PMG-1 Proton Gradiometer



APPLICATIONS
FEATURES
DESCRIPTION

The proton magnetometer PMG1 is a portable instrument which can be powered by an internal battery or by an external source. It is intended for ground measuring of the absolute value of the magnetic induction vector of the Earth´s magnetic field by measuring the frequency of the precession of protons in hydrogen nuclei.
The magnetometer PMG1 allows the Earth´s magnetic field to be measured in three modes:

SINGLE mode is used in a profile magnetic survey with one sensor. It detects the absolute value of the magnetic field in the location of the sensor.
GRAD mode uses two sensors. The absolute values of the magnetic induction vector in the locations of both sensors are measured simultaneously. The horizontal or vertical gradient of the magnetic field between the two sensors is determined by subtraction. The gradient measurement removes to some extent the undesirable influence of disturbing fields, compensates for the influence of the regional field and does not depend on diurnal variations in the Earth´s magnetic field.
AUTO mode allows repeated measurements with one sensor in set time intervals. Both the starting time and the length of the intervals can be set prior to the measurements. This mode is used for measuring diurnal variations in the Earth´s magnetic field.

The results of the measurements can be stored in an internal protected memory. The recorded data are not lost when the instrument is switched off or when the battery is removed. The data can be transmitted to a computer through a standard serial interface RS-232C using the communication program which is supplied with the instrument.
The magnetometer PMG1 is delivered with a power supply, which is a built-in lead acid battery. The non-magnetic rechargeable battery does not contribute to the magnetic moment of the instrument enough to affect measured values. A battery charger is also supplied with the instrument.
All functions of the magnetometer PMG1 are controlled by an internal microprocessor. This internal microprocessor allows an operator to communicate with the instrument via a keyboard and LDC display, controls the measurement process, provides digital signal filtering, storage of readings and times of measurement, testing of signal quality and battery voltage.


SPECIFICATIONS
   
Field strength range: 20,000 - 100,000 nT (gammas)
Absolute accuracy: +/- 1 nT
Resolution: 0.1 nT
Gradient range: 1,000 nT/m
Measurement time: 2 seconds
Data memory: Internal RAM for 18,000 readings
Data storage time: over the lifetime of the lithium battery (ca 10 years)
Display: LCD, 2 x 16 characters, back-light
Keyboard: 17 key, membrane type
Interface: RS-232C serial channel,
300 to 9600 Baud rate (selectable),
10 bits, 1 start, 8 data bits (no parity)
Power source: Internal lead-acid (Pb) battery 12V/3.4Ah
Battery life: 5,000 readings on average in GRAD operation
Option: Battery 12V/2.2Ah or external power supply
Dimensions: Console: 240 x 90 x 200 mm
Sensor: Dia 80 x 200 mm
Weight: Console: 3.5 kg including battery 12V/3.4Ah
Sensor: 0.7 kg
Temperature range: from -10°C to +60°C


STANDARD COMPONENTS

SatisGeo
portable instruments for geophysics and environment