Ice chemistry

This instrument is designed to study ice surfaces relevant to terrestrial and extraterrestrial environment. The basic conditions prevailing there in outer space are ultra high vacuum (base pressure range < 10^-12 torr) and low temperature of the range of 5-200 K. The whole instrument maintained at ultra high vacuum (UHV) with several vacuum pumps connected in series. There is a target of Ru(0001) single crystal (Princeton Scientific Corp.) inside the chamber which can be cooled to a temperature as low as 8 K using a closed cycle helium cryostat connected with a temperature controller and heater to maintain any temperature of interest. Thin layers of various molecular solid (ice) surfaces such as water, alcohols, carbon monoxide etc. are developed by vapour depositing on the precooled single crystal substrate. The reactivity of such a molecular solid surfaces probed by various techniques. Low energy ion scattering mass spectrometry is one of those. The technique uses reactive ions produced by electron impact ionization (EI) which are then mass and energy selected by quadrupole mass analyzer and subjected to collide on the desired molecular solid surfaces. The scattered ions from the surfaces are analysed by another quadrupole mass spectrometer. Together with this we have a temperature programmed desorption mass spectrometer (TPD-MS) to probe the surface desorbing species, low energy alkali-ion gun to trigger out the neutral species present on the surface, Reflection absorption infra-red spectrometer (RAIRS) for getting the infra-red spectrum of surface species.

Components of low energy mass spectrometer & temperature programmed desorption mass spectrometer: Extrel CMS, USA
Vacuum Components: Pfeiffer Vacuum GmbH, Germany
Reflection Absorption IR spectrometer: Bruker Optik GmbH, Vertex 70
Low energy alkali-ion gun: Kimball Physics Inc, USA
Closed cycle He cryostat: ColdEdge Technologies, USA