25 years old, want restraining order against 53 year old mother?

My mother and I have had a falling out over the life choices she has made and have exposed my children to. It seems like she has snapped mentally and continuously harasses me. She shows up to my apt. door and pounds/rings for an hour or more at a time. She leaves threatening voice mails. She has called child protective services on me which went unfounded in their records. It's gotten to the point where I fear for the safety of my children. I am paranoid to the point where I don't even want to allow them outside. Her husband has a LARGE criminal record in the US and Canada. Is there anyway legal to file a restraining order? I have no idea how all this works.