Author: Payne, S.J.
Paper Title Page
TUPC147 A Micro-Channel Plate Based Gas Ionization Profile Monitor with Shaping Field Electrodes for the ISIS H− Injector 1371
 
  • P.G. Barnes, G.M. Cross, B.S. Drumm, S.A. Fisher, S.J. Payne, A. Pertica, C.C. Wilcox
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  
  Beam pro­file mea­sure­ments with­in the ISIS H− in­jec­tor line are achieved using de­struc­tive de­vices such as mov­ing wire scan­ners. To avoid dam­age to the wires, mea­sure­ments are made with the in­jec­tor op­er­at­ing on re­duced power. This paper re­ports the de­vel­op­ment of a Mi­cro-Chan­nel Plate based pro­file mon­i­tor which al­lows beam mea­sure­ments to be made under nor­mal op­er­at­ing con­di­tions. The mon­i­tor pro­duces pro­files by mea­sur­ing the +ion cur­rent re­sult­ing from the in­ter­ac­tion of the H− beam with the sur­round­ing resid­u­al gas. The 32 chan­nel Mi­cro-Chan­nel Plate is mount­ed on a ro­tat­ing arm to en­able it to be po­si­tioned par­al­lel to the beam for cal­i­bra­tion (all chan­nels then mea­sure the same +ion cur­rent) and per­pen­dic­u­lar to the beam for pro­file mea­sure­ments. A 15kV drift field is used to­geth­er with field shap­ing elec­trodes to en­sure a flat elec­tric field gra­di­ent across the mon­i­tor, there­by min­imis­ing dis­tor­tion of the pro­file due to the elec­tric field. This paper de­tails all as­pects of the de­sign and con­struc­tion of this pro­file mon­i­tor. Beam pro­files are com­pared to pre­vi­ous wire scan­ner re­sults. Shap­ing field up­grades are dis­cussed to im­prove the lon­gi­tu­di­nal field shape.  
 
WEPS106 Status of Injection Upgrade Studies for the ISIS Synchrotron 2760
 
  • C.M. Warsop, D.J. Adams, D.J.S. Findlay, I.S.K. Gardner, S.J.S. Jago, B. Jones, R.J. Mathieson, S.J. Payne, B.G. Pine, A. Seville, H. V. Smith, J.W.G. Thomason, R.E. Williamson
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
  • J. Pasternak
    Imperial College of Science and Technology, Department of Physics, London, United Kingdom
  • C.R. Prior, G.H. Rees
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
  
  ISIS is the spal­la­tion neu­tron source at the Ruther­ford Ap­ple­ton Lab­o­ra­to­ry in the UK. Op­er­a­tion cen­tres on a high in­ten­si­ty pro­ton ac­cel­er­a­tor, con­sist­ing of a 70 MeV linac and an 800 MeV rapid cy­cling syn­chrotron, which pro­vides a beam power of 0.2 MW. Ob­so­les­cence is­sues are mo­ti­vat­ing plans to re­place the age­ing 70 MeV linac, and this paper sum­maris­es the sta­tus of stud­ies look­ing at how a new, high­er en­er­gy linac (~180 MeV) could be used to in­crease beam power in the ex­ist­ing syn­chrotron. Re­duced space charge and op­ti­mized in­jec­tion might allow beam pow­ers in the 0.5 MW regime, thus pro­vid­ing a very cost ef­fec­tive up­grade. The key areas of study are: de­sign of a prac­ti­cal in­jec­tion straight and mag­nets; in­jec­tion paint­ing and dy­nam­ics; foil spec­i­fi­ca­tions; ac­cel­er­a­tion dy­nam­ics; trans­verse space charge; in­sta­bil­i­ties; RF beam load­ing; beam loss and ac­ti­va­tion; di­ag­nos­tics and pos­si­ble damp­ing sys­tems. Re­sults from work on most of these top­ics sug­gest that beam pow­ers of ~0.5 MW may well be pos­si­ble, but a num­ber of top­ics, par­tic­u­lar­ly trans­verse sta­bil­i­ty, still look chal­leng­ing. Con­clu­sions so far are pre­sent­ed, as is progress on R&D on the main in­ten­si­ty lim­it­ing is­sues.