A method and apparatus for in situ refurbishment of valve seats are disclosed in which a worn valve seat is initially ground to a flat surface, a buildup of weld metal is deposited on the flat surface, and the weld buildup is machined to the final dimensions of the valve seat. An optical camera 5 for photographing a fluoroscopy object W on a sample stage 3 is provided. This realizes a high breakdown voltage with a low ON voltage. A pulse of laser light decomposes the phosphorous nitride and briefly melts the region of semiconductor to be doped to allow incorporation of dopant atoms from the phosphorous nitride into the semiconductor. In the illustrative embodiment, the second system is a Personal Computer, the first system is a peripheral adapted to be connected to the computer, the first protocol is a Bluetooth protocol and the second protocol is a Universal Serial Bus protocol.