IPAC2012 - List of Authors (Yamamoto, Y.)

Paper	Title	Page
WEPPC012	High Power Tests of CW Input Couplers for cERL Injector Cryomodule	2230
	E. Kako, S. Noguchi, T. Shishido, K. Watanabe, Y. Yamamoto KEK, Ibaraki, Japan
	High power tests of a pair of the prototype input couplers were performed by using a newly developed 300 kW CW klystron. The input couplers were successfully processed up to 100 kW in a pulsed operation with a duty of 10% and 50 kW in a CW operation for 30 minutes. The conditioning was limited by excessive heating at bellows of an inner conductor at a coaxial line locating between a coaxial RF window and a doorknob-type transition. Improvement of a sufficient cooling at the inner conductor is necessary to achieve the required input RF power of 170 kW in a CW operation. Six input couplers to be installed in the injector cryomodule for the cERL project were completed, and they are under preparation for conditioning at a high power test stand.

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.

WEPPC014	Construction and Beam Operation of Capture Cryomodule for Quantum Beam Experiments at KEK-STF	2236
	Y. Yamamoto KEK, Ibaraki, Japan
	Construction of capture cryomodule for Quantum Beam Project has started since September, and will be finished by the end of December in 2011 at KEK-STF. Two MHI cavities (MHI-12, -13), which reached ILC specification (0.8x10¹⁰ at 35MV/m) at the vertical test, were installed into a short cryomodule with improved input couplers. Slide-Jack tuner was attached at different position (center or end of helium jacket) for each cavity same as S1-Global. From January 2012, this cryomodule will be cooled down to 2K, and the high power test will be started including check of the cavity/coupler/tuner performance, LFD measurement, LFD compensation by Piezo, dynamic loss measurement and so on. From March, the beam operation with the beam current of 10mA and the maximum beam energy of 40MeV, will be started to generate x-rays by collision between electron beam and laser. At this stage, two cavities will be operated at the lower gradient of 15-20MV/m, and the stable operation is crucial. In this report, the test results of various performances at the Quantum Beam Project will be presented in detail.

WEPPC015	Construction of Injector Cryomodule for cERL at KEK	2239
	E. Kako, S. Noguchi, T. Shishido, K. Watanabe, Y. Yamamoto KEK, Ibaraki, Japan
	The cERL injector cryomodule includes three 2-cell cavities, and each cavity has 2 input couplers and 5 HOM couplers. Three 2-cell cavities for cERL has already completed. Vertical test of the three cavities has been going on. The first cavity have achieved Eacc of 30 MV/m. Vertical tests will be carried out twice in each cavity, till the end of December, 2011. Six cw input couplers for cERL has already completed. RF processing at the high-power test stand with a cw 300kW-klystron will be carried out in Jan.-Feb., 2012. After the cavities were covered with a He jacket, assembly of the cERL injector cryomodule will be carried out in March-April, 2012. The first cool-down of the cryomodule is scheduled in June 2012.

Paper

Title

Page

High Power Tests of CW Input Couplers for cERL Injector Cryomodule

2230

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

High power tests of a pair of the prototype input couplers were performed by using a newly developed 300 kW CW klystron. The input couplers were successfully processed up to 100 kW in a pulsed operation with a duty of 10% and 50 kW in a CW operation for 30 minutes. The conditioning was limited by excessive heating at bellows of an inner conductor at a coaxial line locating between a coaxial RF window and a doorknob-type transition. Improvement of a sufficient cooling at the inner conductor is necessary to achieve the required input RF power of 170 kW in a CW operation. Six input couplers to be installed in the injector cryomodule for the cERL project were completed, and they are under preparation for conditioning at a high power test stand.

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.

WEPPC014

Construction and Beam Operation of Capture Cryomodule for Quantum Beam Experiments at KEK-STF

2236

Y. Yamamoto
KEK, Ibaraki, Japan

Construction of capture cryomodule for Quantum Beam Project has started since September, and will be finished by the end of December in 2011 at KEK-STF. Two MHI cavities (MHI-12, -13), which reached ILC specification (0.8x10¹⁰ at 35MV/m) at the vertical test, were installed into a short cryomodule with improved input couplers. Slide-Jack tuner was attached at different position (center or end of helium jacket) for each cavity same as S1-Global. From January 2012, this cryomodule will be cooled down to 2K, and the high power test will be started including check of the cavity/coupler/tuner performance, LFD measurement, LFD compensation by Piezo, dynamic loss measurement and so on. From March, the beam operation with the beam current of 10mA and the maximum beam energy of 40MeV, will be started to generate x-rays by collision between electron beam and laser. At this stage, two cavities will be operated at the lower gradient of 15-20MV/m, and the stable operation is crucial. In this report, the test results of various performances at the Quantum Beam Project will be presented in detail.

WEPPC015

Construction of Injector Cryomodule for cERL at KEK

2239

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

The cERL injector cryomodule includes three 2-cell cavities, and each cavity has 2 input couplers and 5 HOM couplers. Three 2-cell cavities for cERL has already completed. Vertical test of the three cavities has been going on. The first cavity have achieved Eacc of 30 MV/m. Vertical tests will be carried out twice in each cavity, till the end of December, 2011. Six cw input couplers for cERL has already completed. RF processing at the high-power test stand with a cw 300kW-klystron will be carried out in Jan.-Feb., 2012. After the cavities were covered with a He jacket, assembly of the cERL injector cryomodule will be carried out in March-April, 2012. The first cool-down of the cryomodule is scheduled in June 2012.