1. 01SEP17

2. 15.5* MeV/m original LCLS-II baseline [04NOV16] 15.5* MeV/m present
0.25 GeV L2
1.6 GeV L3
4.0 GeV
BC2
44.18 m
original
LCLS-II baseline
[04NOV16]
COL2
EXT 4 15 16 25 26 35
DB1
15+2
DB2 20
BRB1
(to NIT)
15.5* MeV/m
0.25 GeV L2
1.6 GeV L3
4.0 GeV
BC2
present
LCLS-II baseline
[09MAY17] m
EMIT2 4 15 16 25 26 35
21 m
BRB1
(to NIT)
DB1
15+2
DB2 20
NOTE: not to scale
18* MeV/m
20.8* MeV/m
0.25 GeV
L2 (φ=-21°)
1.873 GeV
L3 (φ=5°)
3.749 GeV
L4 (φ=3.8°)
8.0 GeV
BC2
40.95 m
LCLS-II-HE
[next]
EMIT2 4 15 16 25 26 28 29 35 41 42 55
12.4 m
BRB1
(to NIT)
DB1
15+2
DB2 14
DB3 26
accelerating gradients:
18.0 MeV/m includes 3% overhead
20.8 MeV/m includes 6% overhead

3. BC2 L2
DOG
EMIT2 L3
LEX L4
EXT
30° / cell FODO
low-energy
extraction

4. NOTE: kickers, septum, and final bend rotated ~50° counter-clockwise

5. 2nd order dispersion correction match to SIT bypass line
rotated
sextupoles
-28°
-1°
-17°
match to SIT bypass line

7. “Stripline-15” (new type)
SLTR QF1545 (a.k.a. QF-1)
“1.013Q3.42” SA
bore = 1.013”
chamber φ = 0.9” (22.9 mm)
core length = 3.42”
full core width = 6.5”
GLmax = A
BPM
“Stripline-15” (new type) SA
strip φ = 1.057” (26.9 mm)

8. septum
kickers
CM29 L3 L4
CM29
kickers
septum

9. name area type Bmax Egev B % Esgev Bs %
BKRL3X1 LEDOG K
BKRL3X2 LEDOG K
BKRL3X3 LEDOG K
BKRL3XD LEDOG K
BLRL3X LEDOG SD
BRL3X LEDOG 1.0D
name area type GLmax Egev GL % Esgev GLs %
QL3X1 LEDOG Q
QL3X2 LEDOG Q
QL3X3 LEDOG 1.26Q
QL3X4 LEDOG 1.26Q
QL3X5 LEDOG 1.26Q
QL3X6 LEDOG 1.26Q
QL3X7 LEDOG 1.26Q
QL3X8 LEDOG 1.26Q
name area type G’Lmax Egev G’L % Esgev G’Ls %
SL3X1 LEDOG 1.38S
SL3X2 LEDOG 1.38S
SL3X3 LEDOG 1.38S

11. E= 3.749 GeV, γε= 1 μ, σWS= 250 μ E= 3.749 GeV, γε= 1 μ, σCOLL= 300 μ
45° / cell FODO
E= GeV, γε= 1 μ, σWS= 250 μ
45° / cell FODO
E= GeV, γε= 1 μ, σCOLL= 300 μ WS WS WS WS CX CY CX CY

12. DC merge
bend

13. X Z A-line BSY wooden door SXR DASEL new low-energy dump line
LCLS Cu linac
scH
NIT
SIT
scS
HXR
scSX
new B-line
connector Z

14. Y Z scH scS new low-energy dump line NIT SIT scSX merge A-line cuS scD
LCLS Cu linac
NIT
SIT
DASEL
A-line
scH
scS
cuS
new low-energy
dump line
new B-line
connector Y Z
scSX
merge
scD
scH

15. NOTE: kickers, septum, and final bend rotated ~2° counter-clockwise

17. Changes (w.r.t. 04JUL17) L3/L4 split moves 1 cryomodule upstream
L3: CM16-CM25(10) / vacuum break / CM26-CM28(3)
L4: CM29-CM41(13) / vacuum break / CM42-CM55(14)
energy profile (see slide 2)
updated gradients, phases, overheads
BC2 energy now GeV
LEX energy now GeV (max 4 GeV)
low-energy extraction now includes one “DIAG0-style” kicker (25 mm ID pipe)
low-energy dogleg now uses
2 “1.013Q3.42” quadrupoles with 2 “Stripline-15” BPMs
6 “1.26Q12” quadrupoles with 6 “Stripline-6” BPMs
numbered of powered spreader kickers for both HXR and SXR increased to 5, plus one “DIAG0-style” kicker (25 mm ID pipe) at the end of each string
low-energy dump line now included
possible future connector between BSY dump line and B-line tunnel included
will not be released as part of baseline

18. Issues
no dedicated differential pumping stay-clear spaces at end of L3 and beginning of L4 … pumps assumed to be interleaved with other devices in warm section (assumed particle-free)
only one R56 compensation chicane associated with low-energy dogleg (at downstream end)
dogleg R56 = -2.3 mm (maximum R56 in compensation chicane at 4 GeV is mm)
SXR safety dump bends (permanent magnets) at 8 GeV
B-field of safety dump bends magically doubled in MAD deck to retain layout