SLAC Magnetic Measurements
Date: 02-13-1995
Time: 14:46:25

Magnet Name: 2Q4-16
Project: PEP II Injection Line
Test Stand: Rotating Coil Stand 2
Measurement Coil: DC100
Operator: Wendy Sibbring
Run Number: 5
Comment: Standard Run/O-Rings broke

Standardization Currents (A):
    45.0     2.0    45.0     2.0    45.0     2.0

Test Currents (A):
     3.0     6.0     9.0    12.0    15.0    21.0    24.0
    27.0    30.0    36.0    40.0    45.0    40.0    30.0
    20.0    10.0



                   INTEGRATED GRADIENT VS CURRENT

Double Coil: Effective Radius =  .0268618  m, # Turns =  30 
Average: # Rotations/Measurement =  10 , # Measurements =  4 

  Imag    sigImag    GL     sigGL     GL/I   sigGL/I 
  (A)       (A)      (T)     (T)     (T/kA)   (T/kA) 
--------+-------- --------+-------- --------+--------
   3.000    0.000  0.05169  0.00002  17.2285   0.0081
   6.001    0.000  0.09455  0.00002  15.7559   0.0026
   9.001    0.000  0.13823  0.00001  15.3576   0.0011
  12.001    0.000  0.18233  0.00005  15.1930   0.0043
  15.002    0.000  0.22683  0.00021  15.1200   0.0139
  20.998    0.000  0.31615  0.00010  15.0559   0.0047
  23.998    0.000  0.36092  0.00007  15.0394   0.0028
  26.997    0.000  0.40603  0.00021  15.0400   0.0079
  29.997    0.000  0.45078  0.00008  15.0276   0.0027
  35.998    0.000  0.54078  0.00031  15.0226   0.0086
  39.996    0.000  0.60082  0.00035  15.0218   0.0087
  44.995    0.000  0.67530  0.00030  15.0083   0.0066
  39.995    0.000  0.60470  0.00014  15.1194   0.0036
  29.997    0.000  0.45809  0.00025  15.2709   0.0083
  19.998    0.000  0.30887  0.00026  15.4450   0.0132
  10.001    0.000  0.15865  0.00006  15.8629   0.0061


           SUMMARY OF THE CALCULATIONS AND CONVENTIONS USED


Calculation of GL using a double coil (assumed flat):
V2 = (Nturns * velocity * B2 * L)_1 + (Nturns * velocity * B2 * L)_2
   = (Nturns1 * Rcoil1 * ang_freq * GL * Rcoil1)
          + (Nturns2 * Rcoil2 * ang_freq * GL * Rcoil2)
   = (Nturns1 * Rcoil1^2 + Nturns2 * Rcoil2^2) * ang_freq * GL
If Nturns1 = Nturns2 == Nturns12, then
V2 = Nturns12 * (Rcoil1^2 + Rcoil2^2) * ang_freq * GL
Let Reff^2 = Rcoil1^2 + Rcoil2^2, then
V2 = Nturns12 * Reff^2 * ang_freq * GL
Or,
GL = V2 / (Nturns12 * Reff^2 * ang_freq)


Calculation of the harmonics:
The integrated radial field for the n'th harmonic at the
coil radius is given by
BLn(th) = BLn * cos(n*(th - THspole))
The coil voltage is V = Nturns * v_theta * B_r * L
Vn(th) = Nturns * velocity * BLn(th)
       = Nturns * Rcoil * ang_freq * BLn * cos(n*(th - THspole))
The FFT gives Vn and PhiVn in the formula
Vn(i) = Vn * cos(n*2pi*i/N + PhiVn)
Then,
Vn = Nturns * Rcoil * ang_freq * BLn
PhiVn = - n * THspole
Or,
BLn = Vn / (Nturns * Rcoil * ang_freq)
THspole = - PhiVn / n


Calculation of the magnetic center:
Xcenter = - (1/GL) * BL1 * sin(THspole1)
Ycenter = - (1/GL) * BL1 * cos(THspole1)