Supernova Detection via a Network of Neutral Current Spherical TPC's

The coherent contribution of all neutrons in neutrino nucleus scattering due to the neutral current offers a realistic prospect of detecting supernova neutrinos. For a typical supernova at 10 kpc, about 1000 events are expected using a spherical gaseous detector of radius 4 m and employing Xe gas at a pressure of 10 Atm. We propose a world wide network of several such simple, stable and low cost supernova detectors with a running time of a few centuries.Comment: 7 pages, 2 figures. Talk presented at the International Symposium on Origin of Matter and Evolution of Galaxies (OMEG05)- New Horizon of Nuclear Astrophysics and Cosmology November 8-11, 2005, University of Tokyo, Tokyo, Japa

Low-background applications of MICROMEGAS detector technology

The MICROMEGAS detector concept, generally optimized for use in accelerator experiments, displays a peculiar combination of features that can be advantageous in several astroparticle and neutrino physics applications. Their sub-keV ionization energy threshold, excellent energy and space resolution, and a simplicity of design that allows the use of radioclean materials in their construction are some of these characteristics. We envision tackling experimental challenges such as the measurement of neutral-current neutrino-nucleus coherent scattering or Weakly Interacting Massive Particle (WIMP) detectors with directional sensitivity. The large physics potential of a compact (total volume O(1)m$^{3}$), multi-purpose array of low-background MICROMEGAS is made evident.Comment: 5 pg, presented at IMAGING-2000, Stockholm, June 2000. To appear in Nucl. Instr. & Meth. Final version after referees' inpu

A Network of Neutral Current Spherical TPC's for Dedicated Supernova Detection

The coherent contribution of all neutrons in neutrino nucleus scattering due to the neutral current offers a realistic prospect of detecting supernova neutrinos. As a matter of fact. for a typical supernova at 10 kpc, about 1000 events are expected usinga spherical gaseous detector of radius 4 m andemploying Xe gas at a pressure of 10 Atm. We propose a world wide network of several such simple, stable and low cost supernova detectors with a running time of a few centuries.Comment: 17 LaTex pages, 9 PostScript figure

Micromegas TPC studies at high magnetic fields using the charge dispersion signal

The International Linear Collider (ILC) Time Projection Chamber (TPC) transverse space-point resolution goal is 100 microns for all tracks including stiff 90 degree tracks with the full 2 meter drift. A Micro Pattern Gas Detector (MPGD) readout TPC can achieve the target resolution with existing techniques using 1 mm or narrower pads at the expense of increased detector cost and complexity. The new MPGD readout technique of charge dispersion can achieve good resolution without resorting to narrow pads. This has been demonstrated previously for 2 mm x 6 mm pads with GEMs and Micromegas in cosmic ray tests and in a KEK beam test in a 1 Tesla magnet. We have recently tested a Micromegas-TPC using the charge dispersion readout concept in a high field super-conducting magnet at DESY. The measured Micromegas gain was found to be constant within 0.5% for magnetic fields up to 5 Tesla. With the strong suppression of transverse diffusion at high magnetic fields, we measure a flat 50 micron resolution at 5 Tesla over the full 15 cm drift length of our prototype TPC.Comment: 7 pages, 3 figure

On the search of sterile neutrinos by oscillometry measurements

It is shown that the "new" neutrino with a high mass squared difference and a small mixing angle should reveal itself in the oscillometry measurements. For a judicious monochromatic neutrino source the "new" oscillation length $L_{42}$ is expected shorter than 1.5 m. Thus the needed measurements can be implemented with a gaseous spherical TPC of modest dimensions with a very good energy and position resolution. The best candidates for oscillometry are discussed and the sensitivity to the mixing angle $\theta_{14}$ has been estimated: $\sin^2{(2\theta_{14})}$=0.05 (99{%}) for two months of data handling with $^{51}$Cr.Comment: 4 Latex Pages, 1 Figure, 1 tabl