常伝導技術での LC の可能性LC feasibility consideration

with normal conducting technology

第５回「機構の研究推進について」の意見交換会(ILC の推進について )

平成 24 年 2 月 13 日加速器・肥後寿泰

Why normal conducting for LC now?• Normal conducting (NC) X-band high gradient

research has been pursued for the past twenty years at SLAC, KEK and now at CERN.

• It is worthwhile to continue this research in order to merge the present NC technology with that currently being developed for a future CLIC-type machine.

• If a low energy machine is needed, NC X-band technology may serve as a compact, extendable and versatile (e+e-/γγ) machine.

• For higher energies, it can serve as a prototype for a CLIC type machine.

2　肥後 機構の意見交換会（ 2 月 13 日）

Physics playground

　肥後 機構の意見交換会（ 2 月 13 日） 3

Stage 1: e+ e- Z, WW, HZ @ Eee ～ 90 – 250 GeV

Stage 2: e+ e- t t e- e- γγ H, HH

@ Eee ～ 170 – 350 GeVStage 3: e+ e- H H Z, t t H

@ Eee ～ 500 GeVR. Belusevic, KEK Preprint 2008-33

Accelerator layout

4　肥後 機構の意見交換会（ 2 月 13 日）

GLC configuration 2004

Design: 500 GeV and extendable to 1TeV

5　肥後 機構の意見交換会（ 2 月 13 日）

GLC Project, KEK Report 2003-7

GLC two tunnel schematic

SLED-II pulse compression 1.6microsec400nsec

Klystron peak power 75MW 60cm effective length

accelerator structure

6　肥後 機構の意見交換会（ 2 月 13 日）

GLC Project, KEK Report 2003-7

GLC RF configuration

Loaded gradient 50 MV/m

75 MW, 400ns /

structure

4 klystrons / modulator

PPM klystron75MW, 1.6 microsec

29m SLED-II

7　肥後 機構の意見交換会（ 2 月 13 日）

GLC Project, KEK Report 2003-7

Rough-rough design parameters (1)GLC CLIC500 CLIC Stage 1

Total CM energy (GeV) 500 500 3000 250

Loaded accelerator gradient (MV/m) 50 80 100 85

Effective gradient (MV/m) 44 70

Linac length (km) 14.5 3.6

Klystron peak power (MW) 75 40

Klystron pulse length (ms) 1.6 1.0

Pulse compression ratio 4 4

Power / structure 75 52

RF pulse length 400 250

Beam current 0.86 2.2 1.2 1.2

8　肥後 機構の意見交換会（ 2 月 13 日）

Rough-rough design parameters (2)GLC CLIC500 CLIC Present

Number of particles in a bunch 10 10 0.75 0.68 0.37

Bunch spacing (ns) 1.4 0.5 0.5

Number of bunches / train 192 354 392

Bunch train length (ns) 267 177 196

……….

Wall plug power (MW) 233

Peak luminosity (1034) 2.5

Cost

9　肥後 機構の意見交換会（ 2 月 13 日）

Rough-rough design parameters (3)GLC CLIC500 CLIC Present

Modulator

Klystron XL4/PPM

Pulse compression Cavity comp.

Power delivery Low loss WG

Acc. structure length (m) 0.6 0.25 0.25

Phase advance / cell 5p/6 5p/6 2p/3 2p/3

Structure filling time (ns) 120 50 67 67

Beam hole aperture 2a (mm) 0.21-0.15 <0.145> <0.11> <0.11>

Vg/c (%) 5.1 – 1.1 1.9 – 1.1 1.7 – 0.8 1.7 – 0.8

………….

10　肥後 機構の意見交換会（ 2 月 13 日）

1m RF unit configuration

　肥後 機構の意見交換会（ 2 月 13 日） 11

40MW X 1.0 ms X 2kly

250MW X 250 nsec

52MW / structure

Compressor cavity

Klystron feasibility

12　肥後 機構の意見交換会（ 2 月 13 日）

0

20

40

60

80

100

120

0 200 400 600 800 1000 1200 1400 1600

Pulse Shotening of PPM#4 KlystronPower [MW]

Pulse width [ns]

1/Tpulse

XL4 NLCTA

PPM Nextef

PPM Nextef

13

Fabrication – 6/7 of the above tests, with all best results achieved with KEK-coordinated machining of structures.Testing – 4/7 with best performance of all categories of structures in tests made in NEXTEF at KEK.High-gradient science – Extensive measurements of high-gradient rf instrumental in developing theory.

KEK’s Fundamental Contributions to 100 MV/m Accelerating Structures

　肥後 機構の意見交換会（ 2 月 13 日）

Oide, Steinar: KEK/Japan – CERN Collaboration on Linear Collider Studies, Dec. 2011

TD24

T24

Preliminary and at 240ns FLT pulse

CLIC req.

14　肥後 機構の意見交換会（ 2 月 13 日）

Conclusion • Worthwhile to reconsider NC choice for low energy

Higgs physics.• High gradients imply compact accelerator complex.• First stage may be built within a KEK-size site.• Operation can serve as a rigorous test of CLIC design,

with exception of drive beam.• Energy extendable.• Physics potential increased using e+e-/γγ• Critical issues still to be discussed are

– Overall design– Proof of RF system configuration– Cost

　肥後 機構の意見交換会（ 2 月 13 日） 15