Electron Irradiation and Thermal Chemistry Studies of Interstellar and
  Planetary Ice Analogues at the ICA Astrochemistry Facility
  The modelling of molecular excitation and dissociation processes relevant to
astrochemistry requires the validation of theories by comparison with data
generated from laboratory experimentation. The newly commissioned Ice Chamber
for Astrophysics-Astrochemistry (ICA) allows for the study of astrophysical ice
analogues and their evolution when subjected to energetic processing, thus
simulating the processes and alterations interstellar icy grain mantles and icy
outer Solar System bodies undergo. ICA is an ultra-high vacuum compatible
chamber containing a series of IR-transparent substrates upon which the ice
analogues may be deposited at temperatures of down to 20 K. Processing of the
ices may be performed in one of three ways: (i) ion impacts with projectiles
delivered by a 2 MV Tandetron-type accelerator, (ii) electron irradiation from
a gun fitted directly to the chamber, and (iii) thermal processing across a
temperature range of 20-300 K. The physico-chemical evolution of the ices is
studied in situ using FTIR absorbance spectroscopy and quadrupole mass
spectrometry. In this paper, we present an overview of the ICA facility with a
focus on characterising the electron beams used for electron impact studies, as
well as reporting the preliminary results obtained during electron irradiation
and thermal processing of selected ices.
