[en] Dornier has been engaged in development, manufacturing and testing of Cu-, Cu/Nb- and Nb-cavities for many years. Recently, several different types of RF cavities were manufactured. A prototype superconducting (s.c.) B-Factory accelerating cavity (1-cell, 500 MHz) was delivered to Cornell University, Laboratory of Nuclear Studies. A second lot of 6 s.c. cavities (20-cell, 3000 MHz) was fabricated on contract from Technical University of Darmstadt for the S-DALINAC facility. Finally, the first copper RF structures (9-cell, 1300 MHz) for TESLA were finished and delivered to DESY, two s.c. niobium structures of the same design are in production. Highlights from the manufacturing processes of these cavities are described and first performance results will be reported

[en] Published in summary form only

[en] We have proposed that a new type of microwave resonator, based on Photonic Band Gap (PBG) structures, may be particularly useful for high energy accelerators. We provide an explanation of the PBG concept and present data which illustrate some of the special properties associated with such structures. Further evaluation of the utility of PBG resonators requires laboratory testing of model structures at cryogenic temperatures, and at high fields. We provide a brief discussion of our test program, which is currently in progress

[en] Four types of rf cavities - multiple cell and single cell, superconducting (sc) and normal conducting (nc) - have been compared with respect to the specific needs of the SSC collider. The single cell cavity is preferable to the multi-cell one because its higher order modes (HOM) are easier to damp. The sc cavity has a number of advantages over the nc one. But its mechanical complexity and operational reliability may present a concern. The impact of different rf frequencies on the beam parameters have also been studied. In the range from 180 MHz to 480 MHz, the parameter variations are generally small

[en] We propose a realizable experimental scheme to prepare a superposition of the vacuum and one-photon states using a typical cavity QED-setup. This is different from previous schemes, where the superposition state of the field is generated by resonant atom-field interaction and the cavity is initially empty. Here, we consider only dispersive atom-field interaction and the initial state of the cavity field is coherent. Then, we determine the parameters to prepare the desired state via atomic postselection. We also include the effect of cavity losses and detection imperfections in our analysis, against which this preparation of the optical qubit in a real Fabry–Pérot superconducting cavity is robust. Additionally, we show that this scheme can be used for the preparation of other photon number Fock state superpositions. In summary, our task is achieved with a high fidelity and a postselection probability within experimental reach. (paper)

[en] Niobium is the principal material of advanced superconducting cavities. Mechanical properties of niobium samples have been measured after various thermomechanical treatments: rolling, annealings at different time and temperature, to achieve high deformations of Nb tubes as required for forming a cavity. Comparison with data from literature is made, and the accuracy of the different measurable parameters is discussed in view of RF cavity fabrication. (author)

[en] Wall losses can cause a coupling between eigenmodes in a cavity. The magnitude of the effect can be determined by means of eigenmode expansion. The influence on rise time of forced oscillations is calculated. Results for a brick resonator and a six-cell iris structure are presented

[en] Published in summary form only

[en] This invention deals with a linear accelerator intended for the production of charged particles of variable energy. The particle accelerator described is provided with a resonance acceleration circuit consisting of at least three cavities. These three cavities, which have the same resonance frequencies, are electromagnetically coupled in cascade. The first and the third cavities are provided with holes in their walls for the passage of a particle beam and for coupling the electromagnetic energy with the beam. The second cavity is coupled with the first and the third cavities without being coupled to the beam. The accelerator is thus characterized inasmuch as it is provided with a device for modifying the resonance mode in the second cavity in order to generate a phase change in the wave energy coupled between the first and third cavities

No abstract available