Gamma-particle spectroscopy

We thank P. Bowen for initial fabrication of the water manifolds in the system. Most of the fabrication of the equipment was done by R. Flores who also performed some of the initial flow tests on the peristaltic pumps. J. Bushman and M. Edwards modified and maintained the equipment W. Beiriger performed the x-ray diffraction analyses C. Slettevold and A. Biermann performed the particle analysis and determined the surface area on the samples. J. Wittmayer took the SEM photos. We also thank L, Gazlay and D. Hosmer for the gamma-ray spectroscopy analysis,... 

Whereas most magnetic-transport beams are a few m long in order to shield the annihilation gamma detector from the source, this length is notrequired if we are interested in particle spectroscopies, especially if electrostatic transport and focusing is incorporated into the design. Canter [45] has published several papers on positron optics to which the reader is referred. Figure 3.13 shows an example from the author s laboratory. 

Kreuter and Speiser [77] developed a dispersion polymerization producing adjuvant nanospheres of polymethylmethacrylate) (PMMA). The monomer is dissolved in phosphate buffered saline and initiated by gamma radiation in the presence and absence of influenza virions. These systems showed enhanced adjuvant effect over aluminum hydroxide and prolonged antibody response. PMMA particles could be distinguished by TEM studies and the particle size was reported elsewhere to be 130 nm by photon correlation spectroscopy [75], The particle size could be reduced, producing monodisperse particles by inclusion of protective colloids, such as proteins or casein [40], Poly(methylmethacrylate) nanoparticles are also prepared... 

Another important characteristic is that ion beams can produce a variety of the secondary particles/photons such as secondary ions/atoms, electrons, positrons. X-rays, gamma rays, and so on, which enable us to use ion beams as analytical probes. Ion beam analyses are characterized by the respectively detected secondary species, such as secondary ion mass spectrometry (SIMS), sputtered neutral mass spectrometry (SNMS), electron spectroscopy, particle-induced X-ray emission (PIXE), nuclear reaction analyses (NRA), positron emission tomography (PET), and so on. 

PIGE particle-induced gamma-ray emission spectroscopy... 

The basic information in the study of sorption processes is the quantity of substances on the interfaces. In order to measure the sorbed quantity accurately, very sensitive analytical methods have to be applied because the typical amount of particles (atoms, ions, and molecules) on the interfaces is about I0-5 mol/m2. In the case of monolayer sorption, the sorbed quantity is within this range. As the sorbed quantity is defined as the difference between quantities of a given substance in the solution and/or in the solid before and after sorption processes (surface excess concentration, Chapter 1, Section 1.3.1), all methods suitable for the analysis of solid and liquid phases can be applied here, too. These methods have been discussed in Sections 4.1 and 4.2. In addition, radioisotopic tracer method can also be applied for the accurate measurement of the sorbed quantities. On the basis of the radiation properties of the available isotopes, gamma and beta spectroscopy can be used as an analytical method. Alpha spectroscopy may also be used, if needed however, it necessitates more complicated techniques and sample preparation due to the significant absorption of alpha radiation. The sensitivity of radioisotopic labeling depends on the half-life of the isotopes. With isotopes having medium half-time (days-years), 10 14-10-10 mol can be measured easily. 

See also Radiochemical Methods Gamma-Ray Spectrometry. Surface Analysis X-Ray Photoelectron Spectroscopy. X-Ray Absorption and Diffraction X-Ray Diffraction - Singie Crystal. X-Ray Fluorescence and Emission X-Ray Fluorescence Theory Wavelength Dispersive X-Ray Fluorescence Energy Dispersive X-Ray Fluorescence Total Reflection X-Ray Fluorescence Particle-Induced X-Ray Emission Synchrotron X-Ray Fluorescence. 

In another smdy, samples of depleted uranium oxide manufactured through different processes were characterized (Hastings et al. 2008). Three types of uranium oxides were prepared from uranyl nitrate hexahydrate (U02(N03)2-6H20) at different temperatures UO2 at 500°C-700°C, UjOg at 800°C-1100°C, and UO3 at 350°C-450°C. Optical spectroscopy and particle fractionation were used to characterize the oxides. The color of the oxides, their density, and granular appearance (aerodynamic diameter and size distribution) were somewhat affected by the preparation conditions. The gamma spectrum of the samples was also recorded. The conclusion was that variations in the processing conditions of the uranium oxides were reflected in the density and particle size distribution and these characteristics could be used for nuclear forensics. 

Usually, direct analysis of alpha, beta and some gamma emitters is impossible if the sample is not previously isolated and preconcentrated. There is little use of direct radiometric detection of beta emitters by beta spectroscopy or liquid scintillation because of its low capacity to discriminate between different beta particles. This is because beta particles from a single isotope are emitted with a range... 

In large experimental animals, with only small numbers available, the kinetics of this clearance pathway can be analyzed using insoluble particles with an appropriate radiolabel and imaging gamma-spectroscopy (gamma-camera). A series of lung scans will provide activity accumulation at the sites of the TBLN as an indicator of particle transport to the TBLN, but this must finally be proved by lymph node tissue analyses at the time of sacrifice. Although carefiil radiation dose estimates would be required, this approach may also be applicable to human subjects. 

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