CW Linac Lattice August, 29 N.Solyak, B.Shteynas

Previous Baseline lattice Released March MeV; Chopper included; SSR0 (18 cav) not segmented, norm. emit.(x,y,z) = 0.25,0.25, 0275 mm*mrad -Good performances, robust to misalignment and components failure Several recent updates was studied: – Energy starts from 2.1 MeV – New segmentations of SSR0: 3*7 =21 cavities and 2*9=18 cavities, – Re-optimization of SSR2 section with beta=0.47 spoke cavity New lattice (3.9) includes all recently proposed changes (2.1 MeV): – SSR0 segmentation with missing solenoid: 2x9 cavities – Shorter SSR1 cryomodule (8 vs. 10 cavities) – Shorter SSR2 cryomodule (9 vs. 11 cavities) – Matched for lower emittances from Staples RFQ: 0.14,0.14, mm*mrad

New design: RFQ-MEBT-SSR0: 10 MeV acceleration 1σ envelopes Match from RFQ to chopper SSR0 (2x9cav) MEBT Chopper SRR0 Match to SRR0 Triplet focusing in Chopper and matching sections (+1 SC solenoid) Six RT 325 MHz bunching cavities in MEBT SSR0 is splitted in two ~5.1 m cryomodules with 9 cavities a 8 solenoids inside

ɛ n x,y,z = 0.139, 0.14, mm∙mmrad; Energy: 2.1 _> MeV; Current: Envelope X&Y (mm)- Z(mm) (chopper-front end) MEBT, Chopper SSR0 (2x9cav) SSR1(2x8cav) SSR2 (4x9cav) Missing solenoid Spoke cavity part of the Linac (up-to ~180 MeV) 2 shorter SSR1 CMs with 8 cavities/8solenois (vs. 10 in previous version) 4 shorter SSR2 CMs with 9 cav /5 solenoids (vs. 11cav/6 solenoids). beta=0.47 All spacing between CMs kept the same

Comparison of current design and version Section Freq, MHz Energy, MeVLength m Cav/mag/CM Period m CM Length* Type SSR – / 16 / SSR, solenoid SSR – / 16 / SSR, solenoid SSR2 (β=0.47) – / 20 / SSR, solenoid LB – / 14 / cell, doublet HB – / 19 / cell, doublet Section Freq, MHz Energy, MeV Length, m Cav/mag/CMType SSR – /18/1SSR, solenoid10.98 SSR – /20/2SSR, solenoid8 SSR2 (β=0.42) – /24/4SSR, solenoid8.84 LB – /14/75-cell, doublet7.1 HB – /19/195-cell, doublet11.2 Current variant (total length = 437 m, incl m MEBT) Lattice (total length = 444 m, incl m MEBT) Savings in cavities (current vs ): ΔSSR1 = 4; ΔSSR2= 8; Total savings: 12 cavities / 10 solenoids / 7 m of tunnel

Emittance: 0.139, 0.14, Energy: 2.1 MeV– 3064 MeV; Current: 5 Full lattice for 3 GeV Linac SSR0 SSR1 SSR2 LE650 (7CMs /6 cav) HE650, beta 0.9 (19 CMs with 8 cav)

Emittance: 0.139, 0.14, 0.217mm*mrad Energy: 2.1 MeV – 3064 MeV; Current: 5 Phase advance Note: In chopper section used cavity period, not magnet

Emittance: 0.139, 0.14, mm*mrad, Energy: 2.1 MeV – 3064 MeV; Current: 5 Phase advance per meter

Emittance: 0.139, 0.14, 0.217mm*mrad Energy: 2.1 MeV – 3064 MeV; Current: 5 Synchronous phase

Emittance: 0.139, 0.14, 0.217mm*mrad Energy: 2.1 MeV – 3064 MeV; Current: 5 Emittances: Longitudinal (green), Transv. (pink)

Emittance: 0.139, 0.14, 0.217mm*mrad Energy: 2.1 MeV – 3064 MeV; Current: 5 Envelope of 99% of long. emittance

Emittance: 0.139, 0.14, 0.217mm*mrad Energy: 2.1 MeV – 3064 MeV; Current: 5 Sync. Phases vs. longitudinal beam size

Emittance: 0.139, 0.14, 0.217mm*mrad Energy: 2.1 MeV – 3064 MeV; Current: 5 Surface magnetic field

Emittance: 0.139, 0.14, 0.217mm*mrad Energy: 2.1 MeV – 3064 MeV; Current: 5 Cryogenic Losses

Emittance: 0.139, 0.14, 0.217mm*mrad Energy: 2.1 MeV – 3064 MeV; Current: 5 Surface electric field

Emittance: 0.139, 0.14, 0.217mm*mrad Energy: 2.1 MeV – 3064 MeV; Current: 5 Energy gain

Emittance: 0.139, 0.14, 0.217mm*mrad Energy: 2.1 MeV – 3064 MeV; Current: 5 Gradient

Back-up slides