USES OF RADON 75 



If the nucleus emits gamma rays of several different frequencies, the 

 result will be a series of groups of electrons emitted with velocities char- 

 acteristic of their orbital origins. These orbital electrons account for 

 the beta-ray line spectrum of the radioactive elements. In addition, 

 further secondary effects take place. The removal of an electron from 

 its orbital level will be followed by adjustment transitions giving rise 

 to very hard x-radiations also characteristic of the electron configuration 

 of the element. 



The beta-ray photoelectron spectrum is a clue to the relative wave- 

 length of the nuclear gamma radiation. Suppose that a gamma photon 

 of energy content hv is emitted as a result of a beta-particle ejection 

 from the nucleus. The absorption of this energy in the K, L, ■ ■ • elec- 

 tron levels of the resulting atom will lead to electron emissions having 

 energy E\ = hv — w K , E 2 = hv — w L , • • •, respectively, where w K , 

 w L • • • denote the energies necessary to remove the photoelectron from 

 its level. The energy of each electron group can be found from measure- 

 ments of its magnetic deflection, and the absorption energies which are 

 known from x-ray data. The frequency v, and hence the wavelength 

 of the gamma radiation which gives rise to the group, can therefore be 

 calculated. 



Physical Properties of Radon 



Radium, upon the emission of an alpha particle from its nucleus, 

 degenerates into the inert gas radon. 



Radon is the heaviest of the inert rare gases. Its boiling point is 

 — 62° C, and its freezing point —71° C. 



Its coefficient of distribution between water and air at 20° C amounts 

 to 0.255. It is readily soluble in water. It is easily occluded by solids 

 such as hard rubber, celluloid, wax, carbon, and especially platinum 

 and palladium. Solid salts of radium occlude as much as 65 per cent of 

 radon. With increase in temperature the solubility decreases in strict 

 accordance with Henry's law. The solubility is also reduced by the 

 addition of salts to the water. 



Uses of Radon 



Radon is primarily used for medical purposes. The gas is compressed 

 into small volumes containing sufficient radioactive material for the 

 widely different requirements that have to be met in particular surgical 

 and experimental needs. If placed under pressure it is confined in 

 capillary tubes cut to various lengths, which are referred to as seeds. 



