ˈɔfən, fˈoʊkəst hˈaɪˈɛnɚdʒi ᵻlˈɛktɹɑːnz fɹʌm wˈʌn ʌvðɪ ᵻlˈɛktɹɑːn ɡˈʌnz ɔːɹ ˌɪnfɹɚɹˈɛd lˈaɪt fɹʌm hˈiːɾɚ lˈæmps ɪz jˈuːzd tə pɹɪhˈiːt ðə sˈʌbstɹeɪt.
Often, focused high-energy electrons from one of the electron guns or infrared light from heater lamps is used to preheat the substrate.