john trent [email protected] april 20, 2006 ucrl-pres-218897 fac: xtod beam transport x-ray slit and...
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John Trent
April 20, 2006 UCRL-PRES-218897
FAC: 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
April 20, 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.
John Trent
April 20, 2006 UCRL-PRES-218897
Front End Enclosure (FEE) Configuration
Fast Valve
X-ray Slit
Ion Chamber
Attenuator
Fixed Mask
Diagnostics
Offset Mirrors
John Trent
April 20, 2006 UCRL-PRES-218897
X-ray Slit Key Requirements
Defines precision aperture of x-ray laserAble to choose any rectangular area inside clear aperture of fixed mask (45 x 15 mm)
Attenuate spontaneous radiation energy 1000 times
Compatible with high vacuum environment
Opens to clear aperture for diagnostics
Resistant to damage by FEL
John Trent
April 20, 2006 UCRL-PRES-218897
X-ray Slits Concept
Fixed Mask ApertureSlit Block
John Trent
April 20, 2006 UCRL-PRES-218897
Slit Block Concept
Single block larger than entire aperture of Fixed Mask
70 mm thick block50 mm Heavy Met
Tungsten Alloy
Great attenuation
20 mm Boron CarbideGreat damage resistance
Boron Carbide
Heavy Met
Radiation
Cutting Face
John Trent
April 20, 2006 UCRL-PRES-218897
X-ray Slit Concept
Vertical Slit
Horizontal Slit
Stand
Linear Stage
Size (in):
28.62 long (Z)
54.45 wide
81.22 high
John Trent
April 20, 2006 UCRL-PRES-218897
Slit Block Support and Cooling
Slit block can be water cooled or air cooledSix DOF adjustment for each slit block: 3 struts, 3 push-pull screw pairsBellows isolate block assemblies from vacuum vesselDesign features borrowed from SSRL
Slit Block
Bellows Strut
Water Cooling
John Trent
April 20, 2006 UCRL-PRES-218897
X-ray Slits Features
Slits close to zero aperture, open beyond clear aperture of fixed mask
Slits allow extremely little radiation past that will stop in scintillator
Blocks align to beam direction manually
Negative rake on slit blocks (~3 mrad)Set using alignment features external to vacuum
Blocks are offset in Z – they can’t touch
Compatible with UHV
John Trent
April 20, 2006 UCRL-PRES-218897
Slit Pair Remote Motions
Each slit block pair has adjustable degree of freedom
Aperture width – linear stage adjustment
Aperture center – linear stage adjustment
Linear motion specs based on IDC DS4 stage:
50 or 100 mm travel, 1.3 m repeatability
200 lb axial load capacity – 100 lb axial load
John Trent
April 20, 2006 UCRL-PRES-218897
Slit Block Assembly Thermal Model – Water Cooling
Heat in: internally generated 1 W input from spontaneous radiationConduct heat through block, interface, and end of Glidcop support rodHeat out: remove by forced convection with waterSteady state model
Qin
Qcond
Qconv
Qout
John Trent
April 20, 2006 UCRL-PRES-218897
Thermal Model Results – Water Cooling
Slit block is 1.2 C hotter than cooling water
Rod in contact with water is 0.1 C hotter than cooling water
Total expansion is 0.6 micron due to heating from radiation
Slit block expands 0.5 micron
Support rod expands 0.1 micron
John Trent
April 20, 2006 UCRL-PRES-218897
Thermal Model Results – Air Cooling
Slit block is 6 C hotter than ambient
Rod in contact with air is 5 C hotter than ambient air
Total expansion is 4 micron due to heating from radiation
Slit block expands 1.4 micron
Support rod end expands 2.5 micron
John Trent
April 20, 2006 UCRL-PRES-218897
Stability
Stability is based on temperature variationRoom temperature effects stand
Incident power effects slit block assembly
PRD gives diurnal room temperature variation of +/- 1 C
1.4 m tall steel stand moves 16.4 microns
Incident power adds 0.3 m for water cooling or 2 m for forced air cooling (plus/minus)
John Trent
April 20, 2006 UCRL-PRES-218897
Predicted Stability and Repeatability
Predicted Long-termStability: 17 m (Water), 18.5 m (Air)
Repeatability: 18 m (Water), 19.5 m (Air)
Predicted Short-termStability: 2 m (Water), 3.6 m (Air)
Repeatability: 3.3 m (Water), 4.9 m (Air)
Recommend forced air cooling for simplicity
John Trent
April 20, 2006 UCRL-PRES-218897
Vacuum
Ion pump under fixed mask – pumps Fast Valve, Fixed Mask, and X-ray Slit
Single pump is more efficient design
Good conductance 2.7m long section
4 in tube or larger
Gate ValveX-ray SlitFixed
MaskFast
Valve
Ion Pump
John Trent
April 20, 2006 UCRL-PRES-218897
Slit Block First Article
The is some risk is in the manufacture of the slit blocks themselves
Bonding of Boron Carbide to Heavy MetTime to produce and yield
Step 1: Use bonding coupons to prove bonding process – coupons are on orderStep 2: Make slit block pair this FY to lessen risk and shorten production timeFirst article to be used in final assembly
John Trent
April 20, 2006 UCRL-PRES-218897
Attenuation Simulation – It will work!
After Fixed Mask After Slit at Direct Imager
With slit closed, nothing stops in scintillator plate – full distributionIn fully closed slit simulation – 100,000,000 high energy (1.2 MeV+) photons to slit, 17,260 after slit, zero stopped in scintillator of DI
John Trent
April 20, 2006 UCRL-PRES-218897
X-ray Slit Schedule Summary
System Concept Review 1 – 3/1/06
System Concept Review 2 – April ‘06
Preliminary Design Review – July ‘06
Final Design Review – September ‘06
X-ray Slit Available at SLAC – June ‘07
John Trent
April 20, 2006 UCRL-PRES-218897
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-lineVertical and lateral adjustments, at a minimum
John Trent
April 20, 2006 UCRL-PRES-218897
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
Bellows
John Trent
April 20, 2006 UCRL-PRES-218897
Pump Stand
Stand is designed to support ion or turbo pump, a gate valve, and load from beam-line tubingTop of stand will include features for 5 DOF adjustment (no beamline)Defined lift points – Four threaded holes for swivel lifting eyesAligned using clamp-on fixture
Ion Pump
Pump Cross
Stand
John Trent
April 20, 2006 UCRL-PRES-218897
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
Adjustments
Beamline Clamp
John Trent
April 20, 2006 UCRL-PRES-218897
Stress from 2” wide Tube Clamp is Acceptable
Maximum stress: 11200 psi
3600 lb. load from 2 in. clamp using ¼” bolts
Vacuum contributes 350 psi stress (included)
John Trent
April 20, 2006 UCRL-PRES-218897
Structural Engineering Inputs
Pump spacingYields stand spacing of approx. 60 ft.
Sections isolated by bellowsComponent weights
Ion pumps, tubing, gate valves, etc.
Accelerations due to seismic loadingFrom SLAC Seismic Design Specification1.6g’s horizontal,1.35 g’s vertical - 2% damping, 17 HzHorizontal acceleration applied in worst case direction – beamline for pump stand, lateral for tube support
John Trent
April 20, 2006 UCRL-PRES-218897
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
John Trent
April 20, 2006 UCRL-PRES-218897
Output of Seismic FEA – Tube Support
Maximum deflections:
0.000” Beamline
0.045” Lateral
0.012” Vertical
Load applied in lateral and vertical directions
Maximum stresses:
13% of allowable stress in Tube Supports
Per AISC LRFD
First mode 16 Hz
John Trent
April 20, 2006 UCRL-PRES-218897
50 100 150 200Z, meters
0.8
1.0
1.2
0.6
0.4
Pressure,10-6 Torr
Pressure Profile with 6-75 L/s Ion Pumps at 100 hrs
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!
Peaks wellwithin designat 3 x 10-6
Life shouldexceed9 yrs here
9 yr life at this pump pressure
John Trent
April 20, 2006 UCRL-PRES-218897
Pressure profile and time response with 4th pump failed
Pmax = 3.4 x 10-6 Torr
Pmin = 3.4 x 10-7 Torr
P(4th pump) goes from 3.4 x 10-7 to
3.4 x 10-6 Torr within 2 minutes
Pressure,10-6 Torr
1
2
3
0.5
1
2
0.2
Pressure,10-6 Torr
seconds0 10 100 200 300
2 min
Even with one failed pump,peak pressure is below 6x10-6
and pump pressures are safelyin the -7 range
50 100 150 200Z
John Trent
April 20, 2006 UCRL-PRES-218897
100 1000 10000 100000
.
Vacuum model provides 100 hr historyof pressure at any location
100 hrs311
Scroll
Turbo
Ion
Pressure,Torr
Time, sec
100
1
10-2
10-4
10-6
10-8
John Trent
April 20, 2006 UCRL-PRES-218897
Scroll
Turbo
Ion
100 1000 10000secondshrs1.51
Normal pumpdowns will be much faster than 100 hrs
Most optimistic rate of constant10-10 Torr-lit/sec/cm2 is assumed
Pressure,Torr
100
10-2
10-4
10-6
1
600 DS would roughin 30 min vs. 60 min for the 300DS = Volume/Speed
John Trent
April 20, 2006 UCRL-PRES-218897
Ethernet
IOC
Gauge Controller
Ion Pump Controller
Vacuum set points and alarms
TunnelGate Valves
Ion Pump
Pirani , CCG
Gate Valve I/O
Eth
erne
t Int
erfa
ce
17
56 E
NE
T
17
94 A
EN
TFlex I/O
EtherNet/IP
Scroll PumpScroll pump control
Vacuum Interlocks
Ser
ial i
nter
face
OPIPC/Linux
Co
ntr
ol L
og
ix
RS-232
RS-232
Magnetic Starter
LCLS XTOD Vacuum System Controls Block Diagram
PC/WindowsRSLogix software
OPIPC/Linux
John Trent
April 20, 2006 UCRL-PRES-218897
X-ray Tunnel Schedule Summary
Preliminary Design Review – Complete
Seismic Safety Document – In Review
Final Design Review – May ‘06
Equipment Available at SLAC – July ‘07