"ionising radiation such as \alpha and \beta particles and \gamma rays" is what i have typed (without quotation marks). But when I build it the pdf output is wrong: it does put in the correct symbols, but it leaves no spaces at all from after the word "as" and puts everything after "as" in italics for some reason. I'm totally new to this so, it's probably just something small I'm missing. Could you show me what I should type to get the line to read normally? i.e. no italics except for the greek letters, and proper spacing.