The crown chakra is known in Sanskrit terms as Sahasrara.
The crown chakra is activated through being, not through doing like the lower chakras.
The sacred tone to chant for the crown chakra is um.
The corpus gives this center a tone to chant rather than a frequency: um. That is a practice, and it does not need a scan.
What is not claimed here. The material does not say what closes a center or what opens one, so neither do we. The familiar red-to-violet color chart is a twentieth-century Western arrangement rather than an ancient one, and the Sanskrit sources describe the colors differently again.
This one is not scanned. The crown is solid bone. A tone meets it and turns back rather than answering, the way a voice returns off a wall. There is nothing here that sounds like you, and inventing one would make everything else we tell you worth less. Offering a reading here would mean generating one, so we do not.