(Solid+gas) equilibrium studies for neptunium dioxide

The vaporisation behaviour of americium dioxide by use of mass spectrometry

“…The final Am content (in wt.%) was determined by gravimetric analysis before and after the infiltration step, with an absolute accuracy of about 1%. The O/ (Pu + Am) ratio obtained by this treatment is estimated to be between 1.75 and 1.85, typical for these sintering conditions [10]. It should, however, be noted that these values are not representative for the temperatures at which the mass spectrometric measurements in this study have been made.…”

Mass spectrometric studies of the vapour phase in the (Pu+O) system

“…A significant difference between vacuum and oxygen conditions is observed, indicating that a shift in composition occurred and the variation of the PuO 2 pressure with temperature is dependent on the composition of the condensed phase. In contrast, the vapour pressure of NpO 2 does not change under similar conditions [22]. The slightly higher PuO þ 2 signal observed in oxygen (figure 7) compared to the measurements in vacuum (figure 3) at similar temperature, indicates that the sample clearly has a higher O/Pu ratio.…”

“…The temperature recording of the Knudsen cell assembly was calibrated by measurement of the melting points of standard materials (Zn, Cu, Fe, Pt, Al 2 O 3 ), as described in a former publication [22]. Temperature is a very important parameter in mass spectrometry as the vapour pressure function is directly dependant on it according to the basic mass spectrometry relation [23,24]:…”

Thermodynamic investigation of Na2U2O7 using Knudsen effusion mass spectrometry and high temperature X-ray diffraction

“…The effusion orifice surface was calculated from its diameter. The expression of Santeler [40] for a cylindrical channel was used for the Clausing factor, as detailed in another publication [41]. The combination of equations (6) and (7) yields the following expression for the total mass effused Dm i ¼ P G i over a period of effusion Dt ¼ P dt (i.e.…”

“…Isothermal scans of the ion intensities were obtained by increasing the cathodic voltage stepwise by 0.5 eV. The applied cathodic voltage was corrected as described previously [41,42] to give the effective electron energy with errors corresponding to a standard deviation of 1r.…”