The Interstellar Astrochemistry Chamber (ISAC)
The Interstellar Astrochemistry Chamber (ISAC) is mainly designed for the study of solids (ice mantles, organics, and silicates) in interstellar and circumstellar environments: characterization of their physico-chemical properties and their evolution due to vacuum-UV and/or cosmic ray irradiation, and thermal processing. ISAC is an ultra high vacuum chamber, with base pressure down to P = 2.5 10^−11 mbar, where an ice layer made by deposition of a gas mixture onto a cold finger at 10 K, achieved by means of a closed-cycle helium cryostat, can be irradiated with UV photons. We intend to incorporate also an ionic source for the simulation of cosmic ray processing. Samples can be heated in a controlled way from 10 K to room temperature. The evolution of the solid sample is monitored by in situ transmittance FTIR and Raman spectroscopy, while the volatile species are monitored by QMS. Gas mixtures typically contain H2O and CH3OH vapors, mixed with gases like CO, CO2 and NH3. The gas line works dinamically, and allows the deposition of gas mixtures with the desired composition, that is monitored in real time by a QMS. A prechamber is used to introduce and extract the samples preserving the ultra high vacuum in the main chamber.