Roentgen luminescence

The Roentgen luminescence (i.e., the emission of an X-ray quantum) is significant only for elements with Z > 20. The ratio of the Auger effect probability to that of Roentgen luminescence is WA/Wx = 106/Z4. 43 In Table II we present the values of the probabilities WA and VYX together with the fluorescence yield for the KLL Auger transition for a number of... 

Fig. 1. Evolution of states with a hole (a) KL Roentgen luminescence (b) KLM Auger effect (c) KLMV double Auger effect.

The purpose of this article is to review the development of radiation chemistry which began with the discovery of x-rays by Roentgen(l) in 1895 and shortly afterwards of radioactivity by Becquerel(2), which in both cases Involved the observation of chemical change in photographic plates and luminescence in certain phosphors. Clearly, in the space available, the review will be restricted and subjective, but will, it is hoped, give the general framework in which the subject has developed. 

USE An aq soln mixed with some adhesive and painted on paper or wood exhibits luminescence when exposed to the invisible ultraviolet rays of the spectrum or to Roentgen, radium, or cathode rays hence used in radiography for making x-ray screens. 

While investigating the nature of cathode rays produced in a Crookes mbe that he had covered with a shield of black cardboard, ostensibly to prevent the cathode rays from escaping, Roentgen (Fig. 3.17) observed in 1895 the luminescent effect on a... 

In those days of 1896 science stood at the crossroads. Roentgen s rays were a new hard fact. The radiation due to luminescence was well known and had been studied for a long time. We must remember that radioactivity was quite unknown. It was discovered in those days during experiments intended for quite other purposes. What Becquerel wanted to verify was the connection between the two phenomena. X-rays and fluorescence. Uranium compounds had good fluorescing properties and could be suitable to use. He had prepared, 15 years earlier, crystals of potassium uranyl sulfate for his father s investigations and he now utilized them for his own experiments. 

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