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.