X-Ray Endstations Update

1. X-Ray Endstations Update John Arthur

2. The X-Ray Endstation Systems group will create the infrastructure required for experimenters to make best scientific use of the LCLS radiation

3. Recent Endstation developments • Low-pass mirrors in Front End Enclosure • Evolving design of Far Experimental Hall • Coordination with LCLS experimental equipment project

4. Integration of permanent low-pass mirrors into the LCLS x-ray beamline

5. The Near Experimental Hall Shops, setup space FEL beam Experimental hutches Massive concrete walls

6. The Front End Enclosure (old plan) Undulator NEH FEL beam straight through

7. Problem with the old plan The straight-through beam contains a significant background of very-high-energy photons from spontaneous undulator radiation and bremsstrahlung • Shielding requirement (2-ft walls) makes hutch access difficult • Shielding makes hutch modification difficult • Making measurements in a high-energy radiation environment is very difficult

8. A possible improvement A pair of x-ray mirrors can serve as a low-pass filter, transmitting desired FEL radiation but not high-energy background Collimator 2 Collimator 1 M2 5 mm M1 10 mm

9. Reflectivity vs energy for a flat SiC mirror at 1.5 mrad incidence angle R > 95% for E < 24 keV R < 10% for E > 28 keV From Berkeley CXRO calculator: <http://www.cxro.lbl.gov/optical_constants/mirror2.html>

10. The Front End Enclosure (new plan) Low-pass mirrors, collimators use about 10m of FEE Undulator FEL beam NEH

11. Advantages of new plan • Shielding requirement reduced: no concrete, just 2mm Pb • Hutch modification possible • Measurements will be vastly easier High-energy background reduced by many orders of magnitude • Alignment is more difficult • Coherence of beam could suffer Disadvantages of new plan

12. Consideration of modification of layout of the Far Experimental Hall

13. The Far Experimental Hall Office and shop space Experimental hutches FEL beams Laser room

14. Disadvantages of the FEE layout • The hutches have minimal length (7-8 m) • Lots of space seems unproductive: long emergency exit tunnels

15. The Far Experimental Hall possible new plan in red 8x10 m 8x10 m 8x10 m

16. Advantages of new the FEE layout • The hutches have > 10 m length • Emergency exit tunnels are more efficient • Support labs moved to space near tunnel exit • Overall underground area about the same This concept is still in draft stage, not final

17. LCLS Endstation systems coordination with the LCLS experimental equipment project The experimental equipment project is a separate project from LCLS construction, which is just starting up The ground rules for coordination between LCLS and the experimental equipment project have recently become clear

18. The experimental equipment project will outfit most of the experimental stations, but • This project will run past 2009, when LCLS becomes operational • By 2009, the project will have finished only a couple of stations • LCLS will build one station, for soft x-ray atomic physics • LCLS-funded items and experimental equipment items must be kept separate So LCLS resources and schedule within the Endstation systems group are being rearranged so as to provide maximum capability for the LCLS-funded atomic physics station

19. The Endstation systems group is responding to new ideas from potential experimental groups and to perceived problems with existing design • If implemented soon, these changes will not be disruptive • Group is coordinating with conventional construction and x-ray transport groups, and will work closely with instrument development project Summary