Abstract: A modular channel electron multiplier mounting arrangement for an analytical instrument, which reduces the labor required for assembly and, at the same time, results in a more rigid structure with lower susceptibility to microphonic noise has been developed. A circuit board and an attached end support has slotted portions for engaging support studs on the instrument. A channel electron multiplier is mounted on the circuit board by means of supporting hardware. Printed circuit wiring on the circuit board carries signal and high voltage to receptacles on the circuit board which when installed in the instrument are aligned for securely engaging leads in the instrument. The end support and the receptacles rigidly support the assembly in the instrument such that microphonics noise is significantly reduced.