According to the line-focus principle, what does a smaller anode angle primarily provide?

The line-focus principle is a key concept in radiography and relates to the design of the x-ray tube's anode. A smaller anode angle enhances spatial resolution by allowing for a smaller effective focal spot size. This results in sharper imaging because the x-rays are emitted from a more focused area on the anode, leading to improved detail in the radiographic image.

In this context, improved spatial resolution refers to the clarity and detail in the image that allows for better differentiation of structures, which is vital in diagnostic imaging. The smaller angle reduces the size of the effective focal spot while maintaining the larger physical size of the actual focal spot, which is necessary for heat dissipation.

While improved heat capacity and reduced heel effect are also important aspects related to anode design, they are secondary effects of the anode angle rather than the primary benefit of a smaller anode angle in relation to spatial resolution. Hence, improved spatial resolution is the most direct result of a smaller anode angle according to the line-focus principle.