Summary :
A high intensity photon beam has various applications in advanced accelerators. Optical cavity is an unique system to realize such high intensity photon beam at a high repetition rate. Especially the laser-Compton scheme, which uses the high intensity photon produced in the optical cavity as a target of a high-energy electron beam to produce energetic photon, is a promising technique. At the ILC, it can be used for a polarized positron source, a photon collider system, beam size and polarization diagnostics. It also is the heart of the system in compact Compton light sources recently proposed in LAL and KEK. The goal of this project is to further push the technical limits in the existing optical cavity system.

French members :
N. Delerue, K. Cassou, R. Chiche, D. Jehanno, V. Soskov, A. Variola, F. Zomer

Japanese members :
Y. Honda, S. Araki, M. Kuriki, T. Omori, T. Takahasi, N. Terunuma, J. Urakawa

References :
[1] J Bonis et al 2012 JINST 7 P01017, http://dx.doi.org/10.1088/1748-0221/7/01/P01017
[2] T Akagi et al 2012 JINST 7 P01021, http://dx.doi.org/10.1088/1748-0221/7/01/P01021
[3] ThomX Technical Design Report, http://hal.in2p3.fr/in2p3-00971281

Summary:
We will test a new granular converter consisting of small tungsten spheres in a hybrid positron source configuration. The beam test is scheduled for the summer of 2014 or later at the KEK injector linac. We have already built the granular converters with four different thicknesses at LAL-Orsay for this experiment. The impinging electron with beam energy of 7-8 GeV and bunched charge of 1 nC is foreseen. In these beam tests, the observations of the temperature rise will be done, putting high-precision thermocouples on the exit face of the converter. Additional observations through infrared cameras are considered. The goal of this project is to evaluate the feasibility of this new granular converter toward the high intensity positron sources.

French members :
D. Dauvergne, X. Artru, R. Chehab, M. Chevallier, A. Variola

Japanese members :
M. Satoh, K. Furukawa, T. Kamitani, F. Miyahara, T. Suwada, K. Umemori

References:
[1] Y. Uesugi et al., Nuclear Instrum. Methods B 319 (2014) 17-23.
[2] P. Sievers et al., "Granular Converter Test at KEK"; Presented at the 8-th POSIPOL Workshop (POSIPOL2013), Argonne National Lab., Argonne, IL, U.S.A., Sep. 4-6, 2013.

Summary :
Magnetic shielding is a key technology for super-conducting RF cavities.It is necessary to optimize the shielding method, including the choice of materials and the shape of the magnetic shield, and to establish a method for quality control suitable for large-scale production.We plan to continue to evaluate the permeability of various shielding materials, and also investigate possible causes for the performance degradation of the shielding material at cryogenic temperature. We would also like to study the dependence of cavity performance on the permeability

French members :
J. Ploin, A. Daël, O. Napoly

Japanese members :
M. Masuzawa, K. Tsuchiya, K. Umemori

References :
[1] Mika Masuzawa, et al. “Study of Magnetic Shielding Materials and Fabrication of Magnetic Shield for Superconducting Cavities” IEEE Transactions on Applied Superconductivity, 2014. Volume: 24, Issue: 3
[2] Mika Masuzawa, Juliette Plouin, et al. “MAGNETIC SHIELDING: OUR EXPERIENCE WITH VARIOUS SHIELDING MATERIALS”, Proc. For SRF2013, Paris, 2013.
[3] Juliette Plouin, “Magnetic Shielding Activities for IFMIF/CEA and Study on the Magnetic Shielding in the FJPPL Collaboration”, presented at “MSU FRIB Workshop on Magnetic Shielding for Cryomodules” Feb.4-6, 2013.
[4] Mika Masuzawa, et al. “Magnetic Properties of Shielding Materials for Superconducting Cavities” IEEE Transactions on Applied Superconductivity, 2012. Volume: 22, Issue: 3

Summary

French members :
P. Bambade, C. Rimbault, D. Jehanno, V. Kubytskyi, D. El Khechen (PhD student)

Japanese members :
S. Uehara, Y. Funakoshi, M. Iwasaki

References

website

Summary

French members :
F. Eozénou, C. Antoine, S. Berry, C. Madec, C. Servoin, B. Visentin

Japanese members :
T. Saeki, H. Hayano, S. Kato, H. Monjushiro, M. Sawabe, M. Yamanaka

References

website

Summary

French members :
A. Jeremie, P. Bambade, F. Bogard, P. Cornebise, N. Geffroy, S. Wallon, V. Kubytskyi, S. Liu (PhD student), O. Blanco (PhD student)

Japanese members :
N. Terunuma, S. Araki, K. Kubo, S. Kuroda, T. Okugi, T. Tauchi, J. Urakawa, H. Yamaoka

References

website

Summary

French members :
H. Jenhani, G. Devanz, W. Kaabi

Japanese members :
E. Kako, T. Shishido, S. Yamaguchi

References

website

Summary

French members :
O. Napoly, F. Ardellier-Desages, G. Devanz

Japanese members :
A. Yamamoto, H. Hayano, M. Yamanaka

References

website