| 摘要 |
900,229. Spin echo data storage apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. Sept. 15, 1959 [Dec. 15, 1958], No. 31498/59. Class 106 (1). [Also in Group XL (b)] A resonant cavity for spin echo storage apparatus is designed to support two different modes whereby output pulses may be derived from the cavity in a mode orthogonal to that of the input pulses. As shown in Fig. 1a, two orthogonally disposed rectangular waveguides 6, 7 are coupled by irises 3, 4 to a shallow cavity 5 of square section which is capable of supporting TE 021 and TE 012 modes. The two modes are coupled by the precession of spinning electrons in a chemical sample 8, information and read-out pulses being fed at the processional Larmor frequency of the sample through waveguide 6 and spin-echo pulses being derived in an orthogonal mode through waveguide 7. The cavity may be tuned by screws 9. The two waveguides may extend in the same direction. In the modification of Fig. 3a, the cavity is coupled to pairs of waveguides 12, 13 and 14, 15 by pairs of irises 11a 11b and 16a, 16b. The waveguides form the arms of two magic-T junctions. In a further modification, Fig. 4b, the input and output are fed by means of coaxial lines to a pair of half-wavelength strip lines 20, 21 arranged to cross at right-angles. The sample 22 is placed at the common centre of the lines. Cavities of circular section with central irises may be used (Fig. 5, not shown). These are coupled to rectangular waveguides arranged either with their longitudinal axes or their cross-sections at right-angles to each other. The depth b of the cavity is made small in order to obtain a Q value of less than 100. Specification 795,057 is referred to. |
