ACCELERATED plate

For shock-synthesis and processing experiments, less precise systems are typically employed. These systems use commercial explosives that may be used to accelerate plates or to compress samples in the form of a tube. These systems are suitable for establishing nominal shock conditions for materials processing experiments, but are generally not suitable for careful characterization of materials response [87G02, 88M01]. 

Fig 4 is a diagram of an electron impact 1 source. The sample vapor is admitted into the ion source thru the slit in the back of the chamber and it passes thru a collimated electron beam b . On impact of electrons with the neutral molecules, positive ions (to a small extent negative ions) are produced. A small positive potential ( repeller potential ) between the back wall V of the ion source and first accelerator plate d , expels tile positive ions toward the accelerating region and at the same time attracts the negative ions which are then discharged at repeller plate c . The positive ions are accelerated by the potential difference applied to plates d and e , pass thru the exit slit T and continue toward the collector... 

A small positive potential on the repeller plate of the ion source pushes ions toward the analyzer tube, and a small potential on the ion focus plates creates a focused beam. High voltage ( 1 000-10 000 V) between the ion acceleration plates imparts a high velocity to ions as they are expelled from the bottom of the ion gun. 

Electron ionization in the ion source of the mass spectrometer in Figure 22-2 creates positive ions, M +, with different masses. Let the mass of an ion be m and let its charge be +ze (where e is the magnitude of the charge of an electron). When the ion is accelerated through a potential difference V by the ion acceleration plates, it acquires a kinetic energy equal to the electric potential difference ... 

Figure 8.2 Principle of the streak camera. w, window p, photocathode a, accelerating plates f focussing plates d, deflection plates i, image intensifier c, camera...

In contrast to the large positive accelerating plate potential, the grid is held at a relatively small negative "control" or "grid" potential or bias Ec or Eg... 

Fig. 1.19. Scheme of the experimental setup for infrared multiphoton ionization or dissociation of clusters or of metal clusters-rare gas complexes. The charged and neutral clusters are directly emitted from the laser vaporization/supersonic expansion source. The beam passes a skimmer and is subsequently crossed by the tightly focused beam of the FELIX. At some time after the FELIX pulse is over, the time-of-flight mass spectrometer acceleration plates are pulsed to high voltage, and a mass spectrum is recorded in a standard reflectron setup. Also schematically depicted is the particular pulse structure of the FELIX light [126,127]... 

Positive plates need much more time to form than negatives. The reason for this is the dielectric behaviour of the cured positive paste. Oxidation of the bivalent lead compounds in the paste and formation of the Pb02 positive active mass passes through a number of chemical reactions, some of which proceed at a low rate, which retards the technological process of formation of the positive plate. In an attempt to accelerate the formation process, additives to the positive paste have been looked for, which are characterised by electro-conductive properties and stability in sulfuric acid. These additives create an electro-conductive network in the paste and the process of oxidation proceeds simultaneously within a large paste volume, thus accelerating plate formation. 

As a consequence, the distance between the sample and the acceleration plate varies, causing continuous variation in the MALDI conditions. 

C. E. Synolakis, Determining hydrodynamic force on accelerating plate in fluid with free surface, J. Eng. Mech. 115(11), 2480-2492 (1989). 

In extreme cases of wear, parts inside the feed zone are hard surfaced or specific erosion resistant components are used. Hard surfacing is often used on the accelerator plate, particularly on leading edges and the tips of the vanes, where most wear takes place. Some shaped accelerators have been made completely of urethane rubber. 

Weickgenannt, C. (2015). Rapid stretching of liquid bridges by an accelerated plate. Diss., TU Darmstadt. 

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