Method and apparatus for achieving adiabatic demagnetization of an electron spin echo sample for enhancing the dynamic range and operable repetition rate of electron spin echoes by applying a "preparation" pulsed magnetic field of a predetermined field strength and direction to the sample located in a resonant cavity prior to the application of a pair of successive microwave pulses orthogonally to a relatively smaller static, unidirectional magnetic field so that a spin echo signal is produced before thermal equilibrium of the sample is reached. The static magnetic field is established either after or concurrently with the pulsed magnetic field and in the same direction.
A method for the recording of spin resonance spectra, in which the spins of a nuclear species of a sample located in a magnetic field are excited by a pulsed rf signal and the relaxation oscillations of the spins are repetitively sampled and recorded at predetermined times and in which a radio-frequency decoupling signal is irradiated upon the sample to reduce coupling to the spins of another nuclear species, is characterized in that the decoupling signal consists of a periodic sequence of pulse groups comprising several pulses each, the pulses being so short that the frequency mixture detectable in the pulses according to the Fourier analysis covers the entire range of spin resonances of the other nuclear species.
Information storage is achieved in powdered magnetoelastic materials. Such powdered magnetoelastic materials have the capability of achieving long storage times of information and also allow information to be stored at relatively high temperatures.
4593248 - Oxymeter - Owned by The Medical College of Wisconsin, Inc. (Milwaukee, WI)
An ESR spectrometer is employed to measure the oxygen concentration in a sample material. Electron paramagnetic resonance is produced in a free radical mixed with a standard material of known oxygen concentration. The phase of the signal produced by this resonance is compared with the phase of the signal produced by the electron paramagnetic resonance of the free radical mixed with the sample material. The oxygen concentration in the sample material has a single valued functional relationship with respect to this phase difference and is calculated in a microprocessor-based control system. At low oxygen concentrations, the relationship is a linear one.
A microwave spectrometer includes a sensing chamber into which is introduced a gas or constituent to be analyzed. Microwave radiation is introduced into the chamber and any of the chamber resonant frequency, the microwave frequency, and the center frequency of the absorption peak are varied independently. The resultant variation in intensity of the microwave radiation in the chamber is monitored to determine the concentration of the gas within said chamber. The spectrometer may include a frequency measuring and reference system for measuring the resonant frequency of the chamber.
A dielectric probe, of the type in which an electromagnetic wave is reflected from a dielectric/magnetic structure and spectrum analyzed, further includes a coil for applying a magnetic field to the structure as the wave is being reflected. Information about the intrinsic electromagnetic properties, integrity and structure of the material is obtained by comparing the reflected spectra for both the magnetic field on and off conditions.
