A robust Electron Multiplier detector option is available for all XT and XTP systems. This detection enhancement system operates by converting each ion into an avalanche of electrons. This results in a current amplification which may approach a million. Practical amplifications of a thousand to ten thousand can increase instrument sensitivity by an equal amount. Perhaps most importantly, a desired spectral signal to noise ratio may be achieved in less than 1/1000 of the time as for the equivalent Faraday detector scan.
The XT100M, XT200M, XT300M, XTP-100M, XTP-200M and XTP-300M come with the electron multiplier detection installed. As a field installable upgrade, the multiplier detection system may be added to any of Extorr's 100, 200 and 300 amu systems. The continuous dynode multiplier is installed into the probe by hand. On an XT the upgrade also needs a high voltage mini-module placed into the CCU electronics.
Just as for the ionizer filament and the RF, the built-in Pirani and BA ion gauge protect the multiplier against over pressure. For non-interfering portions of the residual gas spectrum, the multiplier detection system allows for partial pressure readings of lower than 10-14 Torr.