Beam line

The critical requirements for the ion source are that the ions have a small energy spread, there are no fast neutrals in the beam and the available energy is 1-10 keV. Both noble gas and alkali ion sources are conunon. Por TOP experunents, it is necessary to pulse the ion beam by deflecting it past an aperture. A beam line for such experiments is shown in figure B1.23.5 it is capable of producing ion pulse widths of 15 ns. 

The vacuum requirements in the target chamber are relatively modest (10 Pa) and are comparable to those in the accelerator beam lines. All that is required is that the ion beam does not lose energy on its path to the sample and that there is minimal deposition of contaminants and hydrocarbons on the surface during analysis. 

These limitations can be addressed in a number of ways. First, plasma source implantation techniques have the ability to treat compHcated geometries and are presently being evaluated for commercial appHcations. Where the estimated cost for beam-line implantation is estimated to be as high as 0.64/cm (2) or as low as 0.01 /cm for coming generation machines (3), industrial-scale plasma source implantation techniques have also been estimated to cost around 0.01/cm (4). 

The analysis was performed by SRXRF at the XRF beam-line of VEPP-3, Institute of Nuclear Physics, Novosibirsk, Russia. For accuracy control the International Certified Reference Materials were used. There were obtained all metrological characteristics, namely precision, accuracy and lower limits of detections. 

Unlike traditional surface science techniques (e.g., XPS, AES, and SIMS), EXAFS experiments do not routinely require ultrahigh vacuum equipment or electron- and ion-beam sources. Ultrahigh vacuum treatments and particle bombardment may alter the properties of the material under investigation. This is particularly important for accurate valence state determinations of transition metal elements that are susceptible to electron- and ion-beam reactions. Nevertheless, it is always more convenient to conduct experiments in one s own laboratory than at a Synchrotron radiation focility, which is therefore a significant drawback to the EXAFS technique. These focilities seldom provide timely access to beam lines for experimentation of a proprietary nature, and the logistical problems can be overwhelming. 

National Synchrotron Light Source User s Manual Guide to the VUVandX-Ray Beam Lines. (N. F. Gmur ed.) BNL informal report no. 45764, 1991. 

External-beam PDCE refers to measurements with the specimen removed from a vacuum environment. This mode permits the analysis of large or volatile specimens and consists of allowing the panicle beam to exit, through a thin window, the vacuum of the beam line and impinge on the specimen held at atmospheric pressure of air or other gases (e.g., helium). 

ReflEXAES can be used for near-surface structural analysis of a wide variety of samples for which no other technique is appropriate. As with EXAES, ReflEXAES is particularly suited for studying the local atomic structure around particular atomic species in non-crystalline environments. It is, however, also widely used for the analysis of nanocrystalline materials and for studying the initial stages of crystallization at surfaces or interfaces. ReflEXAES was first proposed by Barchewitz [4.135], and after several papers in the early nineteen-eighties [4.136, 4.168-4.170] it became an established (although rather exotic) characterization technique. Most synchrotron radiation sources now have beam-lines dedicated to ReflEXAES experiments. 

The experiments were performed at the energy dispersive absorption beam line of the DCI ring at LURE. In figure 1 we have plotted the XAFS and XMCD signals at the nickel K-edge. 

In situ XRD spectra were collected on beam line X18A at the National Synchrotron Light Source (NSLS) located at Brookhaven National Laboratory (BNL). The X-ray wavelength (X) was 1.195 A. The step size of the 29 scan was 0.02° in the regions with Bragg reflections and 0.05° in the regions without reflections. The XRD spectra were collected in the transmission mode (Liu et al., 2004). 

Potential Mossbauer isotopes for nuclear resonance scattering, which are within the spectral reach of synchrotron radiation sources, are summarized in Table 9.5 [118-120], and the synchrotron radiation sources which provide dedicated beam lines for specific Mossbauer isotopes are listed in Table 9.6 (adopted from [85]). 

UHV is not mandatory in PIXE, and the vacuum shared by the beam-line and specimen chamber is typically 10 6torr. The beam emerging from the accelerator has to be made uniform, while generating the minimum possible X-ray and y-ray background near the Si(Li) detector, and to this end graphite or tantalum collimators are to be preferred. PIXE chambers are often lined with graphite foil. 

If thick samples are placed in the specimen chamber for analysis, the particles are slowed down and eventually stopped in the sample, so the calculation of the X-ray yield and their absorption is more complicated. Some objects may be too large to be placed in the specimen chamber, in which case the external beam technique is employed. The particle beam passes through a window at the end of the beam-line into the air where an object of any size (e.g. an archaeological artefact) may be analyzed. 

For the analysis of large objects which cannot be placed within the irradiation chamber it is possible take the particle beam into the ambient air through a thin window at the end of the beam line. In this way any type of object can be analysed -for example paintings and archaeological artefacts. 

Isothermal crystallization was observed by means of SAXS and a polarizing optical microscope (POM, OLYMPUS, BX or BHS-751-P). The SAXS experiment was carried out using synchrotron radiation on the beam line BL40B2 of SPringS (SP8) at JASRI in Harima and at the BL-10C small angle installation of the Photon Factory (PF) at KEK in Tsukuba. 

The general scheme of an AMS beam line installed in a tandem accelerator has already been represented in Figure 16.1. As an example of one of these systems, Figure 16.3 shows the layout of the AMS facility at the LABEC laboratory in Florence,[28] where a 3 MV tandem accelerator by High Voltage Engineering Europe (HVEE) is installed. 

The scheme is useful as the starting point for the detailed description of the different components along the beam line. 

Figure 16.3 Schematic layout of the AMS beam line at LABEC in Florence. Note that the system is also equipped with two independent ion sources dedicated to Ion Beam Analysis and with a switching magnet with six measurements beam lines (not shown)...

In situ CO-TPR XAFS studies were performed at the Materials Research Collaborative Access Team (MR-CAT) beam line at the Advanced Photon Source,... 

A 0.4 m thick SPP layer was exposed to X-rays followed by a flood exposure using near UV radiation. The resist was then dip-developed in a 0.8 wt% TMAH solution for 60 s at 25 °C. We used two x-ray exposure systems to evaluate the characteristics of the SPP resist. One is SR-114 which has a source composed of a molybdenum rotating anode with a 0.54 nm Mo-La characteristic line. The exposure was carried out in air. The other has a synchrotron radiation source with a central wavelength of 0.7 nm (KEK Photon Factory Beam Line, BL-1B). The exposure was carried out in vacuum (<10-4 Pa). A positive resist, FBM-G,15) was used as a standard, because its sensitivity only weakly depends on the ambient. 

Figure 3. Photon energy distribution for x-ray beam line at SSRL.

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