title: A determination by an analysis of X-ray attenuation in aluminium of the intesity distribution at its point of origin in a thick  tungsten target of bremsstrahlung excited by constant potentials of 60-140 kV.
abstract: A recently described, computer aided method of attenuation analysis has been applied to free-air chamber measurements of the attenuation by up to 30mm A1 of the exposure rate of a narrow beam of X-radiation excited  at a thick W target in a Be window tube by constant potentials of 60, 80, 100, 120 and 140 kV.  It has been shown that the general characteristics of the intensity distributions of the bremsstahlung at its point of origin within the target found by an earlier analysis are fully confirmed but that, for radiation excited at potentials appreciably above the K-absorption edge of the tungsten target, the attenuation measurements must first be corrected for the pressure of target characteristic K-fluorescence radiation. A method for doing this from published estimates of the relative amounts of  W K-fluorescence at various filtrations in radiation excited by the same potentials is described, and it is shown that these amounts come into reasonable agreement when translated to the target surface. Curves of the intensity distribution of the bremsstrahlung at its point of origin within the target are presented which are consistent with attenuation data corrected according to these estimates. They show a good general agreement with theoretical expectation.
mesh_terms: D000388:Air; D000535:Aluminum / Q000528:radiation effects*; D003201:Computers; D004307:Dose-Response Relationship, Radiation; D005453:Fluorescence; D011834:Radiation Monitoring; D013057:Spectrum Analysis; D014414:Tungsten / Q000528:radiation effects*; D014965:X-Rays
chemical_list: D000535:Aluminum; D014414:Tungsten