Phase mode analysis of directional elements in a circular array
A technique for analyzing the directional elements of a circular array is presented. The technique is based on phase mode decomposition of measured element patterns. It can be used to calibrate the array and may help identify sources of measurement errors. It is illustrated with patterns from a 108-element circular array.
Determination of element locations in a circular array from measurements in the Fresnel region
The electrical locations of the elements in a large circular array are determined from phase measurements in the Fresnel region. A closed-form solution for the element phase center locations is presented which contains the required range correction. The technique is applied to a 108-element, L-band circular array of log-periodic dipoles. It is shown that coupling between the elements and the array structure almost completely obscures frequency dependent effects
The REX-ISOLDE project
The Radioactive Beam Experiment REX-ISOLDE [1–3] is a pilot experiment at ISOLDE (CERN) testing the new concept of post acceleration of radioactive ion beams by using charge breeding of the ions in a high charge state ion source and the efficient acceleration of the highly charged ions in a short LINAC using modern ion accelerator structures. In order to prepare the ions for the experiments singly charged radioactive ions from the on-line mass separator ISOLDE will be cooled and bunched in a Penning trap, charge bred in an electron beam ion source (EBIS) and finally accelerated in the LINAC. The LINAC consists of a radiofrequency quadrupole (RFQ) accelerator, which accelerates the ions up to 0.3 MeV/u, an interdigital H-type (IH) structure with a final energy between 1.1 and 1.2 MeV/u and three seven gap resonators, which allow the variation of the final energy. With an energy of the radioactive beams between 0.8 MeV/u and 2.2 MeV/u a wide range of experiments in the field of nuclear spectroscopy, astrophysics and solid state physics will be addressed by REX-ISOLDE.