Proton beam energy

Johansson et al. (1995) illustrate the detection limits for the above type of specimens in terms of concentrations (ppm). Contours are shown in Figure 4.18 showing the dependence of the detection limit upon the trace element atomic number (Z) and the proton beam energy Ep. 

Effect of Proton Beam Energy on the Sensitivity and Contrast of Select Si-Containing Resists... 

Figure 4. The effect of proton beam energy on the sensitivity (QH) of the MOTSS copolymer resists.

X-radiation can also be induced by high energy (several Me proton beams from ion accelerators. Such particle-induced x-ray emission (PIXE) (284) is useful for thin samples and particulates, having detection Hmits of g. Intense synchrotron x-ray sources have found appHcations in... 

Straggling effects become more dominant further into the sample. They are most pronounced with proton beams, because the ratio of energy straggling to energy loss decreases with increasing ion mass. For protons, these effects may be quite substantial for example, depth resolutions in excess of 1000 A are typical for 1-MeV protons a few pm into a material. 

Principles and Characteristics Particle-induced X-ray emission spectrometry (PIXE) is a high-energy ion beam analysis technique, which is often considered as a complement to XRF. PIXE analysis is typically carried out with a proton beam (proton-induced X-ray emission) and requires nuclear physics facilities such as a Van der Graaff accelerator, or otherwise a small electrostatic particle accelerator. As the highest sensitivity is obtained at rather low proton energies (2-4 MeV), recently, small and relatively inexpensive tandem accelerators have been developed for PIXE applications, which are commercially available. Compact cyclotrons are also often used. 

Si(Li) spectroscopy, with the capability of simultaneous quantitative analysis of 72 elements ranging from sodium through to uranium in solid, liquid, thin film and aerosol filter samples. The penetrating power of protons allows sampling of depths of several tens of microns, and the beam itself may be focussed, rastered or varied in energy. The use of a proton beam as an excitation source offers several advantages over other X-ray techniques, for example there is a higher rate of data accumulation across the entire spectrum which allows for faster analysis. 

MeV required in proton-therapy for an effective treatment of deep seated tumors [26]. Fuchs and co-authors have proposed a scaling law [27], allowing the necessary laser parameters to produce proton beams of interest for such applications to be estimated. In their work, best suited to hundreds of fs/some ps duration laser pulses, they use the self-similar fluid model proposed by Mora [28] giving the following estimate for the maximum FWD proton energy ... 

In summary, we have shown that the proton beam sensitivity of an HS-MOTSS copolymer decreases and the contrast increases with increasing proton energy, and that the influence of the proton energy on the sensitivity of these materials is diminished with the more sensitive resists. 

Finally, fluorine-18 can be reliably and routinely produced at the multi-Curie level [19] on widely implemented biomedical cyclotrons of relatively low-energy proton beam (e.g. 18MeV). This fact, combined with its favourable half-life. 

Figure 5 Microdosimetric spectra at the proximal, central, and distal positions of a therapeutic proton beam with an initial energy of 155 MeV.

Figure 13 Depth-dose curves for proton beams of different energy. The position of the Bragg peak depends on energy and can thus be adjusted according to the clinical requirements. (From PSI, Villigen, courtesy of Pedroni and Scheib.)...

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