2nd Workshop of the IHEP 1.3 GHz SRF R&D Projectand

2nd IHEP-KEK 1.3 GHz SRF Meeting

Opening Remark

J. Gao

December 2-3, 2009, IHEP, Beijing, China

The aim of this workshop and meeting

1. Review the annual progress of IHEP 1.3GHz SC project and next year plan

2. STF status

3. Collaboration between IHEP and KEK on 1.3GHz SC R&D items and schedule

4. Discussion on IHEP new SC lab

Chairman:Y.L. Chi

Chairman:H. Hayano

Chairman:J. Gao

The key technical issues

1. 1.3GHz 9cell SC cavity surface treatment and vertical test (kek)

2. 1.3GHz 9cell SC cavity final design issues (RF calculation, magnetic shielding, helium vessel…)

3. Tuner and LLRF design and fabrication

4. Main coupler design, fabrication and test

5. Cryomodule design and fabrication

6. SC lab facility development (including vertical cryostat, cavity inner surface inspection, T-Mapping, … ）

7. ERL SC cavity issues

Some comments

Yield Plot• The gradients for DESY data were off by +2MV/m• Not 08/09: large component of 2007, and very small component of 2009• Not 1st or 2nd test: instead, last (DESY) or best (JLab)

• Included cavities fabricated by ACCEL, ZANON, AES, JLab-2, KEK-Ichiro This is not the ideal data selection from which to infer a production yield

0

10

20

30

40

50

60

70

80

90

100

>10 >15 >20 >25 >30 >35 >40 >45

maximum gradient [MV/m]

yiel

d (

%)

DESY (25 cavities) JLab (14 cavities)

Revised version (corrected only for mistakes) - same data shown

11/39 1st test13/39 2nd test 7/39 3rd test 3/39 4th test 3/39 5th test 1/39 8th test

Old version,shown at PAC, 2009

Standard Process for Yield PlotStandard Cavity Recipe

Fabrication Nb-sheet (Fine Grain)

Component preparation

Cavity assembly w/ EBW (w/ experienced venders)

Process 1st Electro-polishing (~150um)

Ultrasonic degreasing with detergent, or ethanol rinse

High-pressure pure-water rinsing

Hydrogen degassing at > 600 C

Field flatness tuning

2nd Electro-polishing (~20um)

Ultrasonic degreasing or ethanol

High-pressure pure-water rinsing

Antenna Assembly

Baking at 120 C

Cold Test (vert. test)

Performance Test with temperature and mode measurement (1st / 2nd successful RF Test)

7

Comparison ‘Old’ vs ‘New’ Yield Plots

Electropolished 9-cell Cavities

0

10

20

30

40

50

60

70

80

90

100

>10 >15 >20 >25 >30 >35 >40

max gradient [MV/m]

yiel

d [

%]

DESY last test (25 cavities)JLab best test (14 cavities)DESY first successful test of cavities from qualified vendors - ACCEL+ZANON (15 cavities)JLab first successful test of cavities from qualified vendors - ACCEL (7 cavities)

OldNew

S1 Goal: Reached at DESY PXFEL1

reported by H. Weise, at SRF-09

Average field gradient at CMTB : > 31.5 MV/m

Note: DESY prepared cavities and assembled with the cryomodule cold mass contributed by IHEP for XFEL prototype

Global Plan for SCRF R&D

Year 07 2008 2009 2010 2011 2012

Phase TDP-1 TDP-2Cavity Gradient in v. test

to reach 35 MV/m >> Yield 50% >> Yield 90%

Cavity-string to reach 31.5 MV/m, with one-cryomodule

Global effort for plug-compatible string(DESY, FNAL, INFN, KEK)

System Test with beam

acceleration

FLASH (DESY) NML (FNAL)

STF2 (KEK)

Preparation for Industrialization

Mass Production Technology R&D

10

TTF/FLASH 9mA Experiment

XFEL ILC FLASHdesign

9mA studies

Bunch charge

nC 1 3.2 1 3

# bunches 3250 2625

7200* 2400

Pulse length

s 650 970 800 800

Current mA 5 9 9 9

Full beam-loading long pulse operation “S2”

• Stable 800 bunches, 3 nC at 1MHz (800 s pulse) for over 15 hours (uninterrupted)

• Several hours ~1600 bunches, ~2.5 nC at 3MHz (530 s pulse)

• >2200 bunches @ 3nC (3MHz) for short periods

BXFEL-ERL Test Facility

• L-Band（ 1.3 GHz） Eacc ~ 20 MV/m、 Energy gain ~ 60 MeV, Current 10 mA

Main Parameter of ERL Test Linac

模 式 ERL / FEL

能 量 (MeV) 65 / 77

电 流 (mA) 10 (ERL)

束流能散度 ≤ 0.3 % / 1%

归一化发射度 ≤ 3 mm mrad

注入器能量 (MeV) 5 / 20

束团重复频率 130 MHz / 13 Hz

电场梯度 (MV/m) 16 ~ 20

相位 (degree) 0 / -15

束团电量 (pC) 77 pC / 1 nC

主加速器腔数 4

单腔输入功率 (kW) 15~20

Have a good discussion and enjoy our research works and collaboration!

Thanks