Author: Bourianoff, G.
Paper Title Page
S18BPA01 Operational Decoupling in the SSC Collider 576
 
  • G. Bourianoff
    SSCL, Dallas, TX, USA
  
  This paper will sum­ma­rize a re­cent study of the ef­fects and cor­rec­tion of lin­ear cou­pling in the Su­per­con­duct­ing Super Col­lider (SSC) lat­tice. There are sev­eral as­pects of the SSC lat­tice that make di­rect ex­trap­o­la­tion of tech­niques used on ex­ist­ing ma­chines un­re­li­able. The most ob­vi­ous as­pect of the SSC which de­parts from pre­vi­ous ex­pe­ri­ence is the small dy­namic aper­ture which lies well within the beampipe. A sec­ond as­pect is the ex­is­tence of long arcs with low su­per­pe­ri­od­ic­ity which allow var­i­ous sources of skew quadru­pole to ac­cu­mu­late to large, and, per­haps, non­lin­ear val­ues. A third as­pect is the rel­a­tively large value of sys­tem­atic skew quadru­pole error in the main dipoles. This re­sults from asym­met­ric place­ment of the cold mass in the cryo­stat Cou­pling must be con­sid­ered harm­ful if it leads to ir­re­versible emit­tance blow-up, a de­crease in the dy­namic aper­ture, or in­op­er­abil­ity of the ma­chine. These neg­a­tive ef­fects are gen­er­ally re­lated to cou­pling terms that ac­cu­mu­late to large and, hence, non­lin­ear val­ues prior to cor­rec­tion. The harm­ful ef­fects can also be caused by the lin­early cou­pled or­bits in­ter­act­ing with high-or­der mul­ti­pole fields that exist in the other mag­nets. The er­rors that lead to lin­ear cou­pling are well known. They are sys­tem­atic and ran­dom skew quadru­pole error fields in the other mag­netic el­e­ments, an­gu­lar align­ment er­rors in the quadrupoles and feed­down from the sex­tu­pole fields as­so­ci­ated with chro­matic­ity cor­rec­tion, and per­sis­tent cur­rent fields in the dipoles. A study of the rel­a­tive im­por­tance of the var­i­ous cou­pling terms for a sim­pli­fied SSC lat­tice has been done by Richard Tal­man.
Operated by the Universities Research Association, Inc., for the U.S. Department of Energy under Contract No. DE-AC35-89ER40486. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-ICALEPCS1991-S18BPA01  
About • Received ※ 11 November 1991 — Accepted ※ 20 November 1991 — Issued ※ 04 December 1992  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)