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Papers by Janic Chambrillon

The Superconducting Proton Linac (SPL) is an R&D effort coordinated by CERN in partnership with o... more The Superconducting Proton Linac (SPL) is an R&D effort coordinated by CERN in partnership with other international laboratories. It is aiming at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art RF superconducting technology, which would serve as a driver in new physics facilities for neutrinos and/or Radioactive Ion Beam (RIB). Amongst the main objectives of this R&D effort, is the development of 704 MHz bulk niobium beta=1 elliptical cavities, operating at 2 K with a maximum accelerating gradient of 25 MV/m, and the testing of a string of cavities integrated in a machine-type cryomodule. The cavity together with its helium tank had to be carefully designed in coherence with the innovative design of the cryomodule. New fabrication methods have also been explored. Five such niobium cavities and two copper cavities are in fabrication. The key design aspects are discussed, the results of the alternative fabrication methods presented and the status of the cavity manufacturing and surface preparation is detailed.

The potential for a superconducting proton linac (SPL) at CERN started to be seriously considered... more The potential for a superconducting proton linac (SPL) at CERN started to be seriously considered at the end of the 1990s. In the first conceptual design report (CDR), published in 2000 [1], most of the 352 MHz RF equipment from LEP was re-used in an 800 m long linac, and the proton beam energy was limited to 2.2 GeV. During the following years, the design was revisited and optimized to better match the needs of a high-power proton driver for neutrino physics. The result was a more compact (470 m long) accelerator capable of delivering 5 MW of beam power at 3.5 GeV, using state-of-the-art superconducting RF cavities at 704 MHz. It was described in a second CDR, published in 2006 [2]. Soon afterwards, when preparation for increasing the luminosity of the LHC by an order of magnitude beyond nominal became an important concern, a low-power SPL (LP-SPL) was studied as a key component in the renovation of the LHC injector complex. The combination of a 4 GeV LP-SPL injecting into a new 50...

The Superconducting Proton Linac (SPL) is an R&D effort conducted by CERN in partnership with oth... more The Superconducting Proton Linac (SPL) is an R&D effort conducted by CERN in partnership with other international laboratories, aimed at developing key technologies for the construction of a multimegawatt proton linac based on state-of-the-art SRF technology. Such an accelerator could serve as a driver in new physics facilities for neutrinos and/or radioactive ion beams [1]. Amongst the main objectives of this effort, are the development of 704 MHz bulk niobium beta=1 elliptical cavities (operating at 2 K and providing an accelerating gradient of 25 MV/m) and the test of a string of cavities integrated in a machine-type cryo-module. In an initial phase, only four out of the eight cavities of the SPL cryo-module will be tested in a half-length cryo-module developed for this purpose, which nonetheless preserves the main features of the full size module. This paper presents the final design of the cryo-module and the status of the construction of the main cryostat parts. Preliminary plans for the assembly and testing of the cryo-module at CERN are also presented.

CERN is currently upgrading and refurbishing its RF and cryogenic facilities in the SM18 assembly... more CERN is currently upgrading and refurbishing its RF and cryogenic facilities in the SM18 assembly hall with the aim of testing SRF cavities and cryo-modules of various provenience. They concern new and spare cavities for the HIE-Isolde upgrade, SPL study and LHC collider. These projects require a redistribution of space, refurbishment of cleanrooms, modification of SRF test stands, of vertical cryostats and of all cryogenic lines. This article presents the specifications of the refurbished facility and the technical choices required for the assembling, processing and testing of superconducting RF cavities.

The HIE-ISOLDE project has initiated a new development phase in the SRF domain at CERN. In partic... more The HIE-ISOLDE project has initiated a new development phase in the SRF domain at CERN. In particular, the HIE-ISOLDE project aims at the construction of the 32 Quarter Wave Resonators using the Nb on Cu sputtering technology. This paper describes the refurbishment of the test infrastructure and the activities from the cavity production to the cold test, including quality assurance procedure for the correct handling of the resonators.

The IFMIF LIPAc cryomodule, whose final design and fabrication status is presented in [1], houses... more The IFMIF LIPAc cryomodule, whose final design and fabrication status is presented in [1], houses eight halfwave resonators and eight solenoids which will be assembled on a support frame in clean room. Due to the short lattice defined by beam dynamics constraints, there is not much room between two elements for the operators’ hands to connect them. In order to test, optimize and validate the clean room assembly procedures and the associated tools, a test bench, consisting of a frame, a little bigger than one eight of the final support has been manufactured. In order to start the tests before the delivery of the actual key components of the cryomodule, a dummy cavity, solenoid and coupler were manufactured and will be used to perform tests outside and inside the clean room to validate the assembly procedure and the tools. The mock-up will then be used to train the operators for the assembly of the whole string. THE IFMIF LIPAC CAVITY STRING The cavity string of the IFMIF LIPAc cryomo...

The IFMIF accelerator aims to provide an accelerator-based D-Li neutron source to produce high in... more The IFMIF accelerator aims to provide an accelerator-based D-Li neutron source to produce high intensity high energy neutron flux to test samples as possible candidate materials to a full lifetime of fusion energy reactors. A prototype of the low energy part of the accelerator is under construction at Rokkasho in Japan. It includes one cryomodule containing 8 half-wave resonators (HWR) operating at 175 MHz .The first manufactured HWR has passed low power tests at 4.2K in vertical cryostat succesfully and exceeds the specifications. It has also been tested in the dedicated horizontal Sathori cryostat equiped with its cold tuning system. The serial production and qualification tests of the 8 cavities which will eventually equip the cryomodule are carried out in parallel. In this paper, we focus on the HWR preparation and test results and give a status of the manufacturing activities.

The IFMIF accelerator aims to provide an acceleratorbased D-Li neutron source to produce high int... more The IFMIF accelerator aims to provide an acceleratorbased D-Li neutron source to produce high intensity high energy neutron flux to test samples as possible candidate materials to a full lifetime of fusion energy reactors. A prototype of the low energy part of the accelerator is under construction at Rokkasho Fusion Institute in Japan. It includes one cryomodule containing 8 half-wave resonators (HWR) operating at 175 MHz and eight focusing solenoids. This paper presents the status of the IFMIF SRF Linac. THE IFMIF LIPAC SRF LINAC The IFMIF LIPAc SRF Linac mostly consists of one cryomodule designed to be as short as possible along the beam axis to meet the beam dynamic requirements. As depicted in Figure 1, it is made of a rectangular section vacuum vessel, a warm magnetic shield, a thermal shield cooled with helium gas. A titanium frame supports the cold mass made of a cylindrical phase separator with cryogenic piping, the cavities and the solenoids. Figure 1: The IFMIF LIPAc cryom...

The SaTHoRI test stand (Satellite de Tests HOrizontal des Résonateurs IFMIF) aims at characterizi... more The SaTHoRI test stand (Satellite de Tests HOrizontal des Résonateurs IFMIF) aims at characterizing a jacketed and fully dressed cavity with its RF coupler and frequency tuner. A dedicated test cryostat has been manufactured and connected to an existing horizontal test cryostat which provides the cryogenic coolant. A RF source – provided by the IFMIF/EVEDA project has been installed and commissioned at CEA-Saclay. This paper describes the test stand and presents the first results.

This paper gives the status in the manufacturing of the IFMIF cryomodule. This cryomodule will be... more This paper gives the status in the manufacturing of the IFMIF cryomodule. This cryomodule will be part of the Linear IFMIF Prototype Accelerator (LIPAc) whose construction is ongoing at Rokkasho Fusion Institute, Japan. It is a full scale of one of the IFMIF accelerator, from the injector to the first cryomodule. The cryomodule contains all the necessary equipment to transport and accelerate a 125 mA deuteron beam from an input energy of 5 MeV up to the output energy of 9 MeV. It consists of a horizontal vacuum tank of around 6 m long, 3 m high and 2.0 m wide, which includes 8 superconducting HWRs for beam acceleration, working at 175 MHz and at 4.45 K, 8 Power Couplers to provide RF power to cavities up to 70 kW CW in LIPAc case and 200 kW CW in IFMIF case, and 8 Solenoid Packages as focusing elements. THE IFMIF LIPAC SRF LINAC The IFMIF LIPAc SRF Linac mostly consists of one cryomodule designed to be as short as possible along the beam axis to meet the beam dynamic requirements. A...

This article presents the preparation work performed by CEA for the assembly of the IFMIF Cryomod... more This article presents the preparation work performed by CEA for the assembly of the IFMIF Cryomodule. Before the shipping of the components to Japan many tests and trial assemblies has been realized on the CEA site of Saclay, France. The cryomodule, which is part of the Linear IFMIF Prototype Accelerator (LIPAc) under construction at Rokkasho in Japan, will be assembled there under the responsibility of F4E (Fusion for Energy) with CEA assistance. To fulfill the assembly of the cavity string, a cleanroom will be built at Rokkasho under the responsibility of QST.