385 research outputs found
Four-gap glass RPC as a candidate to a large area thin time-of-flight detector
A four-gap glass RPC with 0.3mm gap size was tested with hadron beam as a
time-of-flight detector having a time resolution of ~ 100ps. A thickness of the
detector together with front-end electronics is ~ 12mm. Results on time
resolution dependently on a pad size are presented. This paper contains first
result on the timing RPC (with ~ 100ps resolution) having a strip read-out.
Study has been done within the HARP experiment (CERN-PS214) R&D work. A obtaned
data can be useful if a design of a large area thin timing detector has to be
done.Comment: 18 pages, 13 figure
Dynamical Susceptibility in KDP-type Crysals above and below Tc II
The path probability method (PPM) in the tetrahedron-cactus approximation is
applied to the Slater-Takagi model with dipole-dipole interaction for
KH2PO4-type hydrogen-bonded ferroelectric crystals in order to derive a small
dip structure in the real part of dynamical susceptibility observed at the
transition temperature Tc. The dip structure can be ascribed to finite
relaxation times of electric dipole moments responsible for the first order
transition with contrast to the critical slowing down in the second order
transition. The light scattering intensity which is related to the imaginary
part of dynamical susceptibility is also calculated above and below the
transition temperature and the obtained central peak structure is consistent
with polarization fluctuation modes in Raman scattering experiments.Comment: 8 pages, 11 figure
Test of an LED Monitoring System for the PHOS Spectrometer
Preprint submitted to Elsevier Print on 26th January 2000A prototype monitoring system for the Photon Spectrometer (PHOS) of the ALICE experiment at LHC is described in detail. The prototype consists of Control and Master modules. The first one is 8x8 matrix of Light Emitting Diodes coupled with stable generators of current pulses. The system provides an individual control for each of the 64 channels of PHOS prototype based on lead-tungstate crystals. A long term stability of order of 10-3 has been achieved in integral beam tests of the monitoring system and PHOS prototypes
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