Numis is a modular MRS equipment designed to allow measurements at remote locations, as each component of the system weighs 25 kg or less, making it one man portable.
- The Tx / Rx unit is the core of the system. It ensures the production of the energizing pulses at the Larmor frequency, also the measurement of the MRS response with filtering,amplification and analog to digital conversion.
- The PC computer receives raw data, then processes, displays and stores them for further interpretation.
- The two DC / DC converter units are required for a maximum investigation depth of 150 m), to energize the 150 m side square loop (600 m total length). However, if an investigation of 100 m is sufficient, one converter unit only is required with a 100 m side square loop (400 m total length). With one only converter, just the transverse time constant (T2*) is measured, while with two converters, the transverse and the longitudinal (T1) time constants are measured; T1offers a better estimation of the permeability than T2*
- The two tuning units must be used at lower magnetic latitudes (for an Earthís field lower than 31 000 nT with the 150 m side square loop, or 37 000 nT with the 100 m side square loop), while one tuning unit only is needed at medium and higher latitudes.