1. Lehman Review: XTOD Beam Transport
X-ray Slit and Tunnel Design
Pat Duffy, Kirby Fong, Keith Kishiyama, Steve Lewis, Stewart Shen, Pete Tirapelle, John Trent, Louann Tung
February 8, 2006
This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

2. XVTS Overall Layout
FEE
NEH
FEH
Tunnel

3. Front End Enclosure (FEE) Configuration
Fast Valve
Fixed Mask
Diagnostics
X-ray Slit
Ion Chamber
Attenuator
Offset Mirrors

4. X-ray Slit Key Requirements
Defines precision aperture of x-ray laser
Able to choose any rectangular area inside clear aperture of fixed mask – 0.16 mm or larger
Attenuate spontaneous radiation energy 1000 times
6 micron linear resolution
Blocks align to beam axis within 47 arc-seconds
Compatible with high vacuum environment
Opens to clear aperture for diagnostics
Resistant to damage by FEL

5. Slit Block Concept
Heavy Met
Single block can cover entire aperture of Fixed Mask
70 mm thick block
50 mm Heavy Met
Tungsten Alloy
Great attenuation
20 mm Boron Carbide
Great damage resistance
Radiation
Boron Carbide

6. X-ray Slit General Specifications
Two slit block pairs – horizontal and vertical
Blocks align to each other manually, align to beam remotely
Slits open beyond clear aperture
Compatible with 1E-6 Torr
Slit Blocks
Linear Stage
Rotary Stage

7. X-ray Slit Stage Specifications
Vertical Slit
Linear motion
100 mm travel
1.3 m repeatability
8 m accuracy
Based on IDC DS4 stage
Horizontal Slit
Radial motion
3 arc-sec resolution
30 arc-sec accuracy
6 arc-sec repeatability
Based on Aerotech ART 330 stage

8. Angular Alignment Simulation
Geometrical model of light passing through slit as it is rotated
Monte Carlo simulation of light passing through slit as detected by the WFOV imager downstream.

9. Attenuation Simulation – It will work!
After Slit at Direct Imager
After Fixed Mask
In fully closed slit simulation – 10,000,000 photons to slit, 9 after slit, zero stopped in scintillator of DI

10. X-ray Slit Schedule Summary
Conceptual Design Review – 2/24/06
Preliminary Design Review – 6/13/06
Final Design Review – 8/16/06
X-ray Slit Available at SLAC – 6/5/07

11. X-ray Tunnel

12. Key Tunnel Design Requirements
Provides environment to transport x-ray laser
Average vacuum < 1 E-5 Torr
Does not obstruct FEL
Ion pumps to last 10 years
Meets SLAC Seismic Design Standard
Aligns to laser beam-line
Vertical and lateral adjustments, at a minimum

13. Typical Section of Tunnel Beamline
Bellows
Pump Stand with Gate Valve
Beam Tube, 4” OD, 10.5 foot sections
Tube Support Stand
Pump Stand w/ Ion Pump

14. Pump Stand
Stand is designed to support ion or turbo pump, a gate valve, and load from beam-line tubing
Top of stand will include features for 5 DOF adjustment (no beamline)
Defined lift points – Four threaded holes for swivel lifting eyes
Aligned using clamp-on fixture
Pump Cross
Ion Pump
Stand

15. Tube Support Stand Constrains vertical and lateral motion
5 DOF adjustment (no beamline)
Clamps to tube - beamline adjustment is not required
Aligned using clamp-on fixture
Beamline Clamp
Adjustments

16. Stress from 2” wide Tube Clamp is Acceptable
Maximum stress: psi
3600 lb. load from 2 in. clamp using ¼” bolts
Vacuum contributes 350 psi stress (included)

17. Structural Engineering Inputs
Pump spacing
Yields stand spacing of approx. 60 ft.
Sections isolated by bellows
Component weights
Ion pumps, tubing, gate valves, etc.
Accelerations due to seismic loading
From SLAC Seismic Design Specification
1.6g’s horizontal,1.35 g’s vertical - 2% damping, 17 Hz
Horizontal acceleration applied in worst case direction – beamline for pump stand, lateral for tube support

18. Output of Seismic FEA – Pump Stand
Maximum deflections:
0.000” Beamline
0.010” Lateral
0.000” Vertical
Formed bellows allow 0.25” lateral offset
Maximum stress:
18% of allowable stress in
3/4” threaded supports
Per AISC LRFD
First mode 31 Hz
Load applied in lateral and vertical directions

19. Output of Seismic FEA – Tube Support
Maximum stresses:
13% of allowable stress in Tube Supports
Per AISC LRFD
First mode 16 Hz
Maximum deflections:
0.000” Beamline
0.045” Lateral
0.012” Vertical
Load applied in lateral and vertical directions

20. Pressure Profile with 6-75 L/s Ion Pumps at 100 hrs
1.2
Peaks well
within design
at 3 x 10-6
1.0
Pressure,
10-6 Torr
9 yr life at this pump pressure
0.8
0.6
Life should
exceed
9 yrs here
0.4 50
100
150
200 Z ,
meters
For SnomimalTotal = 450 L/s, SnetTotal = 327 L/s
Theory: P=Q/S = 4.1 x10-7 Torr. The best that can be achieved.
Code: Pavg = 8.4 x10-7 Torr. So our design is efficient!

21. Pressure profile and time response with 4th pump failed
10-6 Torr 3
Pmax = 3.4 x 10-6 Torr
Pmin = 3.4 x 10-7 Torr 2
Even with one failed pump,
peak pressure is below 6x10-6
and pump pressures are safely
in the -7 range 1 50
100
150
200 Z
0.5 1 2
0.2
Pressure,
10-6 Torr
seconds 10
100
200
300
P(4th pump) goes from 3.4 x 10-7 to
3.4 x 10-6 Torr within 2 minutes
2 min

22. Vacuum model provides 100 hr history of pressure at any location
1000
10000
100000 .
100
Scroll
Pressure,
Torr 1
10-2
Turbo
10-4
Ion
10-6
10-8
Time, sec 1 31
100 hrs

23. Normal pumpdowns will be much faster than 100 hrs
600 DS would rough
in 30 min vs. 60 min
for the 300DS
t = Volume/Speed
100
Scroll
Pressure,
Torr 1
Most optimistic rate of constant
10-10 Torr-lit/sec/cm2 is assumed
10-2
Turbo
10-4
Ion
10-6
100
seconds
1000
10000 1
1.5
hrs

24. LCLS XTOD Vacuum System Controls Block Diagram
OPI
OPI
PC/Linux
PC/Linux
Ethernet
EtherNet/IP
RSLogix software
PC/Windows
1756 ENET
Ethernet Interface
Serial interface
ControlLogix
IOC
Flex I/O
1794 AENT
Tunnel
Gate Valve I/O
Gate Valves
Vacuum set points and alarms
Scroll pump control
Magnetic Starter
Scroll Pump
RS-232
Gauge Controller
Pirani , CCG
RS-232
Ion Pump Controller
Ion Pump
Vacuum Interlocks

25. X-ray Tunnel Schedule Summary
Preliminary Design Review – Complete
Seismic Safety Document – In Review
Final Design Review – 3/30/06
Equipment Available at SLAC – 7/16/07