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Injection path for MR & particle losses at MR_SCR. Alexander Molodozhenstev KEK MR commissioning group January 17, 2006. Schematic layout of Injection Path for MR. Beam from RCS. BP2. BP1. BP3. Kicker magnets. Magnet Septum. Circulating beam. QDX. QFR. QDT. QFP.
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Injection path for MR &particle losses at MR_SCR Alexander Molodozhenstev KEK MR commissioning group January 17, 2006
Schematic layout of Injection Path for MR Beam from RCS BP2 BP1 BP3 Kicker magnets Magnet Septum Circulating beam QDX QFR QDT QFP
Time pattern (h=9) 2nd batch 3rd batch 4th batch 1st batch 40 msec ~ 7’435 turns ~ 120 msec ~850nsec OPMS BP ~ 1 msec ~ 200 turns Opposite Field Magnet Septum – PULSE (sinusoidal) Bump Magnets – like DC
Elements representation (for MAD & ORBIT) * Edge focusing effect will lead to the vertical beta-beating
INJECTION_Path_MR Lattice parameters With OMS Without OMS Qx = 22.4279 (22.4281) Qy = 20.8227 (20.8199) x,max = 40.715m (40.812m) y,max = 33.922m (33.257m) Dx,max = 3.072m (3.057m) ORIGINAL Qx = 22.4281 Qy = 20.8195 x,max = 40.818m y,max = 33.197m Dx,max = 3.057m Vertical -beating ~ 2…3 % (without quadrupole components of OMS) D:\Alex\Work\2005\MR\MAD\mad050509I_for_ORBIT_YES_Inj_Bump\ Teapot_ORBIT_Tracker\22428_20819\Yes_CCSX\Test#3_COD\Check_Dec05\DR_Short\INJD_short.mad
Simulation approach #1 #1 … Lattice with BP & OMS (rectangular pulse) & CFQDT:: 200 turns #2 … Lattice with BP & --- & CFQDT :: 7’235 turns
Simulation approach #2 • RCS 0.6MW beam (v050906/Transverse:: 95254mp) • RCS_MR Beamline Collimator :: 54 mm.mrad (90935mp) • Matched beam at MR_SCR position for Qx=22.428, Qy=20.82 including injection dogleg • Sextupole magnets for chromaticity correction are ON • Uniform Longitudinal distribution: = ± 60 degree (Bf = 0.3), p/p = ± 0.002 • MR scraper acceptance = 70 mm.mrad • RF:: h=9; VRF= 140 / 91 kV • Beampipe:: Rectangular shape / size(X,Y) = ± 70 mm • NFFT: 100×100 / Nbin: 512 / z < 1.5m • INJECTION DOGLEG:: Bump Magnets (1,2,3) + Opposite Field Magnet Septums (1,2,3) + Combined Function QDT • Different conditions for Bump Magnets and Opposite Field Magnet Septums…(#1: DC for ALL; #2: DC for Bumps and PUSLE for Opposite MS; #3: only DC Bumps) • Overall number of turns = 2’000.
NO Injection Dogleg 99% emittance LOST particles V H MRSCR=70 mm.mrad
Case 1: DC for ALL elements of INJECTION dogleg 99% emittance LOST particles V H 2000 turns BP & OMS & CFQDT …
Case 2: DC for Bump-magnets and PULSE for OMS of INJECTION dogleg 99% emittance LOST particles V H 200 turns BP & OMS & CFQDT plus 1800 turns BP & CFQDT …
Footprint for case #2 after 2000turns Only Space-Charge resonances and Normal Sextupole resonances are indicated Qx+2Qy=64 2Qx–2Qy=3 4Qx=89 Qx 4Qy = 83 4Qx = 90 -Qx+2Qy=19 3Qx=67 Qy Red – Space Charge resonances Blue – Normal Sextupole resonances
Case 1_2: DC for ALL elements of INJECTION doglegNO CC_Sextupoles, dp=0 99% emittance LOST particles 2000 turns BP & OMS & CFQDT … NO influence of Normal Sextupole Resonances NO_CCSX:: dp/p = 0
99% Emittance behavior during the injection process (MR_SCR70) V H
Particle losses at MR_SCR70 during injection process 1st batch 1.63% 2nd batch 0.92% 3rd batch 0.35% 4th batch 0.10 % 40msec 80msec 120msec
Budget of MR particle losses RCS_Beam (TR::v050906, LD::Uniform) MR_SCR_Acceptance = 70 π mm.mrad (CLM54 in RCS_MR_BeamLine) Injection time:: 120 msec Power of the lost beam at the injection energy for each batch … Total power of the lost beam at the injection energy for 8 bunches ~ 214 W (120msec injection time) … < 450W !!!
… continue • Introduction of realistic field-error of the MR magnets • (2) Introduction of misalignment of MR magnets (excitation of skew-resonances)