Copper atoms are converted into positive ions in a mass spectrometer through a process called electron ionization. In electron ionization, a high-energy electron beam is directed at the copper atoms, knocking off one or more electrons from the atoms and leaving them with a net positive charge.

The ionization process can be represented by the following equation:

Cu(g) + e- ---> Cu+(g) + 2e-

In this equation, Cu(g) represents a neutral copper atom, e- represents the electron beam, Cu+(g) represents a positively charged copper ion, and 2e- represents the two electrons that are emitted from the copper atom upon ionization.

The electron ionization process is typically carried out in a vacuum chamber to prevent the ions from colliding with air molecules and losing their charge. The positive ions that are produced are then accelerated by an electric field and separated according to their mass-to-charge ratio in the mass analyzer.