Author
J.A. Cookson
Bio: J.A. Cookson is an academic researcher. The author has contributed to research in topics: Proton & Beam (structure). The author has an hindex of 5, co-authored 5 publications receiving 310 citations.
Papers
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TL;DR: In this paper, a focusing system using high precision magnetic quadrupoles was designed and built for use with the IBIS 3 MeV Van de Graaff generator, which was measured to have a diameter of less than 4 μm.
Abstract: Well focused beams of protons and other ions provide a very powerful means of determining how the elemental composition of a sample varies over its surface. Observation of the X-rays from proton bombardment can provide great sensitivity in most cases, while detection of nuclear effects has special applicability for elements of low atomic weight. A focusing system using high precision magnetic quadrupoles was designed and built for use with the IBIS 3 MeV Van de Graaff generator. Measurements of the first order focusing and aberrations agreed satisfactorily with theoretical predictions. The focused beam of 3 MeV protons was measured to have a diameter of less than 4 μm. The target chamber, deflection system and display system are described and examples given of use of the system. Backgrounds in X-ray detection are discussed and limits of detection are given.
184 citations
TL;DR: The proton induced X-ray method with a finely focused beam was used to measure the variation of trace elements across the diameter of human hairs in the hope that this will throw light on the origin of the trace elements in hair and assist the correlation of other analytical data as mentioned in this paper.
Abstract: The proton induced X-ray method with a finely focused beam to measure the variation of trace elements across the diameter of human hairs in the hope that this will throw light on the origin of the trace elements in hair and assist the correlation of other analytical data.
66 citations
TL;DR: A system of quadrupole lenses has been provided for Harwell's 3 MeV IBIS accelerator, giving focused beams of protons, deuterons or α-particles down to a spot size of 4 μm diameter as discussed by the authors.
34 citations
TL;DR: Proton induced X-ray analysis of biological material in air is discussed and the microbeam system of magnetic quadrupoles which has been developed by Cookson and Pilling is discussed.
Abstract: Proton induced X-ray analysis of biological material in air is discussed. The microbeam system of magnetic quadrupoles which has been developed by Cookson and Pilling (see J. Radioanal. Chem., vol.12, p.39, 1972), for a 3 MeV accelerator, provides proton, deuteron or alpha beams focused to a spot of diameter less than 4 mu m. The beam emerges into air through a 7.5 mu m kapton foil, and in order to preserve positional resolution the specimens are mounted directly on the outside of the beam exit foil.
23 citations
Cited by
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TL;DR: Small amounts of arsenic are metabolized in a variety of ways and are largely rapidly methylated and excreted by man and animals, and toxic manifestations in man occur at the cellular level and may appear in many organ systems.
Abstract: (1986). Clinical and Environmental Aspects of Arsenic Toxicity. CRC Critical Reviews in Clinical Laboratory Sciences: Vol. 23, No. 4, pp. 315-347.
210 citations
TL;DR: The aim of this article is to present the recent achievements in the field of cellular chemical element imaging, and direct speciation analysis, using proton and synchrotron radiation X-ray micro- and nano-analysis, and the potential of these methods in biomedical investigations.
Abstract: The direct detection of biologically relevant metals in single cells and of their speciation is a challenging task that requires sophisticated analytical developments. The aim of this article is to present the recent achievements in the field of cellular chemical element imaging, and direct speciation analysis, using proton and synchrotron radiation X-ray micro- and nano-analysis. The recent improvements in focusing optics for MeV-accelerated particles and keV X-rays allow application to chemical element analysis in subcellular compartments. The imaging and quantification of trace elements in single cells can be obtained using particle-induced X-ray emission (PIXE). The combination of PIXE with backscattering spectrometry and scanning transmission ion microscopy provides a high accuracy in elemental quantification of cellular organelles. On the other hand, synchrotron radiation X-ray fluorescence provides chemical element imaging with less than 100 nm spatial resolution. Moreover, synchrotron radiation offers the unique capability of spatially resolved chemical speciation using micro-X-ray absorption spectroscopy. The potential of these methods in biomedical investigations will be illustrated with examples of application in the fields of cellular toxicology, and pharmacology, bio-metals and metal-based nano-particles.
162 citations
TL;DR: A comprehensive review of the production and use of beams of protons, deuterons and heavier ions with spot sizes as small as 2 μm is given in this article, where the formation of such beams either by collimation or by focusing is described.
142 citations
TL;DR: Blood arsenic levels are transitory, however urine levels are useful for monitoring ongoing exposure and hair arsenic is useful as a confirmatory feature in chronic arsenic poisoning provided external contamination by arsenic can be excluded.
122 citations
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TL;DR: Proton Radiography has high penetrating power, high detection efficiency, small-scattered background, inherent multi-pulse capability, and large standoff distances between test objects and detectors.
Abstract: With the nuclear weapons program moving to Science Based Stockpile Stewardship (SBSS), new diagnostic techniques are needed to replace weapons testing. Proton Radiography is being developed within the SBSS program as one such tool. It is analogous to transmission X-ray radiography, but uses protons instead of photons. Proton Radiography has high penetrating power, high detection efficiency, small-scattered background, inherent multi-pulse capability, and large standoff distances between test objects and detectors. Multiple images on a single axis through progressively smaller angle-cutting apertures can provide material identification. Proton Radiography can make multi-axis, multi-frame radiographs: i.e., 3D radiographic movies. This approach to SBSS is being developed at the Los Alamos National Laboratory (LANL) and the Lawrence Livermore National Laboratory (LLNL). This new method of radiography, as well as radiography experiments performed at the LANSCE accelerator at LANL and at the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory, are discussed.
113 citations