439 research outputs found
Long sandwich modules for photon veto detectors
Long lead-scintillator sandwich modules developed for the BNL experiment
KOPIO are described. The individual 4 m long module consists of 15 layers of 7
mm thick extruded scintillator and 15 layers of 1 mm lead absorber. Readout is
implemented via WLS fibers glued into grooves in a scintillator with 7 mm
spacing and viewed from both ends by the phototubes. Time resolution of 300 ps
for cosmic MIPs was obtained. Light output stability monitored for 2 years
shows no degradation beyond the measurement errors. A 4 m long C-bent sandwich
module was also manufactured and tested.Comment: 14 pages, 13 figures, 1 tabl
Self-force of a point charge in the space-time of a symmetric wormhole
We consider the self-energy and the self-force for an electrically charged
particle at rest in the wormhole space-time. We develop general approach and
apply it to two specific profiles of the wormhole throat with singular and with
smooth curvature. The self-force for these two profiles is found in manifest
form; it is an attractive force. We also find an expression for the self-force
in the case of arbitrary symmetric throat profile. Far from the throat the
self-force is always attractive.Comment: 18 pages, 3 figures Comments: corrected pdf, enlarged pape
Casimir effect in a wormhole spacetime
We consider the Casimir effect for quantized massive scalar field with
non-conformal coupling in a spacetime of wormhole whose throat is rounded
by a spherical shell. In the framework of zeta-regularization approach we
calculate a zero point energy of scalar field. We found that depending on
values of coupling , a mass of field , and/or the throat's radius
the Casimir force may be both attractive and repulsive, and even equals to
zero.Comment: 2 figures, 10 pages, added 2 reference
Thermal analysis of charge-transfer complex formed by nitrogen dioxide and substituted calix[4]arene: Characterization of complexation reversibility
Simultaneous thermal analysis with evolved gas analysis (STA-EGA) was used to study the ability of 1,3-alternate conformer of tert-butylcalix[4]arene with four n-propoxy substituents (1) to be applied for detection of nitrogen dioxide in reversible sensors. Solid calixarene 1 forms an intensively colored charge-transfer complex (CTC) with gaseous NO2/N2O4. Using the STA-EGA method, the nature and conditions of CTC bleaching were characterized, including the conditions of its reversible change of color from white to dark blue and back at CTC formation and decomposition. For this, the thermal stability of CTC and its regeneration products were studied. This, together with the ion thermograms for evolved gases, gives the information on the oxidation of 1 by nitrogen dioxide if present. © Akadémiai Kiadó, Budapest, Hungary 2011
Test of exotic scalar and tensor interactions in K_e3 decay using stopped positive kaons
The form factors of the decay K+ --> pi0 e+ nu (K_e3) have been determined
from the comparison of the experimental and Monte Carlo Dalitz distributions
containing about 10^5 K_e3 events. The following values of the parameters were
obtained: lambda_+ = 0.0278 +- 0.0017(stat) +- 0.0015(syst), f_S/f_+(0) =
0.0040 +- 0.0160(stat) +- 0.0067(syst) and f_T/f_+(0) = 0.019 +- 0.080(stat) +-
0.038(syst). Both scalar f_S and tensor f_T form factors are consistent with
the Standard Model predictions of zero values.Comment: 10 pages, 5 figures, contributed to the proceedings of NANP
Conference, Dubna, June 19-23, 200
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