Massachusetts Institute of Technology

Universita′ Degli Studi Di Milano

Fritsch Gmbh

Infm Istituto Nazionale Per La Fisica Della Materia

Marzio Giglio

Richard J Cohen

George B Benedek

Marco Potenza

Gustav K Von Schulthess

Marco Alberto Carlo Potenza

David S Cannell

Doriano Brogioli

Alberto Vailati

Umberto Perrini

A method of measuring properties of particles includes generating a beam of radiation (IW); illuminating with the beam (IW) an observation region (MR) which is transited by a particle (B). A portion of the beam (IW) gives rise to radiation (SW) which is scattered by scattering interaction with the particle (B), and another portion (TW) is transmitted substantially undisturbed through the observation region (MR). In a detection plane (M), a plurality of radiation intensity values are detected which are determined by the interference between the scattered radiation (SW) and the transmitted radiation (TW). The detection of the radiation intensity values in the detection plane (M) is carried out according to a time sequence of acquisitions corresponding to successive transit positions of the particle through the observation region (MR). On the basis of the time sequence of acquisitions, the trend of a parameter of asymmetry of the distribution of the plurality of radiation intensity values with respect to the optical axis (z), due to the successive transit positions of the particle (B), is determined as a function of time. Depending on the trend of the parameter of asymmetry determined as a function of time, the trends of phase delay and amplitude of the scattered radiation (SW) with respect to the transmitted radiation (TW) are determined as a function of time, and the properties of the particle (B) are determined on the basis of the trends of the phase delay and amplitude of the scattered radiation (SW) as a function of time.

Method of measuring properties of particles and corresponding apparatus

A method of measuring properties of particles immersed in a body (B), comprising the performing of a series of instantaneous acquisitions by illumination of the body with a temporally coherent light beam () of predetermined width D and predetermined wavelength &#x3bb; such as to generate scattered radiation () by scattering interaction of the light beam with the particles, and the detection of a plurality of values of the intensity of the total radiation (') coming from the body at a plurality of points simultaneously, the points being at a distance z from the body such that the points can receive the scattered radiation (&#x2032;) which comes from substantially all of the directions in which the particles are capable of scattering, and that each of the points receives the scattered radiation (&#x2032;) of a large number of particles, and processing () of the series of acquisitions in a manner such as to determine the properties of the particles.

Method of measuring properties of dispersed particles in a container and corresponding apparatus

An apparatus for determining grain size distribution patterns of particles for selected measuring ranges, wherein a specimen cell (15) is arranged in a convergent monochromatic light beam (4) and the produced diffraction patterns (5a, 6a, 7a) are received by a photo detector. By altering the spacing of the specimen cell (15) from the photo detector (44), the measuring range can be selected for differing grain sizes.

Apparatus for determining grain size

Method and apparatus for determining the concentration of any of a wide range of antigen or antibody molecules with a high degree of specificity, accuracy and sensitivity. Antigen or antibody concentration is determined by effecting an agglutination reaction between carrier particles in a liquid medium, exposing the liquid medium to a beam of light, and measuring the ratio of the intensities of light scattered at two different angles as a function of antigen or antibody concentration. The unknown concentration of antibody or antigen is determined by comparison with similar measurements of the anisotropy ratio using known concentrations of the molecule being tested for. The agglutination reaction is performed using carrier particles coated with an agglutinant. The carrier particles should be fairly uniform in size and their diameter can be less than or comparable to the wavelength of light. By this invention, one may specifically ascertain the absolute concentration of the antigen or antibody in question in the sample being analyzed. In addition to detecting antigen or antibody molecules, the process of this invention can be used to determine the concentration of any substance capable of specifically promoting or inhibiting an agglutination reaction.

Immunoassay by light scattering intensity anisotropy measurements

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Milan, Italy

Marzio Giglio