Proton bombardment

Figure 1. Source chamber and ion-accelerating system for m.e.v. proton bombardment of gases at relatively high pressures...

Table I. Elements Produced by Proton Bombardment of Indium...

The apparatus used by Mills (1981) for the first observation of Ps was similar to that shown in Figure 8.2. Slow positrons were guided by an axial magnetic field onto a 40 A thick carbon film G2. The kinetic energy of the positrons was adjusted so that some could penetrate the foil and emerge bound to two electrons as Ps. The geometry and method are analogous to the production of H by proton bombardment of thin foils (see e.g. Allison, 1958). 

Spallation occurs in a particle accelerator when a high-energy proton bombards a heavy atomic nucleus, resulting in some neutrons being knocked out or spalled . 

Pierce, T. B., P. F. Peck, and W. M. Henry Determination of Carbon in Steels by Measurement of the Prompt Gamma-Radiation Emitted During Proton Bombardment. Nature 204, 571 (1964). 

Naturally occurring francium is the product of a side reaction of the decay pathway of actinium. Actinium-227 generally undergoes /3-decay to produce thorium-227, but about 1 percent of the actinium emits an -particlc to form francium-223. Francium can be produced in the laboratory via proton bombardment of thorium and during oxygen 18 (0-18) bombardment of heated gold. 

Often it is assumed that the potential energy barriers resisting internuciear collision are electrostatic and that nuclei are quite nearly spherical. Consider the proton bombardment of two nuclei of comparable size, A and B. Show that the potential barriers against proton collision associated with A and B are roughly proportional to the two-thirds powers of their atomic, numbers—that is, that ... 

Figure 1. PIXE X-ray spectra from 1 MeV proton bombardments of an untreated sample of H2Pc, and samples heat treated at 400 °C for 1, 2, and 3 hours respectively.

Figure 6. The X-ray spectra firom 1.0 MeV proton bombardment of a) furnace black, b) mar resistant, and c) and d) two samples of the extra clean super smooth semiconductive compound. Note the improvement and the inhomogeneity of the remaining silicon and calcium.

Gerakines PA, Moore MH, Hudson RL. (2000) Carbonic acid production in H20 C02 ice. UV photolysis vs. proton bombardment. Astronom Astroph 357 793-800. 

Highly enriched xenon-124 is expensive (US 150,000 per litre STP) due to its natural abundance of only 0.096%. This calls for an effective gas target and a reliable gas handling system. In the past considerable experience has been obtained in handling enriched krypton-82 gas for the production of rubidium-81 for krypton-8 Im generators. Since June 1984 this technology is being applied and further improved for the production of iodine-123 via proton bombardment of the enriched xenon-124. 

The only radioi.sotope of gallium that is prc.sently used is gallium-67, which is produced in a cyclotron by proton bombardment of a zinc metal target by a " Zn(p.2n) Ga nuclear reaction. Gallium-67 U n = 78.2 hours) decays by electron... 

Another factor which would lead to increased diffusion under the proton bombardment conditions is the temperature of 75°. Sizmann and Daunert (122) found that the radiation-induced smoothing of copper is strongly temperature dependent. At 0°, 10 a/cm produced no pronounced smoothing at 70°, ca. 5 x lO a/cm produced a practically flat surface. These two factors may be sufficient to account for the large difference, but, on the other hand, the difference may be less than supposed because of uncertainties in dosimetry. 

The nuclide F can be introduced using a number of standard methods using fluorine, HF or fluoride anion. In contrast to normal chemistry, F2 (as a dilute mixture in argon or neon) is a convenient reagent in the PET context, being prepared directly by proton bombardment of 02 in argon, or deuteron bombardment of neon. An example of its use is the preparation of labelled 5-fluorouracil and its ribosides by direct electrophilic fluorination. ... 

Gallium-67, used in the diagnosis of Hodgkin s disease, is prepared by proton bombardment. 

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