1. In Vacuum Magnetic Field Measurement System for CPMU of HEPS-TF
Wan Chen,Shuchen Sun, Lingling Gong, Zhiqiang Li, Huhua Lu
Institute of High Energy Physics, CAS，CN
IMMW Taiwan Hsinchu

2. Outline
1. Introduction of HEPS(HEPS-TF) 2. Measurement Requirements of CPMU 3. Challenges 4. Solutions of other Labs 5. Our proposal 6. New status and Next steps

3. 1. Introduction of HEPS High Energy Photon Source High energy: 6GeV
Low emmitance: <0.1nm·rad(0.01nm·rad)
Brilliance: >1022phs/s/mm2/mrad2/0.1%BW

4. The schedule of HEPS construction
HEPS-TF: R&D of HEPS
HEPS-TF project was approved in Feb. 2015
The preliminary research was supported by IHEP.
HEPS
Construction will start in 2018.
Commissioning in 2023.

5. 2. Measurement Requirements of CPMU
CPMU is for Time-Resolved Beamline
Physical parameter
Type
Hybrid
Period Length
13.5 mm
Working Gap
5～9 mm
Peak Field
1.0 gap=5mm
Phase Error (RMS)
< g=5-9mm
First Field Integral
<100Gs·cm
Second Field Integral
<20000Gs·cm2
Quadrupole Normal/Skew
<50Gs
Sextupole Normal/Skew
<100Gs/cm
Octupole Normal/Skew
<100Gs/cm2

6. CPMU physical design Magnet material: PrFeB
Working temperature:<85K
Unti-symmertry

7. CPMU performance measurement
Magnetic field measurement at room temperature and cryogenic temperature
Local field mapping
Phase error(RMS)
I1 and I2(vertical and horizontal)
Harmonic field
Hall probe measurement system
Stretch Wire measurement system

8. 2. challenges Small gap and Closed structure
-the space for measurement system is very limited . Conventional measurement system is inapplicable
In vacuum and cryogenic undulator
-the materials of measurement system should suit in vacuum environment.
short period length(13.5mm)
-Undulator field with shorter λu is more sensitive to spatial positioning

9. 3. Solutions of other Labs
ESRF
SOLEIL
Spring-8
HZB

10. 4.Our proposal
Measurement of magnetic modules at room temperature：

11. in vacuum magnetic field measurement system
CPMU magnetic field performance Measurement before and after installing the vacuum chamber
SW system
Hall probe system

12. Specification of Hall probe system
Vertical position tolerance: 30um
Horizontal position tolerance: 30um
Longitudinal position tolerance : 10 um
Roll tolerances: 150urad
Yaw tolerances: 50urad
Pitch tolerances: 133urad
Zachary Wolf, “Requirements For The LCLS Undulator Magnetic Measurement Bench”, LCLS-TN-04-08, August 23, 2004, SLAC

13. Guide rail position adjustment
Mechanical structure
support
2-axis stage:
Guide rail position adjustment

14. Mechanical structure Longitudinal range:3000mm Horizontal range:10mm
Vertical range:5mm
motor
2- axis Piezo actuator

15. critical points of mechanical structure
All materials of the measurement system in the vacuum chamber are non-magnetic material.
Guide rail –AL or Ti
Piezo actuators…..
The materials of the measurement system can be used in vacuum environment
Cable
lubricant….

16. Position monitor Laser scale PSD interferometer
longitudinal position reading
PSD
Nonlinearity error of longitudinal axis and roll error monitoring
interferometer
Pitch and yaw errors monitoring

17. Correction of the position error
The deviation of X and y axis along the longitudinal direction.
Dynamic correction by X / Y axis piezo actuators
Yaw
corrected by data analysis

18. Hall probe 3 hall sensors-Bx,By,Bz PT100 FW-BELL GH701
Ceramic substrate
PT100

19. critical points of Hall probe
calibration of Hall sensors
Temperature dependence of flux density(voltage)
Coefficient of flux density and voltage
Relative positions and orthogonality of 3 Hall sensors will be calibrated
Reference “ Status of magnetic measurements at ALBA, J. Campmany”

20. Stretch wire system
Data acquisition:
2182A
Φ0.125mm beryllium copper

21. Now status and Next steps
The design scheme has been accepted
Next steps
Hall Probe manufacture
Design scheme optimization
Call for tender ……

22. Thank you for your attention