Field measurement results of MQXA in KEK

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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Field measurement results of MQXA in KEK
Norihito Ohuchi KEK, High Energy Accelerator
Research Organization

• Field measurement results of MQXA-116
• (2) Geometrical measurement for alignment
• (3) Data process
• (4) Summary

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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING

• Measurement results of MQXA-116
• Transfer Function

After improvement of the warm tube
Average and standard deviation for 16 magnets
Magnet Current (A)
Average TF (T/m/kA)
Standard Deviation (T/m/kA)

392
31.543
0.016
2011
0.008
31.468
3208
31.387
0.008
187T/m
6184
30.305
0.010
201T/m
6677
30.102
0.012
216T/m
7228
29.923
0.013
Data for MQXA-3 during the 2nd thermal cycle is
not included.
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Effective Magnetic Length
Effective magnetic length for the straight
section, Leff-ST ( P21 - P5 ) 600 . For the
return end, Leff-RE 600 ? ( TFP23 ) / TF
. For the lead end, Leff-LE 600 ? ( TFP1 TFP3
) / TF .
Leff Leff-ST Leff-RE Leff-LE
Magnet Current (A)
Average Eff. Mag. Len. (mm)
Standard Deviation (mm)

392
6364.48
1.10
2011
0.98
6364.41
3208
6364.40
0.90
6184
6367.20
0.92
6677
6367.70
1.01
7228
6368.11
1.11
Data for MQXA-3 during the 2nd thermal cycle is
not included.
After improvement of the warm tube
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Field Quality _at_ Rref17mm (whole magnet _at_ 216 T/m)
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Field Quality _at_ Rref17mm (whole magnet _at_ 216 T/m)
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Average and standard deviation for 16 magnets
(whole magnet)
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
MQXA-116 bn as a function of current (_at_ magnet
center)
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
MQXA-116 an as a function of current (_at_ magnet
center)
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
MQXA-116 bn as a function of time _at_12.38 T/m
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
MQXA-116 an as a function of time _at_12.38 T/m
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
(2) Geometrical measurement for alignment
Sag of MQXA
P1
P2
P6
P7
P3
P4
P5
P8
SPn (LPn RPn) / 2
The base line (axis) is defined by the positions
at SP2 and SP7.
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Twist of MQXA
P1
P2
P6
P7
P8
P3
P4
P5
????? angle sPn (RPN - LPN) / 522 522 mm
Distance between the two fiducials
of the right and left side
Roll angle q ( 0.5 ? sP1 ? sPn 0.5 ? sP8)
/ 7 This angle is transferred on the plate at P1
by the scribe line.
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Straightness of MQXA
The straightness of MQXA is measured by the
fiducials on the top of the magnet.
CP1
CP2
CP6
CP7
CP8
CP3
CP4
CP5
The base line (axis) is defined by the positions
at CP2 and CP7.
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Magnetic center position (in z ) from the groove
in the lead end
L1, mm
L2, mm
L1, mm
L2, mm
3318.5
3319.4
MQXA-1
16.8
MQXA-10
15.1
16.5
17.3
MQXA-2b
3320.4
MQXA-11
3320.7
MQXA-3
15.5
3317.6
MQXA-12
15.8
3319.8
MQXA-4
17.0
3320.6
MQXA-13
14.8
3319.1
MQXA-5
16.8
3321.9
MQXA-14
17.0
3321.0
MQXA-6
14.5
3318.5
MQXA-15
3319.4
15.3
MQXA-7
MQXA-16
14.5
3318.1
3319.4
15.0
MQXA-9
12.2
3315.8
MQXA-17
MQXA-8
MQXA-18
3319.8
15.7
L1 distance from the groove L2 distance from
the scribe line on the magnet cylinder (15 mm
in design)
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Data Process (Correction of Transfer Function)
MQXA-116 transfer function as a function of time
_at_216 T/m
After improvement of the warm tube
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Harmonic coil center shift for MQXA-10 and MQXA-14
Before improving the warm tube
After improving the warm tube
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Time decay measurements at magnet center z4650mm
(magnet center) for MQXA before improving the
warm tube
(warming the harmonic coil)
By comparing the transfer functions during the
time decay measurements and the z-scan
measurements, we try to estimate the effect on
the harmonic coil geometry change by cooling.
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
For the data on the field gradient of 216 T/m,
MQXA-10
MQXA-14
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
For the data on the field gradient of 216
T/m correction with data of time dependence
measurements
Average and standard deviation for 16 magnets _at_
216 T/m
Magnet Current (A)
Average TF (T/m/kA)
Standard Deviation (T/m/kA)

29.923
0.013
7228
7228
29.945
0.010
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Data Process for MQXA-816 (Current dependence)
DC-loop measurements are preformed at z1350mm,
5850mm, 4650mm, 3450mm and 7650mm.
Lead end
Return end
Magnet body
Cn (Leff_at_1350/ Leff)? Cn_at_1350 (Leff_at_st/ Leff)?
(Cn_at_5850 Cn_at_4650 Cn_at_3450 )/3 (Leff_at_7650/
Leff)? Cn_at_7650
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Data Process for MQXA-17 (Current dependence)
Difference of b6 and b10 between the whole magnet
and the straight section
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2004/Feb./24-25 CERN-FNAL-KEK JOINT MEETING
Summary

• Field measurements for MQXA-116 were completed.
• Transfer functions data are influenced by the
  geometry change of the harmonic coil cooled from
  the warm tube. The data should be corrected and
  the method of correction is under consideration.
• Multipole components are stable over the 16
  magnets.
• The current dependence of multipole including the
  magnet ends will be reported for the MQXA-819
  magnets. For the early magnets, this measurement
  on the magnet ends was not performed. We try to
  make the dependence from the present data.
• The magnet geometry measurements were performed,
  and the magnetic center and the mid-plane were
  reported.