Is the screw in the picture called a hexagon socket head cap screw? What is the tool for removing this screw? Where can I buy ah?

From this top view, it looks similar to a hexagon socket screw, and the disassembly tool is generally available at hardware stores. If you want to disassemble that screw on top, you may be able to remove it with a pair of sharp-nosed pliers, just jam the pliers in the two opposing notches, hold it tight and then rotate it counterclockwise. Of course, using a vise will work, but it's best to ask the medical instrument manufacturer for specialized tools