Joe Hickerson has been called a "finder of great songs," which is not hard to understand: For the past 18 years, he's headed the Archive of Folk Culture at the Library of Congress. With dozens, and sometimes hundreds of variants on songs in the folk tradition, does Hickerson revel in his repository, rooting out the unique and the unusual?

"Heavens no," he insists. "I don't have much time to do that. I'm helping everyone else. It's the people that walk in the door that have all the luck and all the time to look for stuff. I'm busy answering people's questions."

Hickerson, who has recorded three solo albums for Folk-Legacy and who appears on the National Geographic's "Songs and Sounds of the Sea," likes to emphasize that "everybody and anybody has access" to the ever-expanding folk archives. "We acquire more material now than we did 10 years ago and certainly more than 40 years ago when the well-known people like John Lomax were there.."

Hickerson will perform with his wife, Kathy, this afternoon at 3 in a benefit concert at the Washington Waldorf School on the grounds of the Washington Cathedral. His vast and varied repertoire of American and British ballads, topical and novelty songs, religious and profane, has been drawn from "people, recordings, books, anywhere I can find them." How many songs does Hickerson know? A count, he says, would be "impossible. I once thought it was a thousand, but that's not operative. Who has time to sing 1,000 songs?"

For more information on the concert, call 362-3705.