Isobar Magnetic Field Calculation (2011 Mass Table)

Comments about isobar separation at HRIBF:

• Mass excess values are from the 2011 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/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.
• 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.
• Energy is determined by the anode voltage (+0.150 kV), ion source voltage (+/-40 kV), and platform voltage (+/-160 kV). Typical energy for injection into the tandem is 200.15 keV.