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Nov 18 2014

Potassium Vapour Magnetometers – A Short Summary (Part 1)

By Dr. Ivan Hrvoic, President, GEM Systems, Inc. Introduction This paper is intended to provide a short overview for professionals and students who are interested in learning more about potassium magnetometers and their differences from other types of magnetometers available today. Key topics include: Physical overview of quantum magnetometers Optical pumping of alkali vapours Broad line Cesium, Rubidium and Helium versus narrow line Potassium Standard and super-resolution K-sensors and systems Future directions This paper is based on more than 10 years of research and development into the topic by GEM Systems, Inc. as well as other published results from the…


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Oct 16 2014

Magnetic Data in the Oil & Gas Industry

Did you know ?  In the upstream oil and gas industry, airborne magnetometer surveys can be used to detect a variety of near-surface hazards that are difficult to resolve in seismic data. Magnetic data will help identify fault zones, and orphaned well/drill hole and other iron-based infrastructure, associated with old and undocumented oilfield infrastructure. Gas migrates toward the surface along naturally occurring faults and frequently, it gets trapped in shallow structures also difficult to see on seismic images. Drilling into a shallow gas pocket on the way to a deep target can result in huge unexpected costs for the operator.…


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Sep 22 2014

Using Ultra High Sensitivity Magnetometers to combat Poaching

The group that oversees anti-rhino poaching operations along the western front of the Kruger National Park in South Africa has been looking for a means to improve the detection of armed insurgents. Infra-red sensing has limitations in day-time, due to high ambient temperatures and lack of penetration through vegetation cover. The area is vast (2,000 sq. km’s) but airborne investigations are only launched once there is some information as to the whereabouts of insurgents. Tree and bush cover is dense, and poachers can easily avoid visual detection from the air by taking cover. An item as small as rifle will…


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Sep 15 2014

Are there Earthquakes in Canada?

Earthquakes are among the most devastating natural disasters – particularly as there are no ways to prevent them.Earthquakes occur along active faults in the earth’s crust, when the tectonic plates which comprise this crust slide past each other, collide, or diverge. The Haiti earthquake in 2010 was one of the worst natural disasters in recent years. This magnitude 7.0 earthquake led to over 100,000 deaths from the initial event, aftershocks, and the cholera outbreak resulting from disruption in health services. The tsunami which causedmassivedestruction in Japan in 2011 was caused by a magnitude 9.0 earthquake deep under the ocean. This…


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Aug 28 2014

GEM will be in Athens, Greece!

Come visit GEM at the EAGE Near Surface Geoscience Exhibition in Athens, Greece! Near Surface


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Aug 5 2014

How Magnets and Gravity are Used in Mineral Exploration

Magnetic and gravity surveys differ from traditional seismic surveys in that they are passive, rather than aggressive. Instead of causing detonations or pressure waves, they measure variations in the magnetic and gravitational fields of the Earth. Although both can be used for minerals exploration, they have different strengths and weaknesses and often should be used together to give a more complete map of a potential mining location. The two methods use some common equipment. Aircraft can be used to create large-scale maps of both the magnetic and gravitational anomalies in a large region. Teams on the ground can visit points…


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Jul 28 2014

Different Methods of Geophysical Surveys Used in Mineral Prospecting

Reflection Seismology What it is Reflection Seismology (called “seismic” in the minerals industry) is the practice of inducing a vibration in the Earth’s surface, and analyzing the reflection. The vibration is induced using a vibration machine or a series of dynamite blasts. This creates a seismic wave that travels to the Earth’s mantle, the ball of molten rock below are feet. The mantle reflects the wave back up to the surface, where they are measured. What it is good for Hydrocarbons. Oil, gas, and coal occur in stratified sedimentary rock. This is because they were originally biomass, like forests or…


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Jul 21 2014

Requirements for Obtaining High Accuracy with Proton Magnetometers Part 5

Signal-to-Noise Ratio Limited S/N ratio will make measurement of the average period uncertain. Relative accuracy or repeatability of measurement, а prerequisite for absolute accuracy, depends to a large extent on S/N ratio of the obtained precession signal. Obviously, an effort must be made tо use all thе available information from the noisy precession signal, therefore usually all thе zero crossings are taken and used for calculation of the result. Sensor Cleanliness Obviously, any ferromagnetic inclusion in the sensor or its immediate vicinity may influence the field and cause erroneous result. Presence of AC Magnetic Fields AC magnetic fields caused by…


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Jul 14 2014

Requirements for Obtaining High Accuracy with Proton Magnetometers Part 4

Method of Measurement Proton precession frequency is of acoustic range and the measurement interval varies from a fraction of a second tо few seconds. To achieve required resolutions of sub-ppm it is customary tо measure the average period of the precession frequency and convert it to the frequency and the magnetic field. Required accuracies arе achieved by measuring precession frequency to a small fraction of one period down to only few degrees or even a fraction of 1 degree of phase shift. This in turn means that the precession frequency must have a stable phase and good signal tо noise…


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Jul 7 2014

Requirements for Obtaining High Accuracy with Proton Magnetometers Part 3

Time Reference Stability and Accuracy Measurement of frequency is one of the most precise measurements we can do, primary standards going into 10-13 or even better accuracy. In principle, therefore, there is no problem with the time reference for the counters measuring precession frequency. In practice, the situation is different. Due to higher costs and/or higher power requirements in the Observatory magnetometers we usually use tеmреrаturе compensated or at best thermally stabilized crystal oscillators with long term (1 yеar) stabilities of l ppm or similar. Latest development in global positioning systems allows for much better accuracies by locking or periodically…


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