Compare Description Drawings, CAD & Specs Availability Price
Electronics Module, Spinning Rotor Gauge
8 Weeks
8 Weeks
Measurement Head, Spinning Rotor Vacuum Gauge System, Includes Cable
8 Weeks
8 Weeks
Ball and Flange Assembly, Spinning Rotor Vacuum Gauge System, Calibrated
8 Weeks
8 Weeks
Ball and Flange Assembly, Spinning Rotor Vacuum Gauge System, Not Calibrated
8 Weeks
8 Weeks


  • Measurement Range
    5 x 10-5 to 100 Pa
  • Accuracy
    up to 1 Pa: 1% of measuring value + U
    1 to 100 Pa: increasing up to 10% of measured value (typical)
  • Stability
    Better than 1% per year
  • Display
    4½ digit LCD display
  • Display Units
    Pa, mbar, or Torr
  • Analog Output
    0-10 VDC, into 2kΩ min. load, linear or logarithmic
  • Relays
    2 SPDT relays, adjustable, nominal switching capacity (resitive load): 1A 30VDC, 0.5A 25VAC
  • Digital Communication
    RS-232, USB (USB 2.0 compatible)
  • Flange Type
    2¾ CF, made of stainless steel, bakeable up to 450°C (without measuring head)
  • Operating Temperature
    Electronics: 10-40°C
    Measuring head: 10-50°C ball/flange assembly bakeable to 450°C
  • Enclosure
    Half 19-inch rack mount or table top, 241 x 185 x 88 mm
  • Weight
    Electronics: 2.5 kg
    Measuring head: 0.6 kg
    Measuring flange: 0.5 kg
  • Power Requirements
    85 to 256 VAC, 47-63 Hz
  • Wetted Materials
    Ball and Flange
  • Compliance


Principle of a Spinning Rotor Gauge

The sensing element of the SRG is a magnetically levitated stainless steel ball that resides in a tube connected to the vacuum system. The ball is suspended and rotated by the separable drive assembly. Once the ball reaches a certain rotational speed, the ball is allowed to free spin. Collisions of the gas molecules with the surface of the ball impart a drag which decelerates the ball. Pickup coils measure the deceleration. The electronics unit then uses an algorithm based on the sampling time, physical parameters and gas characteristics to accurately determine the pressure.

Since the measurement principle is mechanical, there are no thermal or ionization effects (as is the case with ionization gauges) that will influence the accuracy of the measurements. Also, the calibration constant is only weakly influenced by the ball’s surface roughness, making the SRG a very stable reference standard.


The SRG-3 will find applications in metrology and in experiments where high accuracy and repeatability are essential. Away from the test bench, the MKS Spinning Rotor Gauge may also be used in situ on a process chamber to assure high vacuum gauge reading accuracy and tool-to-tool consistency.This provides repeatable process results, high uptime and optimum cycle times.


MKS Instruments, Inc. delivers the SRG-3 with a calibrated measuring head and ball/flange assembly along with a calibration certificate. Calibration is made against the reference standards of our DKD1 calibration laboratory. As a result, the Spinning Rotor Gauge SRG-3 system offers the user consistent traceability as required for ISO9000. Should measuring flanges with non-calibrated balls be ordered, they will be checked for usability by the factory.

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