IMAGING NEUTRON ACTIVATION ANALYSIS

CHARLES EVANS & ASSOCIATES WILL CONSTRUCT AND TEST AN IMAGING NEUTRON ACTIVATION ANALYSIS DETECTOR CAPABLE OF DISCERNING ELEMENT CONCENTRATIONS ON A POINT-BY POINT BASIS.NEUTRON ACTIVATION ANALYSIS IS AN EXTREMELY POWERFUL METHOD FOR MEASURING MAJOR, MINOR, AND TRACE ELEMENT CONCENTRATIONSIN A WIDE VARIETY OF SAMPLES. IN THIS METHOD, ANALYTE ELEMENTS ABSORB A NEUTRON TO FORM A RADIONUCLIDE WHICH USUALLY DECAYS BY EMITTING A BETA PARTICLE AND A GAMMA RAY. THE GAMMA RAY ENERGIES ARE CHARACTERISTIC OF THE ANALYTE ELEMENT AND THEY ARE NORMALLY MEASURED WITH A GERMANIUM DETECTOR. SECONDARY ELECTRONS PRODUCED AT A SAMPLE SURFACE AS A BETA-PARTICLE PASSES OUT OF A THIN SAMPLE CAN BE ACCELERATED AND IMAGED. WHEN GAMMA RAYS AND BETA-PARTICLES ARE DETECTED IN COINCIDENCE, THE GAMMA RAY ENERGY ANSWERS THE QUESTION "WHAT" AND THE SECONDARY ELECTRON POSITION ANSWERS THE QUESTION "WHERE" FOR AN INDIVIDUAL RADIONUCLIDE DISINTEGRATION. THIS INFORMATION WILL BE ORGANIZED INTO ELEMENT MAPS AND LOCAL AREA GAMMA RAY SPECTRA. IMAGING NEUTRON ACTIVATION ANALYSIS WILL BE USEFUL FOR ANALYSIS OF HETEROGENEOUS SOLIDS. WIDESPREAD APPLICATIONS IN FIELDS SUCH AS GEOLOGY, BIOLOGY, MATERIALS SCIENCE, AND PARTICLE ANALYSIS ARE ANTICIPATED.