Okay, the user wants me to translate "proton-free" into Thai. Let me check the rules again. The first rule says to translate all content into Thai. The second rule states that if the content is already in Thai, leave it as is. The third rule is to provide only the translation without any explanations.
So, "proton-free" is in English. I need to translate it. The term "proton-free" might be a technical term, maybe related to chemistry or physics. In Thai, "proton" is โปรตอน. The suffix "-free" usually translates to "ไม่มี" or "ไม่มี..." in Thai. So "proton-free" would be "ไม่มีโปรตอน" or maybe "ไร้โปรตอน". Let me verify.
"Free" as in "free of" can be "ไม่มี" or "ไร้". "Proton-free" could be "ไร้โปรตอน" which is more concise. Alternatively, "ไม่มีโปรตอน" is more literal. Which one is more commonly used? I think "ไร้โปรตอน" is more likely the correct term in scientific contexts. So the translation should be "ไร้โปรตอน".
I need to make sure there's no existing Thai term that's standard. Since I don't have access to external resources, I'll go with the most logical translation based on standard Thai structure. Therefore, the translation is "ไร้โปรตอน".