172 research outputs found
Is There Quantum Gravity in Two Dimensions?
A hybrid model which allows to interpolate between the (original) Regge
approach and dynamical triangulations is introduced. The gained flexibility in
the measure is exploited to study dynamical triangulation in a fixed geometry.
Our numerical results support KPZ exponents. A critical assessment concerning
the apparent lack of gravitational effects in two dimensions follows.Comment: 20 pages including 4 figures, uuencoded Z-compressed .tar file
created by uufile
Measurement of the Background Activities of a 100Mo-enriched powder sample for AMoRE crystal material using a single high purity germanium detector
The Advanced Molybdenum-based Rare process Experiment (AMoRE) searches for
neutrino-less double-beta (0{\nu}\b{eta}\b{eta}) decay of 100Mo in enriched
molybdate crystals. The AMoRE crystals must have low levels of radioactive
contamination to achieve low background signals with energies near the Q-value
of the 100Mo 0{\nu}\b{eta}\b{eta} decay. To produce low-activity crystals,
radioactive contaminants in the raw materials used to form the crystals must be
controlled and quantified. 100EnrMoO3 powder, which is enriched in the 100Mo
isotope, is of particular interest as it is the source of 100Mo in the
crystals. A high-purity germanium detector having 100% relative efficiency,
named CC1, is being operated in the Yangyang underground laboratory. Using CC1,
we collected a gamma spectrum from a 1.6-kg 100EnrMoO3 powder sample enriched
to 96.4% in 100Mo. Activities were analyzed for the isotopes 228Ac, 228Th,
226Ra, and 40K. They are long-lived naturally occurring isotopes that can
produce background signals in the region of interest for AMoRE. Activities of
both 228Ac and 228Th were < 1.0 mBq/kg at 90% confidence level (C.L.). The
activity of 226Ra was measured to be 5.1 \pm 0.4 (stat) \pm 2.2 (syst) mBq/kg.
The 40K activity was found as < 16.4 mBq/kg at 90% C.L.Comment: 20 pages, 6 figures, 5 table
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