First estimate of the nucleon numbers by VP This is what I have: From the measured vapor pressures, I estimate the temperatures, by looking at a graph I made of P vs. T (I need to invert the function to get more precise answers). For hydrogen, deriving T is straight forward; for deuterium, I start with the assumption that it is pure D2 to get T. From these temperatures, I derive the molar densities of H2 and D2, as well as HD and H2 in the D2 vessel: H2: P = 14.9 psi => T = 20.315 K => rho(H2) = 0.03509 mol/cm3 D2: P = 15.1 psi => T = 23.615 K => rho(D2) = 0.04034 mol/cm3 rho(HD) = 0.03684 mol/cm3 rho(H2) = 0.03302 mol/cm3 From the logbook, the HD fraction per volume in the D2 vessel is 2% and the H2 fraction 3%. From this, I get Number of protons in H2 target: Np(H2) = 0.07018 * N_A * V(H2) Number of protons in D2 target: Np(D2) = 0.08010 * N_A * V(D2) Number of neutrons in D2 target: Nn(D2) = 0.07738 * N_A * V(D2) where V is the volume of the H2 or D2 vessel, and N_A is Avogadro's number. For a more precise determination, I need to iterate (calculate the real D2 pressure, recalculate the temperature, then the pressures of H2 and HD in D2, and repeat until it converges). I would like to automate it, but for this I have to invert the formula I mentioned above (and do it without sacrificing much accuracy). I will also need to check the formulas I am using, because one number in the thesis I was looking at did not agree with the formula, but the number I get makes more sense, i.e., the HD molar density at a given temperature is half-way between the H2 and D2 densities. Let me know if these numbers make any sense, though. Vassili