A new ion source assembly for Knudsen cell mass spectrometry

Mass spectrometric determination of the thermodynamic excess properties of ternary Fe–Co–Cr melts

“…The technique of Knudsen cell mass spectrometry is to determine the vapor pressures from the effusion of vaporized sample material out of an isothermal vessel which is called "Knudsen cell" [3][4][5]. Usually the Knudsen cells are manufactured as (cylindrical) crucibles with a small knife-edge shaped orifice (0.5-1.5 mm diameter) in the lid.…”

“…where T is the temperature in K, x k is the mole fraction of component k, D I is an instrumental geometric constant, and D k (T) is an isotope specific constant (for details see [3]). Using this proportionality the thermodynamic evaluation can be based upon the well known relation between the partial molar excess Gibbs energies G E k (molar excess chemical potentials µ E k ) of alloy components k (in this work: k = Fe, Cr) in condensed phases and the partial pressure p k of the corresponding gas phase:…”

“…(1) depends strongly on the actual position of the Knudsen cell with respect to the ion source, however [3,4].…”

Thermodynamic parameters of liquid cobalt‐palladium alloys by computer‐aided Knudsen cell mass spectrometry

“…where DI, and D,(T) are an instrumental geometric constant, and an isotope specific constant, respectively [5]. In the validity range of Eq.…”

“…However, the value of the geometric factor DI depends Ftrongly on the actual position of the Knudsen cell with respect to the ion source [5]. With binary alloy system -as the investigated Co(1) -Pd(1) -this problem can be overcome conveniently by determining the thermodynamic mixing functions ZE from the difference of the molar excess chemical potentials of the two alloy components Co and Pd, (,uFd-,uEo), which is independent of the geometric constant DI, identical experimental conditions for the measurements of the ion current intensities of the both alloy components supposed …”