IPAC2011 - List of Authors (Wegner, R.)

Paper	Title	Page
MOPC055	High Power Test of the First PIMS Cavity for Linac4	205
	F. Gerigk, J.-M. Giguet, P. Ugena Tirado, R. Wegner CERN, Geneva, Switzerland
	The PI-Mode Structure (PIMS) accelerates the Linac4 beam from 100 to 160 MeV. Twelve 7-cell cavities will be installed in the linac, with a gradient of ~4 MV/m and operating at a frequency of 352.2 MHz. A full-power prototype has been constructed at CERN in 2010 and was high- power tested in autumn 2010. Peak power tests at the Linac4 duty cycle and high-average power tests at increased duty cycles were completed successful, so that this prototype will be the first of the 12 cavities to be installed in Linac4. This paper reports on the high-power tests and the conditioning experience.

MOPC056	The Linac4 Power Coupler	208
	F. Gerigk, J.-M. Giguet, E. Montesinos, B. Riffaud, P. Ugena Tirado, R. Wegner CERN, Geneva, Switzerland
	Linac4 employs 3 types of accelerating structures after the RFQ: a Drift Tube Linac (DTL), a Cell-Coupled DTL (CCDTL), and a Pi-Mode Structure (PIMS) to accelerate the beam to 160 MeV. The structures are designed for a peak power of 1 MW per coupler, which consists of two parts: a ceramic window, which separates the cavity vacuum from the air in the wave-guides, and a so-called "coupling T", which couples the RF power through an iris to the cavity. In the frame of the Linac4 R&D both devices have been significantly improved with respect to their commonly used design. On the coupler side, the wave-guide short circuit with its matched length has been replaced by a fixed length λ/4 short circuit. The RF matching is done by a simple piston tuner, which allows a quick matching to different cavity quality factors. In the window part, which usually consists of a ceramic disc and 2 pieces of wave-guides with matching elements, the wave-guide sections could be completely suppressed, so that the window became very compact, lightweight, and much simpler to manufacture. In this paper we present electromagnetic simulations, and tests on first prototypes, which were constructed at CERN.

TUPS100	Manufacturing the Linac4 PI-mode Structure Prototype at CERN	1774
	G. Favre, A. Cherif, A. Dallocchio, J.-M. Geisser, L. Gentini, F. Gerigk, S.J. Mathot, M. Polini, S. Sgobba, T. Tardy, R. Wegner CERN, Geneva, Switzerland
	The PI-Mode Structure (PIMS) of Linac4 consists of 7-cell cavities made from alternating OFE copper discs and rings welded together with electron beam (EB) welding. A full-scale prototype cavity of almost 1.5 m in length has been manufactured, assembled, and tested at CERN to prepare the series production of 12 PIMS cavities as part of an international collaboration. This paper reports on the construction experience including machining operations, EB welding, vacuum brazing, and metrological measurements results.

Paper

Title

Page

High Power Test of the First PIMS Cavity for Linac4

205

F. Gerigk, J.-M. Giguet, P. Ugena Tirado, R. Wegner
CERN, Geneva, Switzerland

The PI-Mode Structure (PIMS) accelerates the Linac4 beam from 100 to 160 MeV. Twelve 7-cell cavities will be installed in the linac, with a gradient of ~4 MV/m and operating at a frequency of 352.2 MHz. A full-power prototype has been constructed at CERN in 2010 and was high- power tested in autumn 2010. Peak power tests at the Linac4 duty cycle and high-average power tests at increased duty cycles were completed successful, so that this prototype will be the first of the 12 cavities to be installed in Linac4. This paper reports on the high-power tests and the conditioning experience.

MOPC056

The Linac4 Power Coupler

208

F. Gerigk, J.-M. Giguet, E. Montesinos, B. Riffaud, P. Ugena Tirado, R. Wegner
CERN, Geneva, Switzerland

Linac4 employs 3 types of accelerating structures after the RFQ: a Drift Tube Linac (DTL), a Cell-Coupled DTL (CCDTL), and a Pi-Mode Structure (PIMS) to accelerate the beam to 160 MeV. The structures are designed for a peak power of 1 MW per coupler, which consists of two parts: a ceramic window, which separates the cavity vacuum from the air in the wave-guides, and a so-called "coupling T", which couples the RF power through an iris to the cavity. In the frame of the Linac4 R&D both devices have been significantly improved with respect to their commonly used design. On the coupler side, the wave-guide short circuit with its matched length has been replaced by a fixed length λ/4 short circuit. The RF matching is done by a simple piston tuner, which allows a quick matching to different cavity quality factors. In the window part, which usually consists of a ceramic disc and 2 pieces of wave-guides with matching elements, the wave-guide sections could be completely suppressed, so that the window became very compact, lightweight, and much simpler to manufacture. In this paper we present electromagnetic simulations, and tests on first prototypes, which were constructed at CERN.

TUPS100

Manufacturing the Linac4 PI-mode Structure Prototype at CERN

1774

G. Favre, A. Cherif, A. Dallocchio, J.-M. Geisser, L. Gentini, F. Gerigk, S.J. Mathot, M. Polini, S. Sgobba, T. Tardy, R. Wegner
CERN, Geneva, Switzerland

The PI-Mode Structure (PIMS) of Linac4 consists of 7-cell cavities made from alternating OFE copper discs and rings welded together with electron beam (EB) welding. A full-scale prototype cavity of almost 1.5 m in length has been manufactured, assembled, and tested at CERN to prepare the series production of 12 PIMS cavities as part of an international collaboration. This paper reports on the construction experience including machining operations, EB welding, vacuum brazing, and metrological measurements results.