GEM System

GEM’s advanced Proton Precession magnetometer (GSM-19T) is one of the world’s leading instruments for subsurface investigations and exploration. The Proton system is designed to fit the niche for clients who require a low-cost, yet robust and reliable magnetometer for ground geophysical surveys. This system is an entry-level system for clients who require an advanced system without the higher-order features and benefits of GEM’s Overhauser and Potassium systems.

The GSM-19T Proton Precession unit is a unique product only available from GEM. It features highly-effective proton energization and physics, three data acquisition modes (Walking, Mobile and Base Station); has a large-volume on-board storage and memory; and comes complete with a high-resolution (0.6 m) integrated GPS – one of the first magnetometers in the world to offer this time-saving, effective technology.
This proven system offers a range of benefits for different applications. In mineral exploration, the GSM-19T has shown itself to be a mainstay of many programs – offering robustness for a demanding environment around the world. In oil and gas exploration, the GSM-19T offers similar benefits. It is also an effective tool in environmental and engineering work for detection of buried drums, utilities and other man-fabricated
buried objects.
From robust field units to efficient survey modes and fast data downloading, the GSM-19T is designed to deliver the maximum value in a proton precession system. It also provides numerous technologies that differentiate it from other systems, including robust design, no heading errors and other features.


  • Performance sensitivity: <0.1nT @ 1Hz
  • Resolution: 0.01nT
  • Absolute accuracy: 1nT
  • Dynamic range: 10,000 to 120,000nT
  • Gradient tolerance: Over 7000nT/m
  • Sampling rate: 1 reading per 3 to 60sec
  • Operating temperature: -40C to +60C
  • Base station: Time, date and reading stored at 3 to 60 second intervals
  • Remote control: Optional remote control using RS-232 interface
  • Storage: 16Mb (# of readings), mobile: 838,860, base station: 2,796,202, walking mag: 1,677,721
  • Coordinate: DGPS, 12 channel receiver antenna
  • Data download software: Gemlink5.4 version