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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Requirements for Obtaining High Accuracy with Proton Magnetometers Part 2
Gyromagnetic Constant The gyromagnetic constant relates the precession frequency and the magnetic induction or flux density. It is а real constant, i.e. the precession frequency of protons and the applied magnetic inductions are linearly related. Several institutions have been engaged in determination of the gyromagnetic constant: NIST (USA) National Institute of Standards and Technology formerly NBS NPL (UK) National Physical Laboratory VNIIM (Russia) Mendeleyew Institute of Metrology, St.Pеtеrsburg NIМ (China) National Institute of Metrology ASMW (former East Germany) Amt fur Standardisierung Messwesen and Wonenpufung, Berlin They came with their own results and accuracies, unfortunately often far apart from each other.…
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Requirements for Obtaining High Accuracy with Proton Magnetometers Part 1
Definition of Absolute Accuracy Absolute accuracy of a measurement is the difference between measured and true values. Obviously, nobody knows the true value, so we end up defining the limits we know the true value must be within. Presently the limits of accuracy of measurement of the magnetic field of the Earth can be pushed to better than 1ppm. In a field of, say, 50,000nT, this is better than 0.05nT. However, there are numerous difficulties and conditions that must be fulfilled to obtain that kind of absolute accuracy. Parameters that are involved include: • Gyromagnetic constant’s accuracy • Time reference…
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New GPS Option Available
New GPS Option Available As of March31st, GEM is offering a new NovAtel GPS option which can be purchased with any of our instruments. NovAtel CORRECT™ positioning technology is now available with TerraStar’s precise point positioning (PPP) corrections. This system delivers 10 centimeter or better accuracy with no additional base station infrastructure. Along with this feature, other benefits include improved accuracy and performance of solutions. This option optimally combines data from numerous GNSS satellite constellations with corrections from a variety of sources, to deliver the best position solution possible. Image: Terrastar.net For more information on how this GPS…
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GEM’s Proton Precession Magnetometer
Proton Precession Magnetometers have long had a niche as inexpensive portable magnetometers, despite limitations such as relatively large power consumption and relatively low sensitivity. Typical applications include environmental and engineering surveys where targets are relatively near surface and do not require high sensitivities to detect and map, or production-oriented reconnaissance surveys for resource exploration. Operating Principles A proton magnetometer uses hydrogen atoms to generate precession signals. Liquids, such as kerosene, are used because they offer very high densities of hydrogen and are not dangerous to handle. A polarizing DC current is passed through a coil wound around a liquid sample…
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GEM Systems Upcoming Events From Around the World!
GEM Systems Upcoming Events From Around the World! With all of the advancements and innovations GEM Systems pioneers in the magnetometer industry, it’s important that we make our presence felt at the top events around the world. There are three upcoming events we are attending in three distinctly different regions that we are really looking forward to. Expomin – Santiago, Chile The Expomin event takes place in the South American city of Santiago, Chile from April 21 – 25, 2014. Santiago is the capital of Chile and it is more than 1,700 feet above sea level, with both mountains…
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Does Atlantis Exist?
You may know that GEM Systems’ equipment have been used to help assist modern day Indiana Joneses on exhausting archaeological digs. But did you know that researchers have also used our equipment on a hunt for the mythical lost city of Atlantis? Above is a rendering of the rings of Atlantis in Doñana Park, Spain that may have existed thousands of years ago. Image: nationalgeographic.com Our highly advanced magnetometers have been dispatched to the Doñana mud flats in Doñana National Park in southern Spain. There, the sensitive equipment was deployed at the survey site, with the sensors – some strapped…
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How GEM’s Sensors Help Detect Underwater Bombs
GEM Systems produces magnetometers for a variety of applications – even for scouring out still-dangerous bombs hidden underwater. Our technology has been strapped to a rig dangled some 30 metres underneath a helicopter as it is sent flying out over the water. The lowest part of the rig, which contains GEM’s sensitive magnetometer equipment, flies just two metres above the surface of the water. This tight span is carefully measured by a downward-pointing laser positioned towards the back of the rig. The distance does not leave much in the way of wiggle room, making for a very narrow margin of…
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How do Scientists Discover Oil? Part 2
Once geologists have found an area they think may contain oil reservoirs, they turn to several different tools and techniques to ascertain if there really is oil hidden away in the ground below. There are numerous pieces of equipment that can be used in the process of looking for oil. One tactic is to not look but test for the smell of hydrocarbons. These specialized detectors, informally known as sniffers, use ultra-sensitive electronic noses to detect indicators of the presence of hydrocarbons. Another technique is to deploy advance seismic equipment. These machines create special shock waves that are sent down…
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How do Scientists Discover Oil? Part 1
Filling up your tank may be an easy thing to do, but the process by which oil is discovered is anything but. The creation of oil is itself an amazing process – beginning with the death millions of years ago of very small plants and animals, with the organisms sinking into and mud. These remains mixed with sediment to form what’s known as source rock. And when the source rock is pressured and heated by new sedimentary layers, it distils the remains of the organisms into natural gas and crude oil. These fossil fuels then shift into what’s called reservoir…
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