Tuner & LLRF of ILC

Sun YI （孙毅）、 Wang Guangwei （王光伟）Lin Haiying （林海英）、 Qiu Feng （邱丰）

Dec.7, 2010

3th workshop of KEK/IHEP on ILC

Outline

• Conception is changed from RING to Linac

• A tuner have been fabricated and test

• Tuning loop FB on , to locked the frequency of MHI-04 cavity.

First slide jack type tuner have been fabricated and test

LLRF lab.

Slide jack type Tuner and piezograting rule

Tuner & Piezo test

Bandwidth 220KHzQL=5897

8/9∏-mode influence

phase

Z

-3dB f(MHz)

VSWR=6.0

βin=0.17

200V Piezo voltage ~2um ~0.20~600HZ

Piezo test

Test piezo

Bead Pull Perturbation ( by Zhai Jiyuan)

Antenna Coupling and Field Flatness

• Long antennas to increase the coupling (input coupler side 0.17, pickup side 0.32)

• reduced the input power, but made the field flatness worse

• put metal beads on the equator of cell#1 to increase the field and coupling in the input coupler side (not used now):

Ball disturbing

ball disturbing cell #9 ~50KHZ 300 cell #1 ~10KHZ 100

55

5 6mm mm

Tuner FB on under disturbing of cell #1 ~10KHZ 100

ball speed = 0.3mm/s

Piezo actuator

Piezo On (sine 、 sawtooth 、 rectangle)

Piezo=200V 0.1HZ rectangle & sinemeasured by grating rule: 2.5um

Piezo=300V 0.1HZ sine & rectangle

Piezo300V→12um

Measured by grating rule→6.5umWhy ?

0.60←1.5kHz

f

Digital LLRF is under adjusting

Next year plan

• 80K LN2 →MHI-04 for test Tuner mechanic performance

1) vacuum tank

2) motor

• CW→pulse mode for LLRF loops

Summary• The R&D of tuner and LLRF are initial, but

we have the first 1.3GHZ Lab. over China, and have open the history.

• the cavity frequency can be locked by the tuner FB loop within ±0.50, MHI-04 cavity Length can be changed 3um by the piezo.

• A simple vacuum tank is under design for the future 80K cold test of tuner.