Experimental study of channel electron multiplier

Background Channel electron multiplier (CEM) can be used to measure extremely few charged particles, such as electrons and ions. The CEM is widely used in particle detection, so it is very important to study their performance parameters.
Purposes Test and analyze the performance parameters of the CEM, such as resistance, gain, and pulse output for a single entrance photoelectron.
Methods The heated tantalum filament is used as a stable and adjustable planar electron source to test the performance of the CEM in the analog mode. The performance parameters of the CEM in the pulse counting mode are tested by using the ultraviolet LED to excite the gold photocathode to generate a single photoelectron.
Results and conclusions The gain of the CEM in the analog mode can reach more than 10⁶ and the gain in the pulse counting mode can be two orders of magnitude higher. The curved helical channel has a greater advantage than the ordinary straight channel, which is conducive to weakening the ion feedback phenomenon.