BX versus X at Y= 0 and 4 mm for Model of Wiggler 10
and
Effect of Azimuthal Tilt of Upper Half of 8-Pole Wiggler
CESRc Working Group Meeting
6 February 2004
- Recently the first measurements of the horizontal field component as
a function of horizontal position along lines vertically displaced
from the mid-plane at the center of each pole
were shown for an 8-pole wiggler. I have made such
plots for the wiggler field modelling. The model for Wiggler 10 was chosen,
because it has a significant A1 component which is consistent with
earlier measurements of Bx vs x on the midplane. The model shows
curvature in Bx versus x at Y= 4mm which is similar to that observed
in the measurements.
- An azimuthal rotation of 0.5 degrees (10 mrad) of the upper half of the
8-pole wiggler was modelled at the request of SSC. This corresponds to
a separation change of 2 mm between the top and bottom halves over
the full width of the wiggler (24 cm). The gap is nominally 76 mm, so
it varies by 1% over 10 cm in this model. The vertical component was
found to vary
by 0.8%, as in the plot below. The integral of the vertical component
(B0) changes by 1 gauss-m and the skew quad component (A1) was found to change
by less than 0.1 gauss-m/cm. The fourth plot below shows the induced
horizontal field component to vary by +-80 gauss along the axis of
the wiggler.
Since these values remain within specification and
the maximum rotation found by SSC for any wiggler so far is 1.5 mrad,
such a rotation is unlikely to be the source of significant
higher multipoles in the wiggler field.
Creation date: 02/09/04.