Integral Neutron Multiplicity Measurements from Cosmic Ray Interactions in Lead

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Integral Neutron Multiplicity Measurements from
Cosmic Ray Interactions in Lead

• Thomas Ward, Techsource Inc.
• Alexander Rimsky-Korsakov and Nikolai Kudryashev,
  Khlopin Radium Institute
• Denis Beller, University of Nevada at Las Vegas
• Paper presented at the XVII Particles and Nuclei
  International Conference,
• 24-28 October, 2005 held in Santa Fe, New Mexico

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A Modular 60 Element He-3 Neutron Multiplicity
Detector System for use in Cosmic Ray Experiments

• Target consisted of 30x30x30 cm cube (300 kg) of
  Pb surrounded by polyethylene moderator 15 cm
  thick with the He-3 counters placed on all sides.
• In some measurements a plastic scintillator or
  Geiger tube array was added on top for charged
  particle coincidences from above.
• Cf-252 fission neutron efficiency was measured at
  23.2 in agreement with MCNP and other
  Monte-Carlo codes.
• Tests of a second identical system at UNLV
  produced similar results and detector performance
  was measured in-beam at Idaho Accelerator Center
  where the efficiency vs. count rate was measured
  and compared well with MCNPX model calculations.

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Above Ground and Underground Measurements

• Above ground measurements made at KRI (St.
  Petersburg, Russia) and at UNLV (Las Vegas,
  Nevada), several measurements 23-552 hrs. June
  2001-present.
• 185mwe measurements in St. Petersburg metro
  tunnel, 24-432 hrs.
• 583 mwe measurement at Pyhasalmi mine in Finland,
  February 2002 to February 2003, 6504 hrs.
• 1166 mwe measurements at Pyhasalmi mine,
  September 2001 to February 2002, 1440 hrs.

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Temporal Distribution of 583 mwe Data
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COINCIDENCE DATA FROM THE 583 MWE MEASUREMENTS
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Final Remarks

• Peak at M24 appears to be related to light
  charged particles, possibly protons (but not
  muons), which create central collisions
  disintegrating the Pb nucleus. We will continue
  to investigate the nature of this peak.
• Peaks at M31 and M48 observed at a depth of 583
  mwe are of unknown origin and are under further
  investigation.
• Designs are being considered to increase the muon
  shield coverage for the entire target and to
  increase the Pb target volume to 100x100x100 cm,
  about 12 mt, for use in possible exotic dark
  matter or WIMP searches.

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Dark Matter Particle Residual Massive Neutral
Gauge Boson (8.086 GeV)A Possible Candidate for
WIMPPoster paper 111, this conference.
Simplified Extension of EW Mixing and the
Generation of Massive Gauge Bosons, Thomas Ward.

• Off-diagonal mixing of EW Electromagnetic field
  with the scalar (Higgs), vector (EW) and tensor
  (G) fields provides for solution of the Higgs
  mass sectors (and top mass) along with predicting
  a new neutral massive tensor gauge boson, a good
  candidate for the dark matter particle.
• The dark matter particles interaction with
  matter is expected to be primarily gravitational
  in nature with its lifetime determined by the
  weak interaction (WIMP) with ordinary matter and
  little interaction or decay electromagnetically
  or strongly.
• The wavefunction of the WIMP is expected to be
  composed of a combination of lepton and quark
  scalar pair configurations. Given that the
  scalar pairs are deeply bound in the particle
  potentials only the neutral massless neutrino
  pairs are expected to weakly decay from the bound
  state interaction with baryonic matter of a
  nucleus.
• A unique detection signature would be the
  reaction with Pb nucleus in which the Pb nucleus
  would totally disintegrate into neutrons X in
  the 8.086 GeV weak interaction.
• Poster Paper 111,