Aimants supraconducteurs à champ homogène et intense pour resonance nucléaire et électronique

Especially high homogeneity magnets for nuclear and electronic resonance were studied. The magnet for nuclear resonance is a sixth-order solenoid with a 4.5 cm room temperature access. The maximum field obtained is 58 kG with an homogeneity of in two cm³. Computation was made using Garrett\´s method with an electronic computer. The dimensions were optimized in order to obtain a sixth-order field with a minimum weight of superconducting wire. They are: length 338 mm, inner diameter 65.5 mm, outer diameter 161 mm. This solenoid is wound with a single wire of superconducting alloy NbZr. The measured inductance of the solenoid is 300 henry and at maximum field it stores an energy of around 45 000 joules. Very good results have been obtained with this magnet on the protons in high resolution nuclear magnetic resonance at 180 MHz. The magnet for electronic resonance is simple solenoid wound with a 7-strand cable in NbZr alloy. Its dimensions are: length 20.7 cm, inner diameter 2.22 cm, outer diameter 9.42 cm, and the field homogeneity is 10^-4one cm³. This magnet provides the field for a 2-mm wavelength electronic spectrometer. With this spectrometer transition has been observed between fundamental levels of trivalent vanadium ion in Al2O2at 4.2°K and, by this means, the factor and the zero field splitting of this ion have been accurately determined.