Polonium chamber

Polonium chamber Any air compartment connected to two or more ducts, or a slot in an air distribution hood. 

Indirect evidence for the existence of H2P0 has been found in measurements of ionization brought about by a radiation from Po in an H2 atmosphere. The very high increases in observed ionization which were observed (no solid window was present between the polonium source and the ionization chamber) were attributed to formation of H2P0. 

During the detection of ionization over the range of a-rays from polonium in a hydrogen atmosphere, abnormally rapid increases were observed when no solid window was present between the Po and the ionization chamber. This was not explainable by the volatility of Po nor to the transfer of Po together with the recoil atoms of Ra G. This was explained by the assumption that a hydride, H2P0 is formed, which diffuses into the ionization chamber. Such a compound is rapidly destroyed by a small concentration of air or through the action of a-rays. The formation of such a hydride would explain the very high absorption power of Pt and Pd for Po. 

His simple apparatus consisted of a radiation source and an ionization chamber, the chamber connected to a vacuum-tube amplifier and thence to an oscilloscope. The radiation source, an evacuated metal tube strapped to a rough-sawn block of pine, contained a one-centimeter silver disk coated with polonium mounted close behind a two-centimeter disk of pure beryl-... 

After they had identified the positrons they had missed before, the Joliot-Curies had started up their cloud chamber again and looked for the new particle in other experimental arrangements. They found that if they bombarded medium-weight elements with alpha particles from polonium, the targets ejected protons. Then they noticed that lighter elements, including in particular aluminum and boron, sometimes ejected a neutron and then a positron instead of a proton. That seemed evidence for a compound proton. They presented their evidence with enthusiasm as a report to the Solvay Conference. 

The alpha-particle instrument is shown in Fig. 1. The gas, supplied from a conventional gas handling system, is irradiated in the ionization chamber. The radiation is supplied from an enclosed polonium alpha source of a few hundred millicuries. The irradiated gas bleeds through a leak out of the ion source and into the evacuated electrode chamber. There, the ions effusing from the leak are captured by the electric fields while the gas is pumped away. The ions are focused, accelerated, and then subjected to mass analysis and electron multiplier detection in a 90° sector field analyzer tube. 

In 1930 two scientists, W. Bothe and H. Becker, observed that when a-particles in the radiation from the radioactive elements polonium or radium penetrated beryllium a previously unknown radiation was produced. The charge of the particles in this new radiation was examined in a cloud chamber, but no tracks were formed. Thus, the new particles had no charge. James Chadwick in 1932 solved the problem by proposing a particle having a mass about the same as the proton but without a charge. This particle he called the neutron. The reaction that produced the neutron was ... 

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