Ferrite Material Characterization in a Static Bias Field for the Design of a Tunable Cavity
During the development of ferrite-loaded accelerating cavities, the electromagnetic properties of the dispersive ferrite material need to be known. We describe a coaxial short-circuit measurement technique to measure the complex permeability of toroidal-shaped samples (127mm outer and 70mm inner diameter) that are exposed to an external magnetic bias field. The external magnetic bias field is applied perpendicular to the RF magnetic field. With this method it is possible to characterize the frequency dependence of the permeability for a frequency range of 1100MHz. The dependence of the permeability on the external magnetic bias is presented for the ferrite G-510 from Trans-Tech Inc. and the material characterization is shown in the same frequency range. The measurement results are verified by simulations of the measurement set-up.
Ferrite Characterization for the Design of an Accelerating Cavity With Perpendicular Biasing
A perpendicular biased ferrite loaded accelerating cavity is studied for a possible upgrade of the CERN accelerator complex which could help to overcome the intensity limitations occurring at the SPS injection. The required accelerating cavity should cover a frequency range of 18 to 40 MHz with high cavity Q, which poses high demands on the ferrite material properties. A test setup is presented to measure the relative permeability and magnetic losses of full scale ferrite garnets (350 mm outer and 200 mm inner diameter) in a magnetic bias field within the frequency range of interest. An one-port reflection measurement provides adequate input to model the relative permeability of the ferrite in numerical simulations for different magnetic bias fields. A resonant measurement setup was used to cross-check simulation results with measurement data and to investigate the magnetic losses of the ferrite material. A numerical model of a simplified accelerating cavity is used to study the capability of the garnet G-510 as a perpendicular biased tuning ferrite.
The development of a liquid antihistaminic preparation with sustained release properties.
The relative capacity of several cation exchange resins to adsorb methapyrilene has been determined by an in vitro method. It was demonstrated that methapyrilene adsorbed on sulfonic acid cation exchange resin possessed pharmacological activity approximating that of a solution of methapyrilene hydrochloride as measured by the protection against histamine-induced asthma in the intact guinea pig. It is suggested that the use of ion exchange resins as carriers of drugs in liquid dosage forms may be useful in sustained release preparations.