Background
Resonance
Ltd.
has
developed
a system to expose spacecraft materials to thermal
atomic oxygen and VUV-UV light that simulates low earth orbit
conditions. Oxygen atoms are produced upstream from the exposure
chamber by radio frequency dissociation of O2. Atomic oxygen
concentrations to 10^15 atoms/cm^3 can be generated with the high power
RFX-500 generator. This is comparable to an atomic oxygen flux of
roughly 2x10^16 cm^2/sec (equivalent 5 eV atomic flux measured with
Kapton dosimeter).
The
oxygen
density
profile
across the material sample can be measured
in-situ with the Resonance Ltd. Atomic Oxygen Density Profiler using
the technique of resonance absorption. A beam of light from an atomic
oxygen 130.2 nm resonance lamp is directed across the exposure chamber.
This light is absorbed by the oxygen atoms in the chamber and the
amount of absorption measured by a VUV solar blind diode. The density
profile across the sample can be determined by scanning the optical
path.
Resonance
can
also
provide
UV and VUV sources that simulate the solar spectrum in
order to evaluate the effects of exposure to UV and atomic oxygen
simultaneously. The Atomic Oxygen Density Profiler and Solar Simulator
Sources can be easily adapted to existing atomic oxygen exposure
systems.
Resonance
offers
three
complete
ATOMS systems to suit a variety of applications
and budgets. Both the deluxe (ATOMS-SX) and the standard (ATOMS-S)
systems include exposure to atomic oxygen and VUV radiation, as well as
in-situ atomic oxygen density measurement.
Development
of
ATOMS
was
funded by the Canadian
Space Agency (CSA), the National
Research
Council
of
Canada Industrial Research Assistance
Program (IRAP), and Resonance Ltd. internal funds.
- Complete system, including pump,
mounted in standard 47.5 cm (19 in) rack
- Standard system is in full-height
1.8 m (72 in) rack
- Budget system is mounted in half
height rack
- In-Situ Atom and Molecule
Absorption and Fluorescence Measuring Systems
- OAMS and NAMS Oxygen
Absorption and Nitrogen Atom Measuring Systems
- Profiling Systems -
Irradiance, Atomic Oxygen Density and Atomic Nitrogen Density Profilers
Subsystems and
Options
- Atomic Oxygen Exposure
Chamber (AO-EC)
- Pyrex vacuum chamber
- Quick dismount 5 cm
diameter circular specimen holder
- Gas inlet manifold
- Outlet pumping manifold
with ozone filter & throttle valve
- Multiple ports for extra
sample holders, RGA, Atomic Oxygen Density Profiler, VUV-UV Solar
Simulator
- Dual Thermocouple gauges
for pump & system pressure
- 3 VUV-UV sources
covering 115-400 NM
- Irradiates sample with
> one solar equivalent of VUV and near UV light
- CF Mounting Flange with
Lamp Adapter (3 sets)
- Lamps included are:
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