Author: Kumar, N.
Paper Title Page
MOPAB279 Non-Invasive Beam Profile Monitoring for the HL-LHC Hollow Electron Lens 884
 
  • A. Salehilashkajani, N. Kumar, O. Sedláček, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  • M. Ady, N.S. Chritin, N. Jens, O.R. Jones, R. Kersevan, T. Lefèvre, S. Mazzoni, G. Papazoglou, A. Rossi, G. Schneider, R. Veness
    CERN, Meyrin, Switzerland
  • P. Forck, S. Udrea
    GSI, Darmstadt, Germany
  • N. Kumar, O. Sedláček, C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: This work was supported by the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1 and the STFC Cockcroft core grant No. ST/G008248/1.
A Hol­low Elec­tron Lens (HEL) is cur­rently under de­vel­op­ment for the High-Lu­mi­nos­ity up­grade of the Large Hadron Col­lider (HL-LHC). In this de­vice, a hol­low elec­tron beam co-prop­a­gates with a cen­tral pro­ton beam and pro­vides ac­tive halo con­trol in the LHC. To en­sure the con­cen­tric­ity of the two beams, a non-in­va­sive di­ag­nos­tic in­stru­ment is cur­rently being com­mis­sioned. This in­stru­ment is a com­pact ver­sion of an ex­ist­ing pro­to­type that lever­ages beam in­duced flu­o­res­cence with su­per­sonic gas cur­tain tech­nol­ogy. This con­tri­bu­tion in­cludes the de­sign fea­tures of this ver­sion of the mon­i­tor, re­cent progress, and fu­ture plans for tests at the Cock­croft In­sti­tute and the elec­tron lens test stand at CERN.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB279  
About • paper received ※ 18 May 2021       paper accepted ※ 15 June 2021       issue date ※ 02 September 2021  
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MOPAB283 Simulations of Space-Charge and Guiding Fields Effects on the Performance of Gas Jet Profile Monitoring 898
 
  • O. Sedláček, N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  • P. Forck, S. Udrea
    GSI, Darmstadt, Germany
  • N. Kumar, A. Salehilashkajani, O. Sedláček, C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • S. Mazzoni, O. Sedláček
    CERN, Geneva, Switzerland
 
  Gas jet based pro­file mon­i­tors in­ject a usu­ally cur­tain shaped gas jet across a charged par­ti­cle beam and ex­ploit the re­sults of the min­i­mally in­va­sive beam-gas in­ter­ac­tion to pro­vide in­for­ma­tion about the beam’s trans­ver­sal pro­file. Such mon­i­tor will be in­stalled as part of the High Lu­mi­nos­ity LHC up­grade at CERN in the Hol­low Elec­tron Lens (HEL). The HEL rep­re­sents a new col­li­ma­tion stage in­creas­ing the dif­fu­sion rate of halo par­ti­cles by plac­ing a high in­ten­sity hol­low elec­tron beam con­cen­tri­cally around the LHC beam. The gas jet mon­i­tor will use the flu­o­res­cence ra­di­a­tion re­sult­ing due to the beam-gas in­ter­ac­tion to cre­ate an image of the pro­files of both hol­low elec­tron and LHC beams How­ever, the high beam space-charge and strong guid­ing mag­netic field of the elec­tron beam cause sig­nif­i­cant dis­place­ments of the ex­cited mol­e­cules, as they are also ion­ized, and thus image dis­tor­tions. This work pre­sents pre­lim­i­nary sim­u­la­tion re­sults show­ing ex­pected flu­o­res­cence im­ages of the hol­low elec­tron pro­file as af­fected by space-charge and guid­ing fields using sim­u­la­tion tools such as IPM­sim. The in­flu­ence of the es­ti­mated elec­tron beam and gas jet cur­tain pa­ra­me­ters are in­ves­ti­gated.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB283  
About • paper received ※ 18 May 2021       paper accepted ※ 28 July 2021       issue date ※ 19 August 2021  
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TUPAB280 Quantum Gas Jet Scanner Based Beam Profile Monitors 2128
 
  • N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
 
  Funding: This work is supported by the HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1.
A quan­tum gas jet scan­ner-based beam pro­file mon­i­tor is under de­vel­op­ment at the Cock­croft In­sti­tute (CI), the UK for beam di­ag­nos­tics based on the prin­ci­ple of ion­iza­tion de­tec­tion in­duced in a quan­tum gas jet in­ter­act­ing with an ion­iz­ing pri­mary beam that shall be char­ac­ter­ized. It promises su­pe­rior po­si­tion res­o­lu­tion and high sig­nal in­ten­sity re­sult­ing from a strongly fo­cused quan­tum gas jet. In order to achieve the gas jet with a di­am­e­ter of less than 100 µm, a novel fo­cus­ing method ex­ploit­ing the quan­tum wave func­tion of the neu­tral gas atoms, gen­er­ate an in­ter­fer­ence pat­tern with a sin­gle max­i­mum act­ing as an ul­tra-thin gas jet. An ‘atom sieve’ has been de­signed for gen­er­at­ing the in­ter­fer­ence pat­tern, ap­ply­ing the prin­ci­ple of a pho­ton sieve. It will be anal­o­gous to a me­chan­i­cal wire scan­ner though with a min­i­mal in­ter­cep­tion. The idea of mov­ing a quan­tum gas jet through the beam is pro­posed for trans­verse pro­fil­ing. This con­tri­bu­tion pro­vides a gen­eral overview of the de­sign, work­ing prin­ci­ple, the re­sults ob­tained from ini­tial mea­sure­ments car­ried out at CI and Uni­ver­sity of Bergen (Nor­way), for de­sign­ing the same and pos­si­ble meth­ods for op­ti­miz­ing the scan­ner’s de­sign.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB280  
About • paper received ※ 19 May 2021       paper accepted ※ 31 May 2021       issue date ※ 25 August 2021  
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TUPAB281 Gas-Mixing to Improve the Resolution of Non-Invasive Gas Jet-Based Ionization Profile Monitors 2132
 
  • N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
 
  Funding: This work is supported by the HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1.
Ion­iza­tion beam pro­file mon­i­tor using a su­per­sonic gas jet is an at­trac­tive op­tion for the char­ac­ter­i­za­tion of low and medium en­ergy beams. In this scheme, a pri­mary beam crosses a 45-de­gree tilted thin gas cur­tain which causes ion­iza­tion of gas mol­e­cules in the jet. The gen­er­ated ions are then col­lected using an elec­tro­sta­tic ex­trac­tion sys­tem to de­ter­mine the 2D trans­verse pro­file of the pri­mary beam. The most com­monly used gases for the jet are neon and ni­tro­gen. The sig­nal from the gas jet is al­ways su­per-im­posed with the sig­nal re­sult­ing from resid­ual gases in the in­ter­ac­tion cham­ber. CST sim­u­la­tions in­di­cate that the gas jet speed is a key fac­tor for the sep­a­ra­tion of the jet and the resid­ual gas sig­nals. To ob­tain a good sig­nal sep­a­ra­tion, one can in­crease the ve­loc­ity of the gas jet. This can be ac­com­plished by gen­er­at­ing a gas jet that mixes heav­ier and lighter gases. This con­tri­bu­tion gives a gen­eral overview of the mon­i­tor de­sign, dis­cusses the ef­fects of gas mix­ing and CST sim­u­la­tion re­sults. It also pre­sents ex­per­i­men­tal re­sults ob­tained with He­lium, and Ni­tro­gen, as well as a mix­ture of them using dif­fer­ent per­cent­ages and the im­pact on mea­sure­ment res­o­lu­tion.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB281  
About • paper received ※ 19 May 2021       paper accepted ※ 02 June 2021       issue date ※ 13 August 2021  
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TUPAB282 Optical Beam Loss Monitor Based on Fibres for Beam Loss Monitoring and RF Breakdown Detection 2136
 
  • N. Kumar, C.P. Welsch, J. Wolfenden
    The University of Liverpool, Liverpool, United Kingdom
  • N. Kumar, C.P. Welsch, J. Wolfenden
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: This project has received funding from STFC under grant reference ST/V001302/1.
Stan­dard beam loss mon­i­tors are used to de­tect losses at spe­cific lo­ca­tions which is not a prac­ti­cal so­lu­tion for loss mon­i­tor­ing through­out the whole beam-line. Op­ti­cal fibre beam loss mon­i­tors (oBLMs) are based on the de­tec­tion of Cherenkov ra­di­a­tion from high en­ergy charged par­ti­cles hav­ing the ad­van­tage of cov­er­ing more than 100 m of an ac­cel­er­a­tor with a sin­gle de­tec­tor. This sys­tem was suc­cess­fully in­stalled at the Aus­tralian Syn­chro­tron cov­er­ing the en­tire fa­cil­ity for beam loss mea­sure­ments. Suc­cess­ful mea­sure­ments were also demon­strated on the Com­pact Lin­ear Ac­cel­er­a­tor for Re­search and Ap­pli­ca­tions (CLARA), UK with sub-me­tre beam loss res­o­lu­tion. oBLMs are non-in­va­sive mon­i­tors for the de­tec­tion of the beam loss and RF break­down within par­ti­cle ac­cel­er­a­tors, which has been de­vel­oped by the QUASAR Group based at the Cock­croft In­sti­tute/Uni­ver­sity of Liv­er­pool, UK in col­lab­o­ra­tion of D-Beam Ltd, UK. This paper dis­cusses the overview of the sys­tem, the in­cor­po­ra­tion of the mon­i­tor into the ac­cel­er­a­tor di­ag­nos­tic sys­tem, cal­i­bra­tion ex­per­i­ment of oBLM and fu­ture plans for the sys­tem.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB282  
About • paper received ※ 19 May 2021       paper accepted ※ 02 June 2021       issue date ※ 10 August 2021  
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WEPAB213 Optimization of Antiproton-Atom Collision Studies Using GEANT4 3126
 
  • V. Rodin, A. Farricker, N. Kumar, C.P. Welsch
    The University of Liverpool, Liverpool, United Kingdom
  • N. Kumar, V. Rodin, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 721559.
The in­ter­ac­tion be­tween an­tipro­tons and hy­dro­gen or he­lium atoms is a fun­da­men­tal prob­lem in many-par­ti­cle atomic physics, at­tract­ing strong in­ter­est from both the­ory and ex­per­i­ments. Atomic col­li­sions are ideal to study the three and four-body Coulomb prob­lem as the num­ber of pos­si­ble re­ac­tion chan­nels is lim­ited. Cur­rently, only the total cross-sec­tions of such in­ter­ac­tions have been mea­sured in an en­ergy range be­tween keV and a few MeV. This con­tri­bu­tion in­ves­ti­gates the dis­crep­an­cies be­tween dif­fer­ent the­o­ries and avail­able ex­per­i­men­tal data. It also de­scribes a path­way for ob­tain­ing dif­fer­en­tial cross-sec­tions. A pur­pose-de­signed ex­per­i­men­tal setup is pre­sented and de­tailed Geant4 sim­u­la­tions pro­vide an in­sight into the in­ter­ac­tion be­tween short (ns) an­tipro­ton bunches and a dense gas-jet tar­get.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB213  
About • paper received ※ 23 May 2021       paper accepted ※ 30 June 2021       issue date ※ 24 August 2021  
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FRXC05 Gas Jet In-Vivo Dosimetry for Particle Beam Therapy 4548
 
  • J. Wolfenden, N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
    The University of Liverpool, Liverpool, United Kingdom
  • N. Kumar, A. Salehilashkajani, C.P. Welsch, J. Wolfenden, H.D. Zhang
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: This work is supported by the HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1.
Med­ical ap­pli­ca­tions of charged par­ti­cle beams re­quire a full on­line char­ac­ter­i­sa­tion of the beam to en­sure pa­tient safety, treat­ment ef­fi­cacy, and fa­cil­ity ef­fi­ciency. In-vivo dosime­try, mea­sure­ment of de­liv­ered dose dur­ing treat­ment, is a sig­nif­i­cant part of this char­ac­ter­i­sa­tion. Cur­rent meth­ods offer lim­ited in­for­ma­tion or are in­va­sive to the beam, mean­ing mea­sure­ments must be done of­fline. This con­tri­bu­tion pre­sents the de­vel­op­ment of a non-in­va­sive gas jet in-vivo dosime­ter for treat­ment fa­cil­i­ties. The tech­nique is based on the in­ter­ac­tion be­tween a par­ti­cle beam and a su­per­sonic gas jet cur­tain, which was orig­i­nally de­vel­oped for the high lu­mi­nos­ity up­grade of the large hadron col­lider (HL-LHC). To demon­strate the med­ical ap­pli­ca­tion of this tech­nique, an ex­ist­ing HL-LHC test sys­tem with minor mod­i­fi­ca­tions will be in­stalled at the Uni­ver­sity of Birm­ing­ham’s 35 MeV pro­ton cy­clotron, which has prop­er­ties com­pa­ra­ble to that of a treat­ment beam. This con­tri­bu­tion pre­sents the de­sign and de­vel­op­ment of this test setup, plans for ini­tial bench­mark­ing mea­sure­ments, and plans for a fu­ture op­ti­mised med­ical ac­cel­er­a­tor gas jet in-vivo dosime­ter.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-FRXC05  
About • paper received ※ 18 May 2021       paper accepted ※ 23 July 2021       issue date ※ 11 August 2021  
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