This article describes the setup and performance of the near and far detectors in the Double Chooz experiment. The electron antineutrinos of the Chooz nuclear power plant were measured in two identically designed detectors with different average baselines of about 400 m and 1050 m from the two reactor cores. Over many years of data taking the neutrino signals were extracted from interactions in the detectors with the goal of measuring a fundamental parameter in the context of neutrino oscillation, the mixing angle θ13. The central part of the Double Chooz detectors was a main detector comprising four cylindrical volumes filled with organic liquids. From the inside towards the outside there were volumes containing gadolinium-loaded scintillator, gadolinium-free scintillator, a buffer oil and, optically separated, another liquid scintillator acting as veto system. Above this main detector an additional outer veto system using plastic scintillator strips was installed. The technologies developed in Double Chooz were inspiration for several other antineutrino detectors in the field. The detector design allowed implementation of efficient background rejection techniques including use of pulse shape information provided by the data acquisition system. The Double Chooz detectors featured remarkable stability, in particular for the detected photons, as well as high radiopurity of the detector components.
The STEREO experiment is a very short baseline reactor antineutrino experiment aiming at testing the hypothesis of light sterile neutrinos as an explanation of the deficit of the observed neutrino interaction rate with respect to the predicted rate, known as the Reactor Antineutrino Anomaly. The detector center is located 10 m away from the compact, highly ^235U enriched core of the research nuclear reactor of the Institut Laue Langevin in Grenoble, France. This paper describes the STEREO site, the detector components and associated shielding designed to suppress the external sources of background which were characterized on site. It reports the performances in terms of detector response and energy reconstruction.
Fifteen years ago, CEA started the development of cryogenic rotating actuators for the astrophysical infrared camera (VISIR) that is set on the Very Large Telescope (VLT). At the time of the VISIR first light in 2004, 10 cryogenic rotating actuators, also known as "CryoMechanisms" (CM), were present in the instrument. Today VISIR is still operating and the CM that are actuated several times a day, have no reported failure up to now.In continuation of the VISIR project, CEA undertook space qualification tests with the aim of making the CM compatible with space missions. Relying on this background, a smaller model of the mechanism has been built and tested at cryogenic temperatures.Today, the cryomechanisms are selected for the ESA/EUCLID [1] space mission. The qualification program will run throughout 2014.This paper first describes the VISIR's baseline specification, the CM design and its operation principle. Then, the upgrades for the space constrains are shown and the qualification plan with respect to vibrations, thermal cycling and life testing campaigns is given. Some results of the tests carried out on a qualification model are addressed. At end, the design improvements for the EUCLID project are presented and a summary of the CM capabilities is highlighted.
In the framework of the International Fusion Materials Irradiation Facility (IFMIF), which consists of two high power CW accelerator drivers, each delivering a 125 mA deuteron beam at 40 MeV [1], a Linear IFMIF Prototype Accelerator (LIPAc) is presently under design for the first phase of the project. A superconducting option has been chosen for the 5 MeV RF Linac, based on a cryomodule composed of 8 low-beta Half Wave Resonators, 8 Solenoid Packages and 8 RF couplers. This paper will mainly focus on recent tests in laboratory of the main components of this cryomodule: HWR, RF coupler mock up, and solenoid prototypes. A section is dedicated to the HWR activities: realization and preliminary vertical tests of the two HWR prototypes. One prototype was equipped with the innovating cold tuning system, located in the central region of the cavity. Another section gives results on RF coupler’mock-up and solenoids prototypes. Finally, the LIPAc cryomodule current design is also presented.
The R 3 B-Glad superconducting Magnet is a large acceptance dipole, dedicated to the analysis of Reactions with Relativistic Radioactive ions Beams. It takes part in the FAIR Project at GSI. As the superconducting NbTi Rutherford cable was under production, detailed studies of the mechanical structure (with both simulation and experiment on a half-scale mock-up) led to revise the magnet design and to abandon the grading of the coils in three stages. Due to the large magnetic forces (up to 400 tons/m), the maximum shear stress level of 20 MPa was impossible to meet in the coils. The main reasons consist in the orthotropic thermo-mechanical behavior of the coils together with the large differential thermal shrinkage between the Cu stabilized coils and their Al alloy casings. Indeed after several studies of different mechanical designs, we decided to simplify the magnet in order to cope with these difficulties. One innovative point is that the coils are not blocked at room temperature, but only at 4.5 K. This paper presents the magnetic calculations of this active shielded magnet, and shows how the new design features meet the specifications. Currently, the 22 tons magnet cold mass, i.e. the 6 coils and their integration in the casings, is ordered and under construction. Meanwhile, the design of the magnet cryostat has evolved into a shape of elliptical cylinder with a lateral satellite. The total weight is expected to be around 50 tons.