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Migliorati, M.

Paper Title Page
TUPD056 Update of the SPS Impedance Model 2057
 
  • B. Salvant
    EPFL, Lausanne
  • G. Arduini, O.E. Berrig, F. Caspers, A. Grudiev, N. Mounet, E. Métral, G. Rumolo, B. Salvant, E.N. Shaposhnikova, C. Zannini
    CERN, Geneva
  • M. Migliorati, B. Spataro
    INFN/LNF, Frascati (Roma)
  • B. Zotter
    Honorary CERN Staff Member, Grand-Saconnex
 
 

The beam cou­pling impedance of the CERN SPS is ex­pect­ed to be one of the lim­i­ta­tions to an in­ten­si­ty up­grade of the LHC com­plex. In order to be able to re­duce the SPS impedance, its main con­trib­u­tors need to be iden­ti­fied. An impedance model for the SPS has been gath­ered from the­o­ret­i­cal cal­cu­la­tions, elec­tro­mag­net­ic sim­u­la­tions and bench mea­sure­ments of sin­gle SPS el­e­ments. The cur­rent model ac­counts for the lon­gi­tu­di­nal and trans­verse impedance of the kick­ers, the hor­i­zon­tal and ver­ti­cal elec­tro­stat­ic beam po­si­tion mon­i­tors, the RF cav­i­ties and the 6.7 km beam pipe. In order to as­sess the va­lid­i­ty of this model, macropar­ti­cle sim­u­la­tions of a bunch in­ter­act­ing with this up­dat­ed SPS impedance model are com­pared to mea­sure­ments per­formed with the SPS beam.

 
TUPEC027 Microbunching and RF Compression 1776
 
  • M. Migliorati
    Rome University La Sapienza, Roma
  • M. Ferrario, C. Vaccarezza
    INFN/LNF, Frascati (Roma)
  • C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  • M. Venturini
    LBNL, Berkeley, California
 
 

Ve­loc­i­ty bunch­ing (or RF com­pres­sion) rep­re­sents a promis­ing tech­nique com­ple­men­tary to mag­net­ic com­pres­sion to achieve the high peak cur­rent re­quired in the linac drivers for FELs. Here we re­port on re­cent progress aimed at char­ac­ter­iz­ing the RF com­pres­sion from the point of view of the mi­crobunch­ing in­sta­bil­i­ty. We em­pha­size the de­vel­op­ment of a lin­ear the­o­ry for the gain func­tion of the in­sta­bil­i­ty and its val­i­da­tion against macropar­ti­cle sim­u­la­tions that rep­re­sents a use­ful tool in the eval­u­a­tion of the com­pres­sion schemes for FEL sources.

 
TUPEC028 Microbunching Instability Effect Studies and Laser Heater Optimization for the SPARX FEL Accelerator 1779
 
  • C. Vaccarezza, E. Chiadroni, M. Ferrario
    INFN/LNF, Frascati (Roma)
  • G. Dattoli, L. Giannessi, M. Quattromini, C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  • M. Migliorati
    Rome University La Sapienza, Roma
  • M. Venturini
    LBNL, Berkeley, California
 
 

The ef­fects of mi­crobunch­ing in­sta­bil­i­ty for the SPARX ac­cel­er­a­tor have been an­a­lyzed by means of dif­fer­ent nu­mer­i­cal sim­u­la­tion codes and an­a­lyt­i­cal ap­proach. The laser heater coun­ter­act­ing ac­tion has been also ad­dressed in order to op­ti­mize the pa­ram­e­ters of the com­pres­sion sys­tem, ei­ther hy­brid RF plus mag­net­ic chi­cane or only mag­net­ic, and pos­si­bly en­hance the FEL per­for­mance.

 
WEPEB034 Superb Bunch-by-bunch Feedback R&D 2761
 
  • A. Drago, M.M. Beretta
    INFN/LNF, Frascati (Roma)
  • K.J. Bertsche, A. Novokhatski
    SLAC, Menlo Park, California
  • M. Migliorati
    Rome University La Sapienza, Roma
 
 

The Su­perB pro­ject has the goal to build in the Fras­cati or Tor Ver­ga­ta area, an asym­met­ric e+/e- Super Fla­vor Fac­to­ry to achieve a peak lu­mi­nos­i­ty > 1036 cm-2 s-1. The Su­perB de­sign is based on col­li­sions with ex­treme­ly low ver­ti­cal emit­tance beams. A source of emit­tance growth comes from the bunch by bunch feed­back sys­tems pro­duc­ing high power cor­rec­tion sig­nals to damp the beams. To limit any un­de­sir­able ef­fect, a large R&D pro­gram is in progress, par­tial­ly fund­ed by the INFN Fifth Na­tion­al Sci­en­tif­ic Com­mit­tee through the SFEED (Su­perB feed­back) pro­ject ap­proved with­in the 2010 bud­get. One of the first steps of the R&D pro­gram con­sists in the up­grade and test of new 12-bit feed­back sys­tems in the ver­ti­cal plane of the DAΦNE main rings. The sys­tems are the di­rect evo­lu­tion of the pre­vi­ous 8-bit sys­tem de­sign by a KEK/SLAC/LNF col­lab­o­ra­tion, yield­ing a good com­pat­i­bil­i­ty with the pow­er­ful di­ag­nos­tics and anal­y­sis pro­grams de­vel­oped in the past. Stud­ies on their ef­fects in the lon­gi­tu­di­nal plane are also in progress.

 
THPD038 Hybrid Schemes for the Post-acceleration of Laser Generated Protons 4363
 
  • A. Mostacci, M. Migliorati, L. Palumbo
    Rome University La Sapienza, Roma
  • D. Alesini, P. Antici
    INFN/LNF, Frascati (Roma)
  • L. Picardi, C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
 
 

Pro­tons gen­er­at­ed by the ir­ra­di­a­tion of a thin metal foil by a high-in­ten­si­ty short-pulse laser have shown to poss­es in­ter­est­ing char­ac­ter­is­tics in terms of en­er­gy, emit­tance, cur­rent and pulse du­ra­tion. They might there­fore be­come in the next fu­ture a com­pet­i­tive source to con­ven­tion­al pro­ton sources. Pre­vi­ous the­o­ret­i­cal and nu­mer­i­cal stud­ies al­ready demon­strat­ed the pos­si­bil­i­ty of an ef­fi­cient cou­pling be­tween laser-plas­ma ac­cel­er­a­tion of pro­tons with tra­di­tion­al RF based beam-line ac­cel­er­a­tor tech­niques. This hy­brid pro­ton ac­cel­er­a­tor would there­fore ben­e­fit from the good prop­er­ties of the laser-based source and from the flex­i­bil­i­ty and know-how of beam han­dling as given from RF based ac­cel­er­a­tor struc­ture. The pro­ton beam pa­ram­e­ters of the source have been ob­tained from pub­lished laser in­ter­ac­tion ex­per­i­men­tal re­sults and are given as input to the nu­mer­i­cal study by con­ven­tion­al ac­cel­er­a­tor de­sign tools. In this paper we dis­cuss re­cent re­sults in the op­ti­miza­tion and de­sign of the such hy­brid schemes in the con­text of pro­ton ac­cel­er­a­tors for med­i­cal treat­ments.

 
THPD053 Capture and Transport of Electron Beams from Plasma Injectors 4401
 
  • P. Antici, A. Mostacci
    INFN/LNF, Frascati (Roma)
  • C. Benedetti
    Bologna University, Bologna
  • M. Migliorati, L. Palumbo
    Rome University La Sapienza, Roma
 
 

Elec­tron beams pro­duced by laser-plas­ma in­ter­ac­tion are at­tract­ing the in­ter­est of the con­ven­tion­al ac­cel­er­a­tor com­mu­ni­ty. In par­tic­u­lar Laser-ac­cel­er­at­ed elec­trons are par­tic­u­lar­ly in­ter­est­ing as source, con­sid­er­ing their high ini­tial en­er­gy and their strong beam cur­rent. More­over, the ad­van­tages of using laser-plas­ma elec­tron beam can be ex­pressed in terms of size and cost of the glob­al ac­cel­er­at­ing in­fras­truc­ture. How­ev­er, im­prove­ments are still nec­es­sary since, cur­rent­ly, the many laser-ac­cel­er­at­ed beams are char­ac­ter­ized by a large en­er­gy spread and a high beam di­ver­gence that de­grades quick­ly the elec­tron beam prop­er­ties and makes those sources not suit­able as a re­place­ment of con­ven­tion­al ac­cel­er­a­tors. In this paper, we re­port on the progress of the study re­lat­ed to cap­ture, shape and trans­port of laser gen­er­at­ed elec­trons by means of track­ing codes. Our study has fo­cused on laser-gen­er­at­ed elec­trons ob­tained nowa­days by con­ven­tion­al multi hun­dred TW laser sys­tems and on nu­mer­i­cal pre­dic­tions. We an­a­lyze dif­fer­ent lat­tice struc­tures, work­ing on the op­ti­miza­tion of the cap­ture and trans­port of laser-ac­cel­er­at­ed elec­trons. Re­sults and open prob­lems are shown and dis­cussed.