1 BROOKHAVEN SCIENCE ASSOCIATES National Synchrotron Light Source II Damping Wiggler Beamline: XAS Preliminary Design Summary Paul Northrup January 16th,

1 BROOKHAVEN SCIENCE ASSOCIATES

National Synchrotron Light Source II

Damping Wiggler Beamline: XAS Preliminary Design Summary

Paul NorthrupJanuary 16th, 2008


Overall Mission• To provide a versatile and highly productive facility for

hard X-ray Absorption Spectroscopy for a wide range of scientific disciplines: • Catalysis and energy science• Environmental science and low-temperature geochemistry• Life science and biology• Nanomaterials and condensed matter research• Earth and high pressure science

• To pursue and apply cutting-edge XAS capabilities and techniques appropriate to the advanced quality of the NSLS-II source


Preliminary Design• Careful consideration of:

• Community input • User and scientific needs and new opportunities• Technical feasibility• Overall mission of NSLS-II

• Through: • Workshops -- local and national• Beamlines’ staff and representatives of scientific communities• NSLS UEC• White papers

• Technical, EFAC, and DOE reviews


Beamline Requirements, Specifications

• Source requirements: • Broad spectrum, high flux, non-coherent source• Source stability (running in top-off mode):

– position within 10% of source size, – vertical angle within 1 rad (for monochromatic energy stability)

• Specifications: • Energy range: ~5.5-50 keV, provisions to use up to 90 keV• Tunable spot size from 0.2 x 0.2 mm to 5 x 55 mm• Microbeam (1 x 1 micron) available• Standard (10-4) and high (10-5) energy resolution modes available• Controlled sample environment (air-sensitive or hazardous samples)• Beamline stability scan-to-scan: position on sample within 5 microns,

energy calibration within 0.05 eV


Beamline Design -- Overview

Top view:

Side view:

First Optic Enclosure (FOE) containing beamline optics and white-beam components

Bulk XAS (with three sample positions)

Shield wall

2 Experimental Hutches in line

Microbeam XAS Beam

12


Insertion Device

• Damping Wiggler, length 3.5 meters, in high-beta straight section

• Future upgrade: two canted 3.5m wigglers independently serving microbeam and bulk endstations


Damping Wiggler Characteristics

Flux: Brightness:

Highest hard X-ray flux at Highest brightness of broad- NSLS-II spectrum sources


Damping Wiggler Heat Load (3.5m)

• Wiggler output 32 kW, 4 kW reaches beamline at max acceptance of 0.15 mrad (v) x 1.0 mrad (h) defined by optics

• Challenging to maintain broad energy range, stability• “Divide and conquer” approach (absorbs:)

• front end mask 25 kW• white-beam apertures 3-7 kW (pass up to 4 kW)• filters and attenuators 1-2.5 kW• white-beam mirror 0-2.5 kW• monochromator first crystal 100-700 W• monochromator second crystal (scatter)

• Preliminary thermal analyses show that this can be done• Heat load on sample may be significant (>20 mW)


White Beam Components

• Retractable attenuators, sequentially added for higher energy experiments (water-cooled, carbon)

• White-beam mirror • 1.5 meter, Si (or GlidCop) substrate, water-cooled• Two “stripes” (bare Si and Pt-coated) available• Three positions: 2.0 or 3.15 mrad, or removed from beam

– Thus 5 configurations to cover required energy range• Vertical collimation and harmonic rejection

Beam


White Beam Components

• High Heatload Monochromator: • LN2 cooled first and second crystals• Side-by-side sets: Si(111) and Si(311) [or Si(333) instead]

Beam


Beamline Optics

• High energy resolution (10-5 or better) monochromator• In series with high-heatload monochromator • Passes beam when not in use• No LN2 cooling required, high precision mechanism• Several crystal types being considered (less restrictions on

material)• Synchronization with primary monochromator is required

Beam


Beam Conditioning Optics

Focusing mirror (~2:1) • Two toroidal “stripes” match Mirror 1• Reflects in opposite sense to Mirror 1• Initial ray tracing calculations:

spot size 0.2 x 0.2 mm at sample

Beam


Endstation 2: Bulk XAS

• Acceptance up to 0.15 x 1.0 mrad

• Spot size ~0.2x0.2 mm up to 5x55 mm

• Continuous-scan or step-scan modes of data collection• Time-resolved (minutes)

studies• 3 sample positions



Sample position 1: Classic benchtop XAS

• Transmission, fluorescence and grazing-incidence

geometries• In-situ measurements:

electrochemical cells, gas and solution flow-through cells

• Heater, cryostat and LN2 cooling• Standard and high-resolution

(energy selective) detectors• Detector for powder XRD pattern



2: Controlled environment XAS• Multi-use enclosure:

• Glove box: controlled atmosphere• Containment/fume hood for

hazardous samples• Multi-element detector • Low-concentration samples • Hazardous, nano, or radioactive

materials



3: Space for move-in apparatus• Large-volume high-pressure

or catalytic cells• High-field magnet• Available control and

data channels, utilities, etc.• ~2 x 3 m


Endstation 1: Microbeam XAS

• Conventional K-B mirror optics• Focused spot ~1 micron• Microbeam and single-crystal XAS• Diamond anvil cell high-P XAS• Multi-use enclosure• Multi-element detector • XRD detector shared with Endstation 2


1.E+10

1.E+11

1.E+12

1.E+13

1.E+14

1.E+15

0 10000 20000 30000 40000 50000

Estimated flux (delivered to sample at monochromator bandpass) 5.5 keV


Estimated Flux: High Energy Resolution

1.E+10

1.E+11

1.E+12

1.E+13

1.E+14

0 10000 20000 30000 40000


Summary: Initial Project Scope• Two endstations included, one control station• Single source and one set of optics serving both

endstations• Endstation 2 hutch can be accessed for set-up while

Endstation 1 is in use; but not vice versa• Accommodations (space, component design) made for

future canting of source• Heatload R&D

12


Potential Upgrade/Build-out Path

• Add second canted wiggler source and beamline optics to provide independent beam for each endstation

• Addition of mirror in front end to divert low-energy portion of overlapped fans into a third station for high-flux bulk 2-6 keV applications

• Complementary bulk/micro XAS beamline at adjacent dipole for 1-5 keV applications

• Net potential: core cluster of XAS endstations covering 1-90 keV energy range, bulk and microbeam capability

12 3


Lower Energy (2-6 keV) Side Station

1.E+10

1.E+11

1.E+12

1.E+13

1.E+14

1.E+15

0 10000 20000 30000

Documents

1 BROOKHAVEN SCIENCE ASSOCIATES National Synchrotron Light Source II Damping Wiggler Beamline: XAS Preliminary Design Summary Paul Northrup January 16th,