  This paper discusses the emittance growth produced by sextupole fields in
conjunction with a solenoidal focusing. The sextupole emittance is derived and
compared with numerical simulations using a measured sextupole field for a
vacuum chamber in a solenoidal field. It is found that the sextupole emittance
is dominated by the field's radial non-linearity and the growth due to the skew
angle is much smaller. It is shown that a corrector sextupole placed after the
sextupole-solenoid system is effective at cancelling this emittance growth.
Leaving only the growth due to the solenoid's spherical aberration.
