Bartington Grad601-2 Magnetic Gradiometer
The Bartington Grad601-2 Magnetic Gradiometer is a vertical component dual sensor fluxgate gradiometer with data logger and two cylindrical sensor assemblies for use in geophysics and archaeology. Each sensor tube contains two fluxgate magnetometers with a one meter vertical separation. As a magnetic gradiometer, this instrument is sensitive to very slight fluctuations in the Earth's magnetic field as a result of objects buried in the shallow subsurface and surface variations. The on-board data logger records measurements collected during a survey and allows for gradient maps of a study area to be prepared.
This instrument is designed for archaeological prospection and allows geophysical surveys to be completed rapidly. The large non-volatile flash memory and fast downloading of data offer improved survey efficiency. The Grad601 has a linear range of 100nT with a resolution of 0.1nT and a range of 1000nT with a resolution of 1nT. A compressed response is provided to 30,000nT. This instrument operates either in survey mode, where data is recorded while covering an area in parallel or zigzag paths, or in a scanning mode where it is used as a search tool with an audible output without data logging.
Geonics EM38-MK2 Electromagnetic Induction Meter
The Geonics EM38-MK2 is an electromagnetic induction meter, often referred to as a conductivity meter. The instrument measures both magnetic susceptibility and conductivity at two depths (maximum depth is about 1.5 meters) in the ground by inducing an electromagnetic field and then measuring the response of the ground (the secondary electromagnetic field). In this way, electrical conductivity is measured without the use of probes using the electrical component (quadrature) of the secondary electromagnetic field. At the same time, the magnetic susceptibility of the ground is measured from the magnetic component (in phase) of the secondary electromagnetic field. Both of these data types are very useful in archaeology and other near-surface geophysical applications including soil and contamination studies.
GSSI SIR 3000 Ground Penetrating Radar
The GSSI SIR 3000 is a lightweight ground penetrating radar acquisition system manufactured by Geophysical Survey Systems, Inc. This single-channel portable interface device is designed for use by a single operator and allows for field data to be collected, visualized, and stored for later download. The SIR-3000 is compatible with all GSSI antennas for survey flexibility. Depth prospection varies based on antenna frequency and substrate, but typical investigations range from 0.5 - 3 meters in depth.
STING R1 Earth Resistivity Meter
The Sting R1, manufactured by Advanced Geosciences, Inc. (AGI), is a single-channel portable earth resistivity meter with a capacity for 56 probes. The instrument includes the Sting R1 resistivity meter, a Sting switch box, and a Swift box. It operates using both an internal battery and an external 12V wet cell battery. The instrument connects via long cables with an individual take-out for each probe. This enables individual surveys to be conducted at probe spacings of up to 6m. Once a survey is set up, the instrument records resistivity readings for hundreds of points automatically. Numerous default surveys can be selected on the instrument including Pole-Pole, Schlumberger, Dipole-Dipole, and Wenner arrays, or the user may create a custom command file. The Sting R1 is capable of performing both 2D profiles and true 3D surveys. Two-dimensional profiles are processed in AGI’s Earthimager 2D. Three-dimensional surveys are processed using AGI’s Earthimager 3D. All survey types can be topographically corrected to account for surface topography.