1. Recent SCRF Activities in IHEP
Jiyuan Zhai (IHEP, China)
LCWS Workshop
Strasbourg, France, Oct. 24, 2017

2. Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France
Outline
Cavity and N-doping
Variable power coupler
SRF infrastructure
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

3. Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France
TESLA 9-cell Cavity
T-mapping
27.3 7π/9
23.9 π, 4π/9
TESLA FG 9-cell cavity by HERT (new vendor). Processed and tested at KEK. Two more TESLA cavities in fabrication by HERT (material delivered).
High gradient and N-doping / infusion study.
23.8 6π/9
Equator 1
175 deg
~400 μm
EBW spatter?
Equator 2
135 deg
~200 μm
Pit after EP1
Equator 2
175 deg
~200 μm
Pit after EP1
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

4. Furnaces for N-doping/infusion
1) Old Furnace at IHEP
Diffusion pump, not oil free
N-doping failed
not suitable for high Q
2) Furnace at OTIC
Cryo-pump
Successful N-doping
Tantalum heater (not molybdenum). N-infusion not allowed
3) New Furnace at PAPS
Ordered and will deliver in mid 2018
for N-doping & N-infusion
Maximum operation temperature: 1200 ℃
Effective heating zone: Ф 600 mm x 1500 mm
Vacuum pressure at 900 ℃: < 1e-4 Pa
Oil-free pump system with two cryo-pumps (CTI OB400)
N2 injected with feedback controller
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

5. Furnaces for N-doping/infusion
4) New Small Furnace at IHEP (just delivered)
For N-doping and infusion of Nb sample and 1.3 GHz single-cell cavity
Φ300 mm × 500 mm
Outside heating
Cryopump 2500 L/s for H2
MFC vent controlling
Ultimate vacuum
25℃ : 6E-7Pa, 850℃: 2.4E-5Pa
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

6. SIMS Results of N-doping Samples
Doping with Furnace at IHEP
Doping with Furnace at OTIC
after ~5 um EP, N, NbN and CsN all disappear.
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

7. 650 MHz Single-cell Cavity
Before N-doping
Shielded dewar, remnant magnetic field 20 mG. Additional magnetic shield around cavity.
N-doping and BCP treated. Preliminary test result seems to show higher Q0, but lower gradient.
130um BCP + 3 h 750 C annealing + 30um BCP C bake 48 h
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

8. Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France
IHEP EP Facility
In design and construction
Located at OTIC Ningxia
Commission in mid 2018
In collaboration with KEK
Flow chart of acid mixing and storage unit
Flow chart of circulation unit
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

9. Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France
Outline
Cavity and N-doping
Variable power coupler
SRF infrastructure
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

10. Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France
1.3 GHz Variable Coupler
@ CW, 20kW,TW
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

11. Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France
1.3 GHz Variable Coupler
Mechanical design finished. Prototypes fabrication will start soon.
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

12. Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France
Outline
Cavity and N-doping
Variable power coupler
SRF infrastructure
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

13. Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France
PAPS SRF Facility
4500 m2 SRF lab in the Platform of Advanced Photon Source Technology R&D (PAPS), Huairou Science Park, Beijing.
Construction and facility commissioning:
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

14. Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France
PAPS SRF Facility
Mission: World-leading SRF Lab for Superconducting Accelerator Projects and SRF Frontier R&D.
Mass Production: 200 ~ 400 cavities (couplers) test per year, 20 cryomodules assembly and horizontal test per year.
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France

15. Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France
Summary
IHEP R&D works on 1.3 GHz 9-cell cavity and power coupler continue for ILC.
N-doping/infusion study ongoing and will ramp up with EP facility ready in mid 2018.
A large SRF lab with advanced facilities will be ready in for the future R&D and large SRF projects (SCLF, ILC, CEPC …).
2017/10/24
Jiyuan Zhai (IHEP, China), LCWS2017, Strasbourg, France