We have developed a micro-tpc using a pixelized bulk micromegas coupled to dedicated acquisition electronics as a read-out allowing to reconstruct the three dimensional track of a few keV recoils. The prototype has been tested with the Amande facility at the IRSN-Cadarache providing monochromatic neutrons. The first results concerning discrimination of a few keV electrons and proton recoils are presented.
The AMANDE facility produces monoenergetic neutron fields from 2 keV to 20 MeV for metrological purposes. To be considered as a reference facility, fluence and energy distributions of neutron fields have to be determined by primary measurement standards. For this purpose, a micro Time Projection Chamber is being developed to be dedicated to measure neutron fields with energy ranging from 8 keV up to 1 MeV. In this work we present simulations showing that such a detector, which allows the measurement of the ionization energy and the 3D reconstruction of the recoil nucleus, provides the determination of neutron energy and fluence of these neutron fields.
The AMANDE facility at IRSN-Cadarache produces mono-energetic neutron fields from 2 keV to 20 MeV with metrological quality. To be considered as a standard facility, characteristics of neutron field i.e fluence distribution must be well known by a device using absolute measurements. The development of new detector systems allowing a direct measurement of neutron energy and fluence has started in 2006. Using the proton recoil telescope principle with the goal of increase the efficiency, two systems with full localization are studied. A proton recoil telescope using CMOS sensor (CMOS-RPT) is studied for measurements at high energies and the helium 4 gaseous μ-time projection chamber (µ-TPC 4 He) will be dedicated to the lowest energies. Simulations of the two systems were performed with the transport Monte Carlo code MCNPX, to choose the components and the geometry, to optimize the efficiency and detection limits of both devices or to estimate performances expected. First preliminary measurements realised in 2008 demonstrated the proof of principle of these novel detectors for neutron metrology.
Directional detection of galactic Dark Matter is a promising search strategy for discriminating geniune WIMP events from background ones. We present technical progress on gaseous detectors as well as recent phenomenological studies, allowing the design and construction of competitive experiments.Direct detection of Dark Matter is entering a new era as several detectors are starting to exclude the expected supersymetric parameter space 1,2 and new projects of detector are planning to scale-up to ton-scale. 2 An alternative strategy to massive detectors, aiming at high background rejection, is the development of detectors providing an unambiguous positive WIMP signal. This can be achieved by searching for a correlation of the WIMP signal either with the motion of the Earth around the Sun, observed as an annual modulation, 3 or with the direction of the solar motion around the galactic center, observed as a direction dependence of the incoming WIMP flux, 4 towards (ℓ ⊙ = 90 • , b ⊙ = 0 • ), which happens to be roughly in the direction of the Cygnus constellation. The latter strategy is generally referred to as directional detection of Dark Matter and several projects of detector are being developed for this goal. 5-10 Phenomenological studies have shown that not only the forward/backward asymetry can be used to discriminate Dark Matter and background. By studying the recoil spatial distribution with various statistical methods, 11-13 useful information may be extracted from such measurements. Recently, a statistical tool, using a map-based likelihood analysis, has been developed 14 to extract information from data samples of forthcoming directional detec-
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