In-situ gas sorption-desorption and vapour delivery systems

Two systems are described which separately enable neutron scattering experiments with in-situ vapour delivery or multicomponent gas environments at programmable pressures. The gaseous environments are delivered to the sample through a capillary line and valve located centrally between the two sections by virtue of a gas delivery platform such as the Hiden IMI for gas desorption, or Hiden XCS for vapour control. All delivery lines are thermostatted to ensure no pressure errors or condensation. Firstly, the gas delivery system is able to operate from vacuum (10-9 bar) to high pressure (200 bar) in both static and flowing gas delivery modes. The gas delivery system includes a sample positioning system for use in a top loading cryostat. The sample positioning system is separable into two sections with an independently sealable lower section able to be inserted into a glove box for sample cell attachment without risk of contamination. The IMI is capable of programming sequential in-situ sorption/desorption measurements with up to five gas species (including Helium) connected to the sample positioning system simultaneously. Absorption/desorption of gas on a sample is calculated volumetrically using molar balance expressions. Secondly, the vapour delivery system is available in static or dynamic form. The dynamic system can deliver three gases (two of which may transport vapour) up to 200ml/min. The static system controls the vapour pressure above the sample (i.e. no flow of vapour) such that the sample is exposed to only the vapour as no carrier gas is required. Both the gas delivery and dynamic vapour delivery systems can be used in conjunction with a portable quadrupole mass spectrometer, enabling trace analysis of the downstream gas composition.