[en] The authors investigated the R.F. behavior of the B1 type superconductors NbN obtained by reacting Reactor Grade Niobium samples in a high purity (10 ppm of total impurities) Nitrogen atmosphere after a baking at high temperature (1800 Celsius) in a UHV Furnace. The obtained samples were characterized by: Determination of the Critical Temperature Tc via a resistive measurement; Crystallographic measurement by X-ray diffraction in order to detect some unwanted phases having lower Tc; and Measurements of the R.F. properties Residual Resistance (Rres) and limit R.F. magnetic field Hc of a niobium nitride TM-010 cavity reacted together the samples. The authors obtained for the B1 superconductor a critical temperature of 14.6 K for a tetragonally distorted cubic lattice with cell parameter a-4.381 A and c-4.324 A, as determined by X-ray diffraction. The R.F. test showed for the resonator, operating at 4.5 GHz, a surface resistance at 4.2 K of 1.μΩ in good agreement with the value predicted by the B.C.S. Theory. The surface resistance showed a quite high value of Residual Resistance Rres which limited at 6 x 10/sup 8/ the Q of the cavity. The R.F. critical field was 80 Gauss and the limitation was a sharp Thermal breakdown of the whole cavity at a power level of 100 milliwatt

[en] This paper deals with the first results of a study on Nb-N system having as the main goal the performance of niobium nitride rf cavities. The nitrides were obtained by diffusion of nitrogen in bulk niobium at high temperature. Metallurgical and resistive measurements have been done to determine the phases and the critical temperature of the samples. Furthermore, in order to study the rf behavior of the material, a 4.5-GHz niobium nitride cavity has been built and tested. The rf measurements showed, above 4 K, a surface resistance in good agreement with the computed values (1.15 μΩ at 4.2 K), i.e., about a factor of 10 better than the value obtained for niobium at the same temperature and frequency. At temperatures below 4 K, the residual resistance became prevalent, and its value was found to be 0.69 μΩ

[en] The first results of RF tests on a single cell copper niobium cavity operating at 1.5 GHz are presented. The cavity was obtained by spinning an OFHC copper sheet in half cups and tubes. The cavity's components are welded together under vacuum; the so obtained cavity was niobium coated by using a scaled version (to the authors dimension) of the magnetron sputtering system developed at CERN for S/C cavities operating at 350 and 500 MHz. The results of their first tests on two cavities, together with the ancillary measurements performed on several Niobium samples are presented

[en] In the DAΦNE Φ Factory, electrons and positrons circulate in two separate storage rings, whose top view is about elliptical, intersecting in the horizontal plane, giving rise to two interaction points. A hybrid, tunable, p.m. quadrupole prototype, 5.3 T/m, 45 mm bore radius, 280 mm in length, for DAΦNE has been designed and built. Magnetic calculation, constructive design and the first acceptance test results are briefly reported. The magnetic measurement program is not yet completed and a deeper investigation is still needed. (R.P) 5 refs.; 5 figs