Heason Technology has won a £250,000
order from Synchrotron Soleil, the French national synchrotron facility and
research laboratory, to design and manufacture a 14-axis nano-scale manipulator
to position samples.
 |
| The Heason manipulator will position sample for soft X-ray scanning |
Four separate nano-positioning manipulators will be combined to provide the
14 axes that will be used to position samples and optics for an exciting new
soft x-ray scanning photoemission microscope project called ANTARES.
ANTARES will provide the global scientific community with the means to examine
structures at the atomic level and will be of benefit to pioneering research
in soft condensed matter in areas of interest, such as microelectronics and
nanotechnology.
It will benefit from a new and powerful Scanning PhotoEmission Microscope (SPEM)
technique that will use the Heason Technology designed manipulators to both
focus the beam and perform sample scanning with nanometre precision in combination
with three independent detectors producing precise sample mapping, revealing
the location of the elements, their relative abundances, and their chemical
state.
ANTARES' motion requirements involve linear and rotary positioning of the sample
with a 5-axis nanometre resolution manipulator in combination with three separate,
3-axis, beam modification manipulators to ensure nanometre-level linear alignment
of the specialist optical system that comprises several Fresnel Zone plates,
an order sorting aperture (OSA) and a pinhole. Each of the four manipulators
will be arranged on an intricate adapter plate system to effectively form a
single assembly which is housed inside a 550 mm inner-diameter vacuum chamber
that also includes a granite isolation plate base, laser interferometer optics,
and various other components including the experiments' complex detector systems.
The challenge to design a customised solution within the severe space restriction
of the 10-10 mbar ultra-high vacuum chamber is intensified by the need to limit
magnetic materials throughout the manipulators' bearing and mechanical support
system as well as restrict motor heat to within a desired operational temperature
and range of 25º C, +/- 1º C with vacuum bake-out temperatures up
to 120º C.
Such design specifications are considered to be unusual but not impossible
by Heason Technology's design engineers. Heason will choose ceramic servomotor
technology from its specialist partner Nanomotion to ensure the high precision
motion, non-magnetic and low thermal characteristics for each manipulator axis
including both rotary positioners for sample positioning. A further benefit
of the technology is the Nanomotion ceramic motor's ability to hold and lock
position with zero position shift when power is removed to further ensure temperature
stability.
Each axis will include Renishaw optical encoders with either 0.1 or 0.05 micron
feedback resolution to ensure the overall positioning specification is achieved.
To maintain the low magnetic requirement, ensure the high stiffness and minimise
harmonic sensitivity within the positioning system, specialised stainless steel
cross roller bearings with low magnetic permeability will be used. Where possible,
within the tight dimensions provided by the vacuum chamber, all axes will include
overtravel switches and datum position switches for homing the complete assembly.
Heason will also provide its customer with detailed manufacturing and electrical
scheme documentation, design and motor sizing calculations, and material selection
information for the complete project. Through the design phase Heason design
engineers will liaise with Synchrotron Soleil scientist and engineering teams
to develop the final design in conjunction with the selection of other specialised
components that will also be housed in the vacuum chamber whose dimensions are
not yet finalised.
As expected with such pioneering research, the design specification includes
areas that require detailed evaluation before a final specification can be defined.
One such area is the provision of single vertical axis for the sample positioner
which is used to set a course position at initial set-up and will be satisfied
with a stepper motor drive. During the design phase, Heason will carry out full
evaluation to determine whether this motor is to be located within or outside
the vacuum chamber.
The contract also includes full acceptance tests and site visits to Synchrotron
Soleil to assist with installation. During the design phase and at installation,
Heason will also liaise with Synchrotron Soleil's motion control system supplier
to provide specialist software support. This includes developing an auto homing
routine so that all axes can safely establish a datum position without collision,
and a thermal prediction program for each the ceramic motors based upon duty
cycle and environmental conditions. These requirements will also be pre-calculated
and determined using a separate motion controller at Heason Technology during
the design phase with the main parameters transferred to Synchrotron Soleils'
existing motion control system.
The expected installation date for the complete system is during the autumn
of 2009 with acceptance tests and full commissioning by early 2010.
Posted July 19th, 2009
