Tuner & LLRF of ILC Sun YI （孙毅）、 Wang Guangwei （王光伟） Lin Haiying （林海英）、 Qiu Feng （邱丰） Dec.7, th 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 piezo grating rule

Tuner & Piezo test

Bandwidth 220KHz Q L =5897 8/9∏-mode influence phase Z -3dB f(MHz) VSWR=6.0 β in =0.17

200V Piezo voltage ~2um ~0.2 0 ~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 30 0 cell #1 ~10KHZ 10 0

Tuner FB on under disturbing of cell #1 ~10KHZ 10 0 ball speed = 0.3mm/s

Piezo actuator

Piezo On (sine 、 sawtooth 、 rectangle)

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

Piezo=300V 0.1HZ sine & rectangle Piezo 300V→12um Measured by grating rule →6.5um Why ? ← 1.5kHz

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 ±0.5 0, 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.