Abstract: A method for measuring pore pressure is provided using a rigid piezometer that does not need a filter and can be used to measure pore-water pressures in partially frozen soils. This method also can be used to measure pore pressure in a porous media when the hydraulic conductivity of the porous media is low or there is limited amount of pore-fluid available to transfer the pressures. A piezometer is also provided, including: a tube for hydraulic fluid; first and second valves to control fluid flow in the tube and into a porous medium; and a fitting wherein a pressure sensor is positioned to measure fluid pressure in the hydraulic fluid in the tube and a hydraulic fluid droplet ejected from an end of the tube into the porous medium; and an interface of the hydraulic fluid with the pore-fluid within the porous medium, using the droplet placed into the porous medium. The tube (or part of the tube), valves, fittings, and pressure sensor may be enclosed in a housing.

Abstract: A method for measuring pore pressure is provided using a rigid piezometer that does not need a filter and can be used to measure pore-water pressures in partially frozen soils. This method also can be used to measure pore pressure in a porous media when the hydraulic conductivity of the porous media is low or there is limited amount of pore-fluid available to transfer the pressures. A piezometer is also provided, including: a tube for hydraulic fluid; first and second valves to control fluid flow in the tube and into a porous medium; and a fitting wherein a pressure sensor is positioned to measure fluid pressure in the hydraulic fluid in the tube and a hydraulic fluid droplet ejected from an end of the tube into the porous medium; and an interface of the hydraulic fluid with the pore-fluid within the porous medium, using the droplet placed into the porous medium. The tube (or part of the tube), valves, fittings, and pressure sensor may be enclosed in a housing.

Abstract: A method for measuring pore pressure is provided using a rigid piezometer that does not need a filter and can be used to measure pore-water pressures in partially frozen soils. This method also can be used to measure pore pressure in a porous media when the hydraulic conductivity of the porous media is low or there is limited amount of pore-fluid available to transfer the pressures. A piezometer is also provided, including: a tube for hydraulic fluid; first and second valves to control fluid flow in the tube and into a porous medium; and a fitting wherein a pressure sensor is positioned to measure fluid pressure in the hydraulic fluid in the tube and a hydraulic fluid droplet ejected from an end of the tube into the porous medium; and an interface of the hydraulic fluid with the pore-fluid within the porous medium, using the droplet placed into the porous medium. The tube (or part of the tube), valves, fittings, and pressure sensor may be enclosed in a housing.

Abstract: A pellicle which reduces the number of particles that migrate onto a stepping field of the mask is disclosed. The pellicle frame in a preferred embodiment has an inner and an outer wall. The pressure relief system has an indirect air path which reduces the chance of particle migration from outside the frame to the protected area. The pellicle membrane is attached to the top of the outer wall and stretches over the rounded top of the inner wall, which has a slightly greater height than the outer wall. The reticle is attached to the bottom of the outer wall, while the bottom of the inner wall is sealed against the reticle with an O-ring. In this way, none of the adhesives used to attach the frame to the membrane or to the reticle are in direct contact with the protected area of the reticle. The pressure relief system allows for equalization of pressure between the area protected by the pellicle and atmospheric pressure with a reduced chance of particle migration.

Abstract: A pellicle which reduces the number of particles that migrate onto a stepping field of the mask is disclosed. The pellicle frame in a preferred embodiment has an inner and an outer wall. The pressure relief system has an indirect air path which reduces the chance of particle migration from outside the frame to the protected area. The pellicle membrane is attached to the top of the outer wall and stretches over the rounded top of the inner wall, which has a slightly greater height than the outer wall. The reticle is attached to the bottom of the outer wall, while the bottom of the inner wall is sealed against the reticle with an o-ring. In this way, none of the adhesives used to attach the frame to the membrane or to the reticle are in direct contact with the protected area of the reticle. The pressure relief system allows for equalization of pressure between the area protected by the pellicle and atmospheric pressure with a reduced chance of particle migration.