Department of Physics and Astronomy

Permanent link for this collectionhttps://hdl.handle.net/2022/22354

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Browsing Department of Physics and Astronomy by Author "Beltran, B."

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    Dark Matter Spin-Dependent Limits for WIMP Interactions on 19F by PICASSO
    (Elsevier, 2009-11) Archambault, S.; Aubin, F.; Auger, M.; Behnke, Ed; Beltran, B.; Clark, K.; Dai, X.; Davour, A.; Farine, J.; Faust, R.; Genest, M.-H.; Giroux, G.; Gornea, R.; Krauss, C.; Kumaratunga, S.; Lawson, I.; Leroy, C.; Lessard, L.; Levy, C.; Levine, Ilan; MacDonald, R.; Martin, J.-P.; Nadeau, P.; Noble, A.; Piro, M.-C.; Pospisil, S.; Shephed, T.; Starinski, N.; Stekl, I.; Storey, C.; Wichoski, U.; Zacek, V.
    The PICASSO experiment at SNOLAB reports new results for spin-dependent WIMP interactions on 19F using the superheated droplet technique. A new generation of detectors and new features which enable background discrimination via the rejection of non-particle induced events are described. First results are presented for a subset of two detectors with target masses of 19F of 65 g and 69 g respectively and a total exposure of 13.75 ± 0.48 kgd. No dark matter signal was found and for WIMP masses around 24 GeV/c2 new limits have been obtained on the spin-dependent cross section on 19F of oF = 13.9 pb (90% C.L.) which can be converted into cross section limits on protons and neutrons of op = 0.16 pb and on = 2.60 pb respectively (90% C.L). The obtained limits on pro-tons restrict recent interpretations of the DAMA/LIBRA annual modulations in terms of spin-dependent interactions. Keywords: dark matter, WIMPS, superheated droplets, NOLABPACS:95.35.+d, 29.40.-n, 34.50.BW
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    Discrimination of nuclear recoils from alpha particles with superheated liquids
    (New Journal of Physics, 2008) Aubin, F.; Auger, M.; Genest, M.-H.; Giroux, G.; Gornea, R.; Faust, R.; Leroy, C.; Lessard, L.; Martin, J.-P.; Morlat, T.; Piro, M.-C.; Starinski, N.; Zacek, V.; Beltran, B.; Krauss, C. B.; Behnke, Ed; Levine, Ilan; Shepherd, T.; Nadeau, P.; Wichoski, U.; Pospisil, S.; Stekl, I.; Sodomka, J.; Clark, K.; Dai, X.; Davour, A.; Levy, C.; Noble, A. J.; Storey, C.
    The PICASSO collaboration observed for the first time a significant difference between the acoustic signals induced by neutrons and alpha particles in a detector based on superheated liquids. This new discovery offers the possibility of improved background suppression and could be especially useful for dark matter experiments. This new effect may be attributed to the formation of multiple bubbles on alpha tracks, compared to single nucleations created by neutron induced recoils.