Mass difference calculation

Mass difference calculation
Enter mass number (A) and atomic number (Z) of the desired beam.

A =
Z =



Comments about isobar separation at HRIBF:

  • Isobaric mass differences are given as
    M/dM = A * 931.5 / (dM1 - dM2)
    where dM1 is the mass excess of the desired beam and dM2 is the mass excess of the neighboring isobars. Mass excess values are from the 1995 mass table of Audi and Wapstra; this table has been augmented by Moeller & Nix calculations for proton-rich nuclei in the A=90-106 region. Moeller & Nix values are indicated with "M&N" in the systematics column.
  • The isobar separator has a resolving power of M/dM~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 * dM/M (or dE/E if energy spread dominates).
    This corresponds to 0.258 mm for M/dM = 20,000.
  • Partial isobaric separation will usually be possible for M/dM<10,000, but may result in reduced beam intensity.

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

This file last modified Tuesday July 26, 2005