Transcript XCS: Mono Location, Mono Crystals, Hutch Optics Layout

SLAC National Accelerator Laboratory
X-ray Correlation
Spectroscopy
Instrument
Aymeric Robert – XCS Instrument Scientist
LCLS Facilities Advisory Committee Meeting
November 12, 2008
Team Leaders : Brian Stephenson
Gerhard Grübel
Karl Ludwig
Lead Engineer: Eric Bong
11/12/2008
XCS Instrument
1
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
X-ray Photon Correlation Spectroscopy
Coherent X-rays
Coherent
Scattering
(Speckles)
Speckles : scattering patterns
produced by the coherent
illumination of the sample
XPCS : observation of the timefluctuation of speckle patterns
Characterization of the underlying
dynamics of the system
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XCS Instrument
2
XPCS is independent of the scattering
geometry (SAXS, Diff., GI-SAXS,
Refl.,…)
XPCS probes dynamical phenomena
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Photon Shutter
Primary Slits
Diagnostics
Monochromator
Transport Tunnel
Secondary Slits
Diagnostics
Split and Delay
Secondary Slits
Diagnostics
Focusing Lenses
Photon Shutter
Attenuators
Pulse Picker
FEH Hutch 4
Harm. Rej. Mirrors
Defining Slits
Diagnostics
Diffractometer
Large Angle
Detector Stage
Goal
Time-resolved observation of coherent diffraction
patterns using LCLS coherent hard x-rays (6-25keV)
Tailor and characterize X-ray beam parameters
Spatial profile
Intensity
Repetition Rate
Spectral Bandwidth
X-ray Photon Correlation Spectroscopy
Requirements
Versatility of the instrumentation (SAXS, WAXS, GI)
Coherence preservation of x-ray optics (to the extent possible)
Detector with small pixel size/Large sample-detector
distance
Key Performance Parameters
6-20 keV energy range
Using the fundamental and third harmonic
0.1-0.01% energy resolution
11/12/2008
XCS Instrument
3
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Photon Shutter
Primary Slits
Diagnostics
Monochromator
Transport Tunnel
Secondary Slits
Diagnostics
Split and Delay
Secondary Slits
Diagnostics
Large Angle Detector Mover
& Diffractometer
•Sample/detector distance 7-8m
•Decoupled from diffractometer
•SAXS, WAXS, GI
• 2θ up to 55º, vertical tilt
•Height adj.
Focusing Lenses
Photon Shutter
Attenuators
Pulse Picker
FEH Hutch 4
Harm. Rej. Mirrors
Defining Slits
Diagnostics
Diffractometer
Large Angle
Detector Stage
11/12/2008
XCS Instrument
4
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Previous FAC Reports
FAC Report Oct 2007
The committee recommends that the XCS staff retain
flexibility in their designs to facilitate change as
opportunities and problems are discovered.
FAC Report Jun 2008
“ … the committee endorses the decisions that have
been made to date.”
“ The large offset monochromator also requires design
attention and carries risk. This has been recognized by
the project and appropriate efforts are being made to
create a solid design”
11/12/2008
XCS Instrument
5
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Photon Shutter
Primary Slits
Diagnostics
Monochromator
Transport Tunnel
Secondary Slits
Diagnostics
Split and Delay
Secondary Slits
Diagnostics
Focusing Lenses
Monochromatization
scheme for XCS
Photon Shutter
Attenuators
Pulse Picker
FEH Hutch 4
Harm. Rej. Mirrors
Defining Slits
Diagnostics
Diffractometer
Large Angle
Detector Stage
11/12/2008
XCS Instrument
6
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Photon Shutter
Primary Slits
Diagnostics
Monochromator
Transport Tunnel
Secondary Slits
Diagnostics
Motivations
•XCS Science (i.e Early Science)
•XCS Science NEEDS a monochromator
•Satisfaction of the XCS User Community
Split and Delay
Secondary Slits
Diagnostics
First Coherence Workshop
Application of Coherent X-rays at the LCLS
10/17/2008
Focusing Lenses
Photon Shutter
Attenuators
Pulse Picker
FEH Hutch 4
Harm. Rej. Mirrors
Defining Slits
Diagnostics
Diffractometer
Large Angle
Detector Stage
11/12/2008
XCS Instrument
7
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Original Plan for XCS
Near Experimental Hall
Transport Tunnel
X-ray Transport Tunnel
(200m long)
XCS
FEH Hutch 4
Source to Sample distance : ~ 420 m
Far Experimental Hall
X-ray
Correlation
Spectroscopy
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XCS Instrument
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Coherent
X-ray
Imaging
High
Energy
Density
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Original Plan for XCS Monochromator
Transport Tunnel
Total Budgeted cost:
1.2M$
Delivery date :
2012
Associated XRT cost :
~0.8M$
Double crystal Large Offset Monochromator
FEH Hutch 4
•Energy Range : 6-25keV
•Offset : 600mm
•Design similar to XPP
•Location at the entrance of the XRT (200m)
•Possibility of changing the crystal
•Preserve “future” capability of multiplexing (i.e. thin crystals
11/12/2008
XCS Instrument
9
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
New Plan for XCS Monochromator
Transport Tunnel
Total Budgeted cost:
Delivery date :
1.2M$
Associated XRT cost :
~0.8M$
2012
BUT
Double crystal Large Offset Monochromator
FEH Hutch 4
•Energy Range : 6-25keV
•Offset : 600mm
•Design similar to XPP
•Location at the entrance of the XRT (200m)
~35m
•Possibility of changing the crystal
•Preserve “future” capability of multiplexing (i.e. thin crystals
11/12/2008
XCS Instrument
10
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Plan for XCS Monochromator
Release LO-DCM distance from XCS
Transport Tunnel
Advantages
Disadvantages
Relax design parameters for
stability
No change in delivery date (2011)
Identical performances
More but moderate interferences
with ME2 operation
Save the XRT transport cost
(0.8M$)
Still not acceptable by XCS User
Community
FEH Hutch 4
All XCS optical components
located on the same concrete
slab ( gain in stability)
How to satisfy the request for early science
from the XCS User Community and provide
early science capabilities ?
11/12/2008
XCS Instrument
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Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Plan for XCS MonochromatorS
Transport Tunnel
• Use part of the saving from the XRT transport cost to
purchase a commercially available High Resolution Double
Crystal Monochromator ( pseudo channel cut in vertical
scattering geometry )* with small “almost” fixed exit allowing
the use of multiple standard reflections and covering easily the
LCLS hard x-ray range 6-25keV
•Ease polishing of each monochromator crystal
FEH Hutch 4
• This can be purchased early (very early)
* For LCLS hard x-ray beam, there is no heat load issue. The major issue of that type of
monochromator is known to be the cooling system which in our case is irrelevant
11/12/2008
XCS Instrument
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Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Plan for XCS Monochromator
Impact on XCS instrument design :almost NONE
Transport Tunnel
•Operation for some time with just the HR-DCM
•Operation of XCS in CXI line (LCLS main line)
FEH Hutch 4
•The table supports for optics/diagnostics are identical to XPP
instrument and allow that operation with a 600mm offset
•The diffractometer can be placed in either line (CXI/XCS)
•The Large Angle detector mover can have its center of
rotation on both the CXI and XCS line
Provide earlier science capability for the XCS Instrument
Which other benefits ?
11/12/2008
XCS Instrument
13
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
XPP
Monochromator for LCLS Instruments : Phase I
Provide the High Resolution Double Crystal
Monochromator to the XPP Instrument
•Provide the first early LCLS monochromatic beam
•Test the monochromator
X
XCS
CXI
•Provide temporarily monochromatic beam to XPP
11/12/2008
XCS Instrument
•Gives XPP more time to get their own monochromator
•Allow EARLY Coherent Scattering experiments in the XPP
experimental hutch with control of the longitudinal coherence
length (CXI/XCS)
14
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Monochromator for LCLS Instruments : Phase II
Provide the High Resolution DCM to hard Xray Coherence Instruments XCS or CXI
•Provide the first early LCLS monochromatic beam in FEH
•Test the monochromator close to FEH location (far from source
and close to definite monochromator location)
XCS
CXI
•Provide temporarily monochromatic beam to CXI
•Allows early commissioning of XCS Instrument
•Evaluation of the impact of very hard coherent x-rays on XCS
Science Program
•Allow EARLY Static and Dynamic Coherent Scattering Science in
the CXI or XCS experimental hutches with control of the
longitudinal coherence length
11/12/2008
XCS Instrument
15
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Monochromator for LCLS Instruments : Phase III
Return High Resolution DCM to XCS
•Use of HR-DCM as Post Monochromator for experiments
requiring very large longitudinal coherence lengths
XCS
CXI
•Allow to relax the parameters of the LO-DCM to use a single type
of crystal (Si (220) for example) as post monochromatization can
be achieved with the HR-DCM
•The compensation in terms of lower ΔE/E as compared to Si (111)
could be obtained with proper focusing optics (i.e CRL’s)
•If multiplexing : a single and identical crystal in CXI beam (i.e easy
to correct if necessary)
11/12/2008
XCS Instrument
16
Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Monochromator for LCLS Instruments
XCS Team Leader Meeting Oct 19, 2008
Move the large-offset and split/delay from about 200m upstream of experiment to about
40m upstream of experiment
• We therefore endorse moving the large-offset monochromator to the new location.
Adding post-monochromator to scope
• Such a double-crystal monochromator is commercially available, and could be procured
immediately for initial use in providing monochromatic beam to all of the early hard x-ray
experiments. This will be extremely important for the scientific program. In particular, this will
allow the early commissioning of the XCS experiments with the required monochromatic beam
prior to the availability of the large-offset monochromator. All of the other XCS beamline
components are compatible with operation in the in-line configuration without the large-offset
monochromator.
• We therefore endorse the concept of adding to the scope a double-crystal, small-vertical-offset
monochromator with either multiple or easily changeable crystals.
The CXI team was involved in the discussion and supports the proposed plan
11/12/2008
XCS Instrument
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Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Summary
The cost of the post monochromator (2) should be significantly less than
the cost savings associated with moving the location of the large offset
monochromator downstream (1). Thus the net result of these changes
will be to improve performance, improve capability, and making
monochromatic x-ray beam available earlier to all experiments, while
decreasing cost.*
* XCS Team Leader Meeting Summary Oct 2008
•Early Science for XCS, CXI, XPP
•No increase of cost ( i.e even slight cost saving)
•XCS instrument commissioned early (with HR-DCM)
•Satisfies the expectation of the XCS User Community
•Serve the Science Mission of the 3 LCLS hard x-ray instruments
11/12/2008
XCS Instrument
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Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Additional Slides
XCS Science
11/12/2008
XCS Instrument
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Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Sequential XCS
Intensity autocorrelation function
Dt
Dt
Dt
Dt
Dt
Dt
4
3
2
1
1
2
3
Time-average Brilliance
4
10 ms < tC < hrs
Large Q’s accessible
11/12/2008
XCS Instrument
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Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Ultrafast XCS : Split & Delay
Peak Brilliance & Pulse Duration
pulse duration < tC< several ns
Large Q’s accessible
11/12/2008
XCS Instrument
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Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
XCS Science @ LCLS
LCLS Parameters
Full Transverse Coherence
Ultra Fast Mode
8 and 24 keV
High Time–average Brilliance
Rep. Rate 120 Hz
Sequential Mode
High Peak Brilliance
Short pulse duration 230fs
Dedicated 2D-Detector
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XCS Instrument
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Aymeric Robert
[email protected]
SLAC National Accelerator Laboratory
Multi-crystal XCS Monochromator
Crystal
11/12/2008
XCS Instrument
Dl/l
Scattering Angles
(2θ)
Coherence
Length ξL [μm]
1.5 Å
0.5 Å
1.5 Å
0.5 Å
Si(111)
1.4x10-4
27.6
9.1
1
0.3
Si(220)
6.1x10-5
45.8
14.9
2.45
0.8
C*(111)
5.9x10-5
42.5
13.9
2.54
0.9
C*(220)
2.3x10-5
--
22.8
6.5
2.2
23
Aymeric Robert
[email protected]