Progress of the klystron and Cavity test stand for the FAIR proton linac

In collaboration between the FAIR project, GSI, and CNRS, the IPNO lab provided the high power RF components for a cavity and klystron test stand. For initial operation of the 3 MW Thales TH2181 klystron at 325.224 MHz we received a high voltage modulator from CERN Linac 4 as a loan. Here we report, how we integrated the combination of klystron, high voltage modulator, and auxiliaries to accumulate operating experience. RF operation of the klystron started on a water cooled load, soon the circulator will be included and then the prototype CH cavity in the radiation shielded area will be powered. The 45 kW amplifiers for the 3 buncher structures of the FAIR proton Linac were checked at the test stand, and the results are presented here

Study of a spoke cavity for low-beta applications

Abstract Since a few years, intensive studies have been developed on SC cavities (for instance, spoke-type or reentrant cavities) for their use as accelerating structures in the low energy part of high power proton or ions accelerators (typically from 5 to 100 MeV). Within the framework of the EURISOL (EURopean Isotope Separation On-Line) & XADS (eXperimental Accelerator Driven System) European accelerators projects, IPN Orsay decided to plan a R&D program on low-beta spoke-type cavities. In the major part of this paper, we report on the optimization of the geometry of a β=0.35, 2 gap spoke cavity, aiming at achieving good electromagnetic parameters (i.e. lowest E pk /E acc and B pk /E acc ). A mechanical study is also presented, as well as a preliminary design of a proton spoke Linac (12-85 MeV) composed of β=0.18 and β=0.35, 2 gap cavities

Spiral2 cryomodules B tests results

MOP010International audienceAssembly and tests of the SPIRAL2 superconducting linac's cryomodules at CEA/Saclay and IPN/Orsay have now reached cruising speed after having faced a series of problems, among them contamination. 19 cryomodules are composing the whole Linac and IPN Orsay is in charge of the 7 cryomodules B, housing two 88 MHz, beta 0.12 Quarter-Wave Resonators. Threecryomodules have been assembled and successfullytested up to the nominal gradient of 6.5 MV/m for all cavities with also cryogenic losses withinspecifications. Two of them are fully qualified and already delivered to GANIL. The thirdone showed misalignment ofone cavity which could lead to partial disassembly if needed. This paper presents the results of those cryomodules tests as well as the status of the remaining ones

Commissioning of the ALTO 50 MeV electron linac

online : http://accelconf.web.cern.ch/AccelConf/e06/PAPERS/MOPLS113.pdfThe ALTO 50 MeV electron linac is dedicated to the production of neutron-rich radioactive nuclei using the photo-fission process and the optimisation of the targetion source system for SPIRAL 2 and EURISOL projects. The accelerator consists of a 3 MeV injector (old test station of LAL, Laboratoire de l'Accélérateur Linéaire d'Orsay), LIL (Linac Injector of LEP) accelerating structure, RF power plant, beam line, control system and diagnostics. Specified and measured beam parameters will be compared to show the performances of the photofission process and eventually other applications

First Observation of Self-Amplified Spontaneous Emission in a Free-Electron Laser at 109 nm Wavelength

We present the first observation of Self-Amplified Spontaneous Emission (SASE) in a free-electron laser (FEL) in the Vacuum Ultraviolet regime at 109 nm wavelength (11 eV). The observed free-electron laser gain (approx. 3000) and the radiation characteristics, such as dependency on bunch charge, angular distribution, spectral width and intensity fluctuations all corroborate the existing models for SASE FELs.Comment: 6 pages including 6 figures; e-mail: [email protected]

Advances in the Direct Study of Carbon Burning in Massive Stars

The C12+C12 fusion reaction plays a critical role in the evolution of massive stars and also strongly impacts various explosive astrophysical scenarios. The presence of resonances in this reaction at energies around and below the Coulomb barrier makes it impossible to carry out a simple extrapolation down to the Gamow window-the energy regime relevant to carbon burning in massive stars. The C12+C12 system forms a unique laboratory for challenging the contemporary picture of deep sub-barrier fusion (possible sub-barrier hindrance) and its interplay with nuclear structure (sub-barrier resonances). Here, we show that direct measurements of the C12+C12 fusion cross section may be made into the Gamow window using an advanced particle-gamma coincidence technique. The sensitivity of this technique effectively removes ambiguities in existing measurements made with gamma ray or charged-particle detection alone. The present cross-section data span over 8 orders of magnitude and support the fusion-hindrance model at deep sub-barrier energies

Sub-barrier fusion cross section measurements with STELLA

The experimental setup STELLA (STELlar LAboratory) is designed for the measurement of deep sub-barrier light heavy ion fusion cross sections. For background suppression the γ-particle coincidence technique is used. In this project, LaBr3 detectors from the UK FATIMA (FAst TIMing Array) collaboration are combined with annular silicon strip detectors customized at IPHC-CNRS, Strasbourg, and the setup is located at Andromède, IPN, Orsay. The commissioning of the experimental approach as well as a sub-barrier 12C +12C → 24Mg∗ cross section measurement campaign are carried out

Cross section measurements in the \u3csup\u3e12\u3c/sup\u3eC+\u3csup\u3e12\u3c/sup\u3eC system

The 12C+12C fusion reaction is one of the most important for nuclear astrophysics since it determines the carbon ignition in stellar environments. Two experiments which make use of the gamma-particle coincidence technique to measure the 12C+12C S-factors at deep sub barrier energies are discussed. Results are presented showing a decrease of the S-factor below Ec.m. = 3 MeV

The STELLA apparatus for particle-Gamma coincidence fusion measurements with nanosecond timing

The STELLA (STELlar LAboratory) experimental station for the measurement of deep sub-barrier light heavy-ion fusion cross sections has been installed at the Andromède accelerator at the Institut de Physique Nucléaire, Orsay (France). The setup is designed for the direct experimental determination of heavy-ion fusion cross sections as low as tens of picobarn. The detection concept is based on the coincident measurement of emitted gamma rays with the UK FATIMA (FAst TIMing Array) and evaporated charged particles using a silicon detector array. Key developments relevant to reaching the extreme sub-barrier fusion region are a rotating target mechanism to sustain beam intensities above 10μA, an ultra-high vacuum of 10−8 mbar to prevent carbon built-up and gamma charged-particle timing in the order of nanoseconds sufficient to separate proton and alpha particles