CAYLAR

Instrumentation Scientifique

Gausmeters

NMR Gaussmeter

NMR20

Caracteristics

Resolution

0.1 µT (1mG)

Absolute accuracy

<+/-0.5mT

Relative accuracy

<+/-0.1mT

Clock stability

+/-1ppm (0°C-70°C)

Internal clock Year

<1 ppm

Clock Aging after 1 year

<+/-0,2 ppm /year

Required homogeneity

200 – 1000 ppm/cm

Time traking

Imediate

Channels

1 to 64

Control by external PC

Local, RS232, TCP/IP, MODBUS


Documentation (EN)

NMR20 Gaussmeter

The NMR20 Gaussmeter measures magnetic fields using the principle of nuclear magnetic resonance . This is the most precise technology for measuring the magnetic field. 1mG accuracy and 1ppm/year drifting.
There is no temperature drift.

Principle

The meter's probe, which contains a sample of material constructed Hydrogen chains.
The Hydrogen nucleus is a Proton. Nuclear Magnetic Resonance (NMR) comes from High frequency excitation of the Proton, in presence of a Magnetic Field.
There is a direct relationship between the magnetic field and a frequency resonance. This is the “Proton Gyromagnetic Ratio“.
This is a Fundamental Physical Constant referenced in the Source of the CODATA internationally recommended values.
The NIST “Proton Gyromagnetic Ratio, over 2pi” is ɤp/π = 42.5774806 MHz/Tesla.

So, the principle is to place the “NMR” sample in the magnetic field to be measured. Then this material is excited by a wideband variable high frequency wave.
For a frequency depending only on the magnetic field, a resonance is detected.
The value of the magnetic field can be deduced from the measurement of this resonance frequency with a high accuracy (1mG or 0.1µT).

Thus, the absolute precision of the measurement of the magnetic field is in the order of 10e-6.
The relative precision, pertains to the frequency measurement, is ten times better, in the order of 10e-7.