Nextef status and near future plan

Nextef status and near future plan

July 2, 2008K. Yokoyama, S. Matsumoto and T.

Higo

Nextef RF power line ： Nominal value

080513-15 2nd collaboration meeting on X-band 2

Two klystronsACC Structure

Low loss waveguide

2-klystrons 120MW, 300nsklystron—3dB 2.3m3dB— LLWG 1.5mLLWG 5mLLWG—ACC Str 5.0mWR90 flanges ~36sets*7mm SUS

Loss Kly.Str. ~23%Delay ~ 50ns

S+N

ACC-IN

S

N

１２０MW

92MW

Nextef の現状• パワー計測

– パワー計測の校正を確立し、水負荷や複数台の方向性結合器間で ±10 ％程度で矛盾なく計測可能になった。

• ピークパワー– 210nsec 、 80MW ＠合成部　→　加速管入力部で～ 60MW

相当– 300nsec 、 70MW ＠合成部　プロセシング中– 300nsec 、 80MW 達成したら、加速管試験に入る予定

• 放電特定システム– これから至急立ち上げる

• 現システム、 KX03 加速管での高電界運転で行う。• 2 週間程度を予定している。

– 最低必要条件• 各パルスを解析できること。• 加速管の放電を確実に同定できること。

Higo Presentation at 2nd collaboration meeting at KEK May 2008

Nextef: Nominal observables along waveguideSLAC 3dB

ACC structure

Lounine Load(based on SLAC design)

Ohtsuka Load

Guard window TE01-type

IP 30l/s

WR90

DC made by BINP

080513-15 42nd collaboration meeting on X-band

F & Rs

T

VAC

Ra

Nextef inside shield roombasic components are now in line.

2008/4/18 52008 年メカワークショップ（肥後）

Nextef: observables along beam axis

080513-15 2nd collaboration meeting on X-band 6

GVGVPM PMAM

Sl i t

FC

E

E

I P

Louni nel oad

Otsukal oad

DC

I PH

VAC

I nsulVAC

I PDC H

H

Vari an I P

187

KX03 425

FC

I P

Load

Vari anI P

Q-mass

WC WCFC

FC

VAC DC

230

FCFCFCQmass

PM PMAM

GVGVACC str

Higo Presentation at 2nd collaboration meeting at KEK May 2008k

Nextef Run061108 (From Jun.11, 24Hr/day)

•KX03 Acc Structure installed. •Commission Breakdown Detection system. •Established 60MW 300ns RF for Acc structure.

•Modulator runs pretty well.•Klystron_N (North side) runs well.•Klystron_S (South side) sometimes breakdown at gun region.(One~two per day under 25pps.)

•Vacuum Trips in the area of the power combiner (detailed location is yet to be identified) and in the Acc structure area.

Missions of this run:

What we find are

Input Power for KX03 (blue) / pulse width (red) 65MW, 300ns, 25ppsAs of Jul. 1.

Vacuum: Upstream Acc Str (green) / Down stream Acc Str (pink)

Nextef History Plots of Current Run (Starting Jun. 11, KX03 installed.)

Breakdown detection• Inhibit the following pulses

– Big jump in symmetric reflection: exists• Manual threshold setting from time to time

– Vacuum monitored by CCG: exists• Control power rating following vacuum level• Threshold is nominally 10-4Pa

– Other monitors• Faraday cup current: not yet confirmed

– Not yet established, now trying to test with KX03 system

• Light from a guard window monitored by PMT: exists• X-rays: probably start without it

– Scintillator + PMT

• Acoustic emission: start test without it– SLAC VME system being recovered,

Pulse analysis• Every RF pulse analysis: now being implemented

– Four pulses (F, Rs, Ra, T) with DPO7054– System the same to that of study with narrow waveguide– Statistical data is acquired

• To get various distribution, such as missing energy

– 10 pulses are recorded• To see any precursors• To see following pulses in future?

• Other RF pulses or others: start as is– Monitored by Tektro oscilloscope

• Breakdown pulse is recorded for off-line analysis

Near future plan• System power up

– As much as possible with the KX03 structure– Processing mostly the power distribution system

• Installation of T18_VG2.4_Disk– By end of this month, as soon as system establishment

• Operation in July and August– Day-time 9-20 operation by X-band members– Start 24h operation from September

• Sophistication of the system: being prepared– RF pulse width automatic control (Aug.)– Identification of all INTLK information (Sep.)– Acoustic, X-rays, ……