1. Estimation and Protection on Synchrotron Radiation in CEPC Main Ring
Shi Haoyu, Ding Yadong, Ma Zhongjian
IHEP,CAS
1st CEPC SRS Workshop

2. Shi Haoyu -- CEPC SRS Workshop
Outline
Harm of Synchrotron Radiation
Parameters of Synchrotron Radiation in CEPC
Simulation
Shielding Design for Magnets
Effects of the Shielding
Future Work
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

3. Shi Haoyu -- CEPC SRS Workshop
Outline
Harm of Synchrotron Radiation
Parameters of Synchrotron Radiation in CEPC
Simulation
Shielding Design for Magnets
Effects of the Shielding
Future Work
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

4. Harm of Synchrotron Radiation
Synchrotron radiation will induce:
Heating of the vacuum chamber
Radiation damage to machine elements
Formation of ozone and nitrogen oxides in the air
Leading to corrosion of machine components and health hazards for personnel
Radioactivity induced in components
Other issues……
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

5. Harm of Synchrotron Radiation
Direct:
Radiation Damage
Heat Deposition
Indirect:
Radioactivity
Noxious Gas
And so on
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

6. Shi Haoyu -- CEPC SRS Workshop
Outline
Harm of Synchrotron Radiation
Parameters of Synchrotron Radiation in CEPC
Simulation
Shielding Design for Magnets
Effects of the Shielding
Future Work
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

7. Shi Haoyu -- CEPC SRS Workshop
Parameters of SR
Direction of
Deflection
Dipole
Only consider SR produced in Dipole Magnet
SR produced in Quadrupole and Sextupole(except FFS) can be ignored
SR in Injection and Extraction Magnet will study in the future
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

8. Shi Haoyu -- CEPC SRS Workshop
Parameters of SR
Energy spectrum distribution:
Angular distribution:
Formulas listed in Appendix
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

9. Shi Haoyu -- CEPC SRS Workshop
Parameters of SR
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

10. Shi Haoyu -- CEPC SRS Workshop
Parameters of SR
Parameters
Symbols
Units
Values
Beam energy E
GeV
45.5 80
120
Beam current I mA
83.8
90.3
17.7
Bending radius ρ m
10900
Power per unit length P
W/m
42.62
438
435
Critical energy Ec
keV
19.01
103.3
348.8
Bending angle θ
mrad
2.844
Opening angle φ
μrad
11.23
6.387
4.258
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

11. Shi Haoyu -- CEPC SRS Workshop
Outline
Harm of Synchrotron Radiation
Parameters of Synchrotron Radiation in CEPC
Simulation
Shielding Design for Magnets
Effects of the Shielding
Future Work
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

12. Shi Haoyu -- CEPC SRS Workshop
Simulation
Tool: FLUKA, checked with MCNP
Source : Photon, not electron/positron
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

13. Simulation Assumption
Energy:
Lowest 1 keV
Highest 6 MeV
Gap 1keV
Written in Python
Number:
𝑁 𝑝ℎ𝑜𝑡𝑜𝑛 = 𝑃 𝐸 𝑎𝑣𝑒 ∙𝑡
2.363×1016m-1s-1
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

14. Simulation Assumption
Position:
Opening Angel ignored
Take the orbit of beam as straight line
Direction:
X-Z Plane
Left or Right
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

15. Shi Haoyu -- CEPC SRS Workshop
Outline
Harm of Synchrotron Radiation
Parameters of Synchrotron Radiation in CEPC
Simulation
Shielding Design for Magnets
Effects of the Shielding
Future Work
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

16. The Safety of Coils in Dipole
LEP
Spring-8
Materials
Upper dose limit in Gy
Fiberglass
108
Semi-organic coating
Epoxy resin
2×107
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

17. Shielding Design - Dipole
2 cm Lead
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

18. Shielding Design - Quadrupole
2 cm Lead
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

19. Shielding Design - Sextupole
2 cm Lead
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

20. Shielding Design – Vacuum Chamber
2 cm Lead
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

21. Shi Haoyu -- CEPC SRS Workshop
Outline
Harm of Synchrotron Radiation
Parameters of Synchrotron Radiation in CEPC
Simulation
Shielding Design for Magnets
Effects of the Shielding
Future Work
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

22. Effects – Dose in Dipole
Without
Shield
With
Shield
Without Shield
With Shield
Max Dose
5.11E5 Gy/Ah
1.89E4 Gy/Ah
Coil Life-time h h
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

23. Effects – Heat in Dipole
Total power 870 W/m
Beam direction: left W/m
Beam direction: right W/m
Al chamber
 199
186 
Cu chamber
 308
332
Dipole
 186
182
Lead A
 60.6
29.2 
Lead B
 33.5
80.0 
Lead C
 46.8
18.8 
Lead D
14.3
20.4 
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

24. Effects – Heat in Dipole
Total power 870 W/m
Without Shield
With Shield
Al Chamber
199
Al chamber
 199
Cu Chamber
310
Cu chamber
 308
Dipole
255
 186 -
Lead
 155.2
Air
106
21.8
Total Bending Length: ~68,452 m
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

25. Effects – Heat in Dipole
Total power 59.6 MW/turn
Without Shield
With Shield
Al Chamber
13.6
Al chamber
Cu Chamber
21.2
Cu chamber
 21.1
Dipole
17.5
 12.7 -
Lead
 10.6
Air
7.3
1.49
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

26. Effects – Dose in Quadrupole
Without
Shield
With
Shield
Without Shield
With Shield
Max Dose
4.69E5 Gy/Ah
0.82E4 Gy/Ah
Coil Life-time h
1.37E5 h
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

27. Effects – Heat in Quadrupole
Total power 870 W/m
Beam direction: left W/m
Beam direction: right W/m
Quadrupole
 279
268
Lead A
 37.8
36.4 
Lead B
 18.1
21.7 
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

28. Effects – Dose in Sextupole
With
Shield
Without
Shield
Without Shield
With Shield
Max Dose
3.25E6 Gy/Ah
1.67E4 Gy/Ah
Coil Life-time
347.67h h
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

29. Effects – Heat in Sextupole
Total power 870 W/m
Beam direction: left W/m
Beam direction: right W/m
Sextupole
 179
174
Lead A
 95.1
107 
Lead B
 60.3
43.1 
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

30. Effects – Dose in Magnets
Dose in Gy/Ah with/out Shield in Magnets
Magnets
Dipole
Quadrupole
Sextupole
Without Shield
5.11E5 Gy/Ah
4.69E5 Gy/Ah
3.25E6 Gy/Ah
With Shield
1.89E4 Gy/Ah
0.82E4 Gy/Ah
1.67E4 Gy/Ah
Coil Life-time with/out Shield in Magnets (44000h/yr)
Magnets
Coil Life-time Without Pb
Coil Life-time
With Pb
Dipole
0.5 yr
13.59 yr
> 10 yr
Quadrupole
0.54 yr
31.32 yr
Sextupole
0.08 yr
15.38 yr
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

31. Dose Distribution in Tunnel without Shield
Gy/Ah
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

32. Shi Haoyu -- CEPC SRS Workshop
Outline
Harm of Synchrotron Radiation
Parameters of Synchrotron Radiation in CEPC
Simulation
Shielding Design for Magnets
Effects of the Shielding
Future Work
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

33. Thanks for your attention
Future Work
The Extraction of the SR
The Simulation of SR in other magnets
The Improvement of simulation
Thanks for your attention
2018/11/15
Shi Haoyu -- CEPC SRS Workshop

34. Shi Haoyu -- CEPC SRS Workshop
Appendix
SR critical energy：
Solid degree 𝜑 ：
𝐸 𝑐 𝑘𝑒𝑉 =2.2 𝐸(𝐺𝑒𝑉) 3 𝜌(𝑚)
𝜑= 1 𝛾 = 𝑚 0 𝑐 2 𝐸 = 𝐸 𝑒 (𝐺𝑒𝑉)
~ keV
SR Power：
Number of photons (Method 1)：
𝑃 𝑊 𝑚 =14.1 𝐸 𝐺𝑒𝑉 4 𝐼(𝑚𝐴) 𝜌(𝑚) 2
𝑁 𝑝ℎ𝑜𝑡𝑜𝑛 = 𝑃 𝐸 𝑎𝑣𝑒 ∙𝑡
~ 435 W/m
Number of photons (Method 2)：
SR spectrum：
𝑑𝑁 𝑑𝑠 = 0 ∞ 𝐸 𝑐 𝑑 2 𝑁 𝑑𝜀𝑑𝑠 𝑑𝑟=
𝐸 𝜌 0 ∞ 𝑟 ∞ 𝐾 𝜂 𝑑𝜂𝑑𝑟=19.4 𝐸 𝜌
𝑆 𝜔 = 𝜋 𝜔 ∞ 𝐾 (𝜂)𝑑𝜂
𝜔= 𝜔 𝐸 𝜔 𝑐
2018/11/15
Shi Haoyu -- CEPC SRS Workshop