1. LCLS-II Lattice 26FEB16: updates in the areas from bypass to dump
Y. Nosochkov
March 2, 2016

2. Summary of updates New HGVPU undulator in the HXR
March 2, 2016
Summary of updates
New HGVPU undulator in the HXR
Larger separation between fast kicker sections in spreader
5 fast kickers in the Cu-linac to SXR cross-over are replaced with one lower frequency kicker
Two new BPMs between fast spreader kickers and septa for kicker orbit control (both on and off)
BCS system: additional 2 new collimators (with 2 BTMs) and 2 existing collimators, remove one ACM, update device positions
Resolve interference with FACET-2 in sector-20: move 2 collimators downstream, and one wire scanner upstream in the bypass
Resolve numerous magnet/device interferences, mostly in the spreader/BSY area
Add independent power supply for QDL11 to provide matching capability for optics from Cu-linac to SXR LTU
New devices are deferred except existing LCLS-I devices

3. blue-dash=HXR, red-solid=SXR, green-dot=BSY-Dump, magenta=DIAG0
March 2, 2016
LCLS-II layout L3 L2
BC2
BC1 LH
EXT
4-GeV CW SCRF Linac DL
DIAG0
m-wall
HXU
SXU
Sec Linac
HXR kicker
LTUH
LTUS
BYPASS
Sec Linac
Proposed FACET-II
3-15-GeV Cu Linac – LCLS-I
SXR kicker
blue-dash=HXR, red-solid=SXR, green-dot=BSY-Dump, magenta=DIAG0
Downstream areas: bypass, spreader/BSY, LTU, undulator, dump line
P. Emma

4. Complete optics: SC-linac to HXR/SXR
March 2, 2016
Complete optics: SC-linac to HXR/SXR
HXR
SXR
Bypass
Spreader
LTU
Undulator
& Dump

5. Complete optics: Cu-linac to HXR/SXR
March 2, 2016
Complete optics: Cu-linac to HXR/SXR
HXR
SXR
BSY &
CuSXR
LTU
Undulator
& Dump

6. Bypass Resolve FACET2 interference in S20
March 2, 2016
Bypass
One wire scanner moved from S20 to S12
Two vert. collimators moved from S20 & S24 to S22 & S26
Resolve FACET2 interference in S20
Same or very similar optics conditions at new WS and CY positions – no impact on performance

7. Spreader & BSY to A-line Cu-linac HXR SXR LCLS2 X-plane Y-plane Quads:
March 2, 2016
Spreader & BSY
Quads:
SXR – cyan
HXR – green
Dump – black
CuRF – black
DC bends – red
Septa, kickers,
corrector bends
– magenta
Collimators
– small blue boxes
ACMs – small red boxes
BSY dump
– black box
Face of muon
wall – dash
to A-line
HXR
SXR
Cu-linac
LCLS2
X-plane
Y-plane
dump

8. Resolving interferences in spreader & BSY
March 2, 2016
Resolving interferences in spreader & BSY
Device interferences were identified and proposed fixes were suggested by engineers (T. O’Heron and C. Iverson). Quad moves were minimized where possible. The proposed modifications have been implemented in the new lattice. Optics changes are minimal.

9. HXR spreader cross-over: bypass to muon wall
March 2, 2016
HXR spreader cross-over: bypass to muon wall
Many device moves (quad moves ≤0.7 m). Larger separation between fast kicker segments (15 cm  30 cm, T. Beukers) required moving bypass quad QBP28 30 cm upstream. Minimal impact on optics.
kicker
septum
R56=0

10. SXR spreader chicane: bypass to muon wall
March 2, 2016
SXR spreader chicane: bypass to muon wall
Few device moves. 15 cm larger separation between fast kickers.
Minimal impact on optics.
kicker
septum
R56=0

11. Cu-linac to SXR dogleg cross-over
March 2, 2016
Cu-linac to SXR dogleg cross-over
5 fast kickers are replaced with one kicker (based on BYKIK design). The dogleg length is increased 1.2 m to resolve interference with Cu-linac straight ahead line. Separate PS is needed for QDL11 to allow the dogleg match to LTUS.
kicker
septum
R56=0

12. New spreader BPMs to control fast kicker orbit
March 2, 2016
New spreader BPMs to control fast kicker orbit
Two new BPMs (deferred) are placed at mid-point between a spreader kicker and a septum (in HXR & SXR) to tune the kicker orbit as well as steer the un-deflected beam through septa.
BPM

13. March 2, 2016
BCS system in BSY
Stan Mao have been studying BSY protection from miss-steered beams. The new BCS scheme adds 2 new collimators with BTMs and re-uses 2 existing collimators. One BCS ACM is removed.

14. March 2, 2016
BCS devices in BSY
BCS PCs: short blue boxes, BCS ACMs: short red boxes.
Q50Q1
Q50Q2
Q50Q3 Q4 Q5 Q6
QA0 D2
ST60
DM60
ST61
BXSP1H
BXKIK1,2
Spoiler1
TDKIK1
Chicane
Dump
SXR and
dump line
HXR
BRSP2H
QSP12H
QSP13H
QBP30
QBP36
BYSP2D
QBP31
QBP32
QBP33
QBP34
3 stoppers
OTR
CXQ6
CXBP30
CXBP34
Kicker+Septum
A-line
BTM2
BTM3
BTM4
PC90, 119
BTM1

15. March 2, 2016
LTU
Same optics, but with separate PS for QDL11 for Cu-linac to SXR match.
HXR
SXR
dogleg
diagnostic

16. March 2, 2016
HGVPU undulator in HXR
New HGVPU undulator in HXR. Positions optimized relative to existing girders. Same number of undulator segments, but the first undulator starts 5.3 m earlier than in the previous scheme. This fits with the existing LTUH. The undulator cell is ~39 cm shorter. Four empty cells at the end for future upgrade. One upstream RF BPM is moved to downstream of the undulator (in empty cell 49).
Previous scheme with HXR horizontal undulator
New scheme with HXR HGVPU undulator
H-D. Nuhn

17. March 2, 2016
HGVPU cell
Similar cell design, except phase shifter is moved from upstream of a quad to end of cell. Cell length = m, undulator length = m. Same undulator period and K-value as for horizontal undulator.
D. Bruch

18. March 2, 2016
HXR undulator optics
X & Y beta functions are exchanged in HGVPU due to X-focusing in HGVPU.
Old HXR
HGVPU
empty
cells

19. March 2, 2016
Dump line
Minor changes to optics, BCS ACMs near dump moved upstream to avoid potential hazard from high power dump.
HXR
SXR
Tcav
OTR