges on the road to address this problem will be presented. An account will be given of the constitutive models that offer insight into the deformation mechanisms and their possible application in estimating the lifetime of the materials used in the high power target systems. Special attention will be paid to the lessons learned at the current spallation neutron sources and preparation for the next generation of the high power spallation neutron sources.  
slides icon Slides THO4AB01 [7.139 MB]  
 
THO4AB02 DPA and Gas Production in Intermediate and High Energy Particle Interactions with Accelerator Components 433
 
  • A. Konobeev, U. Fischer
    KIT, Eggenstein-Leopoldshafen, Germany
  
  The evaluation of radiation damage and gas production rates in irradiated materials is a challenging task combining the modelling of the various underlying nuclear reaction processes, the simulation of the material behavior, and taking into account, as far as possible, experimental data. This talk presents a brief overview of molecular dynamics and binary collision approximation model simulations performed over the last years for structural materials for the estimation of the number of defects produced under irradiation. The calculation of recoil energy distributions using a Monte Carlo based intranuclear cascade evaporation model (INC), deterministic pre-equilibrium exciton evaporation model (PE), and evaluated data files is discussed. A special attention is given to the evaluation of gas production cross-sections using nuclear models, experimental data, and systematics predictions. Results of calculations using popular INC and PE based codes, including CEM and TALYS, are compared. Perspectives of the use of the evaluated data files for dpa and gas production cross-sections at intermediate and high energies are discussed.  
slides icon Slides THO4AB02 [1.452 MB]  
 
THO4AB03 Novel Materials for Collimators at LHC and its Upgrades 438
 
  • A. Bertarelli, F. Carra, A. Dallocchio, M. Garlaschè, L. Gentini, P. Gradassi, M. Guinchard, E. Quaranta, S. Redaelli, A. Rossi, O. Sacristan De Frutos
    CERN, Geneva, Switzerland
  • E. Quaranta
    Politecnico/Milano, Milano, Italy
  
  Funding: The research leading to these results has received funding from the European Commission under the FP7 Research Infrastructures project EuCARD-2, grant agreement no.312453
Collimators for last-generation particle accelerators like the LHC, must be designed to withstand the close interaction with intense and energetic particle beams, safely operating over an extended range of temperatures in harsh environments, while minimizing the perturbing effects, such as instabilities induced by RF impedance, on the circulating beam. The choice of materials for collimator active components is of paramount importance to meet these requirements, which are to become even more demanding with the increase of machine performances expected in future upgrades, such as the High Luminosity LHC (HL-LHC). Consequently, a far-reaching R&D program has been launched to develop novel materials with excellent thermal shock resistance and high thermal and electrical conductivity, replacing or complementing materials used for present collimators. Molybdenum Carbide - Graphite and Copper-Diamond composites have been so far identified as the most promising materials. The manufacturing methods, properties and application potential of these composites will be reviewed along with the experimental program which is to test their viability when exposed to high intensity particle beams. 		 
slides icon Slides THO4AB03 [9.405 MB]