8,550 research outputs found
New calibrations and time stability of the response of the INTERCAST CR-39
We present new calibrations of different production batches (from 1989 to
1999) of the INTERCAST CR-39, using the BNL-AGS 1 A GeV iron beam. The
comparison with previous results, obtained with the 158 A GeV lead beam from
the CERN-SPS shows that, while each production batch has a different
calibration curve (mainly due to minor differences in the production
conditions), the aging effect is negligible. We also tested the dependence of
the CR-39 response from the time elapsed between exposure and analysis (fading
effect). The fading effect, if present, is less than 10%. It may be compatible
with the experimental uncertainties on the bulk etching rate vB.Comment: 9 pages, 4 EPS figures, .pdf file. Talk presented by M. Giorgini at
the 20 Int. Conf. on Nuclear Tracks in Solids, Portoroz (Slovenia), Aug
28-Sep 1, 200
Nuclear Track Detectors for Environmental Studies and Radiation Monitoring
Several improvements were made for Nuclear Track Detectors (NTDs) used for
environmental studies and for particle searches. A new method was used to
determine the bulk etch rate of CR39 and Makrofol NTDs. It is based on the
simultaneous measurement of the diameter and of the height of etch-pit cones
caused by relativistic heavy ions (158 A GeV Pb(82+) and In(49+) ions) and
their fragments. The use of alcohol in the etching solution improves the
surface quality of NTDs and it raises their thresholds. The detectors were used
for the determination of nuclear fragmentation cross sections of Iron and
Silicon ions of 1.0 and 0.41 GeV/nucleon. These measurements are important for
the determination of doses in hadron therapy and for doses received by
astronauts. The detectors were also used in the search of massive particles in
the cosmic radiation, for the determination of the mass spectrum of cosmic rays
and for the evaluation of Po(210) alpha decay and of natural radon
concentrations.Comment: 7 pages, 5 EPS figures. Presented at the 10th Topical Seminar on
Innovative Particle and Radiation Detectors, 1-5 October 2006, Siena, Ital
Search for nuclearites with the SLIM detector
We discuss the properties of cosmic ray nuclearites, from the point of view
of their search with large nuclear track detector arrays exposed at different
altitudes, in particular with the SLIM experiment at the Chacaltaya high
altitude lab (5290 m a.s.l.). We present calculations concerning their
propagation in the Earth atmosphere and discuss their possible detection with
CR39 and Makrofol nuclear track detectors.Comment: 11 pages, 6 figure
Muon detection at FCC-ee
Muons provide a clean experimental signature, typically traversing the whole experimental apparatus without decaying. Muon detection systems are therefore usually located at a rather large distance from the primary interaction vertex after all other subdetectors. As such, experimental apparatuses at FCC-ee will certainly employ very large muon systems, covering areas of a few thousand square meters. For obvious reasons of cost, the most suitable detectors to realise these large muon systems are gas detectors. In particular, in recent years, micro-pattern gas detectors (MPGDs) have undergone very interesting developments, providing several new types of detectors with very good spatial and time resolution, high efficiency, high rate capability and high radiation tolerance. The good position and time resolution makes a MPGD an excellent particle tracker, reconstructing tracks at 4-5 m from the primary interaction vertex with sub-mm precision. Therefore MPGDs, apart from efficiently detecting muons, can precisely track and help identifying also hypothesized long lived particles (LLP) that would decay outside of the central trackers. MPGDs have the distinct advantage of being, at least for some detectors and some parts of them, mass-producible by industry, since they employ materials and manufacturing procedures that are used extensively for printed circuit boards (PCB) production. A particularly innovative MPGD, the mu RWELL, is considered as a possible candidate to build the large muon system of the IDEA detector concept for FCC-ee and is described in some more detail. Other technologies that could be considered for the realisation of muon detection systems are also briefly discussed
New results on the limit for the width of the exotic Theta^+ resonance
We investigate the impact of the \Theta^+(1540) resonance on differential and
integrated cross sections for the reaction K^+d{\to}K^0pp, where experimental
information is available at kaon momenta below 640 MeV/c. The calculation
utilizes the J\"ulich KN model and extensions of it that include contributions
from a \Theta^+(1540) state with different widths. The evaluation of the
reaction K^+d{\to}K^0pp takes into account effects due to the Fermi motion of
the nucleons within the deuteron and the final three-body kinematics. We
conclude that the available data constrain the width of the \Theta^+(1540) to
be less than 1 MeV.Comment: 5 pages, 5 figures, updated version, accepted for publication in
Phys. Lett.
Search for possible neutrino radiative decays during the 2001 total solar eclipse
We present the results of the observations performed in the occasion of the
June 21, 2001 total solar eclipse, looking for visible photons emitted trough a
possible radiative decay of solar neutrinos. We establish lower limits for the
neutrino proper lifetimes larger than 1000 s/eV, for neutrino masses larger
than 0.01 eV.Comment: 18 pages, 11 figures, accepted by Astopart. Phys, updated reference
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