Abstracts of Bell System Technical Papers Not Published in This Journal (01 January 1953)

* Certain cf these papers are available as Bell System Monographs and may be obtained on request to the Publication Department, Bell Telephone Laboratories, Inc., 463 West Street, New York 14, N. Y. For papers available in this form, the monograph number is given in parentheses following the date of publication, and this number should be given in all requests. Bell Telephone Laboratories. Hughes Aircraft Company, Culver City, California 1 5 255 256 THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1953 1 A Broad-Band Interdigital Circuit for Use in Traveling-Wave-Type Amplifiers. R . C. FLETCHER . I.R.E., Proc., 4 0 , pp. 951-958, August, 1952. 

Because of its high power-handling capacity, the interdigital circuit has been considered for use in traveling-wave-type amplifiers. An analysis is presented here which indicates that this type of circuit can be arranged to give constant phase velocity over a wide bandwidth (30 per cent), as required to give constant gain. The analysis is qualitatively checked experimentally. The impedance parameter (proportional to the cube of the gain in db) is approximately the same as the flattened helix (such as has been used for the magnetron amplifier) and about one-third that of the conventional circular helix. 

Copper as an Acceptor Element in Germanium. C . S . FULLER and J . D. STRUTIIERS . Phys. Rev., 8 7 , pp. 5 2 6 - 5 2 7 , August 1, 1952. Properties of Thermally Produced Acceptors in Germanium. C. S. FULLER , H . C . THEUERER and W . VAN ROOSBROECK .