IGA

IGA (Institutul de Geofizică Aplicată, the Institute of Applied Geophysics) in Bucharest worked on seismometry, electrometry, geomagnetism and geothermometry, with teams of geophysicists, electronics engineers and mechanics; in 1974 it merged with the Geological Institute of Romania (IGR, founded in 1906) into the Institute of Geology and Geophysics, which in 1994 took back the name Geological Institute of Romania [1].

Instruments

Its apparatus sector, later the Laboratory for Geophysical Apparatus (LCAG), designed and made in small series [1]:

• a fluxgate magnetometer for measuring the remanent magnetisation of rocks;
• a proton magnetometer, begun in 1974 and approved in 1976, which showed the field directly in nT on five digits: a coil polarises the hydrogen in its water core, and after about 3 s the polarising field is cut and the precession signal (a few µV, about 2.1 kHz) is amplified, filtered and multiplied in a PLL circuit for a frequency meter; it went to geological and geophysical prospecting enterprises, to universities in Bucharest and Cluj-Napoca and to military units, was unique in the CMEA at the time and was also used for prospecting in Yemen;
• a multichannel seismic station with magnetic drum recording;
• a geophone, the first designed and built in Romania;
• radiometers, resistivity meters and spectrometers, and a marine proton magnetometer, made with the marine gravimetry and magnetometry team.