Mass Difference Calculation (2003 Table)

Mass Difference Calculation (2003 Table)
Enter mass number (A) and atomic number (Z) of the desired beam.

A =
Z =



Comments about isobar separation at HRIBF:

  • Mass excess values are from the 2003 mass table of G. Audi, A. H. Wapstra and C. Thibault, Nuclear Physics A729 (2003) p. 337-676. This version of the Mass Table was taken from NNDC at BNL;
  • Isobaric mass differences are given as
    M/ΔM = A1 * 931.494013 / (M1 - M2)
    where M1 is the mass of the desired beam and M2 is the mass of the neighboring isobars.
  • The isobar separator has a resolving power of M/ΔM~20,000; however, the isobaric separation actually achieved will depend not only on isobaric mass differences but also on the beam emittance, energy spread, and isobar intensity ratios.
  • The dispersion of the isobaric separator is given by:
    dx(mm) = 5163 * ΔM/M (or ΔE/E if energy spread dominates).
    This corresponds to 0.258 mm for M/ΔM = 20,000.
  • Partial isobaric separation will usually be possible for M/ΔM<10,000, but may result in reduced beam intensity.

For questions about this page please contact the HRIBF User Liaison.

This file last modified Monday August 18, 2008