Micromeritics' Gemini VII 2390 Series of surface area analyzers rapidly and reliably produces accurate and repeatable surface area and porosity results. Their high speed, simplicity of use, reliability, and ruggedness have earned the Gemini a place in research and quality control laboratories worldwide.
Surface Area, Total Pore Volume, and Pore Volume Distribution
The Gemini Series of surface area analyzer uses the static volumetric technique to collect an isotherm from which valuable information such as BET surface area, pore-volume, or pore size distribution can be derived.
The design of the Gemini provides unique capabilities found only in more expensive products. Many error sources inherent in traditional static volumetric instruments are eliminated through common-mode rejection. This provides a more accurate, more precise, and more stable measurement tool, therefore providing unique capabilities. For example, using nitrogen, the Gemini is capable of performing measurements on materials with a very low surface area, where similar instruments would require the use of krypton. Krypton is not only more expensive but for a typical analyzer, measuring a krypton isotherm requires lower pressures than can be achieved with low-cost pumps and requires additional components within the instrument to measure these lower pressures. Without additional requirements, both Gemini's price and operating costs remain low.
- The Windows® version includes installation videos and system verification tests to ensure optimum performance and reliability. How-to videos provide on-screen instruction on instrument operation.
- The patented twin-tube design negates free-space errors introduced by thermal gradient variations or by initial mismeasurement of free space.
- Permits low surface area measurements without requiring krypton by essentially eliminating free-space error, the limiting factor in typical static volumetric systems.
- Accelerates delivery of the analysis gas because the sample uptake rate is used to control the rate at which the gas is delivered to the sample. This results in a surface area analyzer that is as fast as the physics of adsorption allows.
- The use of a servo valve to control the rate of gas flow into the sample tube assures accurate attainment of target pressures without pressure overshoot. Since this is not a ‘pulse-and-equilibrate' method, there is no over-dosing.
- Three choices of software control: embedded software with a keypad enabling the Gemini VII to be operated without an external PC, Windows® XP or Vista operating system, or the Gemini VII confirm™ 21 CFR Part 11 option.
Three Gemini VII Model Options
- Gemini VII 2390a - Ideal for rapid and accurate surface area determinations Also provides standard methods for single-point and Langmuir surface areas, total pore volume, micropore analysis by the t-method, and much more. Included is the capability to determine the statistical thickness surface area (STSA) of carbon blacks. (Refer to ASTM D 6556, ASTM D 3765, ISO/DIS 18852.2, or ISO/CD 4652-2/3.)
- Gemini VII 2390p - Provides additional precision with the addition of a P0 (saturation pressure) tube allowing the user to monitor the saturation pressure of the adsorptive on a continuous basis. The instrument is designed to provide a rapid measurement of the adsorption isotherm.
- Gemini VII 2390t - Has all the capability of 2390 with the additional ability to perform a BJH or Dollimore Heal pore size distribution using both adsorption and desorption isotherms of up to 1000 points. This instrument also features a P0 tube as well as a larger Dewar and longer sample tubes for extended analysis.
- Low cost
- Fully automatic operation
- High throughput - up to four Geminis can be operated with a single computer
- Capable of measuring low surface area materials
- Keypad or computer-operated with Windows-driven software
- Choice of analysis mode (scan or equilibrate)
- No pressure overshoot
- Common mode rejection of free-space error effects
- No thermal-diffusion errors
- Optional stainless-steel Dewars
- 21 CFR Part 11 software option
- IQ/OQ Validation service (optional)
- Gemini VII 2390a - Ideal for rapid and accurate surface area determinations by single-point and multipoint BET and Langmuir methods. In addition, provides standard methods for total pore volume, micropore analysis by the t-method, and much more. Included is the capability to determine statistical thickness surface area (STSA) of carbon blacks. (Refer to ASTM D 6556, ASTM D 3765, ISO/DIS 18852.2, or ISO/CD 4652-2/3.)
- Gemini VII 2390p - Provides additional precision with the addition of a saturation pressure (P0) tube that allows the system to monitor the saturation pressure of the adsorptive on a continuous basis during an analysis. This design feature permits a rapid measurement of the adsorption isotherm to near-saturation, as well as determination of pore size distribution.
- Gemini VII 2390t - Has all the ability of the 2390p, including a P0 tube, with the addition of a larger Dewar and longer sample tubes for extended analyses. This provides the additional capability to measure the total adsorption-desorption process. With this data set, one can perform a BJH or Dollimore-Heal pore size distribution using up to 1000 data points.