Gemini Model 2390 - Surface Area and Porosity Analyzer

Micromeritics’ Gemini® VII 2390 Series of surface area analyzers rapidly and reliably produces accurate and repeatable surface area and porosity results. Their low cost, high speed, simplicity of use, reliability, and ruggedness have earned the Gemini a place in research and quality control laboratories worldwide Determines single- and multpoint BET and Langmuir surface areas, total pore volume, and micropore analysis by the t-method. Universal electrical input.

Surface Area, Total Pore Volume, and Pore Volume Distribution

Accurate, Fast and Economical Micromeritics’ Gemini VII 2390 Series of surface area analyzers rapidly and reliably produces accurate and repeatable surface area and porosity results.

Unique Capabilities

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 the additional requirements, both the Gemini’s price and operating costs remain low.

  • The Windows® version includes easy-to-follow 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 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

This option is 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 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

Gemini Has all the capability of the 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.

The Gemini Series of surface area analyzers uses the Static Volumetric Technique to generate high-speed surface area and porosity data.


  • Low cost
  • Fully automatic operation
  • High throughput – up to four Geminis can be operated with 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)