Frank Zimmermann, CLIC “Away Day” 28 March 2006  x * Limitations and Improvements Paths Damping Rings Maxim Korostelev, Frank Zimmermann

Frank Zimmermann, CLIC “Away Day” 28 March 2006 ATF single-bunch emittances:  x ~  m (CLIC: ~0.5  m)  y ~13-18 nm (CLIC: 3 nm)  z ~8640 eVm (CLIC: <5400 eVm) 6D phase-space density in CLIC ~70 times higher how can we go further? ? ATF CLIC new CLIC?

Frank Zimmermann, CLIC “Away Day” 28 March : CLIC-NLC comparison for ITRP “Wise Men” NLC DRCLIC DR energy1.98 GeV2.42 GeV* circumference~299 m364 m arc cell length~6 m1.8 m hor. phase advance/arc cell*108 o 210 o #arc TME cells*~30-40?100 total wiggler length*44 m152 m wiggler period*27 cm10 cm bunch population x x10 9 longit. emittance,  s 10.6 keVm5.5 keVm transv. emittances  x,  y ~3000 nm, 30 nm660 nm, 3.3 nm damping times  x,y,  s 3.63, 4.08 ms, 2.18 ms2.64 ms,1.32 ms *smaller emittance due to smaller bend angle / arc cell, less emittance detuning, more damping, smaller H x in wiggler *higher energy reduces intrabeam-scattering effect

Frank Zimmermann, CLIC “Away Day” 28 March 2006 further progress in 2005 Wiggler 1 permanent magnet Wiggler 3 Nb 3 Sn superconductor BwBw 1.7 T2.5 T w 10 cm4.5 cm  x 550 nm (133 nm w/o IBS) nm (79 nm w/o IBS)  y 3.3 nm (0.8 nm w/o IBS) nm (0.5 nm w/o IBS)  z 4724 eVm (2551 eVm w/o IBS) eVm (3433 eVm w/o IBS) also: less charge per bunch

Frank Zimmermann, CLIC “Away Day” 28 March 2006 possible approaches for achieving even smaller emittance 1) larger damping-ring circumference (weaker arcs & longer wigglers) + increased beam energy 2) damping in linac 3) laser wiggler?

Frank Zimmermann, CLIC “Away Day” 28 March ) larger circumference + higher energy not self-consistent, artificially kept longitudinal emittance at constant value (4500 eVm), opening-angle effect not included w/o IBS horizontal emittance is 100 nm w/o IBS at 3.74 GeV MAD-X calculation

Frank Zimmermann, CLIC “Away Day” 28 March 2006 analytical equations including IBS (Bane approx.) & opening angle H. Braun, M. Korostelev, F. Zimmermann, CLIC Note 594, 2004 dispersive terms opening angle IBS

Frank Zimmermann, CLIC “Away Day” 28 March 2006 result of my analytical calculation includes opening angle Karl Bane’s IBS approximation almost self- consistent (  z fixed = 1 mm) for case 2x circumference, I find large discrepancy in  z (w/o IBS) between analytical formula and MAD-X!?

Frank Zimmermann, CLIC “Away Day” 28 March 2006 exact calculation by Maxim “nominal”2x arc 2x straights E2.42 GeV3.74 GeV C365 m529 m704 m530 m  x 375 nm (79 nm) 421 nm (73 nm) 340 nm (66 nm) 315 nm (135 nm)  y 2.3 nm (0.5 nm) 2.65 nm (0.5 nm) 2.14 nm (0.415 nm) 1.98 nm (0.862 nm)  z 4997 eVm (3433 eVm) 5030 eVm (4100eVm) 4975 eVm (4221 eVm) 5020 eVm (4480 eVm) best

Frank Zimmermann, CLIC “Away Day” 28 March 2006 exact calculation by Maxim cont’d “nominal”2x arc 2x straights Q’ x Q’ y SF [10 3 m -3 ] SD [10 3 m -3 ] >10% larger sextupole strength implies >10% smaller dynamic aperture

Frank Zimmermann, CLIC “Away Day” 28 March 2006 new ring parameters? presentoption circumference357 m530 m energy2.424 GeV3.746 GeV rf frequency1.875 GHz rf voltage2.39 MV20.5 MV energy loss/ turn2.19 MeV18.93 MeV total wiggler length 152 m304 m synchr. radiation power 0.3 MW1.9 MW

Frank Zimmermann, CLIC “Away Day” 28 March ) damping in linac H. Braun, M. Korostelev, F. Zimmermann, CLIC Note 594, 2004  damping factor 2 beam energy34 GeV addt’l linac length640 m / side (~1/B w ) addt’l voltage48 GV (~1/B w ) wiggler peak field B w 10 T wiggler period w 1.5 cm  x,y 1.5 m, 8 m final  x 272 nm (~  x w 2 B w 3 ) final  y 3.5 nm (~  y B w ) wiggler parameters quite challenging

Frank Zimmermann, CLIC “Away Day” 28 March ) laser wiggler naturally small period assume laser parameters of Snowmass Posipol Proposal (CLIC note 639) laser wiggler equivalence: typeYAG A laser 592mJ w 0.53  m  x,y 5  m zz 0.9 mm I laser 5x10 20 W/m 2 BwBw 4090 T undulator regime! ~6% transverse emittance reduction per laser collision! however   →50%!

Frank Zimmermann, CLIC “Away Day” 28 March 2006 conclusions laser wiggler → unacceptable energy spread superconducting wiggler in linac beyond present state of the art double wiggler length & increase beam energy to 3.74 GeV→15% reduction in  x &  y ; but expect impact on dynamic aperture ~20-30% & 6x increased heat load

Frank Zimmermann, CLIC “Away Day” 28 March 2006 spare slide

Frank Zimmermann, CLIC “Away Day” 28 March 2006 DR equilibrium emittance without IBS & w/o 1/  present design: above can also be written as