1. X-band and high-gradient development plans at Tsinghua University
Wei Gai (Tsinghua/ANL)
4-9 December 2016
 LCWS2016, Aiina Certer & MALIOS in Morioka, IWATE (Japan)

2. Outline Overview of X-band at Tsinghua Development of Structures
Preparations for the test stand
Summary

3. X-band HG at Tsinghua University
CLIC-study collaboration (From 2009)
“Choke-mode damped structure”, design, producing, …
T24_THU_#1 structure
Single-cell choke
TD24-choke
Tsinghua Thomson scattering source
Status
Upgrade
New X-band power source

4. Tsinghua Production – Key facilities to HG
High-precision machine tools
and CNC Machine
Clean room for RF Measurement
Hydrogen furnace

5. Outline Summary Overview of X-band at Tsinghua
Development of Structures
Preparations for the test stand
Summary

6. Development of T24_THU_#1
X-band high gradient structure，frequency：11.424GHz
Bench test, diffusion bonding, brazing, tuning and Vacuum bake at Tsinghua
T24 is high-gradient prototype accelerating structure for CLIC main linac
Bench test
Diffusion bonding
T24 at KEK

7. High power test of T24_THU_#1
High power test was carried out in Nextef at KEK
Running at 110 MV/m, 250 ns stably
Very good performance!
T24 during the high power test

8. Diffusion bonding test Single-cell structures
Choke-mode structure
Study X-band high gradient choke-mode damped structure
New choke design meets the CLIC requirement of wakefield suppression
Three single-cell choke-mode structures were designed, fabricated to study the performance of choke under high power
THU-CHK-G1.68/THU-CHK-G2.1/THU-REF
High power test ongoing at KEK
RF design
Diffusion bonding test
Single-cell structures

9. High power test of Choke-mode
THU-CHK-G1.68 can reach a maximum gradient of 75 MV/m
Two types of breakdowns were observed during the test
Breakdown with current flash-breakdown in the cavity
Breakdown without current flash-breakdown in the choke
Further analysis still ongoing

10. A X-band (Copper) Power Extractor for ANL

11. C3 structure at 11.7GHz
Design at ANL, 3 regular cells + 2 matching cells
Brazing design

12. C3 structure at 11.7GHz Drive off Drive on Drive Beam RF Witness Beam
Higher energy

13. Outline Overview of X-band at Tsinghua Development of Structures
Preparations for the test stand
Summary

14. Location of X-band high power test stand
Layout of accelerator laboratory at Tsinghua University
X-band structures
X-band klystron
Main experimental hall
（TTX）
Square hall
实物图来不及制作，所以先用一些简单的结构代替
Aisle

15. X-band high power test stand
Preparations for the test stand
Available
Ordered
Designed
In design
Variable RF power splitter
X-band structures
Vacuum pumping port
RF load
Computer
Modulator
(Scandinova)
Directional coupler
LLRF system
可调功率分配器使得实验平台使用起来更加灵活
Microwave signal generator
SSA
Klystron
Directional coupler
Pulse compressor
R&S® SMB100A

16. X-band high power test stand
R&S® SMB100A（Available）
Klystron
Frequency : 100kHz to 12.75GHz
Peak power: 27dBm
X-Band 1300W Pulsed Power Amplifier
这一页是否必要？

17. Pulse compressor Coupling hole Polarizer E-Field 66mm 179mm
TE114
f0=11.424GHz
Coupling hole
Polarizer
E-Field
179mm
66mm
Compact Design:
Q0: 94000
Peak Power Gain : 6.2
Compression ratio: 10

18. Variable RF power splitter
RF components
Variable RF power splitter
Vacuum pumping port
Port 1
Port 2
Port 3
Port 4

19. X-band stainless steel RF load
RF components
Directional coupler
X-band stainless steel RF load
Port 1
Port 1
Port 1
Port 2

20. X-band application for Thomson scattering Source
1.5us,50MW
Pulse compressor
X-band constant impedance structure
1.5m x30MV/m(S-band) &&2x0.6m x80MV/m(X-band)

21. X-band structure design, Preliminary
Will be refined with the info of RF power source available.
parameters
frequency
11.424
GHz
Phase adv
120
degree
# cells 72
length
630 mm
Filling time
104 ns a
3.5
vg/c
2.01
R/Q
13.9
(kOhm/m) Q
6955
P Input
64.5 (14.3) MW
Eacc 80
MV/m
S21
-4.7 dB

22. Outline Overview of X-band at Tsinghua Development of Structures
Preparations for the test stand
Summary

23. Summary T24_THU_#1 successfully assembled and tested
Discussion: 1) baking 2) careful handling/cleaning
Choke-mode damped structures, SW single-cell test
Gap1.68, Gap2.1, high-power KEK
New Choke-mode cell in design
X-band high power test stand
Location settled
Klystron、SSA and RF components in preparation
T24_THU_#2 in preparation
Two 0.6m X-band structures in design

24. Thanks for your attention !
 LCWS2016, Aiina Certer & MALIOS in Morioka, IWATE (Japan)