A versatile source
to make complex
nanoscopic objects
fly under vacuum
We designed a versatile source chamber
capable of producing, under vacuum,
beams of clusters and nanoparticles for
studying their interaction with soft X rays.
In its design, special care was taken to use
standard components and enable rapid
switching between different experimental
configurations.
The MPSC was designed and built in
the framework of the Nano-PLEIADES
ANR project. It can be coupled with two
permanent end stations, a reflectron mass
spectrometer belonging to the consortium,
or any external user experiment with
a CF200 port. Mechanical design and
fabrication was performed by the local
company, Mecaconcept SARL.
Figure
➊
depicts cuts of the MPSC
chamber in the two configurations:
nanoparticles and clusters. The large
chamber (B) is a vertical cylinder with
a plexiglass top lid (for quick inspection
and servicing without disconnecting
the source and experimental chamber).
Attached to this chamber are two turbo
pumps connected to a Root backing pump.
A differential pumping wall holding the
skimmer guarantees a pressure in the
experimental chamber in the 10
-5
mbar
range. The source comprises a holder tube
together with either the aerodynamic lens
system or the molecular/cluster beam
system. The holder tube and skimmer can
move (with µm accuracy) under vacuum
in order to allow the source's outlet and
the skimmer to be aligned to each other,
and the latter to the synchrotron beam and
detector axis. An optional extra differential
pumping stage (D') can be used for more
demanding nanoparticles. Furthermore, to
decrease the time to change the source
configuration, it can be isolated from the
experimental chamber by retracting it and
closing the vacuum tight valve (C).
The PLEIADES Multi Purpose Source Chamber (MPSC)
Clusters and nanoparticles are important
forms of matter bridging the gap between
isolated atoms, molecules and the solid
state. These systems are therefore
of interest in diverse research fields
ranging from stellar cloud chemistry,
heterogeneous catalysis, to aerosol
physics, for example. Studying the physical
properties of these different complex
systems by sophisticated spectroscopic
methods requires the samples to be either
generated or introduced into the high
vacuum environment of the spectrometers.
Experiments on clusters or nanoparticles
have already been implemented at
different synchrotron facilities [1,2],
but for the first time, the same synchrotron
beamline proposes to these two
communities the possibility to study these
objects with a panel of spectroscopic
tools, such as conventional high-resolution
electron spectroscopy (VG-Scienta end
station), Auger electron-ion coincidence
technique (EPICEA end station) or mass
spectrometry. Our aim was to create a
source chamber with a versatile, modular,
and transportable design. Emphasis
was also put on using standard, off-the-
shelf products for as many components
as possible, to ease experimental
maintenance and flexibility. The source
chamber also had to be integrated
into the SOLEIL TANGO control system
for computer control. This enables the
recording of all actuators’ positions, giving
a comprehensive view of experimental
settings, and automated scans of actuator
positions versus different sensor values.
This point is crucial for quick experimental
set up, and for finding optimum source
conditions.
Introduction
MODELING, METHODOLOGY AND INSTRUMENTATION
124
SOLEIL
HIGHLIGHTS
2013
