A method for operating a peer network on a computer network is presented. Each of the N species has a spectral absorption band. A plurality of grid electrodes 2 is prepared in such a way that a column of the grid electrodes corresponds to two columns of the anode electrodes 3 and each of the anode electrodes 3 and the grid electrodes 2 are divided into two areas to form anode wiring patterns in the form of quadruple anode matrix at each of the area. The transformed query may be applied against the transformed sensitive data to construct a query result. The spindle unit is attached to the support shafts by means of a plurality of second screw members that are screwed to the support shafts and are manipulatable from the outside.