In the LHC main magnets, using Rutherford type cable, the eddy current loss and dynamic magnetic field error depend largely on the electrical resistance between crossing (Rc) and adjacent (Ra) strands. Cables made of strands with pre-selected coatings have been studied at low temperature using a DC electrical method. The significance of the inter-strand contact is explained. The properties of resistive barriers, the DC method used for the resistance measurement on the cable, and sample preparation are described. Finally the resistances are presented under various conditions, and the effect is discussed that the cable treatment has on the contact resistance. Abstract In the LHC main magnets, using Rutherford type cable, the eddy current loss and dynamic magnetic field error depend largely on the electrical resistance between crossing (Rc) and adjacent (Ra) strands. Cables made of strands with pre-selected coatings have been studied at low temperature using a DC electrical method.The significance of the inter-strand contact is explained. The properties of resistive barriers, the DC method used for the resistance measurement on the cable, and sample preparation are described. Finally the resistances are presented under various conditions, and the effect is discussed that the cable treatment has on the contact resistance.

The contact resistance between crossing strands of Rutherford type superconducting cables has been proven to be an essential parameter for the behaviour of the main magnets i n accelerators like the LHC. A strong development program to study the parameters fixing its value has been launched at CERN.The electrical contact resistance of individual strands with pre-selected coatings has been studied at 4.2 K under varying loading force by means of a 3 contacts DC method.The electro-mechanical properties of contacts have been studied on bare strands and strands w i t h Sn, or Ni, or Zn based coatings.The contact resistances measured on strands were compared t o measurements made on cables. Contact resistance properties were analysed with respect to t h e requirements for the LHC main magnet cables.

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The main phenomena that may be responsible of radiation detecting mechanisms in superconductors are described in a first part of this paper. Several examples are given, ranging from broadband and sensitive bolometric devices to ultrafast nonbolometric infrared detectors. The second part is devoted to the study of various transition edge bolometers designed to be built at low cost. Polycrystalline zirconia substrates have been used, to grow YBaCuO films by both in situ and ex situ oxygenation after radiofrequency sputtering. The voltage responsivity at 10.6 im wavelength has been studied with respect to the modulation frequency of the incident radiation, both experimentally and theoretically. A 2D thermal model has been developped, allowing to interpret the complex (amplitude and phase) experimental frequency responses of various devices. In particular, the amplitude response can be described as a succession off andf112 segments. Noise measurements show NEP and detectivity values reaching a very satisfactory level for granular films.