Disclosed herein is a photomultiplier tube (PMT) comprising: an electron ejector configured for emitting primary electrons in response to an incident photon; a detector configured for collecting electrons and providing an output signal representative of the incident photon; and a series of electrodes between the electron ejector and the detector, wherein each of the electrodes is configured for emitting secondary electrons in response to incident electrons, and each of the electrodes includes a bi-metal arc-shaped sheet.