A method of designing the electrical breakdown protection in the vacuum chamber for multiple-layer ion mobility cyclotron devices at the elevated pressure is proposed. The protection designed devices include electrical shield for cyclotron PCB inlet and outlet, the insulation plates for multiple layers of cyclotron and the shield for electrical feedthroughs. The non-conductive plates are mounted in between the ion mobility cyclotrons for physically supporting and for electrical insulation purposes. The spacing of the PCBs can be adjusted by replacing different height of the spacers at the corners and edges of the plates. Special shields are also designed to extend the highest allowable voltage difference applied on adjacent electrodes at an elevated pressure environment.