IPAC2012 - List of Authors (Hayano, H.)

Paper	Title	Page
TUPPD034	Multi-bunch Beam Generation by Photo-cathode RF Gun for KEK-STF	1479
	M. Kuriki, S. Hosoda, H. Iijima HU/AdSM, Higashi-Hiroshima, Japan A. Ayaka Sokendai, Ibaraki, Japan H. Hayano, J. Urakawa, K. Watanabe KEK, Ibaraki, Japan G. Isoyama, R. Kato, K. Kawase ISIR, Osaka, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan K. Sakaue RISE, Tokyo, Japan
	Funding: MEXT, Quantum beam project. KEK-STF is doing R&D of Super-Conducting (SC) accelerator technology for ILC (International Linear Collider), based on 1.3 GHz RF system. For STF and ILC, the pulse length is 1ms and the repetition is 5Hz. We developed a L-band Normal-Conducting RF gun designed by DESY to provide electron beam over such long pulse duration. For NC Photo-cathode RF gun, such high duty and long pulse operation is a challenging task, because the detuning by the heat load of cavity dissipation power is significant. The RF gun provides the electron pulse train to SC accelerator modules which will be operated at 31.5 MV/m gradient. Precise RF control is essential for SC accelerator because the beam loading and input RF power should be well ballanced for a stable operation. The beam test to demonstrate the stable opeation is very important for SC accelerator R&D. The system is also used to demonstrate high-flux quasi-monochromatic X-ray generation by inverse Compton scattering at KEK-STF. The experiment is carried out from April 2012 to November 2012 at KEK-STF. We report the latest status of the multi-bunch generation by the RF gun.

WEPPC013	Progress of High Gradient Performance in STF 9-cell Cavities at KEK	2233
	Y. Yamamoto, H. Hayano, E. Kako, S. Noguchi, T. Shishido, K. Watanabe KEK, Ibaraki, Japan
	Vertical tests for ILC have been carried out since 2008 at KEK-STF. Measured cavities are from MHI#5 to MHI#22 (not yet for MHI#18-#22 at the end of November 2011), and MHI#12, #13 and #17 reached the ILC specification of 0.8x10¹⁰ at 35MV/m. The MHI cavity was added into the “qualified vendor” for the cavity yield. These three cavities (#12, #13 and #17) had no defect on every EBW seam of equator, iris and beampipe. On the other hand, the other cavities had a few or several defects on EBW seam. Especially, defect on the EBW seam of the equator is the worst case, and cavity performance is limited “certainly”. MHI#10, #15 and #16 cavities were limited by this kind of defect. As for iris region, MHI#14 had large defect at the iris between cell #8 and #9, and the performance was limited by the heavy field emission with “explosive event”. However, after the locally mechanical grind for this defect, the cavity performance was drastically improved with no field emission at 37MV/m. In this paper, the recent progress of the cavity performance at KEK-STF will be reported with the “detailed” defect analysis.

Paper

Title

Page

Multi-bunch Beam Generation by Photo-cathode RF Gun for KEK-STF

1479

M. Kuriki, S. Hosoda, H. Iijima
HU/AdSM, Higashi-Hiroshima, Japan
A. Ayaka
Sokendai, Ibaraki, Japan
H. Hayano, J. Urakawa, K. Watanabe
KEK, Ibaraki, Japan
G. Isoyama, R. Kato, K. Kawase
ISIR, Osaka, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
K. Sakaue
RISE, Tokyo, Japan

Funding: MEXT, Quantum beam project.
KEK-STF is doing R&D of Super-Conducting (SC) accelerator technology for ILC (International Linear Collider), based on 1.3 GHz RF system. For STF and ILC, the pulse length is 1ms and the repetition is 5Hz. We developed a L-band Normal-Conducting RF gun designed by DESY to provide electron beam over such long pulse duration. For NC Photo-cathode RF gun, such high duty and long pulse operation is a challenging task, because the detuning by the heat load of cavity dissipation power is significant. The RF gun provides the electron pulse train to SC accelerator modules which will be operated at 31.5 MV/m gradient. Precise RF control is essential for SC accelerator because the beam loading and input RF power should be well ballanced for a stable operation. The beam test to demonstrate the stable opeation is very important for SC accelerator R&D. The system is also used to demonstrate high-flux quasi-monochromatic X-ray generation by inverse Compton scattering at KEK-STF. The experiment is carried out from April 2012 to November 2012 at KEK-STF. We report the latest status of the multi-bunch generation by the RF gun.

WEPPC013

Progress of High Gradient Performance in STF 9-cell Cavities at KEK

2233

Y. Yamamoto, H. Hayano, E. Kako, S. Noguchi, T. Shishido, K. Watanabe
KEK, Ibaraki, Japan

Vertical tests for ILC have been carried out since 2008 at KEK-STF. Measured cavities are from MHI#5 to MHI#22 (not yet for MHI#18-#22 at the end of November 2011), and MHI#12, #13 and #17 reached the ILC specification of 0.8x10¹⁰ at 35MV/m. The MHI cavity was added into the “qualified vendor” for the cavity yield. These three cavities (#12, #13 and #17) had no defect on every EBW seam of equator, iris and beampipe. On the other hand, the other cavities had a few or several defects on EBW seam. Especially, defect on the EBW seam of the equator is the worst case, and cavity performance is limited “certainly”. MHI#10, #15 and #16 cavities were limited by this kind of defect. As for iris region, MHI#14 had large defect at the iris between cell #8 and #9, and the performance was limited by the heavy field emission with “explosive event”. However, after the locally mechanical grind for this defect, the cavity performance was drastically improved with no field emission at 37MV/m. In this paper, the recent progress of the cavity performance at KEK-STF will be reported with the “detailed” defect analysis.