Dog-leg Status

I. Syratchev for the CLIC team

29.01.2014

Introduction

Unloaded

Loaded (CLIC)

Testing of accelerating structure with nominal beam loading is a missing block in our testing program. Such a test will be done using CTF3 (1.2 A) drive beam and RF power delivered from X-box1 (90 MW) via modified 30 GHz low loss transfer line (60MW).The main target of this experiment is to compare loaded and unloaded accelerating structure breakdown trip rate.

Incr

easi

ng c

urre

nt

Gradient along the structure

CLIC nominal

Unloaded

Accelerating gradients achieved in tests. Status: 4-9-2012

loaded

Location of the Dog-leg experiment

structure

Former 30 GHz RF transfer line X-box1

Beam dog-leg

Structure under test:CERN’s T24 (12WNDSvg1.8 KEK N1)No damping

Dog-leg experiment phase #1 (beam only)

Drive beam, 1-3A, 100-50 MeV

Main objective of this phase: To establish routine beam transportation through the structure without losses. To integrate RF signal acquisition and the beam control systems.

Beam direction

IN

OUT

T24 is installed in dog-leg…

Dog-leg experiment phase #1.

Dog-leg experiment phase #1 results.

May 2013

Dec. 2013

The measurement fully supported expected performance!

Complete Dog-leg test RF network layout (expected RF transfer efficiency ~0.75)

RF

Beam

Mode converter type#2

50 mm circular waveguide

The number of 12 GHz new RF components were fabricated by CERN and CEA to re-adjust ‘old’ 30 GHz low losses transfer line to the new frequency.

H10-> H01 mode converters and tapers #1 (CEA)

H10-> H01 Jog mode converters #2 (CEA)

New RF components (closer view)

Compact RF pumping port with high vacuum conductivity.

RF/vacuum gate valve and pumping port

Dog-leg waveguide line installation status.

All the components are installed. Connected to accelerated structure and closed for vacuum. Vacuum leaks checked (tight).

Ready to be connected to XBOX1.

RF power transmission measurementsS11 data

Short circuit(+offset)

Matched load

S21 Reconstructed(Xiaowei Wu)

Transmission (simulated)

Reflection

• The measured RF power transmission efficiency is 80%.• Reflection is below -27dB.• The group delay time is 75 ns (~23.5 m).

CTF2 CTF3Xbox1 wall

0.87 0.8

Overall power transmission efficiency

• The overall measured RF power transmission efficiency is 67%.• The round group delay time is 230 ns (~35 m).• To provide nominal CLIC RF pulse, XBOX1 klystrons needs to deliver 36 MW x 1.5s

S. Doebert,J.L. NavarroS.F. ReyL. Timeo F. Tecker T. Wisznowski

This progress is a result of coherent efforts of many colleagues:

CTF3

M. FilippovaD. GudkovP. GuyardA. OlyuninS. LebetG. RiddoneA. SolodkoP. De SouzaA. Samochkine

RF/PM XBOX

A. Degiovanni B. WoolleyX. Wu

TE-VCS

E. Paju

Special thanks to F. Peauger (CEA, France) – mode converts; S. Kuzikov (INP, Russia) – circular waveguides line.