Target material

Experience is available with target materials such as gold (Au), silver (Ag), uranium (U), chrome (Cr), and rhodium (Rh). 

On firings the gases from the propellant accelerate the piston that compresses the light gas in front of it. At a preestablished pressure, the projectile is propelled down the launch tube accelerated by the low molecular weight gas which follows the projectile to the mouth of the tube. The target material is placed in front of the launch tube, and appropriate instmmentation used to estabUsh the characteristics of the interface reaction between projectile and target (117-120). 

A.ccekrator-Producedlsotopes. Particle accelerators cause nuclear reactions by bombarding target materials, which are often enriched in a particular stable isotope, with rapidly moving protons, deuterons, tritons, or electrons. Proton reactions are most commonly used for production purposes. 

K = Constant (depends on target material, particle abrasiveness and size distribution)... 

The constant, K, depends on the target material, particle abrasiveness, and size distribution of the particles. The kinetic energy of the particles is Mp x Vp + 2. This parameter includes the solids loading, or concentration, and velocity of the particle. Alpha is the angle of impingement of the particle on the blade surface. 

These theoretical predictions have been verified experimentally for numerous target materials (Fig. 3.53 [3.139]). Note that in Fig. 3.53 there is a pronounced difference between the neutralization of carbon atoms in a carbide and in graphite, respectively. This is one of the rare examples where matrix effects are observed. 

Reasonable estimates of ultimate sensitivity and depth resolution in ERDA can hardly be given because of the large range of projectiles and energies (from He ions of several MeV up to 200-MeV Au ions), and the use of different detection systems. In addition, stability of the sample under irradiation (which, of course, depends on the target material) is also important in the discussion of sensitivity and detection limits. The sensitivity is mainly determined by the recoil cross-section, the solid an-... 

Fig. 1.1. The pressure range over which shock-compression events are of interest is very broad. Quite different and distinctive behaviors are to be expected at the various pressures. The figure shows pressures produced by impact and detonation as well as physical (p), mechanical (m), and chemical (c) events at selected pressures. The indicated impact pressures are those for impactor and target materials which are the same.

Fig. 3.5. The experimental arrangement used for a typical compressed gas gun is shown. The apparatus is designed to impact a selected impactor upon a target material with precision on the alignment of the impacting surfaces. Velocity at the impact surface can be measured to an accuracy and precision of 0.1%. This loading produces the most precisely known condition of all shock-compression events.

Typical current-versus-time responses recorded with the various impactor-target materials are shown in Fig. 5.6. In each case the shape of the pulse... 

As the current pulse is largely dominated by the stress differences, a short duration current pulse is observed upon loading with a quiescent period during the time at constant stress. With release of pressure upon arrival of the unloading wave from the stress-free surface behind the impactor, a current pulse of opposite polarity is observed. The amplitude of the release wave current pulse provides a sensitive measure of the elastic nonlinearity of the target material at the peak pressure in question. 

In the majority of spectrometers, A1 and Mg are commonly used as x-ray target materials. With two anodes, A1 and Mg, it is possible to resolve overlapping photoelectron and Auger electron peaks. This is because in an XPS spectrum the position of the Auger peaks changes if Al radiation is replaced by Mg K radiation, but the positions of the photoelectron peaks are unaltered. 

Thus we have succeeded in preparing the target material of LiAl1/4Ni3/402 (.R3m), which is a solid solution of a-LiA102 and LiNi02 (R3m) in a ratio of 1 3. 

The continuous spectrum is thus characterized by a short-wavelength limit and an intensity distribution. Experiments on other target materials have shown that these characteristics are independent of the target material although the integrated intensity increases with atomic number. (See Equation 1-3.) The continuous spectrum, therefore, results generally from the interaction of electrons with matter. Attempts (none completely successful) have been made to treat this interaction theoretically by both classical and quantum mechanics. 

A choice of target materials is offered, including copper and molybdenum (as well as tungsten) for the generation of monochromatic characteristic... 

Fig. 9-4. A Machlett AEG-50-S tube, (a) Photograph of the tube, (b) Schematic diagram. This tube was constructed to give a clean spectrum, with no characteristic lines of consequence other than those of the target material. Comparable tubes are the Philips FA-60, FA-100, and the Machlett OEG-60. (Courtesy of Machlett Laboratories, Inc., Springdale, Conn.)...

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