Author: Welsch, C.P.
Paper Title Page
MOPC14 Beam Position Monitors R&D for keV Ion Beams 78
 
  • S. Naveed, A.A. Nosych, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • S. Naveed, A.A. Nosych, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • A.A. Nosych, L. Søby
    CERN, Geneva, Switzerland
  
  Funding: Work supported by the EU within the DITANET and oPAC projects under contracts 215080 and 289485, HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute core grant ST/G008248/1.
Beams of cooled antiprotons at keV energies shall be provided by the Ultra-low energy Storage Ring (USR) at the Facility for Low energy Antiproton and Ion Research (FLAIR) and the Extra Low ENergy Antiproton ring (ELENA) at CERN's Antiproton Decelerator (AD) facility. Both storage rings put challenging demands on the beam position monitoring system as their capacitive pick-ups should be capable of determining the beam position of beams at low intensities and low velocities, close to the noise level of state-of-the-art electronics. In this contribution we describe the design and anticipated performance of BPMs for low-energy ion beams on the examples of the USR and ELENA orbit measurement systems. We also present the particular challenges encountered in the numerical simulation of pickup response at very low beta values and describe an experimental setup realized at the Cockcroft Institute for BPM callibration. Finally, we provide an outlook on how the implementation of faster algorithms for the simulation of BPM characteristics could potentially help speed up such studies considerably. 		 
 
MOPC47 Monte Carlo Simulations of Beam Losses in the Test Beam Line of CTF3 189
 
  • E. Nebot Del Busto, S. Mallows, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • E. Branger
    Linköping University, Linköping, Sweden
  • S. Döbert, E.B. Holzer, R.L. Lillestøl, S. Mallows, E. Nebot Del Busto
    CERN, Geneva, Switzerland
  • R.L. Lillestøl
    University of Oslo, Oslo, Norway
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  The Test Beam Line (TBL) of the CLIC Test Facility 3 (CTF3) aims to validate the drive beam deceleration concept of CLIC, in which the RF power requested to boost particles to multi-TeV energies is obtained via deceleration of a high current and low energy drive beam (DB). Despite a TBL beam energy (150-80 MeV) significantly lower than the minimum nominal energy of the CLIC DB (250 MeV), the pulse time structure of the TBL provides the opportunity to measure beam losses with CLIC-like DB timing conditions. In this contribution, a simulation study on the detection of beam losses along the TBL for the commissioning of the recently installed beam loss monitoring system is presented. The most likely loss locations during stable beam conditions are studied by considering the beam envelope defined by the FODO lattice as well as the emittance growth due to the deceleration process. Moreover, the optimization of potential detector locations is discussed. Several factors are considered, namely: the distance to the beam, the shielding provided by the different elements of the line, the detector sensitivity and possible saturation effects of both the radiation detectors and electronics.  
 
MOPF03 Laser Diode Velocimeter-Monitor Based on Self-Mixing Technique 200
 
  • A.S. Alexandrova, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A.S. Alexandrova, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: Work supported within LA3NET which is funded by the European Commission under contract PITN-GA-2011-289191 and STFC under the Cockcroft Institute Core Grant No.ST/G008248/1.
Gas targets are important for a number of accelerator-based applications, in particular as cold targets for collision experiments and beam diagnostics purposes where gas jets have been successfully used as least intrusive beam profile monitors, however, detailed information about the gas jet is important for its optimization and the quality of the beam profile that can be measured with it. A laser velocimeter shall be used for an in-detail characterization of atomic and molecular gas jets and allow investigations into the jet dynamics. Existing methods are currently not efficient enough, hard to build, and rather expensive. A laser velocimeter based on the self-mixing technique can provide unambiguous measurements from a single interferometric channel, realizable in a compact experimental setup that can be installed even in radiation-exposed environments. In this contribution, an introduction to the underlying theory of self-mixing is given, before the design and functioning principle of the velocimeter is described in detail. Finally, preliminary experimental results with different solid targets are presented and an outlook on measurements with fluid and gaseous targets is given. 		 
poster icon Poster MOPF03 [1.045 MB]  
 
MOPF04 Results of the High Resolution OTR Measurements at KEK and Comparison with Simulations 204
 
  • B. Bolzon, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A.S. Aryshev
    KEK, Ibaraki, Japan
  • B. Bolzon, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  • B. Bolzon, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • P. Karataev, K.O. Kruchinin
    Royal Holloway, University of London, Surrey, United Kingdom
  • P. Karataev
    JAI, Egham, Surrey, United Kingdom
  
  Optical Transition Radiation (OTR) is emitted when a charged particle crosses the interface between two media with different dielectric properties. It has become a standard tool for beam imaging and transverse beam size measurements. At the KEK Accelerator Test Facility 2 (ATF2), OTR is used at the beginning of the final focus system to measure a micrometre beam size using the decrease in visibility of the OTR Point Spread Function (PSF). In order to study and improve the resolution of the optical system, a novel simulation tool has been developed in order to characterize the PSF in detail. Based on the physical optic propagation mode of ZEMAX, the propagation of the OTR electric field can be simulated very precisely up to the image plane, taking into account aberrations and diffraction coming through the designed optical system. This contribution will show the results of measurements performed after a first improvement of the ATF2 OTR optical design to confirm the very high resolution of the imaging system and the performance of this simulation tool.  
poster icon Poster MOPF04 [1.590 MB]  
 
MOPF09 A Gas-Jet Profile Monitor for the CLIC Drive Beam 224
 
  • A. Jeff, E.B. Holzer, T. Lefèvre
    CERN, Geneva, Switzerland
  • A. Jeff, V. Tzoganis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • V. Tzoganis, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 1015 electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. Profile monitors using gas ionisation or fluorescence have been used at a number of accelerators. Typically, extra gas must be injected at the monitor and the rise in pressure spreads some distance down the beampipe. In contrast, a gas jet can be fired across the beam into a receiving chamber, with little gas escaping into the rest of the beam pipe. In addition, a gas jet shaped into a thin plane can be used like a screen on which the beam cross-section is imaged. In this paper we present some arrangements for the generation of such a jet. In addition to jet shaping using nozzles and skimmers, we propose a new scheme to use matter-wave interference with a Fresnel Zone Plate to bring an atomic jet to a narrow focus.  
 
MOPF10 Off-Axis Undulator Radiation for CLIC Drive Beam Diagnostics 228
 
  • A. Jeff, T. Lefèvre
    CERN, Geneva, Switzerland
  • A. Jeff, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Jeff, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 1015 electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. In this paper we propose the use of relatively inexpensive permanent-magnet undulators to generate off-axis visible Synchrotron Radiation from the CLIC Drive Beam. The field strength and period length of the undulator should be designed such that the on-axis undulator wavelength is in the ultra-violet. A smaller but still useable amount of visible light is then generated in a hollow cone. This light can be reflected out of the beam pipe by a ring-shaped mirror placed downstream and imaged on a camera. In this contribution, results of SRW and ZEMAX simulations using the CLIC Drive Beam parameters are shown.  
 
MOPF25 Cryogenic Current Comparator as Low Intensity Beam Current Monitor in the CERN Antiproton Decelerators 267
 
  • M.F. Fernandes, J. Tan
    CERN, Geneva, Switzerland
  • M.F. Fernandes, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • M.F. Fernandes, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: Work supported by the EU within the oPAC project under contract 289485.
In the low-energy Antiproton Decelerator (AD) and the future Extra Low ENergy Antiproton (ELENA) rings at CERN, an absolute measurement of the beam intensity is essential to monitor any losses during the deceleration and cooling phases. However, existing DC current transformers can hardly reach the μA level, while at the AD and ELENA currents can be as low as 100 nA. A Cryogenic Current Comparator (CCC) based on a superconducting quantum interference device (SQUID) is currently being designed and shall be installed in the AD and ELENA machines. It should meet the following specifications: A current resolution smaller than 10 nA, a dynamic range covering currents between 100 nA and 1 mA, as well as a bandwidth from DC to 1 kHz. Different design options are being considered, including the use of low or high temperature superconductor materials, different CCC shapes and dimensions, different SQUID characteristics, as well as electromagnetic shielding requirements. In this contribution we present first results from a comparative analysis of different monitor options, taking into consideration the external electromagnetic sources at the foreseen device locations. 		 
poster icon Poster MOPF25 [1.059 MB]  
 
MOPF29 A Non-Invasive Beam Monitor for Hadron Therapy Beams 283
 
  • T. Cybulski, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • T. Cybulski, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Kacperek, B. Marsland, I. Taylor, A. Wray
    The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
  
  Funding: Work supported by the EU under contract PITN-GA-2008-215080 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1
Hadron therapy allows for precise dose delivery to the tumour volume only and hence decreases the dose delivered to the nearby organs and healthy tissue. Ideally, the beam would be monitored whilst being delivered to the patient. A novel, real–time and non-interceptive beam monitor for hadron therapy beams has been developed in the QUASAR Group. It is based on the LHCb VErtex LOcator (VELO) detector and couples to the treatment beam’s transverse halo to determine the intensity, position and ultimately the dose of the treatment beam. This contribution presents the design of a stand-alone version of the VELO detector which was developed for the Clatterbridge Cancer Centre (CCC) treatment line. The mechanical and electronic design of the monitor and its data acquisition system are shown, with a focus on the detector positioning and cooling system. Monte Carlo simulations into expected signal distributions are compared against first measurements with the 60 MeV proton beam at CCC. 		 
 
TUPF02 Secondary Emission Monitor for keV Ion and Antiproton Beams 495
 
  • A.G. Sosa, E. Bravin, A. Jeff
    CERN, Geneva, Switzerland
  • J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: Work supported by the EU within the DITANET and CATHI projects under contracts 215080 and 264330, HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute core grant ST/G008248/1.
Beam profile monitoring of low intensity keV ion and antiproton beams remains a challenging task. A Secondary electron Emission Monitor (SEM) has been designed to measure profiles of beams with intensities below 107 and energies as low as 20 keV. The monitor is based on a two stage microchannel plate (MCP) and a phosphor screen facing a CCD camera. Its modular design allows two different operational setups. In this contribution we present the design of a prototype and discuss results from measurements with protons at INFN-LNF and antiprotons at the AEgIS experiment at CERN*. This is then used for a characterization of the monitor with regard to its possible future use at different facilities.
* Measurements at the AD carried out with the AEgIS collaboration. 		 
poster icon Poster TUPF02 [1.934 MB]  
 
TUPF22 Beam Halo Monitor Based on an HD Digital Micro Mirror Array 557
 
  • B.B.D. Lomberg, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • B.B.D. Lomberg, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: This work is supported by the European Union under contract PITN-GA-2011-289485 and by STFC under the Cockcroft Institute Core Grant No. ST/G008248/1.
A beam halo monitor is an essential device to pursue studies of halo particles produced in any particle accelerator as to investigate the effects of disturbances, such as field kicks, gradient errors, etc. A fast, least intrusive, high dynamic range monitor will allow the detection and potentially control of particles at the tail of a transverse beam distribution. Light generated by a beam of charged particles is routinely used for beam diagnostic purposes. A halo monitor based on a digital micro-mirror device (DMD) used to generate an adaptive optical mask to block light in the core of the emitted light profile and hence limit observation to halo particles has been developed in close collaboration with CERN and University of Maryland. In this contribution an evolution of this monitor is presented. A high definition micro-mirror array with 1920x1080 pixels has been embedded into a MATLAB-based control system, giving access to even higher monitor resolution. A masking algorithm has also been developed that automates mask generation based on user-definable thresholds, converts between CCD and DMD geometries, processes and analyses the beam halo signal and is presented in detail. 		 
poster icon Poster TUPF22 [1.558 MB]  
 
TUPF26 Laser-Based Beam Instrumentation R&D within LA3NET 567
 
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: LA³NET is funded by the European Commission under Grant Agreement Number 289191.
Within LA3NET, Laser Applications for Accelerators are being developed by an international NETwork of more than 30 partner institutions from across the world. Laser-based beam instrumentation is at the core of this EU-funded project which will train 17 fellows during its four year project duration. In this contribution, we will present the consortium's recent research results in beam diagnostics, ranging from development of a laser velocimeter and laser emittance meter, over measurement of the bunch shape with electro-optical sampling in an electron accelerator and precision determination of electron beam energy with Compton backscattered laser photons to measurement of electron bunches with a time resolution of better than 20 femtoseconds. We will also provide a summary of past training events organized by the consortium and give an overview of future workshops, conferences and schools. 		 
 
WECL3 The LUPIN Detector: Supporting Least Intrusive Beam Monitoring Technique Through Neutron Detection 648
 
  • G.P. Manessi, M. Silari
    CERN, Geneva, Switzerland
  • M. Caresana
    Politecnico/Milano, Milano, Italy
  • M. Ferrarini
    CNAO Foundation, Milan, Italy
  • G.P. Manessi, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G.P. Manessi, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  The Long interval, Ultra-wide dynamic Pile-up free Neutron rem counter (LUPIN) is a novel detector initially developed for radiation protection purposes, specifically conceived for applications in pulsed neutron fields. The detector has a measurement capability varying over many orders of neutron burst intensity, from a single neutron up to thousands of interactions for each burst, without showing any saturation effect. Whilst LUPIN has been developed for applications in the radiation protection fields, its unique properties make it also well suited to support other beam instrumentation. In this contribution, the design of LUPIN is presented in detail and its main characteristics are summarized. Its potential use as beam loss monitor and complementary detector for non-invasive beam monitoring purposes (e.g. to complement a monitor based on proton beam “halo” detection) in medical accelerators is then examined. In the context of its application as a beam loss monitor for hadrontherapy accelerators, results of measurements performed at the Italian National Centre of Hadrontherapy (CNAO) are presented and analyzed.  
slides icon Slides WECL3 [1.431 MB]  
 
WEPC43 Update on Beam Loss Monitoring at CTF3 for CLIC 787
 
  • L.J. Devlin, S. Mallows, C.P. Welsch, E.N. del Busto
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • E. Branger
    Linköping University, Linköping, Sweden
  • L.J. Devlin, S. Mallows, C.P. Welsch, E.N. del Busto
    The University of Liverpool, Liverpool, United Kingdom
  • E. Effinger, E.B. Holzer, S. Mallows, E.N. del Busto
    CERN, Geneva, Switzerland
  
  Funding: Work supported by STFC Cockcroft Institute Core Grant No. ST/G008248/1
The primary role of the beam loss monitoring (BLM) system for the compact linear collider (CLIC) study is to work within the machine protection system. Due to the size of the CLIC facility, a BLM that covers large distances along the beamline is highly desirable, in particular for the CLIC drive beam decelerators, which would alternatively require some ~40,000 localised monitors. Therefore, an optical fiber BLM system is currently under investigation which can cover large sections of beamline at a time. A multimode fiber has been installed along the Test Beam Line at the CLIC test facility (CTF3) where the detection principle is based on the production of Cherenkov photons within the fiber resulting from beam loss and their subsequent transport along the fiber where they are then detected at the fiber ends using silicon photomultipliers. Several additional monitors including ACEMs, PEP-II and diamond detectors have also been installed. In this contribution the first results from the BLMs are presented, comparisons of the signals from each BLM are made and the possible achievable longitudinal resolution from the fiber BLM signal considering various loss patterns is discussed. 		 
 
WEPF01 Alignment of a Nozzle-Skimmer System for a Non Invasive Gas Jet Based Beam Profile Monitor 803
 
  • V. Tzoganis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • V. Tzoganis, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: Work supported by EU under contract 215080, Helmholtz Association and GSI under contract VH-BG-328, STFC under the Cockcroft Institute Core Grant No.ST/G008248/1 and a Liverpool - Riken fellowship.
A non-invasive gas jet-based beam profile monitor has been developed in the QUASAR Group at the Cockcroft Institute, UK. This shall allow monitoring ultra-low energy, as well as high energy particle beams in a way that causes least disturbance to both, primary beam and accelerator vacuum. In this setup a nozzle-skimmer system is used to generate a thin supersonic curtain-shaped gas jet. However, very small diameters of both, the gas inlet nozzle and subsequent skimmers, required to shape the jet, have caused problems in monitor operation in the past. Here, an image processing based technique is presented which follows after careful manual initial alignment using a laser beam. An algorithm has been implemented in Labview and offers a semi-automated and straightforward solution for all previously encountered alignment issues. The procedure is presented in detail and experimental results are shown. 		 
poster icon Poster WEPF01 [0.863 MB]  
 
WEPF23 Beam Diagnostics R&D within oPAC 864
 
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: oPAC is funded by the European Commission under Grant Agreement Number 289485.
Optimization of particle accelerators by combining research into beam physics, beam instrumentation, accelerator control systems and numerical simulation studies is the goal of the oPAC project. Supported with 6 Million Euros by the European Union, the network is one of the largest-ever Initial Training Networks. During the project's four year duration 22 fellows will be trained and a very broad international training program, consisting of schools, topical workshops and conferences will be organized by a consortium of currently more than 30 partner institutions. In this contribution, we will give an overview of oPAC's broad beam diagnostics R&D program, comprising absolute beam intensity measurements for low energy beams, beam diagnostics for synchrotron light sources, cyrogenic beam loss monitors, beam halo monitoring and 3D dose measurements as part of intensity modulated radiotherapy treatment. We will also summarize past oPAC events and give an outlook on future events. 		 
 
MOPC47 Monte Carlo Simulations of Beam Losses in the Test Beam Line of CTF3 189
 
  • E. Nebot Del Busto, S. Mallows, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • E. Branger
    Linköping University, Linköping, Sweden
  • S. Döbert, E.B. Holzer, R.L. Lillestøl, S. Mallows, E. Nebot Del Busto
    CERN, Geneva, Switzerland
  • R.L. Lillestøl
    University of Oslo, Oslo, Norway
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  The Test Beam Line (TBL) of the CLIC Test Facility 3 (CTF3) aims to validate the drive beam deceleration concept of CLIC, in which the RF power requested to boost particles to multi-TeV energies is obtained via deceleration of a high current and low energy drive beam (DB). Despite a TBL beam energy (150-80 MeV) significantly lower than the minimum nominal energy of the CLIC DB (250 MeV), the pulse time structure of the TBL provides the opportunity to measure beam losses with CLIC-like DB timing conditions. In this contribution, a simulation study on the detection of beam losses along the TBL for the commissioning of the recently installed beam loss monitoring system is presented. The most likely loss locations during stable beam conditions are studied by considering the beam envelope defined by the FODO lattice as well as the emittance growth due to the deceleration process. Moreover, the optimization of potential detector locations is discussed. Several factors are considered, namely: the distance to the beam, the shielding provided by the different elements of the line, the detector sensitivity and possible saturation effects of both the radiation detectors and electronics.  
 
MOPF03 Laser Diode Velocimeter-Monitor Based on Self-Mixing Technique 200
 
  • A.S. Alexandrova, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A.S. Alexandrova, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: Work supported within LA3NET which is funded by the European Commission under contract PITN-GA-2011-289191 and STFC under the Cockcroft Institute Core Grant No.ST/G008248/1.
Gas targets are important for a number of accelerator-based applications, in particular as cold targets for collision experiments and beam diagnostics purposes where gas jets have been successfully used as least intrusive beam profile monitors, however, detailed information about the gas jet is important for its optimization and the quality of the beam profile that can be measured with it. A laser velocimeter shall be used for an in-detail characterization of atomic and molecular gas jets and allow investigations into the jet dynamics. Existing methods are currently not efficient enough, hard to build, and rather expensive. A laser velocimeter based on the self-mixing technique can provide unambiguous measurements from a single interferometric channel, realizable in a compact experimental setup that can be installed even in radiation-exposed environments. In this contribution, an introduction to the underlying theory of self-mixing is given, before the design and functioning principle of the velocimeter is described in detail. Finally, preliminary experimental results with different solid targets are presented and an outlook on measurements with fluid and gaseous targets is given. 		 
poster icon Poster MOPF03 [1.045 MB]  
 
MOPF04 Results of the High Resolution OTR Measurements at KEK and Comparison with Simulations 204
 
  • B. Bolzon, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A.S. Aryshev
    KEK, Ibaraki, Japan
  • B. Bolzon, T. Lefèvre, S. Mazzoni
    CERN, Geneva, Switzerland
  • B. Bolzon, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • P. Karataev, K.O. Kruchinin
    Royal Holloway, University of London, Surrey, United Kingdom
  • P. Karataev
    JAI, Egham, Surrey, United Kingdom
  
  Optical Transition Radiation (OTR) is emitted when a charged particle crosses the interface between two media with different dielectric properties. It has become a standard tool for beam imaging and transverse beam size measurements. At the KEK Accelerator Test Facility 2 (ATF2), OTR is used at the beginning of the final focus system to measure a micrometre beam size using the decrease in visibility of the OTR Point Spread Function (PSF). In order to study and improve the resolution of the optical system, a novel simulation tool has been developed in order to characterize the PSF in detail. Based on the physical optic propagation mode of ZEMAX, the propagation of the OTR electric field can be simulated very precisely up to the image plane, taking into account aberrations and diffraction coming through the designed optical system. This contribution will show the results of measurements performed after a first improvement of the ATF2 OTR optical design to confirm the very high resolution of the imaging system and the performance of this simulation tool.  
poster icon Poster MOPF04 [1.590 MB]  
 
MOPF09 A Gas-Jet Profile Monitor for the CLIC Drive Beam 224
 
  • A. Jeff, E.B. Holzer, T. Lefèvre
    CERN, Geneva, Switzerland
  • A. Jeff, V. Tzoganis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • V. Tzoganis, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 1015 electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. Profile monitors using gas ionisation or fluorescence have been used at a number of accelerators. Typically, extra gas must be injected at the monitor and the rise in pressure spreads some distance down the beampipe. In contrast, a gas jet can be fired across the beam into a receiving chamber, with little gas escaping into the rest of the beam pipe. In addition, a gas jet shaped into a thin plane can be used like a screen on which the beam cross-section is imaged. In this paper we present some arrangements for the generation of such a jet. In addition to jet shaping using nozzles and skimmers, we propose a new scheme to use matter-wave interference with a Fresnel Zone Plate to bring an atomic jet to a narrow focus.  
 
MOPF10 Off-Axis Undulator Radiation for CLIC Drive Beam Diagnostics 228
 
  • A. Jeff, T. Lefèvre
    CERN, Geneva, Switzerland
  • A. Jeff, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Jeff, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  The Compact LInear Collider (CLIC) will use a novel acceleration scheme in which energy extracted from a very intense beam of relatively low-energy electrons (the Drive Beam) is used to accelerate a lower intensity Main Beam to very high energy. The high intensity of the Drive Beam, with pulses of more than 1015 electrons, poses a challenge for conventional profile measurements such as wire scanners. Thus, new non-invasive profile measurements are being investigated. In this paper we propose the use of relatively inexpensive permanent-magnet undulators to generate off-axis visible Synchrotron Radiation from the CLIC Drive Beam. The field strength and period length of the undulator should be designed such that the on-axis undulator wavelength is in the ultra-violet. A smaller but still useable amount of visible light is then generated in a hollow cone. This light can be reflected out of the beam pipe by a ring-shaped mirror placed downstream and imaged on a camera. In this contribution, results of SRW and ZEMAX simulations using the CLIC Drive Beam parameters are shown.  
 
MOPF25 Cryogenic Current Comparator as Low Intensity Beam Current Monitor in the CERN Antiproton Decelerators 267
 
  • M.F. Fernandes, J. Tan
    CERN, Geneva, Switzerland
  • M.F. Fernandes, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • M.F. Fernandes, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: Work supported by the EU within the oPAC project under contract 289485.
In the low-energy Antiproton Decelerator (AD) and the future Extra Low ENergy Antiproton (ELENA) rings at CERN, an absolute measurement of the beam intensity is essential to monitor any losses during the deceleration and cooling phases. However, existing DC current transformers can hardly reach the μA level, while at the AD and ELENA currents can be as low as 100 nA. A Cryogenic Current Comparator (CCC) based on a superconducting quantum interference device (SQUID) is currently being designed and shall be installed in the AD and ELENA machines. It should meet the following specifications: A current resolution smaller than 10 nA, a dynamic range covering currents between 100 nA and 1 mA, as well as a bandwidth from DC to 1 kHz. Different design options are being considered, including the use of low or high temperature superconductor materials, different CCC shapes and dimensions, different SQUID characteristics, as well as electromagnetic shielding requirements. In this contribution we present first results from a comparative analysis of different monitor options, taking into consideration the external electromagnetic sources at the foreseen device locations. 		 
poster icon Poster MOPF25 [1.059 MB]  
 
MOPF29 A Non-Invasive Beam Monitor for Hadron Therapy Beams 283
 
  • T. Cybulski, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • T. Cybulski, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • A. Kacperek, B. Marsland, I. Taylor, A. Wray
    The Douglas Cyclotron, The Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom
  
  Funding: Work supported by the EU under contract PITN-GA-2008-215080 and the STFC Cockcroft Institute Core Grant No. ST/G008248/1
Hadron therapy allows for precise dose delivery to the tumour volume only and hence decreases the dose delivered to the nearby organs and healthy tissue. Ideally, the beam would be monitored whilst being delivered to the patient. A novel, real–time and non-interceptive beam monitor for hadron therapy beams has been developed in the QUASAR Group. It is based on the LHCb VErtex LOcator (VELO) detector and couples to the treatment beam’s transverse halo to determine the intensity, position and ultimately the dose of the treatment beam. This contribution presents the design of a stand-alone version of the VELO detector which was developed for the Clatterbridge Cancer Centre (CCC) treatment line. The mechanical and electronic design of the monitor and its data acquisition system are shown, with a focus on the detector positioning and cooling system. Monte Carlo simulations into expected signal distributions are compared against first measurements with the 60 MeV proton beam at CCC. 		 
 
TUPF02 Secondary Emission Monitor for keV Ion and Antiproton Beams 495
 
  • A.G. Sosa, E. Bravin, A. Jeff
    CERN, Geneva, Switzerland
  • J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • J. Harasimowicz, A. Jeff, A.G. Sosa, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: Work supported by the EU within the DITANET and CATHI projects under contracts 215080 and 264330, HGF and GSI under contract VH-NG-328 and STFC under the Cockcroft Institute core grant ST/G008248/1.
Beam profile monitoring of low intensity keV ion and antiproton beams remains a challenging task. A Secondary electron Emission Monitor (SEM) has been designed to measure profiles of beams with intensities below 107 and energies as low as 20 keV. The monitor is based on a two stage microchannel plate (MCP) and a phosphor screen facing a CCD camera. Its modular design allows two different operational setups. In this contribution we present the design of a prototype and discuss results from measurements with protons at INFN-LNF and antiprotons at the AEgIS experiment at CERN*. This is then used for a characterization of the monitor with regard to its possible future use at different facilities.
* Measurements at the AD carried out with the AEgIS collaboration. 		 
poster icon Poster TUPF02 [1.934 MB]  
 
TUPF22 Beam Halo Monitor Based on an HD Digital Micro Mirror Array 557
 
  • B.B.D. Lomberg, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • B.B.D. Lomberg, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: This work is supported by the European Union under contract PITN-GA-2011-289485 and by STFC under the Cockcroft Institute Core Grant No. ST/G008248/1.
A beam halo monitor is an essential device to pursue studies of halo particles produced in any particle accelerator as to investigate the effects of disturbances, such as field kicks, gradient errors, etc. A fast, least intrusive, high dynamic range monitor will allow the detection and potentially control of particles at the tail of a transverse beam distribution. Light generated by a beam of charged particles is routinely used for beam diagnostic purposes. A halo monitor based on a digital micro-mirror device (DMD) used to generate an adaptive optical mask to block light in the core of the emitted light profile and hence limit observation to halo particles has been developed in close collaboration with CERN and University of Maryland. In this contribution an evolution of this monitor is presented. A high definition micro-mirror array with 1920x1080 pixels has been embedded into a MATLAB-based control system, giving access to even higher monitor resolution. A masking algorithm has also been developed that automates mask generation based on user-definable thresholds, converts between CCD and DMD geometries, processes and analyses the beam halo signal and is presented in detail. 		 
poster icon Poster TUPF22 [1.558 MB]  
 
TUPF26 Laser-Based Beam Instrumentation R&D within LA3NET 567
 
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: LA³NET is funded by the European Commission under Grant Agreement Number 289191.
Within LA3NET, Laser Applications for Accelerators are being developed by an international NETwork of more than 30 partner institutions from across the world. Laser-based beam instrumentation is at the core of this EU-funded project which will train 17 fellows during its four year project duration. In this contribution, we will present the consortium's recent research results in beam diagnostics, ranging from development of a laser velocimeter and laser emittance meter, over measurement of the bunch shape with electro-optical sampling in an electron accelerator and precision determination of electron beam energy with Compton backscattered laser photons to measurement of electron bunches with a time resolution of better than 20 femtoseconds. We will also provide a summary of past training events organized by the consortium and give an overview of future workshops, conferences and schools. 		 
 
WECL3 The LUPIN Detector: Supporting Least Intrusive Beam Monitoring Technique Through Neutron Detection 648
 
  • G.P. Manessi, M. Silari
    CERN, Geneva, Switzerland
  • M. Caresana
    Politecnico/Milano, Milano, Italy
  • M. Ferrarini
    CNAO Foundation, Milan, Italy
  • G.P. Manessi, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G.P. Manessi, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  The Long interval, Ultra-wide dynamic Pile-up free Neutron rem counter (LUPIN) is a novel detector initially developed for radiation protection purposes, specifically conceived for applications in pulsed neutron fields. The detector has a measurement capability varying over many orders of neutron burst intensity, from a single neutron up to thousands of interactions for each burst, without showing any saturation effect. Whilst LUPIN has been developed for applications in the radiation protection fields, its unique properties make it also well suited to support other beam instrumentation. In this contribution, the design of LUPIN is presented in detail and its main characteristics are summarized. Its potential use as beam loss monitor and complementary detector for non-invasive beam monitoring purposes (e.g. to complement a monitor based on proton beam “halo” detection) in medical accelerators is then examined. In the context of its application as a beam loss monitor for hadrontherapy accelerators, results of measurements performed at the Italian National Centre of Hadrontherapy (CNAO) are presented and analyzed.  
slides icon Slides WECL3 [1.431 MB]  
 
WEPC43 Update on Beam Loss Monitoring at CTF3 for CLIC 787
 
  • L.J. Devlin, S. Mallows, C.P. Welsch, E.N. del Busto
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • E. Branger
    Linköping University, Linköping, Sweden
  • L.J. Devlin, S. Mallows, C.P. Welsch, E.N. del Busto
    The University of Liverpool, Liverpool, United Kingdom
  • E. Effinger, E.B. Holzer, S. Mallows, E.N. del Busto
    CERN, Geneva, Switzerland
  
  Funding: Work supported by STFC Cockcroft Institute Core Grant No. ST/G008248/1
The primary role of the beam loss monitoring (BLM) system for the compact linear collider (CLIC) study is to work within the machine protection system. Due to the size of the CLIC facility, a BLM that covers large distances along the beamline is highly desirable, in particular for the CLIC drive beam decelerators, which would alternatively require some ~40,000 localised monitors. Therefore, an optical fiber BLM system is currently under investigation which can cover large sections of beamline at a time. A multimode fiber has been installed along the Test Beam Line at the CLIC test facility (CTF3) where the detection principle is based on the production of Cherenkov photons within the fiber resulting from beam loss and their subsequent transport along the fiber where they are then detected at the fiber ends using silicon photomultipliers. Several additional monitors including ACEMs, PEP-II and diamond detectors have also been installed. In this contribution the first results from the BLMs are presented, comparisons of the signals from each BLM are made and the possible achievable longitudinal resolution from the fiber BLM signal considering various loss patterns is discussed. 		 
 
WEPF01 Alignment of a Nozzle-Skimmer System for a Non Invasive Gas Jet Based Beam Profile Monitor 803
 
  • V. Tzoganis, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • V. Tzoganis, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  
  Funding: Work supported by EU under contract 215080, Helmholtz Association and GSI under contract VH-BG-328, STFC under the Cockcroft Institute Core Grant No.ST/G008248/1 and a Liverpool - Riken fellowship.
A non-invasive gas jet-based beam profile monitor has been developed in the QUASAR Group at the Cockcroft Institute, UK. This shall allow monitoring ultra-low energy, as well as high energy particle beams in a way that causes least disturbance to both, primary beam and accelerator vacuum. In this setup a nozzle-skimmer system is used to generate a thin supersonic curtain-shaped gas jet. However, very small diameters of both, the gas inlet nozzle and subsequent skimmers, required to shape the jet, have caused problems in monitor operation in the past. Here, an image processing based technique is presented which follows after careful manual initial alignment using a laser beam. An algorithm has been implemented in Labview and offers a semi-automated and straightforward solution for all previously encountered alignment issues. The procedure is presented in detail and experimental results are shown. 		 
poster icon Poster WEPF01 [0.863 MB]  
 
WEPF23 Beam Diagnostics R&D within oPAC 864
 
  • C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  
  Funding: oPAC is funded by the European Commission under Grant Agreement Number 289485.
Optimization of particle accelerators by combining research into beam physics, beam instrumentation, accelerator control systems and numerical simulation studies is the goal of the oPAC project. Supported with 6 Million Euros by the European Union, the network is one of the largest-ever Initial Training Networks. During the project's four year duration 22 fellows will be trained and a very broad international training program, consisting of schools, topical workshops and conferences will be organized by a consortium of currently more than 30 partner institutions. In this contribution, we will give an overview of oPAC's broad beam diagnostics R&D program, comprising absolute beam intensity measurements for low energy beams, beam diagnostics for synchrotron light sources, cyrogenic beam loss monitors, beam halo monitoring and 3D dose measurements as part of intensity modulated radiotherapy treatment. We will also summarize past oPAC events and give an outlook on future events.