1. 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

2. 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）

3. Physics playground 肥後 機構の意見交換会（ 2 月 13 日） 3 Stage 1: e + e -  Z, WW, HZ @ E ee ～ 90 – 250 GeV Stage 2: e + e -  t t e - e -  γγ  H, HH @ E ee ～ 170 – 350 GeV Stage 3: e + e -  H H Z, t t H @ E ee ～ 500 GeV R. Belusevic, KEK Preprint 2008-33

4. Accelerator layout 4 肥後 機構の意見交換会（ 2 月 13 日）

5. 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

6. GLC two tunnel schematic SLED-II pulse compression 1.6microsec  400nsec 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

7. GLC RF configuration Loaded gradient 50 MV/m 75 MW, 400ns / structure 4 klystrons / modulator PPM klystron 75MW, 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

8. Rough-rough design parameters (1) GLCCLIC500CLICStage 1 Total CM energy (GeV)500 3000250 Loaded accelerator gradient (MV/m)508010085 Effective gradient (MV/m)4470 Linac length (km)14.53.6 Klystron peak power (MW)7540 Klystron pulse length (  s) 1.61.0 Pulse compression ratio44 Power / structure7552 RF pulse length400250 Beam current0.862.21.2 8 肥後 機構の意見交換会（ 2 月 13 日）

9. Rough-rough design parameters (2) GLCCLIC500CLICPresent Number of particles in a bunch 10 10 0.750.680.37 Bunch spacing (ns)1.40.5 Number of bunches / train192354392 Bunch train length (ns)267177196 ………. Wall plug power (MW)233 Peak luminosity (10 34 )2.5 Cost 9 肥後 機構の意見交換会（ 2 月 13 日）

10. Rough-rough design parameters (3) GLCCLIC500CLICPresent Modulator KlystronXL4/PPM Pulse compression Cavity comp. Power delivery Low loss WG Acc. structure length (m)0.60.25 Phase advance / cell 5  /6  /3 Structure filling time (ns)1205067 Beam hole aperture 2a (mm)0.21-0.15 Vg/c (%)5.1 – 1.11.9 – 1.11.7 – 0.8 …………. 10 肥後 機構の意見交換会（ 2 月 13 日）

11. 1m RF unit configuration 肥後 機構の意見交換会（ 2 月 13 日） 11 40MW X 1.0  s X 2kly 250MW X 250 nsec 52MW / structure Compressor cavity

12. Klystron feasibility 12 肥後 機構の意見交換会（ 2 月 13 日） XL4 NLCTA 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） 13 Oide, Steinar: KEK/Japan – CERN Collaboration on Linear Collider Studies, Dec. 2011

14. 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）

15. 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