Author: Pozimski, J.K.
Paper Title Page
TUPF05 Particle Tracking for the FETS Laser Wire Emittance Scanner 503
 
  • J.K. Pozimski
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  
  The Front End Test Stand (FETS) is an R&D pro­ject at Ruther­ford Ap­ple­ton Lab­o­ra­tory (RAL) with the aim to demon­strate a high power (60 mA, 3 MeV with 50 pps and 10 % duty cycle), fast chopped H− ion beam. The di­ag­nos­tics of high power par­ti­cle beams is dif­fi­cult due to the power de­po­si­tion on di­ag­nos­tics el­e­ments in­tro­duced in the beam so non-in­va­sive in­stru­men­ta­tion is highly de­sir­able. The laser wire emit­tance scan­ner under con­struc­tion is based on a photo-de­tach­ment process uti­liz­ing the neu­tral­ized par­ti­cles pro­duced in the in­ter­ac­tion be­tween Laser and H− beam for beam di­ag­nos­tics pur­poses. The prin­ci­ple is ap­pro­pri­ate to de­ter­mine the trans­ver­sal beam den­sity dis­tri­b­u­tion as well as the trans­ver­sal and lon­gi­tu­di­nal beam emit­tance be­hind the RFQ. The in­stru­ment will be lo­cated at the end of the MEBT with the de­tach­ment tak­ing place in­side a di­pole field. Ex­ten­sive par­ti­cle track­ing sim­u­la­tions have been per­formed for var­i­ous set­tings of the MEBT quadrupoles to in­ves­ti­gate the best place­ment and size of the 2D scin­til­lat­ing de­tec­tor and to de­ter­mine the range and res­o­lu­tion of the in­stru­ment. Ad­di­tion­ally the power dis­tri­b­u­tion in the fol­low­ing beam dumps has been de­ter­mined.  
 
TUPF14 Description of Laser Transport and Delivery System for the FETS Laserwire Emittance Scanner 527
 
  • A. Bosco, G.E. Boorman, S. Emery, S.M. Gibson
    Royal Holloway, University of London, Surrey, United Kingdom
  • C. Gabor
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • T. Hofmann
    CERN, Geneva, Switzerland
  • A.P. Letchford
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski, P. Savage
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  A beam emit­tance mon­i­tor for H− beams based on laser-in­duced ions neu­tral­iza­tion is being de­vel­oped at the Front End Test Stand (FETS) at the Ruther­ford Ap­ple­ton Lab­o­ra­tory (RAL). The laser sys­tem that will be used for the photo-neu­tral­iza­tion of the H− beam is a fiber laser emit­ting 110 ns pulses at λ=1064nm, with a rep­e­ti­tion rate of 30 kHz and peak power of 8 kW. The laser will be con­veyed to the in­ter­ac­tion area over a dis­tance of 70 m via an op­ti­cal fiber. An as­sem­bly of two re­motely con­trolled mo­tor­ized trans­la­tion stages will en­able the sys­tem to scan across the H− beam along its ver­ti­cal pro­file. A mo­tor­ized beam ex­pander will con­trol the out­put size of the col­li­mated laser beam in order to en­able the sys­tem to op­er­ate with dif­fer­ent spa­tial char­ac­ter­is­tics of the ions beam. In this paper we pre­sent a full ac­count of the laser char­ac­ter­is­tics, the op­ti­cal trans­port sys­tem and the final de­liv­ery as­sem­bly. All the rel­e­vant mea­sure­ments such as power, spa­tial and tem­po­ral char­ac­ter­is­tics of the laser, fiber trans­port ef­fi­ciency and final de­liv­ery laser beam pa­ra­me­ters will be re­ported.  
poster icon Poster TUPF14 [4.081 MB]  
 
TUPF15 Overview of Laserwire Beam Profile and Emittance Measurements for High Power Proton Accelerators 531
 
  • S.M. Gibson, G.E. Boorman, A. Bosco
    Royal Holloway, University of London, Surrey, United Kingdom
  • G.E. Boorman, A. Bosco, S.M. Gibson
    JAI, Egham, Surrey, United Kingdom
  • C. Gabor
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • T. Hofmann
    CERN, Geneva, Switzerland
  • A.P. Letchford
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski, P. Savage
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  Laser­wires were orig­i­nally de­vel­oped to mea­sure mi­cron-sized elec­tron beams via Comp­ton scat­ter­ing, where tra­di­tional wire scan­ners are at the limit of their res­o­lu­tion. Laser­wires have since been ap­plied to larger beam-size, high power H− ion beams, where the non-in­va­sive method can probe beam den­si­ties that would dam­age tra­di­tional di­ag­nos­tics. While photo-de­tach­ment of H− ions is now rou­tine to mea­sure beam pro­files, ex­tend­ing the tech­nique to trans­verse and lon­gi­tu­di­nal emit­tance mea­sure­ments is a key aim of the laser­wire emit­tance scan­ner under con­struc­tion at the Front End Test Stand (FETS) at the RAL. A pulsed, 30kHz, 8kW peak power laser is fi­bre-cou­pled to mo­tor­ized col­li­mat­ing op­tics, which con­trols the po­si­tion and thick­ness of the laser­wire de­liv­ered to the H− in­ter­ac­tion cham­ber. The laser­wire slices out a beam­let of neu­tral­ized par­ti­cles, which prop­a­gate to a down­stream scin­til­la­tor and cam­era. The emit­tance is re­con­structed from 2D im­ages as the laser­wire po­si­tion is scanned. Re­sults from the de­liv­ery op­tics, scin­til­la­tor tests and par­ti­cle track­ing sim­u­la­tions of the full sys­tem are re­viewed. Plans to de­ploy the FETS laser sys­tem at the Linac4 at CERN are out­lined.  
poster icon Poster TUPF15 [9.196 MB]  
 
TUPF15 Overview of Laserwire Beam Profile and Emittance Measurements for High Power Proton Accelerators 531
 
  • S.M. Gibson, G.E. Boorman, A. Bosco
    Royal Holloway, University of London, Surrey, United Kingdom
  • G.E. Boorman, A. Bosco, S.M. Gibson
    JAI, Egham, Surrey, United Kingdom
  • C. Gabor
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  • T. Hofmann
    CERN, Geneva, Switzerland
  • A.P. Letchford
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  • J.K. Pozimski, P. Savage
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  
  Laser­wires were orig­i­nally de­vel­oped to mea­sure mi­cron-sized elec­tron beams via Comp­ton scat­ter­ing, where tra­di­tional wire scan­ners are at the limit of their res­o­lu­tion. Laser­wires have since been ap­plied to larger beam-size, high power H− ion beams, where the non-in­va­sive method can probe beam den­si­ties that would dam­age tra­di­tional di­ag­nos­tics. While photo-de­tach­ment of H− ions is now rou­tine to mea­sure beam pro­files, ex­tend­ing the tech­nique to trans­verse and lon­gi­tu­di­nal emit­tance mea­sure­ments is a key aim of the laser­wire emit­tance scan­ner under con­struc­tion at the Front End Test Stand (FETS) at the RAL. A pulsed, 30kHz, 8kW peak power laser is fi­bre-cou­pled to mo­tor­ized col­li­mat­ing op­tics, which con­trols the po­si­tion and thick­ness of the laser­wire de­liv­ered to the H− in­ter­ac­tion cham­ber. The laser­wire slices out a beam­let of neu­tral­ized par­ti­cles, which prop­a­gate to a down­stream scin­til­la­tor and cam­era. The emit­tance is re­con­structed from 2D im­ages as the laser­wire po­si­tion is scanned. Re­sults from the de­liv­ery op­tics, scin­til­la­tor tests and par­ti­cle track­ing sim­u­la­tions of the full sys­tem are re­viewed. Plans to de­ploy the FETS laser sys­tem at the Linac4 at CERN are out­lined.  
poster icon Poster TUPF15 [9.196 MB]