Abstract: Gas flow from multiple gas sources into a sample chamber of a beam system is controlled by a cycling valve for each gas source, with the gas pressure in the sample chamber being determined by the relative time that the valve is opened and the upstream pressure at the valve. A gas valve positioned inside the vacuum chamber allows rapid response in shutting off a gas. In some preferred embodiments, a precursor gas is supplied from a solid or liquid material in a container that remains outside the vacuum system while in use and which is readily connected or disconnected to the gas injection system without significant leakage.

Abstract: Gas flow from multiple gas sources into a sample chamber of a beam system is controlled by a cycling valve for each gas source, with the gas pressure in the sample chamber being determined by the relative time that the valve is opened and the upstream pressure at the valve. A gas valve positioned inside the vacuum chamber allows rapid response in shutting off a gas. In some preferred embodiments, a precursor gas is supplied from a solid or liquid material in a container that remains outside the vacuum system while in use and which is readily connected or disconnected to the gas injection system without significant leakage.

Abstract: A carbon dioxide recovery apparatus and process for supercritical extraction includes providing a process stream from a supercritical extraction procedure in which the process stream includes pressurized carbon dioxide, extraction process waste and optionally at least one co-solvent; reducing the pressure of the process stream below critical pressure; venting low pressure carbon dioxide vapor to exhaust; cooling the process stream to form a two phase mixture; separating the two phase mixture into a process liquid, containing co-solvent if present, and a process vapor phase stream; collecting the process liquid; filtering the process vapor phase stream to remove particulates and optionally residual co-solvent; passing the filtered process vapor stream through an adsorber to remove trace impurities to form a purified carbon dioxide vapor stream; and, drying the purified carbon dioxide vapor stream to remove residual water vapor.

Abstract: A carbon dioxide recovery apparatus and process for supercritical extraction includes providing a process stream from a supercritical extraction procedure in which the process stream includes pressurized carbon dioxide, extraction process waste and optionally at least one co-solvent; reducing the pressure of the process stream below critical pressure; venting low pressure carbon dioxide vapor to exhaust; cooling the process stream to form a two phase mixture; separating the two phase mixture into a process liquid, containing co-solvent if present, and a process vapor phase stream; collecting the process liquid; filtering the process vapor phase stream to remove particulates and optionally residual co-solvent; passing the filtered process vapor stream through an adsorber to remove trace impurities to form a purified carbon dioxide vapor stream; and, drying the purified carbon dioxide vapor stream to remove residual water vapor.