Proposed NSLS X13B Microdiffraction Instrument
Source & Optics
James M. Ablett
National Synchrotron Light Source
NSLS 2.8 GeV X-ray Storage Ring
MGU
EPW
X13 Straight-Section
NSLS 'Hard' X-Ray Sources
Photon Energy [keV]
◊MGU
◊ IVUN
NSLS Bending Magnet
X21 / X25 Wigglers
X17 Wiggler
X13 Wiggler
1st Harmonic
2nd Harmonic
3rd Harmonic
Log
[ B
righ
tnes
s (
ph /
sec
/ mm
2 /m
rad2
/ 0.1
% B
W /
300
mA
) ]
X13 Undulator Source
The Mini-Gap Undulator [MGU] – the brightest source of hard x-rays (E ~ 3.7 keV –16 keV) at the NSLS.
MGU parameters:54 pole, 1.25 cm periodAt a gap of 3.3 mm , Magnetic field = 0.92 Tesla and Deflection Parameter, K~1.07Fundamental @ 3.7 keV, 4x1017 ph/sec/mm2/mrad2/0.1%BW/300mA
12 14 161086420
2x1017
6x1017
8x1017
Bri
ghtn
ess
(ph/
sec/
mm
2 /m
rad2 /
0.1%
BW
/300
mA
)
Calculated
Experiment
Photon Energy [keV]
4x1017
2 6 10 14 1814
15
16
17
18
Photon Energy [keV]
Log
[Bri
ghtn
ess
(ph/
sec/
mm
2 /m
rad2 /
0.1%
BW
/300
mA
)]
MGU Spectral Measurements(August 2002 Ablett,Berman)
MGU Brightness – Magnetic Gap=3.3 mm MGU Tuning Curves
Current X13B Beamline Status
monochromatorhutch
27 24 20 15 12
numbers (in meters )indicate distance from center of X13 straight-section, where MGU is located.
Specifications
• The X13B microdiffraction instrument will be modular and compactin design, which will make available a variety of x-ray optics forthe experimentalist.
•Focused X-ray Beams on the micron-length scale and below, together with low and high x-ray divergence will be available with these optics.These will be mounted on a motorized rails and will bereadily accessible.
•Pink Beam (Laue) and Monochromatic modes of operationwill be available.- Energy tunability will be accomplished through a 4 bounce monochromator.
24 272625
Distance from MGU source [meters]
detector circle
four-bounce mono tank
x-ray microfocusing optics
diffractometer
vibration isolation table
X13B Microdiffraction Instrument Layout
vibration isolation table
•Suite of Optics offered Pin Holes
Capillaries
KB Mirrors
Zone Plates
Planar Refractive Lenses (Current R&D)
Key Features:
•Achromatic - Energy independent focusing-pink beam and monochromatic modes
•Accurate Elliptical Figures Achievable (either by bending ormetal deposition ) – Small Spot Sizes
•High Reflectivity at Grazing Incidence Angles
Kirkpatrick-Baez Elliptical Mirrors
Heavy metal
Polished sphericalSilicon substrate
Vertical blade scan current derivative Horizontal blade scan current derivative
blade position [ microns ] blade position [ microns ]
~ 3 microns FWHM
~ 9 microns FWHM
…differentially-deposited elliptical KB optics have been used at X13Bduring the past few years, designed primarily for high-pressure x-ray spectroscopy.
X13B Microprobe
X13B Microprobe
3.7 mm
3.3
mm
1.
2.
3.
1.
3.
2.
Calcium K Fluorescence Mapping of Osteoarthritic Bone
3cm 10 cm
2cm
25 m to MGU source
focal position
incident x-rays
Preliminary KB layout
Expected Parameters1 micro-radian figure error
Spot size – 0.7 x 2 micron2
Divergence – 1mrad (v) x 7 mrad(h)
8 keV, 6x109 ph/secGain 5x104
With Figure Error (1 micro-radian)
Position [mm]In
tens
ity
[arb
. Uni
t]
X13B Microprobe R&D Efforts-Planar Refractive Lenses
(K. Evans-Lutterodt, J.M. Ablett)
Summary
A state-of-the-art hard x-ray microdiffraction instrumentis proposed for NSLS mini-gap undulator beamline X13B.
It will offer a variety of x-ray microfocusing optics –micron scale spatial resolution and below
& high and low divergence.
Big-beam (unfocused ) mode.
Pink Beam and Monochromatic Modes of Operation.
Simultaneous fluorescence and diffraction information.