1. LCLS Photon Systems Overview
John Arthur
SLAC

2. New LCLS Organization Collects all X-Ray Activities into Photon Beam Systems

3. LCLS Photon Systems Includes LCLS x-ray and laser groups
X-ray Transport, Optics and Diagnostics (XTOD)
managed by LLNL (Richard Bionta)
X-ray Endstation Systems (XES)
managed by SLAC (Stefan Moeller)
LCLS Laser Systems
managed by SLAC (Bill White)

4. XTOD Scope
Transport the x-ray beam, in vacuum, to all the experimental stations
Condition the x-ray beam, with attenuators and apertures
Analyze the x-ray beam, with sophisticated diagnostics

5. XES Scope
The X-Ray Endstation Systems group provides the infrastructure required for experimenters to make best scientific use of the LCLS radiation safely

6. Instrument MIE and XES A ~$50M MIE project has been proposed
Will build 4 x-ray instruments for LCLS
Instrumentation needs are becoming much more clear
XES has decided not to build generic instrumentation but rather,
LCLS will dedicate all project effort for experimental instrumentation to one area of science: Soft X-ray Atomic Physics (AMO)

7. Instrument MIE and XES Detectors
LCLS experiments need new detector technology
Dual development strategy for fast 2-d detectors
Several technologies look promising, no clear leader
LCLS will pursue one strategy
MIE will try a different technology
Both prototypes should be ready by 2009

8. LCLS Detector Development Program
Silicon Pixel Array Detector technology
Subcontracted to Gruner group at Cornell
About $3.5M total over 4 years
MOU in signing stage
Detector scientist to be hired soon
Periodic review by LCLS Detector Advisory Committee
Detailed specs being developed to match needs of single-particle imaging experiment

9. Recent Developments affecting all X-ray Systems (and Conv. Facilities)
Suggested Plan for Offset Mirrors in Front End
Suggested Redesign of Far Experimental Hall
These ideas are in the development stage, not yet official
But they look very promising
Have been endorsed by SAC

10. High Energy background problem
Unfiltered LCLS beam contains significant background from spontaneous harmonics (Ec ~ 150 keV) and from Bremsstrahlung from scattered electrons (GeV)
Much of this background lies directly on axis, and it is time-coincident with the FEL pulse
This is a nuisance for radiological shielding, and a huge problem for data taking

11. Solution: Offset mirrors in the FEE
Upstream of all LCLS experiments
FEL radiation reflected (>95%)
SiC 1.5mrad
SiC 1.5mrad
24mm offset
Background from high harmonics and Bremsstrahlung not reflected

12. Two mirror pairs, one pair inserted at a time
SiC gives cutoff at 24 keV
Be gives cutoff at 2 keV
SiC 1.5mrad
Be 13mrad
SiC 1.5mrad
24mm offset
8.0m

13. Reflectivity vs energy for a flat SiC mirror at 1
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: <

14. Proposed new layout of FEE
7 ft Fe
3 ft concrete
4 ft Fe
Mirrors
GAS ATTEN
COLLIM
STOP
STOP
SOLID ATTEN
~30m

15. Advantages of Offset Mirrors
Keep high-energy radiation out of experiments
Eliminate troublesome background
Note: nearly all synchrotron beamlines use some offset
Keep high-energy radiation farther away from experimenters
Reduce shielding requirements, make hutches more easily accessible

16. Far Experimental Hall Redesign
Response to concerns of experimenters and LCLS Technical Advisory Committee
Now in Title-1 planning stage

17. Problems with FEH Experimental hutches (7x8m) TOO SMALL
Office and shop space
(Vac., Mech.,Electr.)
Experimental hutches
(7x8m)
TOO SMALL
FEL beams

18. New design superimposed on old

19. Future tunnel to other stations
New FEH design
Entrance
14ft tunnel
Fire door
Fire door
15x25ft control cabin
46ft tunnel
Sliding hutch door
passage below
beam pipe
6ft
10ft
28x33ft hutch
10ft
29x33ft hutch
36x33ft hutch
10ft
30ft transition
Toilets
20ft tunnel
Future tunnel to other stations
212ft

20. Advantages of new design
Wider main tunnel
Reduced corridor space
More space for x-ray optics
Large hutches
Slightly higher cost

21. Summary Photon sections of LCLS are just starting up
Major staff increase
Experimental needs coming into focus
Design changes
Offset mirrors
FEH redesign