ESCA
Sources
X-ray Source Series
LAX
Dual-anode X-ray Source
High Intensity XPS Measurements
Differential Pumping Option
Cooled Nose Cone
MECS
Monochromated X-ray Source
High Energy Resolution XPS
High Power & Focused Spot Mode
Low Radiation Impact
LAX and MECS X-ray Sources
The SIGMA LAX and MECS X-ray sources are used in Electron Spectroscopy for Chemical Analysis (ESCA), also called X-ray
Photoelectron Spectroscopy (XPS), for exciting photoelectrons from the atoms of the sample surface to be analysed.
Both excitation sources are designed for ease of use and can be easily integrated into the SIGMA NEO control suite, to give
high-performance and enable high-quality XPS measurements.
LAX
The LAX X-ray source is a high power dual-anode excitation
source for high intensity XPS measurements and large
area illumination of samples for imaging XPS applications.
Two main excitation energies can be selected using two
different anode coating materials. Typically, the dualanode operates at 400W when coated with Magnesium
(Mg Ka 1253.6eV) and Aluminium (Al Kα 1486.7eV), a
variety of materials including Zirconium, Silver, Titanium
and more are available on request.
An easy to replace thin foil Aluminium window separates
the X-ray generating part of the source from the sample
area and reduces Bremsstrahlung. If XPS measurements
are performed under elevated pressure in the analysis
chamber the LAX may be pumped differentially so that
the high voltage anode is maintained at a low vacuum
pressure.
LAX dual-anode X-ray source
The LAX source incorporates a water cooled nose cone
and high thermal conductivity of the anode for efficient
heat dissipation even at high power to minimise sample
heating without requiring additional sample cooling.
MECS
The MECS high power monochromated excitation source
is designed for high energy resolution XPS measurements,
especially when radiation and temperature sensitive
materials are analysed.
The monochromator utilises a quartz crystal mirror
for the Bragg reflection and focusing of Al Kα radiation
on a Rowland circle with 500mm diameter. This way,
Bremsstrahlung radiation and satellite photon lines are
eliminated and do not contribute to the photoelectron
spectra.
The lower X-ray flux and thermal radiation from the
heated filaments and anode ensure a reduced sample
damage compared with a dual-anode X-ray source.
MECS monochromated X-ray source
Designed for Easy Integration and High Power Performance
By selecting the filament you can switch the operation
between two modes, high power 600W and focused spot
for ~Ø1mm illumination at the sample.
MECS
monochromated
X-ray source
The monochromator housing is fully bakeable, it mounts
onto a DN63CF (4.5" CF) chamber flange with a port
length of 203mm and will mount to a chamber diameter
of 310mm.
The crystal mirror can be adjusted by two orthogonal
tilts and one linear motion which makes it both rapid and
simple to fine tune the monochromator for reproducible
and maximum performance. The focusing mechanism
is located on the top flange thereby the MECS retains a
compact volume enabling it to be mounted to a range
of XPS platforms. The latest generation is also available
with SIGMA PULSE system on request.
For more information on the PULSE system please see
relevant technical information available.
The PULSE system for Dynamic XPS with the MECS monochromated
X-ray source compactly integrated.
Instrument Control
The operation of the X-ray sources is user friendly. The
supply electronics X-Ray CU is based on a standard 19" rack
unit. Both the LAX and MECS can be operated individually
or in tandem via dedicated electronics. The shared control
saves both space and money for the operator, and a
single digital interface provides safe control of the anode
cooling with a dedicated recirculating water chiller.
Accurate control of both LAX and MECS is a feature of the
cutting-edge NEO control suite either as a stand-alone
instrument or as part of an automated experimental
suite. When operated in combination with the SIGMA
ASPECT analyser the NEO control suite opens up a wide
range of high-performance XPS analysis modes, including
the unique multi-peak monitoring capability, without the
need for user interaction.
User interface in NEO for the X-ray source
The NEO control suite provides the operator with a safe
automated environment to degas the LAX and MECS
X-ray source filaments on start-up following venting.
Once conditioned the anode voltage may be set up to
15kV and the power regulated up to 600W depending on
the source, with safety interlocks as standard.
For more information on the ASPECT Analyser and NEO
control suite please see the relevant technical information
available.
X-ray source integration into the NEO experiment automation
Application
3p
BE [eV]
BE [eV]
3d
7 Sec
Repetition
MNN
Counts/Channel
Counts/Channel
Multi peak monitoring with the ASPECT analyser, NEO
control suite and MECS monochromated excitation
source. The colour coded intensity representation
of the Ag Auger, 3p and 3d peaks, each acquired
successively with 50 repetitions of every cycle within
7 seconds in total. The spectra may be extracted from
this representation over a user-defined duration, in
this example over 10ms and 100ms respectively.
Binding Energy [eV]
Technical Specifications
LAX Dual-anode X-ray Source
Mounting flange:
DN40CF (2.75" CF)
Port length:
254mm
Z-retraction:
50mm
Anode:
Mg 400W/Al 400W
35
76
289
146o
Additional Features:
Efficient cooled nose cone
Differential pumping option
Other anode materials on request
MECS Monochromated X-ray Source
Mounting flange:
DN63CF (4.5" CF)
Port length:
203mm
Rowland circle:
500mm
Anode:
Al 600W
Additional Features
Focused spot operation:
3-axis crystal tuning:
~1mm dia
Roll, pitch and focus
For further information please contact:
[email protected]
345
All dimensions in mm
R92
254
72
741
DN63CF
76
203
Sample
675
Chamber 0D 310
www.sigma-surface-science.com