MIMAC: MIcro-tpc MAtrix of Chambers for dark matter directional detection

Directional detection of non-baryonic Dark Matter is a promising search strategy for discriminating WIMP events from neutrons, the ultimate background for dark matter direct detection. This strategy requires both a precise measurement of the energy down to a few keV and 3D reconstruction of tracks down to a few mm. The MIMAC (MIcro-tpc MAtrix of Chambers) collaboration has developed in the last years an original prototype detector based on the direct coupling of large pixelized micromegas with a special developed fast self-triggered electronics showing the feasibility of a new generation of directional detectors. The first bi-chamber prototype has been installed at Modane, underground laboratory in June 2012. The first undergournd background events, the gain stability and calibration are shown. The first spectrum of nuclear recoils showing 3D tracks coming from the radon progeny is presented.Comment: Proceedings of the 4th International Conference on Directional Dark Matter Detection CYGNUS2013, held in Toyoma (Japan), June 201

MIMAC : A micro-tpc matrix for directional detection of dark matter

Directional detection of non-baryonic Dark Matter is a promising search strategy for discriminating WIMP events from background. However, this strategy requires both a precise measurement of the energy down to a few keV and 3D reconstruction of tracks down to a few mm. To achieve this goal, the MIMAC project has been developed. It is based on a gaseous micro-TPC matrix, filled with CF4 and CHF3. The first results on low energy nuclear recoils (H, F) obtained with a low mono-energetic neutron field are presented. The discovery potential of this search strategy is discussed and illustrated by a realistic case accessible to MIMAC.Comment: 6 pages, Proc. of the fifth international symposium on large TPCs for low energy rare event detection, Paris, France, Dec. 2010. To appear in Journal of Physic

Micromegas detector developments for MIMAC

The aim of the MIMAC project is to detect non-baryonic Dark Matter with a directional TPC. The recent Micromegas efforts towards building a large size detector will be described, in particular the characterization measurements of a prototype detector of 10 $\times$ 10 cm$^2$ with a 2 dimensional readout plane. Track reconstruction with alpha particles will be shown.Comment: 8 pages, 7 figures Proceedings of the 3rd International conference on Directional Detection of Dark Matter (CYGNUS 2011), Aussois, France, 8-10 June 2011; corrections on author affiliation

A 60 GHz electron cyclotron resonance ion source for pulsed radioactive ion beam production

TUCO-A03International audienceElectron Cyclotron Resonance Ion Sources (ECRIS) are very efficient to produce continuous and pulsed ion beams. The ECRIS scaling laws show that the plasma density increases as the square of the microwave frequency. Consequently, the efficiency, the average charge of the ionic charge state distribution and the extracted currents increase as well. LPSC is developing a 60 GHz pulsed ion source prototype. In order to have efficient ionization, the ion source volume has to be small, and due to the frequency value, the magnetic field has to be high (6 T at the injection, 3 T at the extraction, a closed surface with |B| = 2.1 T and a magnetic mirror of 4 T). The generation of the high magnetic field requires the use of helix techniques developed at GHMFL. As a first approach, a cusp structure has been chosen. 2D and 3D simulations were used to define the geometry of the helixes. Calculus has shown that it is necessary to use 2 groups of 2 coaxial helixes. An aluminum helix prototype has been machined to test at low current density the accuracy of the calculations. The axial magnetic field of the prototype was measured and results are in very good agreement with the numerical values

A 60 GHz electron cyclotron resonance ion source for pulsed radioactive ion beam production

TUCO-A03International audienceElectron Cyclotron Resonance Ion Sources (ECRIS) are very efficient to produce continuous and pulsed ion beams. The ECRIS scaling laws show that the plasma density increases as the square of the microwave frequency. Consequently, the efficiency, the average charge of the ionic charge state distribution and the extracted currents increase as well. LPSC is developing a 60 GHz pulsed ion source prototype. In order to have efficient ionization, the ion source volume has to be small, and due to the frequency value, the magnetic field has to be high (6 T at the injection, 3 T at the extraction, a closed surface with |B| = 2.1 T and a magnetic mirror of 4 T). The generation of the high magnetic field requires the use of helix techniques developed at GHMFL. As a first approach, a cusp structure has been chosen. 2D and 3D simulations were used to define the geometry of the helixes. Calculus has shown that it is necessary to use 2 groups of 2 coaxial helixes. An aluminum helix prototype has been machined to test at low current density the accuracy of the calculations. The axial magnetic field of the prototype was measured and results are in very good agreement with the numerical values