BS EN IEC 61788-7 pdf free download

BS EN IEC 61788-7 pdf free download.Superconductivity.
5.2 Measurement apparatus for Rs Figure 2 shows a schematic of a typical measurement apparatus (closed type resonator) for the Rs of HTS films deposited on a substrate with a flat surface. The upper HTS film is pressed down by a spring, which is made of phosphor bronze. The plate type spring should be used for the improvement of measurement uncertainty. This type of spring reduces the friction between the spring and the other part of the apparatus, and allows the smooth movement of superconductor films due to the thermal expansion of the dielectric rod. In order to minimize the measurement uncertainty, the sapphire rod and the copper ring shall be arranged coaxially. Two semi-rigid cables for measuring transmission characteristics of the resonator shall be attached on both sides of the resonator in an axial symmetrical position (φ= 0 and π，where φ is the rotational angle around the central axis of the sapphire rod). Each of the two semi-rigid cables shall have a small loop at the ends. The plane of the loop shall be set parallel to that of the superconductor films in order to suppress the unwanted Transverse Magnetic Wave Modes (TMmn0 modes). The coupling loops shall be carefully checked for cracks in the spot weld joint that may have developed upon repeated thermal cycling. These cables can move right and left to adjust the insertion attenuation (IA). In this adjustment, coupling of unwanted cavity modes to the interested dielectric resonance mode shall be suppressed. Unwanted, parasitic coupling to the other modes reduces the high Q-value of the Transverse Electro-Magnetic Mode (TE mode) resonator. For suppressing the parasitic coupling, special attention shall be paid to designing high-Q resonators. Two other types of resonators along with the closed type shown in Figure 2 can be used. They are explained in A.4.5.3 Dielectric rods Two dielectric rods with the same relative permittivity, ε’, and loss factor, tan δ, preferably cut from one cylindrical dielectric rod, are required. These two rods, standard dielectric rods, shall have the same diameter but different heights: one shall have height three times longer than the other. It is preferable to use dielectric rods with low tan δ to achieve the requisite measurement uncertainty on Rg. Recommended dielectric rods are single-crystal sapphire rods with tan δ less than 2 x 10-7 at 77 K. Specifications on the sapphire rods are described in 7.1. In order to minimize the measurement error in Rs of the superconductor films, both ends of the sapphire rods shall be polished parallel to each other and perpendicular to the axis. Specifications for the sapphire rods are given in Clause 7. The diameter and the heights of the standard sapphire rods shall be carefully designed so that the TE011 and TE013 modes do not couple to other TM, HE and EH modes, since the coupling between TE mode and other modes causes the degradation of unloaded Q. A design guideline for the standard sapphire rods is described in Clause A.5. Table 1 shows typical examples of dimensions of the standard sapphire rods for 12 GHz, 18 GHz, and 22 GHz resonance. In the R。 measurement at 22 GHz, the required film diameter can be set to 20 mm, and the measured QL is small, therefore the effect of the dielectric loss of sapphire rod can be reduced.BS EN IEC 61788-7 pdf download.