P473 – Precision Slits LOREA ALBA CELLS
Application
Exit slit unit for soft X-ray synchrotron radiation
Year of delivery
2019
Installation site
LOREA beamline at ALBA of CELLS, Spain
Design Features
-
Double slit mechanism – vertically and horizontally defining slits (VDS, HDS) mechanisms accommodated into separate vacuum vessels.
-
Motorized and encoded slits opening, symmetric opening, non-linear opening characteristics.
- OFHC slit blades.
- Electrical isolation of horizontally defining slit blades.
- Motorized and encoded translation of the horizontally defining slit transversal to the beam axis.
- Manual rotation of the vertically defining slit mechanism around the beam axis.
- Motorized and encoded translation of the vertically defining slit chamber vertically and along beam axis.
- Gold mesh behind vertically defining slit.
- Isolated bias plate.
- Adjustable support structure.
Performance Features
- Precision and slit opening repeatability smaller than 10 nm.
- Parallelism smaller than 1 µm over 10 mm edge length.
- Straightness smaller than 0.15 µm over 10 mm edgle length.
- Very small deviation (submicrometer) of the slit opening calibration curve from the theoretical non-linear slit opening function.
Outer Dimensions
Technical specifications and performance values
General
Vacuum chamber
(separate chambers
for HDS and VDS)
Chamber type
cylindrical, horizontal axis
Main flanges
DN160CF cluster flanges
Material
1.4301
Base pressure
10-10 mbar range
Translation along beam axis
(VDS chamber)
Range
± 200 mm
Resolution (design value)
0.025 µm /motor fine step
(1/32, recommended)
0.05 µm /encoder count
Resolution (measured value)
2 µm
Linearity
2.42 µm
Hysteresis
12 µm
Repeatability
0.90 µm
Parasitic roll
(rotation about beam axis)
20 µrad
Parasitic pitch
40 µrad
Vertical translation
(VDS chamber)
Range
5 mm
Resolution (design value)
0.025 µm /motor fine step
(1/16, recommended)
0.003 µm /motor step
(at wedge leveler)
0.05 µm /encoder count
Resolution (measured value)
2 µm
Linearity
1.58 µm
Hysteresis
4 µm
Repeatability
0.50 µm
Parasitic roll
(rotation about beam axis)
20 µrad
Parasitic pitch
90 µrad
Horizontally defining slit (HDS)
Slit blades
Material
OFHC
Straightness
< 0.10 µm over 10 mm (1σ)
Parallelism
-0.07 µm /mm
(20 µm slit opening)
-0.06 µm /mm
(50 µm slit opening)
-0.09 µm /mm
(100 µm slit opening)
Slit opening
Range
4.5 µm to 7 mm
Repeatability
± 0.006 µm at 10 µm slit opening
± 0.009 µm at 45 µm slit opening
± 0.020 µm at 100 µm slit opening
Long-term stability (> 2 h)
0.012 µm
Resolution (design value)
0.006 µm /motor fine step
(1/16, recommended)
0.05 µm /encoder count
Slit translation
Range
-5.23 µm to 5.11 mm
Linearity
0.16 µm
Hysteresis
0.90 µm
Long-term stability (> 8 h)
0.20 µm
Resolution (design value)
0.006 µm /motor fine step
(1/16, recommended)
0.05 µm /encoder count
Vertically defining slit (VDS)
Slit blades
Material
OFHC
Straightness
< 0.15 µm over 10 mm (1σ)
Parallelism
-0.04 µm /mm
(20 µm slit opening)
-0.06 µm /mm
(50 µm slit opening)
-0.06 µm /mm
(100 µm slit opening)
Slit opening
Range
2 µm to 7 mm
Repeatability
± 0.009 µm at 10 µm slit opening
± 0.003 µm at 45 µm slit opening
± 0.003 µm at 100 µm slit opening
Long-term stability (> 2 h)
0.006 µm
Resolution (design value)
0.006 µm /motor fine step
(1/16, recommended)
0.05 µm /count
Slit rotation
Range
-0.5 µm to 0.5 mm
Actuator
manual rotary feedthrough
Resolution (design value)
0.153° /turn
Performance Test Results
Slit unit horizontal translation linearity
Slit unit horizontal translation hysteresis
Slit unit horizontal translation
repeatability
Slit unit horizontal translation
positioning resolution
Slit unit vertical translation linearity
Slit unit translation (XSTV) hysteresis
Slit unit vertical translation
repeatability
Slit unit vertical translation
positioning resolution
Slit opening calibration (HDS)
Slit opening repeatability (HDS)
Slit opening repeatability (HDS)
Slit opening repeatability (HDS)
Slit opening repeatability (HDS)
Slit blades parallelism (HDS)
Slit blades parallelism (HDS)
Slit blades parallelism (HDS)
Slit opening long-term stability (HDS)
Slit translation linearity (HDS)
Slit translation hysteresis (HDS)
Slit translation stability (HDS)
Slit opening calibration (VDS)
Slit opening repeatability (VDS)
Slit opening repeatability (VDS)
Slit opening repeatability (VDS)
Slit opening repeatability (VDS)
Slit blades parallelism (VDS)
Slit blades parallelism (VDS)
Slit blades parallelism (VDS)
Slit opening long-term stability (VDS)
Residual gas analysis
