The Experts below are selected from a list of 10062 Experts worldwide ranked by ideXlab platform

J.a. Clarke - One of the best experts on this subject based on the ideXlab platform.

  • Eddy current studies from the undulator-based Positron Source target wheel prototype
    2010
    Co-Authors: I. R. Bailey, J. Gronberg, C. G. Brown, W T Piggott, J.a. Clarke, L. Hagler, L. J. Jenner, D. J. Scott, L. Zang
    Abstract:

    The ef­fi­cien­cy of fu­ture Positron Sources for the next gen­er­a­tion of high-en­er­gy par­ti­cle col­lid­ers (e.g. ILC, CLIC, LHeC) can be im­proved if the Positron-pro­duc­tion tar­get is im­mersed in the mag­net­ic field of ad­ja­cent cap­ture op­tics. If the tar­get is also ro­tat­ing due to heat de­po­si­tion con­sid­er­a­tions then eddy cur­rents may be in­duced and lead to ad­di­tion­al heat­ing and stress­es. In this paper we pre­sent data from a ro­tat­ing tar­get wheel pro­to­type for the base­line ILC Positron Source. The wheel has been op­er­at­ed at rev­o­lu­tion rates up to 1800rpm in fields of the order of 1 Tesla. Com­par­isons are made be­tween torque data ob­tained from a trans­duc­er on the tar­get drive shaft and the re­sults of fi­nite-el­e­ment sim­u­la­tions. Ro­tor­dy­nam­ics is­sues are pre­sent­ed and fu­ture ex­per­i­ments on other as­pects of the Positron Source tar­get sta­tion are con­sid­ered.

  • DESIGN OF A PULSED FLUX CONCENTRATOR FOR THE ILC Positron Source
    2010
    Co-Authors: J. Gronberg, Ryan P. Abbott, C. G. Brown, J Javedani, W T Piggott, J.a. Clarke
    Abstract:

    The Positron Source for the International Linear Collider requires an optical matching device after the target to increase the capture efficiency for Positrons. Pulsed flux concentrators have been used by previous machines to improve the capture efficiency but the ILC has a 1 ms long pulse train which is too long for a standard flux concentrator. A pulsed flux concentrator with a 40 ms flat top was created for a hyperon experiment in 1965 which used liquid nitrogen cooling to reduce the resistance of the concentrating plates and extend the lifetime of the pulse. We report on a design for a 1 ms device based on this concept.

  • The development of a superconducting undulator for the ILC Positron Source.
    2009
    Co-Authors: E. Baynham, J.a. Clarke, Tom W. Bradshaw, A. Brummitt, G. Burton, S. Carr, A. Lintern, J. Rochford, Oleg Malyshev, D. J. Scott
    Abstract:

    The ILC Positron Source relies upon a ~200 m long superconducting helical undulator in order to generate the huge flux of gamma photons required. The period is only 11.5 mm but the field strength is ~1 T. The UK is building and testing a full scale 4 m long ILC cryomodule at the moment. It will be completed in 2008 and the results used to demonstrate the feasibility of the full (200 m long) system

  • A PROTOTYPE TARGET WHEEL FOR THE ILC Positron Source
    2008
    Co-Authors: I. R. Bailey, J. Gronberg, J.a. Clarke, V. Bharadwaj, D. G. Clarke, K. P. Davies, A. G. Gallagher, L. Hagler, L. J. Jenner, C. J. Nelson
    Abstract:

    In this paper we describe the design, construction and commissioning of a prototype based on the Positron production target wheel planned for the International Linear Collider (ILC) Positron Source. The eciency of the current baseline Positron Source design for the ILC can be improved if the conversion target is partially immersed in the magnetic eld of the capture optics, thereby increasing the overall capture eciency for Positrons by a factor of two or more. However, immersion of the rotating target wheel generates strong eddy currents leading to additional heating and stresses on the wheel. The primary purpose of our prototype, which has been assembled at Daresbury Laboratory, is to investigate the eects of eddy currents induced in a titanium alloy wheel moving with rim speeds up to 100 ms

  • The Design of the Positron Source for the International Linear Collider
    2008
    Co-Authors: J.a. Clarke, V. Bharadwaj, I. R. Bailey, E. Baynham, Tom W. Bradshaw, A. Brummit, Adriana Bungau, F. S. Carr, N. Collomb, J. B. Dainton
    Abstract:

    The high luminosity requirements and the option of a polarized Positron beam present a great challenge for the Positron Source of a future linear collider. This paper provides a comprehensive overview of the latest proposed design for the baseline Positron Source of the International Linear Collider (ILC). We report on recent progress and results concerning the main components of the Source: including the undulator, capture optics, and target.

Andriy Ushakov - One of the best experts on this subject based on the ideXlab platform.

  • Status of the undulator-based ILC Positron Source
    arXiv: Accelerator Physics, 2019
    Co-Authors: Felix Dietrich, S Riemann, Gudrid Moortgat-pick, Peter Sievers, Andriy Ushakov
    Abstract:

    The design of the Positron Source for the International Linear Collider (ILC) is still under consideration. The baseline design plans to use the electron beam for the Positron production before it goes to the IP. The high-energy electrons pass a long helical undulator and generate an intense circularly polarized photon beam which hits a thin conversion target to produce $e^+e^-$ pairs. The resulting Positron beam is longitudinally polarized which provides an important benefit for precision physics analyses. In this paper the status of the design studies is presented with focus on ILC250. In particular, the target design and cooling as well as issues of the optical matching device are important for the Positron yield. Some possibilities to optimize the system are discussed.

  • Undulator-Based Positron Source at 250 GeV CM Energy with Different Optical Matching Devices: Pulsed Flux Concentrator and Quarter Wave Transformer
    arXiv: Accelerator Physics, 2018
    Co-Authors: Andriy Ushakov, S Riemann, Gudrid Moortgat-pick
    Abstract:

    In the baseline design of the International Linear Collider (ILC) an undulator-based Source is foreseen for the Positron Source. In this study the energy deposition in the pulsed flux concentrator (FC) of Positron Source is calculated for the ILC at 250 GeV center-of-mass energy. The peak energy of 33 J/g deposited by one beam pulse in the current design of the FC is above the limit for copper material. Several promising options were considered to solve the issue of overheating the FC: the quarter wave transformer (QWT) has a significantly bigger aperture and is considered as an valuable and safe alternative for the FC. Since the Positron Source with a QWT is expected to lead to a lower Positron capture efficiency, also the expected Positron yield was calculated in addition to the energy deposition in QWT.

  • Photon collimator system for the ILC Positron Source
    arXiv: Accelerator Physics, 2014
    Co-Authors: S Riemann, F. Staufenbiel, Gudrid Moortgat-pick, Andriy Ushakov
    Abstract:

    High energy e+e- linear colliders are the next large scale project in particle physics. They need intense Sources to achieve the required luminosity. In particular, the Positron Source must provide about 10E+14 Positrons per second. The Positron Source for the International Linear Collider (ILC) is based on a helical undulator passed by the electron beam to create an intense circularly polarized photon beam. With these photons a longitudinally polarized Positron beam is generated; the degree of polarization can be enhanced by collimating the photon beam. However, the high photon beam intensity causes huge thermal load in the collimator material. In this paper the thermal load in the photon collimator is discussed and a flexible design solution is presented.

  • SIMULATIONS OF THE ILC Positron Source AT LOW ENERGIES
    2013
    Co-Authors: Andriy Ushakov, Gudrid Moortgat-pick, V. Kovalenko, F. Staufenbiel
    Abstract:

    The International Linear Collider (ILC) baseline design includes an undulator-based Positron Source. The accelerated electron beam will be used for the Positron generation before it goes to the collision point. For the whole ILC energyrange the Sourcehas to generate1.5 Positronsperelectron. However, the efociency of Positron production goes down with decreasing electron drive beam energy. This effect can be compensated to some extend by the choice of undulator parameters and an optimized capture section. This simulation study considers, for the range of electron beam energiesdown to low values of 120 GeV, the feasibility of achieving the required Positron yield. In particular, the optimum parameters for the undulator and capture section of the Source at 120 GeV electron beam are presented. INRODUCTION The baseline design of the International Linear Collider (ILC) is focused on center-of-mass energies of 500GeV and 350GeV; operation at low energies and upgrade to energy of 1TeV is foreseen. The undulator based Positron Source placed at the end of the main electron accelerator uses the main electron beam for the Positron generation. The discovery of a Higgs boson with 126 GeV mass at the Large Hadron Collider suggests a staged approach in building the ILC. Starting with a Higgs factory at a centerof-massenergyof 250 GeV asorst phase of the ILC project requires a properworking of the Positron Source. However, the efociency of the undulator-based Source goes down rapidly at lower drive beam energies. Therefore, in this work, the Positron yield and polarization have been calculated for a 120GeV electron beam and different settings of the undulator and Positron capture system.

  • heat load and stress studies for an design of the photon collimator for the ilc Positron Source
    arXiv: Accelerator Physics, 2012
    Co-Authors: F. Staufenbiel, Andriy Ushakov, V. Kovalenko, O. S. Adeyemi, L. Malysheva, G Moortgatpick, S Riemann
    Abstract:

    The ILC baseline design for the Positron Source is based on radiation from a helical undulator to produce Positrons in a thin target. Since the photon beam created in the helical undulator is circularly polarized, the generated Positron beam is longitudinally polarized. Using a photon collimator upstream the Positron target the Positron polarization can be enhanced. However, the photon beam intensity yields a huge thermal load in the collimator material. In this paper the thermal load and heat dissipation in the photon collimator is discussed and design solutions are suggested.

D. J. Scott - One of the best experts on this subject based on the ideXlab platform.

  • Eddy current studies from the undulator-based Positron Source target wheel prototype
    2010
    Co-Authors: I. R. Bailey, J. Gronberg, C. G. Brown, W T Piggott, J.a. Clarke, L. Hagler, L. J. Jenner, D. J. Scott, L. Zang
    Abstract:

    The ef­fi­cien­cy of fu­ture Positron Sources for the next gen­er­a­tion of high-en­er­gy par­ti­cle col­lid­ers (e.g. ILC, CLIC, LHeC) can be im­proved if the Positron-pro­duc­tion tar­get is im­mersed in the mag­net­ic field of ad­ja­cent cap­ture op­tics. If the tar­get is also ro­tat­ing due to heat de­po­si­tion con­sid­er­a­tions then eddy cur­rents may be in­duced and lead to ad­di­tion­al heat­ing and stress­es. In this paper we pre­sent data from a ro­tat­ing tar­get wheel pro­to­type for the base­line ILC Positron Source. The wheel has been op­er­at­ed at rev­o­lu­tion rates up to 1800rpm in fields of the order of 1 Tesla. Com­par­isons are made be­tween torque data ob­tained from a trans­duc­er on the tar­get drive shaft and the re­sults of fi­nite-el­e­ment sim­u­la­tions. Ro­tor­dy­nam­ics is­sues are pre­sent­ed and fu­ture ex­per­i­ments on other as­pects of the Positron Source tar­get sta­tion are con­sid­ered.

  • The development of a superconducting undulator for the ILC Positron Source.
    2009
    Co-Authors: E. Baynham, J.a. Clarke, Tom W. Bradshaw, A. Brummitt, G. Burton, S. Carr, A. Lintern, J. Rochford, Oleg Malyshev, D. J. Scott
    Abstract:

    The ILC Positron Source relies upon a ~200 m long superconducting helical undulator in order to generate the huge flux of gamma photons required. The period is only 11.5 mm but the field strength is ~1 T. The UK is building and testing a full scale 4 m long ILC cryomodule at the moment. It will be completed in 2008 and the results used to demonstrate the feasibility of the full (200 m long) system

  • Status of R&D on a superconducting HeLiCal undulator for the ILC Positron Source
    2007 IEEE Particle Accelerator Conference (PAC), 2007
    Co-Authors: Y. Ivanyushenkov, J.a. Clarke, E. Baynham, A. Brummitt, S. Carr, A. Lintern, J. Rochford, T. Bradshaw, O.b. Malyshev, D. J. Scott
    Abstract:

    An undulator based Positron Source is a baseline for the international linear collider (ILC). The HeLiCal collaboration in the UK is carrying out an R&D programme on a short period superconducting helical undulator with the goal to develop modelling, measuring and manufacturing techniques. Several undulator prototypes have been built and successfully tested. This paper summarizes the results of the R&D phase of the project.

  • status of the helical contribution to the polarised Positron Source for the international linear collider
    IEEE Particle Accelerator Conference, 2007
    Co-Authors: D. J. Scott, J.a. Clarke, E. Baynham, A. Brummitt, S. Carr, Y. Ivanyushenkov, T. Bradshaw, A Birch, O B Malyshev, A. Lintern
    Abstract:

    The Positron Source for the International Linear Collider (ILC) is a helical undulator-based design, which can generate unprecedented quantities of polarised Positrons. The HeLiCal collaboration [1] takes responsibility for the design and prototyping of the superconducting helical undulator, which is a highly demanding short period device with very small aperture, and also leads the start to end simulations of the polarised electrons and Positrons to ensure that the high polarisation levels generated survive from the Source up to the collision point. This paper will provide an update on the work of the collaboration, focusing on these two topic areas, and will also discuss future plans.

  • Development of a full scale superconducting undulator module for the ILC Positron Source
    2007 IEEE Particle Accelerator Conference (PAC), 2007
    Co-Authors: Y. Ivanyushenkov, J.a. Clarke, E. Baynham, A. Brummitt, S. Carr, A. Lintern, J. Rochford, T. Bradshaw, O.b. Malyshev, D. J. Scott
    Abstract:

    An undulator based Positron Source is the baseline for the International Linear Collider (ILC). The HeLiCal collaboration in the UK is working on the development of a full scale 4-m long undulator module. Several prototypes have been built and tested in the R&D phase of the programme that culminated in the development of manufacturing techniques suitable for construction of the first full scale undulator sections. This paper details the design and the construction status of 4-m long undulator module.

I. R. Bailey - One of the best experts on this subject based on the ideXlab platform.

  • Eddy current studies from the undulator-based Positron Source target wheel prototype
    2010
    Co-Authors: I. R. Bailey, J. Gronberg, C. G. Brown, W T Piggott, J.a. Clarke, L. Hagler, L. J. Jenner, D. J. Scott, L. Zang
    Abstract:

    The ef­fi­cien­cy of fu­ture Positron Sources for the next gen­er­a­tion of high-en­er­gy par­ti­cle col­lid­ers (e.g. ILC, CLIC, LHeC) can be im­proved if the Positron-pro­duc­tion tar­get is im­mersed in the mag­net­ic field of ad­ja­cent cap­ture op­tics. If the tar­get is also ro­tat­ing due to heat de­po­si­tion con­sid­er­a­tions then eddy cur­rents may be in­duced and lead to ad­di­tion­al heat­ing and stress­es. In this paper we pre­sent data from a ro­tat­ing tar­get wheel pro­to­type for the base­line ILC Positron Source. The wheel has been op­er­at­ed at rev­o­lu­tion rates up to 1800rpm in fields of the order of 1 Tesla. Com­par­isons are made be­tween torque data ob­tained from a trans­duc­er on the tar­get drive shaft and the re­sults of fi­nite-el­e­ment sim­u­la­tions. Ro­tor­dy­nam­ics is­sues are pre­sent­ed and fu­ture ex­per­i­ments on other as­pects of the Positron Source tar­get sta­tion are con­sid­ered.

  • Undulator based Positron Source optimisation for CLIC.
    2010
    Co-Authors: L. Zang, Andrzej Wolski, Maxim Korostelev, I. R. Bailey
    Abstract:

    CLIC will need of order 1014 Positrons per second to achieve its specified luminosity [1]. An undulator based scheme has been proposed as one of the options for the Positron Source to meet this challenge. As CLIC may operate over a wide range of energy (from 0.5 TeV to 3 TeV centre of mass), there is a large scope to push the performance of the whole system to reach high efficiency. We report on the undulator parameters and optimisation of components of the Source, focusing on the undulator, and the adiabatic matching device. In addition to maximising the Positron yield, the polarisation of the Positron beam is also considered.

  • Undulator-based Positron Source for CLIC.
    2009
    Co-Authors: L. Zang, I. R. Bailey, Andrzej Wolski
    Abstract:

    A model has been created in Geant4 [1] to simulate the key elements of an undulator-based Positron Source for CLIC: the goal is to consider such a Source as an alternative to the present baseline concept. The parameters of the undulator and capture device need to be adjusted to cover a range of operating scenarios. We report the results of calculations for two specific operating scenarios, for the rate of Positron production, Positron polarisation, and capture efficiency.

  • STUDIES ON THE ROLE OF A PHOTON COLLIMATOR FOR THE ILC Positron Source
    2008
    Co-Authors: L. Zang, I. R. Bailey, A. Woski
    Abstract:

    A Positron Source based on a helical undulator provides the capability of producing a beam of polarised Positrons. The degree of polarisation of the Positrons depends upon the polarisation of the photons produced from the undulator; the polarisation of the photons in turn depends on the photon energy and production angle. We calculate the photon energy spectrum and polarisation for one design of the helical undulator for the International Linear Collider (ILC), investigate approximations commonly made in calculating these quantities, and explore the role of a photon collimator in improving the Positron polarisation.

  • A PROTOTYPE TARGET WHEEL FOR THE ILC Positron Source
    2008
    Co-Authors: I. R. Bailey, J. Gronberg, J.a. Clarke, V. Bharadwaj, D. G. Clarke, K. P. Davies, A. G. Gallagher, L. Hagler, L. J. Jenner, C. J. Nelson
    Abstract:

    In this paper we describe the design, construction and commissioning of a prototype based on the Positron production target wheel planned for the International Linear Collider (ILC) Positron Source. The eciency of the current baseline Positron Source design for the ILC can be improved if the conversion target is partially immersed in the magnetic eld of the capture optics, thereby increasing the overall capture eciency for Positrons by a factor of two or more. However, immersion of the rotating target wheel generates strong eddy currents leading to additional heating and stresses on the wheel. The primary purpose of our prototype, which has been assembled at Daresbury Laboratory, is to investigate the eects of eddy currents induced in a titanium alloy wheel moving with rim speeds up to 100 ms

S Riemann - One of the best experts on this subject based on the ideXlab platform.

  • Status of the undulator-based ILC Positron Source
    arXiv: Accelerator Physics, 2019
    Co-Authors: Felix Dietrich, S Riemann, Gudrid Moortgat-pick, Peter Sievers, Andriy Ushakov
    Abstract:

    The design of the Positron Source for the International Linear Collider (ILC) is still under consideration. The baseline design plans to use the electron beam for the Positron production before it goes to the IP. The high-energy electrons pass a long helical undulator and generate an intense circularly polarized photon beam which hits a thin conversion target to produce $e^+e^-$ pairs. The resulting Positron beam is longitudinally polarized which provides an important benefit for precision physics analyses. In this paper the status of the design studies is presented with focus on ILC250. In particular, the target design and cooling as well as issues of the optical matching device are important for the Positron yield. Some possibilities to optimize the system are discussed.

  • Undulator-Based Positron Source at 250 GeV CM Energy with Different Optical Matching Devices: Pulsed Flux Concentrator and Quarter Wave Transformer
    arXiv: Accelerator Physics, 2018
    Co-Authors: Andriy Ushakov, S Riemann, Gudrid Moortgat-pick
    Abstract:

    In the baseline design of the International Linear Collider (ILC) an undulator-based Source is foreseen for the Positron Source. In this study the energy deposition in the pulsed flux concentrator (FC) of Positron Source is calculated for the ILC at 250 GeV center-of-mass energy. The peak energy of 33 J/g deposited by one beam pulse in the current design of the FC is above the limit for copper material. Several promising options were considered to solve the issue of overheating the FC: the quarter wave transformer (QWT) has a significantly bigger aperture and is considered as an valuable and safe alternative for the FC. Since the Positron Source with a QWT is expected to lead to a lower Positron capture efficiency, also the expected Positron yield was calculated in addition to the energy deposition in QWT.

  • Photon collimator system for the ILC Positron Source
    arXiv: Accelerator Physics, 2014
    Co-Authors: S Riemann, F. Staufenbiel, Gudrid Moortgat-pick, Andriy Ushakov
    Abstract:

    High energy e+e- linear colliders are the next large scale project in particle physics. They need intense Sources to achieve the required luminosity. In particular, the Positron Source must provide about 10E+14 Positrons per second. The Positron Source for the International Linear Collider (ILC) is based on a helical undulator passed by the electron beam to create an intense circularly polarized photon beam. With these photons a longitudinally polarized Positron beam is generated; the degree of polarization can be enhanced by collimating the photon beam. However, the high photon beam intensity causes huge thermal load in the collimator material. In this paper the thermal load in the photon collimator is discussed and a flexible design solution is presented.

  • heat load and stress studies for an design of the photon collimator for the ilc Positron Source
    arXiv: Accelerator Physics, 2012
    Co-Authors: F. Staufenbiel, Andriy Ushakov, V. Kovalenko, O. S. Adeyemi, L. Malysheva, G Moortgatpick, S Riemann
    Abstract:

    The ILC baseline design for the Positron Source is based on radiation from a helical undulator to produce Positrons in a thin target. Since the photon beam created in the helical undulator is circularly polarized, the generated Positron beam is longitudinally polarized. Using a photon collimator upstream the Positron target the Positron polarization can be enhanced. However, the photon beam intensity yields a huge thermal load in the collimator material. In this paper the thermal load and heat dissipation in the photon collimator is discussed and design solutions are suggested.

  • Spin Tracking at the ILC Positron Source
    arXiv: Accelerator Physics, 2012
    Co-Authors: V. Kovalenko, S Riemann, F. Staufenbiel, Gudrid Moortgat-pick, O. S. Adeyemi, Anthony Hartin, L. Malysheva, Andriy Ushakov
    Abstract:

    In order to achieve the physics goals of future Linear Colliders, it is important that electron and Positron beams are polarized. The baseline design at the International Linear Collider (ILC) foresees an e+ Source based on helical undulator. Such a Source provides high luminosity and polarizations. The Positron Source planned for ILC is based on a helical undulator system and can deliver a Positron polarization of 60%. To ensure that no significant polarization is lost during the transport of the e- and e+ beams from the Source to the interaction region, precise spin tracking has to be included in all transport elements which can contribute to a loss of polarization, i.e. the initial accelerating structures, the damping rings, the spin rotators, the main linac and the beam delivery system. In particular, the dynamics of the polarized Positron beam is required to be investigated. In the talk recent results of Positron spin tracking simulation at the Source are presented. The Positron yield and polarization are also discussed depending on the geometry of Source elements.