60 likes | 248 Views
Drive Beam Generation - (toughts about) 500 GeV c.m. options. 241 ns structures. Case 2: Structure CLIC_502 500GeV: <E a >=80MV/m, N=6.8x10 9 => P in = 74.2MW . Adjust drive beam current & energy to produce 2x74 MW per PETS instead of 2x64 MW (nominal at 3TeV)
E N D
Drive Beam Generation - (toughts about) 500 GeV c.m. options
241 ns structures • Case 2: Structure CLIC_502 • 500GeV: <Ea>=80MV/m, N=6.8x109 => Pin = 74.2MW. • Adjust drive beam current & energy to produce 2x74 MW per PETS instead of 2x64 MW (nominal at 3TeV) • 500GeV: N=6.8x109, Pin = 64MW => <Ea>=73MV/m. • Collision energy is lower (456GeV) • 3TeV: N=3.72x109, Pin = 64MW => <Ea>=82MV/m, • reduced gradient in the part of the main linac • Make different ramping of the pulse for beam loading compensation (filling time is different in CLIC_G and CLIC_502) • Case 4: Structure CLIC_504 • 500GeV: <Ea>=80MV/m, Pin = 64MW => N=5.7x109. • Reduced luminosity • 3TeV: N=3.72x109, Pin = 64MW => <Ea>=87MV/m, • reduced gradient in the part of the main linac but still higher than for CLIC_502 • Make different ramping of the pulse for beam loading compensation (filling time is different in CLIC_G and CLIC_504)
Case 2: Structure CLIC_502 • <Ea>=80MV/m, (Bunch population 3.7 6.8 109) • HDS power : 64 74.2 MW Alexej • Drive Beam current : 101 109 A • Drive Beam energy : 2.48 2.57 GeV Small adjustments of PETS length & or PETS R’/Q possible e.g. R’/Q 2295 2122 W/m • Drive Beam current : 113 A • Drive Beam energy : 2.47 GeV
483 ns structures • In both cases: • Doubling pulse length means combination factor 12 instead of 24 but higher charge per bunch in drive beam • DB linac : Higher current compromises efficiency versus cost: Different structures or lower efficiency ? (but maybe not if you do off crest acceleration effectively reducing R’/Q) • Deccelerators: Lower energy and double bunch spacing of DB: Stability issue ? Ramping for beam loading compensation? • Case 5: Structure CLIC_G • 500GeV: <Ea>=80MV/m, N=3.3x109 => Pin = 42.1MW. • Same structure as for 3 TeV • 3TeV: Nominal • Case 6: Structure CLIC_506 • 500GeV: <Ea>=80MV/m, N=4x109 => Pin = 50.1MW. • Higher luminosity • 3TeV: N=3.72x109, Pin = 64MW => <Ea>=93.7MV/m, • lower gradient in the part of the main linac • Make different ramping of the pulse for beam loading compensation (filling time is different in CLIC_G and CLIC_506)
Case 6: Structure CLIC_506 • <Ea>=80MV/m, (Bunch population 3.7 4 109) Pulse length241 483 ns double pulse scheme • HDS power : 64 50 MW Alexej • Drive Beam current : 101 90 A • Drive Beam energy : 2.48 2.12 GeV Drawbacks: higher charge per bunch ?