LCLS-II Undulator Installation Sequence and Expansion

M. Rowen1-18-2012

LCLS-II Und. Installation & Expansion, 1-18-12

Goals

Slide 2LCLS-II Und. Installation & Expansion, 1-18-12

• Goal Installation Plans:• Expansion planning is to minimize changes as undulator segments

and seeding mono’s are planned. 1) Keep source point fixed. 2) Keep mono position fixed, once installed.

• HXR line the source should be as far from the end stations as possible to get maximum defocused spot.

• SXR line the source should be down stream as far as possible to limit over filling of mirrors at low energies. This does increase power density on absorbers. If branch lines have limited energy ranges, i.e. low energy and high

energy branches, then mirror angles on low energy line can be increased reducing the over filling and the source can be further away.

• Two Cases: 198 & 255m undulators.

HXU Expansion Plan

Slide 3LCLS-II Und. Installation & Expansion, 1-18-12

Tapered Und. Seg. 12-57202.4m

Seed Und. Seg. 1-1148.4m M

on o4.

4m

0 48.4 52.8 255.2

TW Taper to 13keV, No Contingency, In Longer Tunnel:

Source Point 92-138

Drift4.4mM

on o4.

4m

0 39.6 44.0 198.0

TW Taper to 8keV, No Contingency, in CD-1 Tunnel:

Source Point 83-130

Drift8.8m

Seed Und. Seg. 1-730.8m

Tapered Und. Seg. 8-41149.6m

8.8 193.6

Drift8.8m

0

Base Und. Seg. 7-32114.4m

20% 1-626.4m

35.2 149.6 255.2

Drift105.6m

Source Point 108-139

SASE in Longer Tunnel:

8.8

0

Base Und. Seg. 7-32114.4m

20% 1-626.4m

26.4 140.8 198.0

Drift57.2m

Source Point 99-130

CD-1 Scope, SASE:

SXU Expansion Plan

Slide 4LCLS-II Und. Installation & Expansion, 1-18-12

Seed Und. Seg. 1-939.6m

Tapered Und. Seg. 10-2461.6mM

ono 8.

8m

0 127.6 136.4 198.0

350 GW Taper to 1keV, No Contingency, in CD-1 Tunnel:

Source Point 1 keV, ~161m

88.0

Drift88.0m

0 255.2

350 GW Taper to 1keV, No Contingency, In Longer Tunnel:

Tapered Und. Seg. 10-2461.6m

193.6

Drift145.2m

Seed Und. Seg. 1-939.6m

Mo

no 8.8m

184.8145.2 Source Point 1 keV, ~218m

Drift13.2m

0

20% 1-417.6m

105.6 123.2 198.0

Drift105.6m

Source Point 153-175m

CD-1 Scope, SASE:

Base Und. Seg. 5-1861.6m

184.4

0 255.2

SASE in Longer Tunnel:

Drift162.8m

20% 1-417.6m

162.8 180.4 Source Point 210-233m

Drift13.2m

Base Und. Seg. 5-1861.6m

242.0

Assumption and Conclusions

Slide 5LCLS-II Und. Installation & Expansion, 1-18-12

• Assumptions:• Post saturation taper the source point is ~1/2 distance from saturation point

to end undulator. For strong taper Juhao provided more exact estimate for 8,10 and 18 keV.

(Assumed observation point was 150m from end HXR undulator & 110m end SXR.)

Extrapolated strong taper sto date. ource point to 4keV. Only 1 point for SXR at 1keV

• Conclusions:• The HXR undulators should be pushed to the upstream end of the

tunnel.• The SXR undulator should be pushed to the downstream end of the

tunnel.• This will have implications on spacing and number service

buildings.