1. LCLS2sc MAD files: Injector to Bypass Line
lattice version 1.2 (October 30, 2013)
M. Woodley
SXU
HXU
proposed FACET-II
LCLS-I
LCLS-II SC Linac
cross-over
bypass line
m-wall
A-line
B-line
Sector-10
Sector-20
Sector-30
Sector-0
extension line L3 L2 L1
s (m)

2. new linac beam axis defined
X= m , Y= m w.r.t. original linac axis
Z= original linac Z-coordinate
Z= 0 at start of LI01
Z= -20 m at cathode

3. LCLS-II - Linac and Compressor Layout for 4 GeV Cavities per Amplifier
j = *
V0 =94 MV
Ipk = 12 A
Lb = 2.0 mm L1
j =-21°
V0 =223 MV
Ipk = 12 A
Lb =2.0 mm L2
j = -21°
V0 =1447 MV
Ipk = 50 A
Lb = 0.56 mm L3
j = 0
V0 =2409 MV
Ipk = 1.0 kA
Lb = mm HL
j =-165°
V0 =55 MV
CM01
CM2,3
3.9GHz
CM04
CM15
CM16
CM35
LTU
E = 4.0 GeV
R56 = 0
sd  0.016%
2-km LH
E = 95 MeV
R56 = mm
sd = 0.05 %
BC1
E = 250 MeV
R56 = -55 mm
sd = 1.4 %
BC2
E = 1600 MeV
R56 = -60 mm
sd = 0.46 %
GUN
0.75 MeV
100-pC machine layout: Oct. 8, 2013; v21 ASTRA run; Bunch length Lb is FWHM
Linac
Sec. V
(MV) j
(deg)
Acc. Grad. (MV/m)
No. Cryo Mod’s
No.
Avail.
Cav’s
Spare Cav’s
Cavities per Amplifier L0 94 *
13.2 1 8 L1
220
-21
14.3 2 16 HL
-55
-165
14.5 3 12 L2
1447
15.5 96 6 48 L3
2409
15.4 20
160 10
Includes 2-km RW-wake
* L0 cav. phases: ~(3.4, -15.2, 0, 0, 0, 15, 15), with cav-2 at 22% of other L0 cavity gradients.

4. Gun + L0 Egun = 750 KeV Einj = 98 MeV L0 :
α =
Egun = 750 KeV
Einj = 98 MeV
L0 :
8 cavity cryomodule (layout courtesy XFEL Mad deck)
gradients and phases per P. Emma layout (version of October 8, 2013)
initial Twiss are “artificial”
final Twiss from C. Papadopoulos ("GUN2013_10_08v3“)

5. Matching + Laser Heater + L1
98 MeV
250 MeV
Einj = 98 MeV
EBC1 = 250 MeV
6 quadrupole matching section between L0 and Laser Heater
Laser Heater chicane:
lengthened version of LCLS system (L= m)
ηmax= 7.5 cm, R56= 14.5 mm
βX = βY = 10 m (α = 0) at center of chicane
includes momentum collimator
space for kicker (L= 2 m) and long drift (L= 8 m) provided for extraction to diagnostic line
L1 :
2 x 8 cavity cryomodules (layout courtesy XFEL Mad deck) … φ= -22°
3 x 4 cavity harmonic linearizer cryomodules (3.9 GHz) … φ= -165°
90° FODO lattice

6. BC1 + Betatron Collimation
EBC1 = 250 MeV
BC1 chicane :
copy of LCLS system
R56= 55 mm
small βX at fourth bend (CSR)
space for kicker (L= 2 m) and long drift (≈ 15 m total) provided for extraction to diagnostic line
betatron collimation system :
2 x 90 ° FODO cells (Lcell ≈ 16 m)
β = 25 m at collimators (2 x horizontal collimation + 2 x vertical collimation)

7. L2
250 MeV
1.6 GeV
EBC1 = 250 MeV
EBC2 = 1.6 GeV
L2 :
12 x 8 cavity cryomodules (layout courtesy XFEL Mad deck) … φ= -21°
30° FODO lattice

8. BC2 + Betatron Collimation
EBC2 = 1.6 GeV
BC2 chicane :
copy of LCLS system
R56= 60 mm
small βX at fourth bend (CSR)
space for kicker (L= 2.5 m) and long drift (≈ 30 m total) provided for extraction to diagnostic line
betatron collimation system :
2 x 90 ° FODO cells (Lcell ≈ 24 m)
β = 38.4 m at collimators (2 x horizontal collimation + 2 x vertical collimation)

9. L3 + Extension to LI10 EBC2 = 1.6 GeV Efinal = 4.0 GeV L3 :
20 x 8 cavity cryomodules (layout courtesy XFEL Mad deck) … φ= 0
15° FODO lattice
L3 extension :
4 x 90° FODO cells (Lcell= 45 m)
at start of Bypass Dogleg, Z= m (≈ 22.5 m into LI10)

10. Bypass Dogleg + Match to Bypass Line FODO
Efinal = 4.0 GeV
dogleg bending system :
from X/Y = +0.28/-0.99 m to X/Y = / m (ΔX/ΔY = -0.37/+1.64 m)
two 1.06° bends, rolled to 60.4°
4 x 90° FODO cells (Lcell= 25.4) cancel dispersion in both planes
momentum collimator and wire scanner included
total Z-length = m

11. To Do for “Baseline” release
update compression parameters to latest version of P. Emma layout
use M. Venturini’s laser heater undulator parameters
exchange X and Y collimators in HXR diagnostics section
upload files to SharePoint site
MAD8 input files
MAD8 output files
ELEGANT input files
generate upload files for Oracle Database
To Do after “Baseline” release
reduce chromaticity of initial matching section (L0 to LH) and other sections identified by Paul
design extraction systems and diagnostic lines (LH, BC1, BC2)
more relaxed β-functions in L2 and L3 (FFODDO rather than FODO?)
add correctors, BPMs, and other diagnostics
more …

12. https://portal. slac. stanford