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

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

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. 11-20 Linac HXR kicker LTUH LTUS BYPASS Sec. 21-30 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

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

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

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

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

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.

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

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

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

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

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.

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

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

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

March 2, 2016 HGVPU cell Similar cell design, except phase shifter is moved from upstream of a quad to end of cell. Cell length = 4.0127 m, undulator length = 3.3740 m. Same undulator period and K-value as for horizontal undulator. D. Bruch

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

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