**P _{0} = r_{0}B_{0}cKk´**

**where P _{0} is the central momentum in units
of eV/c, r_{0} is the design bend radius of the spectrometer (r_{0}
= 8.4 m), B_{0} is the central magnetic field in the spectrometer
in tesla, c is the speed of light in ms^{-1}, K is a correction
factor for fringing fields in the dipole (K = 1.00708), and k´ is
a correction factor for a known misalignment of the Q3 quadrupole (k´
= 0.999833). The uncertainty on the absolute value of P_{0} is
estimated to be plus or minus 2 x 10^{-3} of the value of P_{0}.
An expression is also given for the determination of B_{0} based
on the field read in the "low field" NMR probe.**

Go to the Hall A Technical Notes Home Page