Date of Award

5-1950

Degree Type

Bachelors Essay

Degree Name

Bachelor of Science (BS)

Department

Physics

First Advisor

Jack B. Greene

Second Advisor

Virgil Roach

Abstract

The purpose of this paper is to determine by the mass absorption coefficients of various substances, namely, aluminum, copper and iron, the effective wave-length of an X-ray beam which passes through particular thicknesses of the above materials. Since an X-ray tube does not emit a monochromatic wavelength but emits heterogeneous wave-lengths, we had to use a comparative method in order to obtain the desired results. It happens that the mass coefficient of absorption of carbon does not vary appreciably with an increase or decrease in wavelength, hence, we can use carbon as our standard or material to which we can compare our results. Let us now consider Just how X-rays are emitted so that we may better understand our problem. X-rays are emitted then material has incident upon it: 1) electrons of sufficient velocity to cause emission, 2) a beam of primary X-rays which have energy enough to produce secondary or fluorescent radiation.

We will now consider case one which deals with the production of X-rays in tubes. The target of an X-ray tube is known to emit a spectrum which consists of a continuous spectral background with bright lines characteristic of the element or the target which is subjected to the bombarding electrons. The continuous background, which is called "general radiation" or "independent radiation", does not depend on the type or target used. It is composed of a great number of frequencies. When the electrons penetrate the target they are decelerated by the atomic fields of the target and the magnitude and direction of their velocities change, hence, the emission of radiation results.

Comments

A Thesis submitted to the Faculty of the College of Liberal Arts of Marquette University, in partial fulfillment of the Requirements for the Degree of Bachelor of Science, Milwaukee, Wisconsin.

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