Magnetic Susceptibility Meters

SM-30 Magnetic Susceptibility Meter - Field Meter for Outcrops

Magnetic Susceptibiity meter, hand held, for field use - High Sensitivity - 1 x 10^-7 SI

Heritage GeoPhysics is pleased to announce a new high sensitivity magnetic susceptibility meter called the SM-30. It is designed for measurement of rocks and sediments with very low susceptibility, yet is still autoranging through the full scale up to 0.1 SI units. It features a large 50mm sensor that allows the instrument to measure the first 20mm of the surface. This deeper penetration yields better readings from uneven surfaces.

The small size of the SM-30 allows it to be carried without any thought. Accurate measurements may be made on materials such as limestone, quartz, and even water. Four operating modes offer various methods of drift compensation, as well as a scan mode. Power is from two small lithium camera type batteries that will typically give 80 hours of operation. As the SM-30 features an automatic shut off after three minutes the batteries can be expected to last quite some time.

The SM-30 offers an internal memory of 250 readings with data transfer cable and software provided as standard. An audio tone provides indication of instrument function during operation. Easy to carry, easy to use, and sensitivity to measure most any sample of interest, the SM-30 is an indispensable tool for every geologist.

Specifications:

• Sensitivity: 1 x 10^-7 SI
• Power: Two Lithium CR2430
• Operating Frequency: 9KHz
• Battery Life: 80 Hours Typical
• Display: Four Digit LCD
• Operating Temperature: -20°C to 50°C
• Sensor: 50mm Coil
• Weight: 6 Ounce(0.180 Kg)
• Size: 4x2.5x1"(100x65x25mm)

SM-30, leather case, RS232 cable, data transfer software, manual.

SM-100 Magnetic Susceptibility Meter, Portable Core Sample System

The SM-100 Portable Magnetic Susceptibility Meter is designed for laboratory or field use to measure bulk susceptibility of standard 25.4 mm cores. Sensitivity of 2 x 10^-7 SI. Small sample fragments can be measured, with specimen shape not affecting measurement.

The SM-100 Portable Magnetic Susceptibility Meter is designed for laboratory or field use to measure bulk susceptibility of standard 25.4 mm cores. Small sample fragments can be measured in the pot with inner volume 25 cm3. The SM-100 design reflects the latest in electronic advances and offers unrivalled features:

• Field intensity and operating frequency may be adjusted in several steps by user.
• Integrated housing incorporates the measurement zone, electronics, and power supply connected to PC.
• Simple operation without any control knobs.

Calibration samples are supplied. Checking the calibration takes only a few minutes.

Features:

• High Sensitivity: 2 x 10^-7 SI at 8KHz.
• Measurement not sensitive to specimen shape.
• Adjustable field intensity and operating frequency.
• Battery operated.
• Standard system includes SM-100, set of specimen vials, software and cable, calibration standard, external power unit, and manual.

• Sensitivity: 2 x 10^-7 SI units at 8KHz
• Operating Frequency: 0.5, 1.0, 2.0, 4.0, and 8.0KHz, adjustable in 5 steps
• Field Intensity: 5, 10, 20, 40, 80, 160, or 320 A/m
• Field Homogenity: < 1%
• Inner Diameter of Coil: 40mm
• Operating Temperature: -10°C to 50°C
• Measurement Time: < 5s
• PC Interface: RS232C
• Battery: 8 x 1.5V (size AA)
• Battery Life: 100 hrs, approximate
• Dimensions: 90 x 200 mm (diameter x height)

SM-400 In-Situ Soil Measurement System

The SM-400 instrument is designed for measuring the magnetic susceptibility in holes with diameters of 40 mm and up to 530 mm deep. The instrument's sensor is located in a protective tube and during measurement, it moves up and down. The measured values are recorded and at the end of the measurement, they are transferred to a graph and saved in the computer memory. The sophisticated method for processing the signal significantly suppresses the effect of external electro-magnetic interference. The SM-400 is controlled by computer and does not have any control components. It is delivered with a transport box together with an accumulator, charger and cables.

Specifications:

• Sensitivity: 1.x10^-5 SI Units
• Dimensions of Transport Box: 100 x 65 x 25 mm
• Weight: 9.3Kg
• Operating Frequency: 8kHz
• Measurement Time: approx 90 sec
• Controls: all from PC
• Diameter of the Tube: 40mm
• Operating Temperature: -20°C to 50°C
• Power: 12VDC, accu
• Time Between Charges: typically 20 hours
• Communication with Computer: RS232, 9pins

The SM-400 susceptibility meter requires a computer with a MS WINDOWS operating system for operation. The computer is used for data processing, data display and archiving and also for controlling the instrument including switching on and off. Switching off always takes place upon disconnecting the communications cable. There are no control components on the SM-400. Communication with the computer is via a COM serial port (RS232).

The SM-400 is supplied by a 12 V accumulator. The SM-400 instrument is in the shape of a tube 40 mm in diameter with a length of 820 mm. A mobile carriage with a sensor moves inside the tube. The box with the electronics and a motor is attached to the tube at the upper end of the tube. The mobile carriage is connected to the box by three flexible wires. The total length of the instrument with the box is 890 mm.

There is a freely mobile sleeve on the tube connected by a cable to the box with electronics. During measurements, the sleeve automatically sets on the surface of the soil. Its position in regard to the tube during measurement is automatically determined and this data is used for assigning the depth to the measured data. On the lower side of the box there are three connectors. The middle one serves for communication with the computer. One of the two outer connectors is for connecting the sleeve; the other connects the instrument to the accumulator. The pins of both outer connectors are identically connected and therefore the appropriate cables may be interchanged.

Operating Principles:

The mobile sensor contains an oscillator, part of which is the pick-up coil. If we insert the tube into a hole in the ground, the soil will affect the inductance of the pick-up coil, and causes a change the frequency of the oscillator. A change in frequency is proportional to the susceptibility of the soil. In order to determine the change in frequency, we must also measure the frequency of the oscillator without soil.

It is done like this. The section in which we are measuring includes not only soil but also a space of 80 mm above the ground in the air. During processing of the measured data, we set the air susceptibility at 0.0 SI Units. Unfortunately, the inductance of the pick-up coil is also affected by temperature, resulting in the occurrence of temperature drift. In order to limit temperature drift, we perform the measurement twice. Once during the movement of the sensor upward and once during the movement downward.

From data corresponding to the same depth we calculate the average value. Using this simple procedure the linear component of the temperature drift is eliminated. For suppressing temperature drift, the chosen measuring method also helps. The base position of the sensor is in the very bottom of the tube. After start, the sensor begins to move upwards. Above the ground surface, it moves only 80 mm and immediately begins to return downwards, to the bottom position. The soil has a stable temperature and the short period above the ground surface does not greatly affect the temperature of the sensor. Furthermore, the tube in a space just above the ground is protected by the mobile sleeve.

We can decrease temperature drift if we thermally stabilize the instrument after the tube is inserted to the hole to be measured. The SM-400W program enables insertion of an arbitrarily long waiting period. After activation of the instrument, the sensor always begins to move upward. Attaining the upper position is ensured by an optical sensor and the movement stops. After this, the position is immediately and precisely measured, by an optical encoder, which is part of the motor. The sensor now automatically shifts to the very bottom position, where it awaits instructions for measurement.