Specialized mass spectrometer for determining the isotopic composition of lithium by ERIAD (electrospray with in source atomization)

A specialized isotope mass spectrometer for determining the isotopic ratio of lithium by ERIAD (electrospray with atomization in an ion source) is described. The device uses a Mattuha–Herzog-type mass analyzer with double focusing to use ion beams with a large spread in energy and simultaneous registration of signals of both lithium isotopes ($^6$Li and $^7$Li), and a two-channel receiver based on a doublet of microchannel plates. The gas-dynamic interface is built according to the Kontorowitz–Gray scheme; from the gas-dynamic point of view, it is “long”, that is, the distance between the nozzle and the skimmer is 4 times the size of the “Mach barrel” at the operating pressure (200 Pa). The device is desktop, its weight does not exceed 20 kg. The measurement time is 1000 s, sample replacement time is 100 s, measurement accuracy is $\sim$0.1%.