ADJUSTABLE STRONG PERMANENT MAGNET FOR FINAL FOCUS QUADRUPOLE. T. MIHARA, Y.IWASHITA Kyoto University M. KUMADA N.I.R.S. C.M.Spencer S.L.A.C. The first prototype of “superstrong” Permanent Magnet Quad. Soft iron. PM. Axial view. Cut plane view. PHOTO.
T. MIHARA, Y.IWASHITA Kyoto University
M. KUMADA N.I.R.S.
Cut plane view
Integrated strength GL=28.5T (29.7T by calc.)
magnet size. f10cm
Field gradient is about 300T/m
Double Ring Structure QUADRUPOLE–Adjustable PMQ-
First Quadrant shows the flux plot.
The double ring structure
PMQ is split into inner ring and outer ring. Only the outer ring is rotated 90around the beam axis to vary the focal strength.
Definition of “ QUADRUPOLESwitched-On” Length
16 series of outer ring switching
Design Parameter of QUADRUPOLEthe Adjustable PMQ
Outgoing beam line is 7cm distant from incoming beam line.
Outer ring is rotated by DC motors.
Measurement with Rotation Coil @SLAC QUADRUPOLE
Strength variability QUADRUPOLE
Integrated strength is proportional to the “switched-on ” length
It allows us simple adjustment
This PMQ can generates GL 1/5 of the maximum GL.
X center and Y center shift when GL is changed. Mechanical adjustment may reduce shift.
Fig. shows the skew rotation angle as the function of switched-on length.
This will be reduced by adjustment.
NBS (For Head on)
SBS (For 2mrad)
MBS (For 7mrad)
LBS(2nd prototype)(For 20mrad)
NBS=No Beam Separation, SBS=Small Beam SeparationMBS=Medium Beam Separation, LBS=Large Beam Separation