The spinning target of a general purpose x-ray tube is primarily made of which material?

The spinning target of a general purpose x-ray tube is primarily made of tungsten due to its high atomic number and excellent thermal conductivity. Tungsten's high atomic number (74) allows for efficient x-ray production as it generates a higher quantity of x-rays when bombarded by electrons. Additionally, tungsten withstands the intense heat generated during the x-ray production process because it has an exceptionally high melting point (over 3,400 degrees Celsius), making it ideal for continuous use in a spinning target design.

While other materials like aluminum and lead have their uses in x-ray equipment (with aluminum often utilized as a filter to reduce low-energy x-rays and lead for radiation shielding), they do not possess the combination of thermal and x-ray production efficiency that tungsten offers. Gadolinium, though it is used in some specialized applications, is not suitable for the high heat and radiation absorption requirements of a general purpose x-ray tube target. Thus, tungsten is the optimal choice for the spinning target in general-purpose x-ray tubes.