The invention comprises an ion beam focusing method and apparatus used as part of an ion beam injection system, which is used in conjunction with multi-axis charged particle or proton beam radiation therapy of cancerous tumors. The resulting thin beam has a long dimension that is formed by the concatenation of the cross-sectional portions of the original beam. The operating method includes: communicating the server and the BBU with each other; the BBU providing a status information and a previous self-discharging test information to the server for the server to judge a status of the BBU; and providing power from the BBU to the server and adjusting a loading of the server according to the status information of the BBU when an input power is interrupted. Then, a fourth measured voltage is determined, and the flow velocity re-determined from the third magnetic flux density, the fourth measured voltage and the determined interference voltage. More particularly, the integrated position determination system and communication system is horizontally balanced about the centerline of the range pole and is vertically balanced about a carrying point. A process for producing a water-soluble polymer is provided, which comprises polymerizing water-soluble radical-polymerizable monomers comprising a cationic radical-polymerizable monomer as an essential component in a presence of a polysaccharide, an azo polymerization initiator, and a hydrogen-abstracting agent.