Recent Progress on the Design of a Rotatable Copper Collimator for the LHC Collimation Upgrade

The Phase II up­grade to the LHC col­li­ma­tion sys­tem calls for com­ple­ment­ing the 30 high ro­bust Phase I graphite col­li­ma­tors with 30 high Z Phase II col­li­ma­tors. One op­tion is to use metal­lic ro­tat­able col­li­ma­tors and this de­sign will be dis­cussed here. The Phase II col­li­ma­tors must be ro­bust in var­i­ous op­er­at­ing con­di­tions and ac­ci­dent sce­nar­ios. De­sign is­sues in­clude: 1) Col­li­ma­tor jaw de­flec­tion due to heat­ing and sagi­ta must be small when op­er­at­ed in the steady state con­di­tion, 2) Col­li­ma­tor jaws must with­stand tran­si­to­ry pe­ri­ods of high beam im­paction with no per­ma­nent dam­age, 3) Jaws must re­cov­er from ac­ci­dent sce­nario where up to 7 full in­ten­si­ty beam puls­es im­pact on the jaw sur­face and 4) The beam impedance con­tri­bu­tion due to the col­li­ma­tors must be small to min­i­mize co­her­ent beam in­sta­bil­i­ties. The cur­rent de­sign will be pre­sent­ed.